JP2004144261A

JP2004144261A - Toroidal continuously variable transmission

Info

Publication number: JP2004144261A
Application number: JP2002312398A
Authority: JP
Inventors: Fumi Kikuchi; 菊池　文; Hiroshi Kato; 加藤　寛; Takashi Nogi; 野木　高
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 2002-10-28
Filing date: 2002-10-28
Publication date: 2004-05-20

Abstract

<P>PROBLEM TO BE SOLVED: To improve transmission efficiency of a toroidal continuously variable transmission by preventing a breakdown of a holder 34b to be assembled in a thrust ball bearing for supporting a power roller, and miniaturizing the holder 34b to reduce weight thereof. <P>SOLUTION: Both axial directional surfaces of the holder 34b are formed with recessed grooves 40a and 40b for flowing the lubricating oil into a pocket 36. When radial directional length of a part 41 between the inner surface of the pocket 36 and the peripheral edge of the holder 34b is b, depth in the axial direction is H, width in the circumferential direction is 2L, thickness of the holder 34b in the axial direction is 2t and diameter of a ball 33 is Da, a formula (1): (Da<SP>2</SP>/b<SP>2</SP>)äL/(t-H)}≤146.7 is obtained. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明に係るトロイダル型無段変速機は、例えば自動車用自動変速機の変速ユニットとして、或は各種産業機械用の変速機として、それぞれ利用する。
【０００２】
【従来の技術】
自動車用自動変速機の変速ユニットとして、図５〜６に略示する様なトロイダル型無段変速機を使用する事が研究され、一部で実施されている。このトロイダル型無段変速機は、例えば特許文献１に開示されている様に、入力軸１と同心に入力側ディスク２を支持し、出力軸３の端部に出力側ディスク４を固定している。トロイダル型無段変速機を納めたケーシングの内面、或はこのケーシング内に設けた支持ブラケットには、上記入力軸１並びに出力軸３に対して捻れの位置にある枢軸５、５を中心に揺動するトラニオン６、６を設けている。
【０００３】
即ち、これら各トラニオン６、６は、それぞれの両端部外側面に上記枢軸５、５を、互いに同心に、且つ、上記入力軸１及び出力軸３の方向に対し直角若しくはほぼ直角な方向に設けている。又、これら各トラニオン６、６の中心部には変位軸７、７の基端部を支持し、上記枢軸５、５を中心として各トラニオン６、６を揺動させる事により、各変位軸７、７の傾斜角度の調節を自在としている。又、これら各トラニオン６、６に支持した変位軸７、７の周囲には、それぞれパワーローラ８、８を回転自在に支持している。そして、これら各パワーローラ８、８を、上記入力側、出力側両ディスク２、４同士の間に挾持している。これら入力側、出力側両ディスク２、４の互いに対向する内側面２ａ、４ａは、それぞれの断面が上記枢軸５の中心軸上の点をその中心とする円弧形である、凹面をなしている。そして、球面状の凸面に形成した各パワーローラ８、８の周面８ａ、８ａを、上記内側面２ａ、４ａに当接させている。
【０００４】
又、上記入力軸１と入力側ディスク２との間には、ローデイングカム式の押圧装置９を設け、この押圧装置９によって、上記入力側ディスク２を出力側ディスク４に向け、弾性的に押圧している。この押圧装置９は、入力軸１と共に回転するカム板１０と、保持器１１により保持された複数個（例えば４個）のローラ１２、１２とから構成している。上記カム板１０の片側面（図５〜６の左側面）には、円周方向に亙る凹凸面であるカム面１３を形成し、又、上記入力側ディスク２の外側面（図５〜６の右側面）にも、同様のカム面１４を形成している。そして、上記複数個のローラ１２、１２を、上記入力軸１の中心に対して放射方向の軸を中心とする回転自在に支持している。
【０００５】
上述の様に構成するトロイダル型無段変速機の使用時、入力軸１の回転に伴ってカム板１０が回転すると、カム面１３によって複数個のローラ１２、１２が、入力側ディスク２の外側面に形成したカム面１４に押圧される。この結果、この入力側ディスク２が、上記複数のパワーローラ８、８に押圧されると同時に、上記１対のカム面１３、１４と複数個のローラ１２、１２との押し付け合いに基づいて、上記入力側ディスク２が回転する。そして、この入力側ディスク２の回転が、上記複数のパワーローラ８、８を介して出力側ディスク４に伝達され、この出力側ディスク４に固定の出力軸３が回転する。
【０００６】
入力軸１と出力軸３との回転速度を変える場合で、先ず入力軸１と出力軸３との間で減速を行なう場合には、前記各トラニオン６、６を、前記枢軸５、５を中心として所定方向に揺動させる。そして、図５に示す様に、上記各パワーローラ８、８の周面８ａ、８ａを、入力側ディスク２の内側面２ａの中心寄り部分と出力側ディスク４の内側面４ａの外周寄り部分とにそれぞれ当接する様に、前記各変位軸７、７を傾斜させる。反対に、増速を行なう場合には、上記トラニオン６、６を上記所定方向とは逆方向に揺動させる。そして、図６に示す様に、上記各パワーローラ８、８の周面８ａ、８ａを、入力側ディスク２の内側面２ａの外周寄り部分と出力側ディスク４の内側面４ａの中心寄り部分とに、それぞれ当接する様に、上記各変位軸７、７を傾斜させる。各変位軸７、７の傾斜角度を、図５と図６との中間にすれば、入力軸１と出力軸３との間で、中間の変速比を得る事ができる。
【０００７】
更に、図７は、特許文献２に記載されたトロイダル型無段変速機で、自動車用変速機として、より具体化した構造を示している。エンジンのクランク軸の回転は、クラッチ１５を介して入力軸１６に伝達し、この入力軸１６の中間部にスプライン係合したカム板１０を回転させる。そして、このカム板１０を含んで構成する押圧装置９の作動により、入力側ディスク２を、出力側ディスク４に向け図７で左方に押圧しつつ回転させる。入力側ディスク２の回転は、パワーローラ８、８によって出力側ディスク４に伝達される。
【０００８】
この出力側ディスク４は上記入力軸１６の周囲に、ニードル軸受１７により支持している。又、上記出力側ディスク４と一体に形成した円筒状の出力軸１８をハウジング１９の内側に、アンギュラ型の玉軸受２０により支持している。一方、上記入力軸１６の一端（図７の右端）は上記ハウジング１９の内側にころ軸受２１により、他端は上記ハウジング１９の内側にアンギュラ型の玉軸受２２によりスリーブ２３を介して、それぞれ回転自在に支持している。
【０００９】
又、上記出力軸１８の外周面には、駆動側前進ギヤ２４と駆動側後退ギヤ２５とを一体とした伝達ギヤ２６を、スプライン係合させている。車両の前進時にはこの伝達ギヤ２６を図７の右方に移動させて、上記駆動側前進ギヤ２４と、取り出し軸２７の中間部に設けた従動側前進ギヤ２８とを直接噛合させる。これに対して、後退時には上記伝達ギヤ２６を図７の左方に移動させて、上記駆動側後退ギヤ２５と、上記取り出し軸２７の中間部に固定した従動側後退ギヤ２９とを、図示しない中間ギヤを介して噛合させる。
【００１０】
上述の様に構成する、トロイダル型無段変速機の使用時には、エンジンによりクラッチ１５を介して入力軸１６を回転させ、上記伝達ギヤ２６を適宜の方向に移動させれば、上記取り出し軸２７を任意方向に回転させる事ができる。又、各トラニオン６、６を揺動させて、各パワーローラ８、８の周面８ａ、８ａと、入力側、出力側両ディスク２、４の内側面２ａ、４ａとの接触位置を変えれば、上記入力軸１６と取り出し軸２７との回転速度比を変える事ができる。
【００１１】
上述の様なトロイダル型無段変速機の運転時には、前記押圧装置９の作動に基づき、入力側ディスク２を出力側ディスク４に向け押圧する。この結果、上記押圧装置９を構成するカム板１０を支持した入力軸１６には、図７で右方向のスラスト荷重が、上記押圧に基づく反力として加わる。このスラスト荷重は、上記入力軸１６の端部に蝶合したナット３０と前記スリーブ２３とを介して、前記玉軸受２２により支承する。又、押圧装置９の作動により前記出力軸１８には、図７で左方向のスラスト荷重が、入力側、出力側両ディスク２、４とパワーローラ８、８とを介して加わる。このスラスト荷重は、上記出力軸１８に外嵌したストップリング３１を介して、前記玉軸受２０により支承する。
【００１２】
又、上述の様なトロイダル型無段変速機の運転時には、上記入力軸１６及び出力軸１８にスラスト荷重が加わる他、上記各パワーローラ８、８にも、スラスト荷重が加わる。この為、これら各パワーローラ８、８と上記各トラニオン６、６との間にスラスト玉軸受３２、３２を設けて、これら各パワーローラ８、８に加わるスラスト荷重を支承している。これら各スラスト玉軸受３２、３２はそれぞれ、複数の玉３３、３３と、これら複数の玉３３、３３を転動自在に保持する為の保持器３４と、外輪３５とから構成している。上記複数の玉３３、３３は、軸受鋼、或はセラミックにより、球状に形成している。この様な玉３３、３３は、上記各パワーローラ８、８の外端面に形成した軌道面（内輪軌道）と、上記外輪３５の内面に形成した軌道面（外輪軌道）とに転がり接触する。又、上記保持器３４は、金属或は合成樹脂により円輪状に構成すると共に、直径方向中間部で円周方向等間隔位置に複数のポケット３６、３６を形成しており、これら各ポケット３６、３６内にそれぞれ上記玉３３、３３を、１個ずつ転動自在に保持している。更に、軸受鋼、或はセラミック等により円輪状に構成した上記各外輪３５、３５は、スラスト軸受３７（次述する図８参照）を介して、上記各トラニオン６の内側面に突き当てている。
【００１３】
上述の様なスラスト玉軸受３２、３２は、トロイダル型無段変速機の運転時に、上記各パワーローラ８、８に加わるスラスト荷重を支承しつつ、高速で回転する。従って、トロイダル型無段変速機の運転時に、上記各スラスト玉軸受３２、３２には、十分な量の潤滑油を供給しなければならない。この為従来から、図８に示す様に、上記外輪３５の一部に１乃至複数の給油孔３８、３８を形成し、トロイダル型無段変速機の運転時には、これら各給油孔３８、３８内に潤滑油を強制的に送り込む事が行なわれている。上記各給油孔３８、３８内に強制的に送り込んだ潤滑油は、上記外輪３５の内面と前記保持器３４の外面との間の隙間、並びにこの保持器３４の内面と上記パワーローラ８の外端面との間の隙間を通じて流れ、その間に上記複数の玉３３、３３の転動部分を潤滑する。
【００１４】
ところで、上述の様な構造によりスラスト玉軸受３２、３２に潤滑油を送り込む構造の場合には、部分的に潤滑油の供給が不足する可能性がある。即ち、図９（Ａ）に示す様に、保持器３４が外輪３５の内面とパワーローラ８の外端面との中間に位置すれば、上記外輪３５の内面と上記保持器３４の外面との間の隙間、並びにこの保持器３４の内面と上記パワーローラ８の外端面との間の隙間の何れにも潤滑油が流れる為、特に問題を生じない。ところが、上記外輪３５に形成した給油孔３８から保持器３４の外面に向けて潤滑油を吐出すると、この潤滑油の流れに押されて上記保持器３４が、図９（Ｂ）に示す様に、パワーローラ８側に変位する。この様な変位に基づき、上記保持器３４の内面と上記パワーローラ８の外端面とが密接すると、この外端面に形成した軌道面と各玉３３の転動面との当接部に十分量の潤滑油が存在しない状態となる。この結果、上記パワーローラ８の外端面の軌道面と各転動体３３の転動面との当接部での摩耗量が増大したり、著しい場合には当該当接部が焼き付く可能性がある。
【００１５】
この様な問題をなくす為の構造として、特許文献３には、図１０〜１３に示す様な、潤滑性を向上させたスラスト玉軸受３２ａを組み込んだトロイダル型無段変速機が記載されている。このスラスト玉軸受３２ａを構成する保持器３４ａの主体３９は、合成樹脂、或は真鍮の如き銅系合金等の金属により、全体を円輪状に構成している。この主体３９の直径方向中間部で円周方向複数個所にはポケット３６を、保持すべき玉３３の形状に合わせて形成している。又、上記主体３９の内外両面には凹溝４０、４０を、この主体３９の直径方向に、上記各ポケット３６を横切る状態で形成し、これら各凹溝４０、４０により、上記主体３９の内周縁と外周縁との間に設けられた潤滑油流路を構成している。
【００１６】
上述の様に構成する、潤滑性を向上させたスラスト玉軸受３２ａを組み込んだトロイダル型無段変速機によれば、外輪３５に形成した給油孔３８から吐出する潤滑油の勢い等により、スラスト玉軸受３２ａを構成する保持器３４ａが軸方向に変位して、図１３に示す様に、この保持器３４ａの内面とパワーローラ８の外端面とが密接した場合でも、上記各凹溝４０、４０の内面とパワーローラ８の外端面で囲まれた空間が潤滑油流路となる。そして、各玉３３を保持したポケット３６内に十分な量の潤滑油が、上記各凹溝４０、４０を通じて流れる。この結果、上記パワーローラ８の外端面に形成した軌道面と玉３３の転動面との当接部に存在する潤滑油が不足する事を防止して、前記スラスト玉軸受３２ａの一部が著しく摩耗したり、或は焼き付いたりする危険性を低くできる。
【００１７】
更に、特許文献４には、上記保持器３４ａに生ずる曲げ応力を一定に保ちつつ、上記各凹溝４０、４０の断面形状を最適化する事によって、言い換えれば、上記曲げ応力を大きくする事なく上記各凹溝４０、４０の断面積を大きくする事によって、上記ポケット３６内を流通する潤滑油の流量を多くし、潤滑性の向上を図る構造が記載されている。即ち、上記特許文献４に記載された構造の場合には、潤滑油流路である上記各凹溝４０、４０の形状を、上記保持器３４ａの軸方向に関する深さをＨ、円周方向の幅を２Ｌとした場合に、０．２９≦Ｈ／Ｌ≦０．８８を満たす様にしている。この構成により、上記各凹溝４０、４０の断面積が不必要に大きくなって保持器３４ａが破損し易くなる事を防止しつつ、上記各凹溝４０、４０を流れる潤滑油の流量を多くして、潤滑性を向上させる様にしている。
【００１８】
【特許文献１】
実開昭６２−７１４６５号公報
【特許文献２】
実願昭６１−８７５２３号（実開昭６２−１９９５５７号）のマイクロフィルム
【特許文献３】
実用新案登録第２６０３５５９号公報
【特許文献４】
特開２００２−８９６４６号公報
【００１９】
【発明が解決しようとする課題】
トラニオン６、６に対しパワーローラ８、８を支持する為のスラスト玉軸受３２、３２ａに組み込んだ保持器３４、３４ａは、トロイダル型無段変速機の運転時に高速で回転して動力の一部を消費する反面、この保持器３４、３４ａ自体は特に動力伝達に寄与するものではない。この為、トロイダル型無段変速機の伝達効率を向上させる為には、上記保持器３４、３４ａをできるだけ小型・軽量にする事が望まれる。但し、むやみにこの保持器３４、３４ａの小型化を図ると、この保持器３４、３４ａの外周縁と各ポケット３６、３６の内周面との距離が短くなり、運転時に加わる曲げ応力によって、この保持器３４、３４ａに亀裂等の損傷が発生し易くなる。
【００２０】
例えば、図１０に示す様に、保持器３４ａが各玉３３のピッチ円に対し偏心する事によって、何れかの玉３３からポケット３６の内面にラジアル方向の荷重Ｆが作用する場合に就いて考える。この場合、上記保持器３４ａの外周縁と上記ポケット３６の内面との間に位置して凹溝４０、４０を形成した間部分４１を、両端固定の支持梁に近似できるとして考えられる。従って、上記間部分４１を力（荷重）Ｆで押した場合にこの間部分４１に生ずる最大の曲げ応力σは、材料力学的に次の（１）式で表される。
σ＝３ＦＬ／　｛４ｂ^２　（ｔ−Ｈ）｝　−−−　（１）
【００２１】
この（１）式中、Ｌは上記各凹溝４０、４０の円周方向の幅の１／２を、ｂは、上記保持器３４ａの直径方向に関する上記間部分４１の長さを、Ｈは、この保持器３４ａの軸方向に関する上記各凹溝４０、４０の深さを、それぞれ表している。又、ｔは、これら各凹溝４０、４０から外れた部分での、上記保持器３４ａの軸方向の厚さの１／２である。この様な（１）式から、上記間部分４１の長さｂが小さくなると、この間部分４１に加わる曲げ応力σが大きくなり、上記保持器３４ａが破損し易くなる事が分かる。
本発明は、この様な事情に鑑みて、上記間部分４１に生ずる曲げ応力を小さくして上記保持器３４ａを破損しにくくし、トロイダル型無段変速機の耐久性及び信頼性向上を図るべく発明したものである。
【００２２】
【課題を解決するための手段】
本発明のトロイダル型無段変速機は、前述した従来のトロイダル型無段変速機と同様に、それぞれの内側面同士を互いに対向させた状態で互いに同心に配置された第一、第二のディスクと、これら第一、第二のディスクの中心軸に対し捻れの位置にある枢軸を中心として揺動するトラニオンと、このトラニオンに支持された変位軸と、この変位軸の周囲に回転自在に支持された状態で、上記第一、第二の両ディスクの内側面同士の間に挟持されたパワーローラと、このパワーローラと上記トラニオンとの間に設けられ、このパワーローラに加わるスラスト方向の荷重を支承するスラスト玉軸受とを備える。そして、上記第一、第二のディスクの内側面はそれぞれ断面が円弧形の凹面であり、パワーローラの周面は球面状の凸面であり、この周面と上記各内側面とが互いに当接しており、上記スラスト玉軸受は、複数の玉と、この複数の玉を転動自在に保持する保持器とを備えたものである。又、上記保持器は、円輪状の主体と、それぞれがこの主体の直径方向中間部に形成されて、その内側に上記各玉を１個ずつ転動自在に保持する複数のポケットと、これら各ポケットを横切る状態で、上記主体の内周縁と外周縁との問に設けられた複数の潤滑油流路とを備える。
特に、本発明のトロイダル型無段変速機に於いては、上記保持器の軸方向の厚さを２ｔとし、上記各潤滑油流路のうちで上記各ポケットと上記保持器の外周縁との間に存在する部分の、この保持器の半径方向に関する長さをｂとし、軸方向に関する深さをＨとし、円周方向の幅を２Ｌとし、上記各玉の直径をＤａとした場合に、（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝≦１４６．１７の関係をを満たす。
【００２３】
【作用】
上述の様に構成する本発明のトロイダル型無段変速機が、第一、第二のディスク同士の間で動力を伝達する作用、並びにこれら第一、第二のディスクの回転速度の比を調節する作用は、前述の図５〜７に示した従来のトロイダル型無段変速機の場合と同様である。又、保持器を構成する主体に設けた複数の潤滑油流路を介して保持器のポケット内に潤滑油を流通させる事により、上記保持器が軸方向に変位した状態でも上記ポケット内に潤滑油を供給する作用は、前述の図１０〜１３に示した従来のトロイダル型無段変速機の場合と同様である。
【００２４】
特に、本発明のトロイダル型無段変速機に於いては、各潤滑油流路のうちで各ポケットと保持器の外周縁との間に存在する部分の形状（ｂ、Ｌ、Ｈ、ｔ）とスラスト玉軸受を構成する玉の直径Ｄａとの関係を、（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝≦１４６．１７の範囲に設定している為、保持器が限界を超えて小さくなり、この保持器が破損し易くなる事を防止できる。この為、この保持器を組み込んだトロイダル型無段変速機の伝達効率を、耐久性及び信頼性を確保しつつ、向上させる事ができる。
【００２５】
次に、（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝≦１４６．１７とする事で、保持器の破損防止を図れる理由に就いて説明する。前述の式（１）と同様に、各潤滑油流路のうちで各ポケットと保持器の外周縁との間に存在する部分に生ずる最大の曲げ応力σは材料力学的に次の（１）式で表される。各符号の意味は、前述した通りである。
σ＝３ＦＬ／｛４ｂ^２　（ｔ−Ｈ）｝　−−−　（１）
この（１）式で、玉が保持器を外径側へ押す荷重Ｆは、「Ａｄｖａｎｃｅｄ　Ｄｙｎａｍｉｃｓ　ｏｆ　Ｒｏｌｌｉｎｇ　Ｅｌｅｍｅｎｔｓ　」に記載の方法と同様の解析によるとＦ＝Ｃ・Ｄａ^２　となるので、これを上記（１）式に代入すると、次の（２）式を得られる。
σ＝３Ｃ・Ｄａ^２　・Ｌ／｛４ｂ^２　（ｔ−Ｈ）｝　−−−　（２）
【００２６】
この（２）式中、Ｃは定数であり、この値は、上記文献に記載の方法と同様の解析を行なうと、最大荷重の場合でも１．３９程度である事が分かった。一方、保持器材料の疲労強度をσｗとすると、σ／σｗと（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝との関係は、図１４に示す様になる。ここで、トロイダル型無段変速機のスラスト玉軸受の保持器を構成する為の材料として真鍮（ＨＢ_Ｓ　Ｃ１）や鉄系の金属材料が一般的であり、このうち真鍮の疲労限度σｗは１５０ＭＰａ程度であるから、上記図１４から分かる様に、（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝＝１４６．１７でσ／σｗ＝１となる。この図１４から分かる様に、σｗが変化すると（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝も変化するが、このσｗの値の小さい上記真鍮（ＨＢ_Ｓ　Ｃ１）の値を考慮して設計を行なえば、疲労破壊を防止する事ができる。従って、上記保持器の破損防止を図ってこの保持器を組み込んだトロイダル型無段変速機の耐久性及び信頼性を確保する面から、上記（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝の値を１４６．１７以下とする事が好ましい事が分かる。
【００２７】
【発明の実施の形態】
図１〜３は、本発明の実施形態の第１例として、潤滑油流路として、断面形状が矩形である凹溝４０ａ、４０ｂを設けた場合に就いて示している。尚、本発明の特徴は、これら各凹溝４０ａ、４０ｂのうちで各ポケット３６と保持器３４ｂの外周縁との間に存在する凹溝４０ｂ、４０ｂを設けた間部分４１の形状（ｂ、Ｌ、Ｈ、ｔ）と、玉３３の直径Ｄａとの関係を規制する事によって、上記保持器３４ｂの外径が限界を超えて小さくなり、この保持器３４ｂが破損し易くなる事を防止する点にある。その他の部分の構造及び作用は、前述した従来構造の場合と同様であるから、同等部分に関する図示並びに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。
【００２８】
上記保持器３４ｂを構成する円輪状の主体３９の直径方向中間部には複数のポケット３６を、円周方向に亙り互いに等間隔で形成している。そして、上記主体３９の内外両面（軸方向両面）に複数の凹溝４０ａ、４０ｂを、上記各ポケット３６を横切る状態で形成している。これら各凹溝４０ａ、４０ｂが、上記主体３９の内周縁と外周縁との間に設けられた、複数の潤滑油流路を構成する。トロイダル型無段変速機の運転時に上記各潤滑油流路となる上記各凹溝４０ａ、４０ｂには、上記主体３９の内周縁側から外周縁側に向けて、前述の給油孔３８（図８、９、１３参照）から吐出された潤滑油が流通する。この間にこの潤滑油は、上記各ポケット３６内に保持された玉３３の転動面と相手軌道面との当接部を潤滑する。
【００２９】
本例の場合には、上記各凹溝４０ａ、４０ｂのうち、上記各ポケット３６の内面と上記保持器３４ｂの外周縁とを連通させて、これら各ポケット３６内に送り込まれた潤滑油を上記保持器３４ｂの周囲に排出させる各凹溝４０ｂ、４０ｂ（下流側部分）を形成した間部分４１の形状を、玉３３の直径Ｄａとの関係で規制している。即ち、上記保持器３４ｂの軸方向厚さを２ｔとし、この保持器３４ｂの直径方向に関する上記間部分４１の長さをｂとし、同じく軸方向に関する深さをＨとし、円周方向の幅を２Ｌとした場合に、（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝≦１４６．１７の関係を満たしている。この様に上記間部分４１の形状と上記玉３３の直径Ｄａとの関係を、（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝≦１４６．１７を満たす様に設定している為、上記保持器３４ｂが限界を超えて小さくなり、この保持器３４ｂが破損し易くなる事を防止できる。この為、この保持器３４ｂを組み込んだトロイダル型無段変速機の伝達効率を、耐久性及び信頼性を確保しつつ、向上させる事ができる。
【００３０】
次に、図４は、本発明の実施の形態の第２例を示している。本例の場合には、潤滑油流路である凹溝４０ｃ、４０ｃの断面形状を円弧状としている。この様な断面円弧状の凹溝４０ｃ、４０ｃを形成した本例の場合も、断面形状が矩形状である上述の第１例の場合と同様の考え方に基づき、保持器３４ｃの半径方向に関する上記各凹溝４０ｃ、４０ｃを形成した間部分４１の形状（ｂ、Ｌ、Ｈ、ｔ）と玉３３の直径Ｄａ（図１参照）との関係を、（Ｄａ^２　／ｂ^２　）｛Ｌ／（ｔ−Ｈ）｝≦１４６．１７の範囲に設定している。そして、この様に構成する事により、上記保持器３４ｃの外径を、強度を確保しつつ小さくして、この保持器３４ｃを組み込んだトロイダル型無段変速機の伝達効率を、耐久性及び信頼性を確保しつつ、向上させている。この様に、潤滑油流路である凹溝の断面形状は、矩形状、円弧状等、任意の形状とする事ができる。
【００３１】
【発明の効果】
本発明のトロイダル型無段変速機は、以上に述べた通り構成され作用して、パワーローラに付属のスラスト玉軸受に組み込む保持器の強度を低下させる事なく、このスラスト玉軸受の潤滑性を向上させ、更に保持器の小型・軽量化を図れる。この為、このスラスト玉軸受を組み込んだトロイダル型無段変速機の伝達効率を、信頼性並びに耐久性を確保しつつ向上させる事ができる。
【図面の簡単な説明】
【図１】本発明の実施の形態の第１例を示す、保持器の部分平面図。
【図２】玉を省略して示す、図１のＡ一Ａ断面図。
【図３】図２の左方から見た図。
【図４】本発明の実施の形態の第２例を示す、図３と同様の図。
【図５】従来から知られているトロイダル型無段変速機の基本的構成を、最大減速時の状態で示す略側面図。
【図６】同じく最大増速時の状態で示す略側面図。
【図７】従来の具体的構造の１例を示す断面図。
【図８】スラスト玉軸受並びにその潤滑装置部分の断面図。
【図９】図８に示した装置で潤滑が良好に行なわれる状態と潤滑不良になる状態とを示す、図８のＢ部拡大図。
【図１０】潤滑性を向上させる為の従来構造の１例を示す、保持器の部分平面図。
【図１１】玉を省略して示す、図１０のＣ−Ｃ断面図。
【図１２】図１１の左方から見た図。
【図１３】図１０〜１２に示した保持器を組み込んだスラスト玉軸受部分を示す、図８のＢ部に相当する図。
【図１４】潤滑油流路を設けた間部分の形状（ｂ、Ｌ、Ｈ、ｔ）と玉の直径（Ｄａ）との関係と、この間部分に加わる応力σと疲労強度σｗとの比との関係を示す線図。
【符号の説明】
１　　入力軸
２　　入力側ディスク
２ａ　内側面
３　　出力軸
４　　出力側ディスク
４ａ　内側面
５　　枢軸
６　　トラニオン
７　　変位軸
８　　パワーローラ
８ａ　周面
９　　押圧装置
１０　　カム板
１１　　保持器
１２　　ローラ
１３、１４　カム面
１５　　クラッチ
１６　　入力軸
１７　　ニードル軸受
１８　　出力軸
１９　　ハウジング
２０　　玉軸受
２１　　ころ軸受
２２　　玉軸受
２３　　スリーブ
２４　　駆動側前進ギヤ
２５　　駆動側後退ギヤ
２６　　伝達ギヤ
２７　　取り出し軸
２８　　従動側前進ギヤ
２９　　従動側後退ギヤ
３０　　ナット
３１　　ストップリング
３２、３２ａ　スラスト玉軸受
３３　　玉
３４、３４ａ、３４ｂ、３４ｃ　保持器
３５　　外輪
３６　　ポケット
３７　　スラスト軸受
３８　　給油孔
３９　　主体
４０、４０ａ、４０ｂ、４０ｃ　凹溝
４１　　間部分[0001]
TECHNICAL FIELD OF THE INVENTION
The toroidal-type continuously variable transmission according to the present invention is used, for example, as a transmission unit of an automatic transmission for an automobile or as a transmission for various industrial machines.
[0002]
[Prior art]
The use of a toroidal-type continuously variable transmission as schematically shown in FIGS. 5 and 6 has been studied as a transmission unit of an automatic transmission for an automobile, and has been partially implemented. In this toroidal type continuously variable transmission, for example, as disclosed in Patent Document 1, an input side disk 2 is supported concentrically with an input shaft 1 and an output side disk 4 is fixed to an end of an output shaft 3. I have. The inner surface of a casing containing the toroidal-type continuously variable transmission or a support bracket provided in the casing swings around pivots 5, 5 which are twisted with respect to the input shaft 1 and the output shaft 3. A moving trunnion 6 is provided.
[0003]
That is, these trunnions 6, 6 are provided with the pivots 5, 5 concentrically on the outer surfaces of both ends thereof in a direction perpendicular to or substantially perpendicular to the directions of the input shaft 1 and the output shaft 3. ing. The center of each of the trunnions 6, 6 supports a base end of a displacement shaft 7, 7 and swings each of the trunnions 6, 6 about the pivots 5, 5 to thereby allow the displacement shafts 7 to move. , 7 can be freely adjusted. Power rollers 8, 8 are rotatably supported around displacement shafts 7, 7 supported by the trunnions 6, 6, respectively. These power rollers 8, 8 are held between the input side and output side disks 2, 4. The inner surfaces 2a and 4a of the input and output disks 2 and 4 facing each other are concave, each having a circular cross-section centered on a point on the central axis of the pivot 5. I have. Then, the peripheral surfaces 8a, 8a of the power rollers 8, 8 formed on the spherical convex surfaces are brought into contact with the inner side surfaces 2a, 4a.
[0004]
A loading device 9 of a loading cam type is provided between the input shaft 1 and the input disk 2, and the input disk 2 is directed toward the output disk 4 by this pressing device 9. Pressing. The pressing device 9 includes a cam plate 10 that rotates together with the input shaft 1, and a plurality (for example, four) of rollers 12, 12 held by a holder 11. A cam surface 13 is formed on one side surface (the left side surface in FIGS. 5 to 6) of the cam plate 10, and the outer surface of the input side disk 2 (FIGS. 5 to 6). The same cam surface 14 is also formed on the right side surface. The plurality of rollers 12, 12 are rotatably supported about a radial axis with respect to the center of the input shaft 1.
[0005]
When the toroidal-type continuously variable transmission configured as described above is used, when the cam plate 10 rotates with the rotation of the input shaft 1, the plurality of rollers 12, 12 are moved out of the input side disk 2 by the cam surface 13. It is pressed against the cam surface 14 formed on the side surface. As a result, the input side disk 2 is pressed by the plurality of power rollers 8, 8, and at the same time, based on the pressing of the pair of cam surfaces 13, 14 and the plurality of rollers 12, 12, The input side disk 2 rotates. Then, the rotation of the input disk 2 is transmitted to the output disk 4 via the plurality of power rollers 8, 8, and the output shaft 3 fixed to the output disk 4 rotates.
[0006]
When the rotation speed of the input shaft 1 and the output shaft 3 is changed, and when deceleration is first performed between the input shaft 1 and the output shaft 3, the trunnions 6, 6 are centered on the pivots 5, 5. To swing in a predetermined direction. As shown in FIG. 5, the peripheral surfaces 8a, 8a of the power rollers 8, 8 correspond to the central portion of the inner surface 2a of the input disk 2 and the outer peripheral portion of the inner surface 4a of the output disk 4. The displacement shafts 7, 7 are tilted so as to abut each other. Conversely, when increasing the speed, the trunnions 6 are swung in a direction opposite to the predetermined direction. As shown in FIG. 6, the peripheral surfaces 8a, 8a of the power rollers 8, 8 correspond to the outer peripheral portion of the inner surface 2a of the input disk 2 and the central portion of the inner surface 4a of the output disk 4. Then, the respective displacement shafts 7, 7 are inclined so as to abut each other. If the angle of inclination of each of the displacement shafts 7, 7 is set between those in FIGS. 5 and 6, an intermediate speed ratio can be obtained between the input shaft 1 and the output shaft 3.
[0007]
FIG. 7 shows a toroidal-type continuously variable transmission described in Patent Literature 2, which shows a more concrete structure as an automobile transmission. The rotation of the crankshaft of the engine is transmitted to the input shaft 16 via the clutch 15, and the cam plate 10 spline-engaged with the intermediate portion of the input shaft 16 is rotated. Then, by the operation of the pressing device 9 including the cam plate 10, the input side disk 2 is rotated while being pressed toward the output side disk 4 to the left in FIG. The rotation of the input side disk 2 is transmitted to the output side disk 4 by the power rollers 8, 8.
[0008]
The output side disk 4 is supported by a needle bearing 17 around the input shaft 16. Further, a cylindrical output shaft 18 formed integrally with the output side disk 4 is supported inside a housing 19 by an angular type ball bearing 20. On the other hand, one end (the right end in FIG. 7) of the input shaft 16 is rotated by a roller bearing 21 inside the housing 19 and the other end is rotated by an angular ball bearing 22 inside the housing 19 via a sleeve 23. It is freely supported.
[0009]
Further, a transmission gear 26 in which a drive-side forward gear 24 and a drive-side reverse gear 25 are integrated with each other is spline-engaged with the outer peripheral surface of the output shaft 18. When the vehicle is moving forward, the transmission gear 26 is moved rightward in FIG. 7 to directly mesh the driving-side forward gear 24 with the driven-side forward gear 28 provided at an intermediate portion of the take-out shaft 27. On the other hand, at the time of retreat, the transmission gear 26 is moved to the left in FIG. 7, and the drive-side retreat gear 25 and the driven-side retreat gear 29 fixed to an intermediate portion of the take-out shaft 27 are not shown. The gears are engaged via an intermediate gear.
[0010]
When using the toroidal type continuously variable transmission configured as described above, the input shaft 16 is rotated by the engine via the clutch 15 and the transmission gear 26 is moved in an appropriate direction. It can be rotated in any direction. Further, by swinging the trunnions 6, 6 to change the contact position between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner surfaces 2a, 4a of both the input side and output side disks 2, 4, The rotation speed ratio between the input shaft 16 and the take-out shaft 27 can be changed.
[0011]
During operation of the toroidal-type continuously variable transmission as described above, the input disk 2 is pressed toward the output disk 4 based on the operation of the pressing device 9. As a result, a thrust load in the right direction in FIG. 7 is applied to the input shaft 16 supporting the cam plate 10 constituting the pressing device 9 as a reaction force based on the pressing. This thrust load is supported by the ball bearing 22 via the nut 30 hinged to the end of the input shaft 16 and the sleeve 23. In addition, the thrust load in the left direction in FIG. This thrust load is supported by the ball bearing 20 via a stop ring 31 externally fitted to the output shaft 18.
[0012]
During operation of the toroidal-type continuously variable transmission as described above, a thrust load is applied to the input shaft 16 and the output shaft 18, and a thrust load is also applied to the power rollers 8. Therefore, thrust ball bearings 32 are provided between the power rollers 8 and the trunnions 6 to support a thrust load applied to the power rollers 8. Each of these thrust ball bearings 32, 32 comprises a plurality of balls 33, 33, a retainer 34 for holding the plurality of balls 33, 33 rotatably, and an outer ring 35. The plurality of balls 33, 33 are formed in a spherical shape using bearing steel or ceramic. Such balls 33, 33 are in rolling contact with a raceway surface (inner raceway) formed on the outer end surface of each of the power rollers 8, 8 and a raceway surface (outer raceway) formed on the inner surface of the outer race 35. The retainer 34 is formed in a ring shape from a metal or a synthetic resin, and has a plurality of pockets 36 at circumferentially equal positions in a diametrically intermediate portion. Each of the balls 33, 33 is held in each of the rollers 36 so as to freely roll. Further, each of the outer rings 35, 35 formed in a ring shape from bearing steel, ceramic, or the like abuts against the inner side surface of each of the trunnions 6 via a thrust bearing 37 (see FIG. 8 described below). .
[0013]
The thrust ball bearings 32, 32 described above rotate at high speed while supporting the thrust load applied to the power rollers 8, 8 during operation of the toroidal type continuously variable transmission. Therefore, a sufficient amount of lubricating oil must be supplied to the thrust ball bearings 32 during operation of the toroidal type continuously variable transmission. For this reason, conventionally, as shown in FIG. 8, one or more oil supply holes 38, 38 are formed in a part of the outer ring 35, and when the toroidal type continuously variable transmission is operated, the oil supply holes 38, 38 are formed. The lubricating oil is forcibly fed into the oil. The lubricating oil forcibly fed into the oil supply holes 38, 38 is supplied to the gap between the inner surface of the outer ring 35 and the outer surface of the retainer 34, and the inner surface of the retainer 34 and the outer surface of the power roller 8. It flows through the gap between the end faces and lubricates the rolling parts of the plurality of balls 33 during that time.
[0014]
By the way, in the case of a structure in which lubricating oil is fed into the thrust ball bearings 32 by the above-described structure, there is a possibility that the supply of lubricating oil is partially insufficient. That is, as shown in FIG. 9A, if the retainer 34 is located between the inner surface of the outer race 35 and the outer end surface of the power roller 8, the distance between the inner surface of the outer race 35 and the outer surface of the retainer 34 is increased. And the gap between the inner surface of the retainer 34 and the outer end surface of the power roller 8 causes no problem. However, when lubricating oil is discharged from the oil supply hole 38 formed in the outer race 35 toward the outer surface of the retainer 34, the retainer 34 is pushed by the flow of the lubricating oil, and as shown in FIG. , To the power roller 8 side. Based on such displacement, when the inner surface of the cage 34 and the outer end surface of the power roller 8 come into close contact with each other, a sufficient amount of contact is formed between the raceway surface formed on the outer end surface and the rolling surface of each ball 33. No lubricating oil is present. As a result, the amount of wear at the contact portion between the raceway surface of the outer end surface of the power roller 8 and the rolling surface of each rolling element 33 may increase, or in the case of extreme wear, the contact portion may be seized. .
[0015]
As a structure for eliminating such a problem, Patent Document 3 discloses a toroidal-type continuously variable transmission incorporating a thrust ball bearing 32a having improved lubrication as shown in FIGS. . The main body 39 of the retainer 34a constituting the thrust ball bearing 32a is formed in a ring shape entirely from a metal such as a synthetic resin or a copper-based alloy such as brass. Pockets 36 are formed at a plurality of positions in the circumferential direction at the intermediate portion in the diameter direction of the main body 39 in accordance with the shape of the ball 33 to be held. In addition, concave grooves 40 and 40 are formed on both the inner and outer surfaces of the main body 39 in a state of diametrically crossing the pockets 36 in the diametric direction of the main body 39. A lubricating oil flow path is provided between the peripheral edge and the outer peripheral edge.
[0016]
According to the toroidal-type continuously variable transmission having the lubricating improved thrust ball bearing 32a configured as described above, the thrust ball is driven by the force of the lubricating oil discharged from the oil supply hole 38 formed in the outer race 35 and the like. Even when the retainer 34a constituting the bearing 32a is displaced in the axial direction and the inner surface of the retainer 34a and the outer end surface of the power roller 8 are in close contact as shown in FIG. A space surrounded by the inner surface of the power roller 8 and the outer end surface of the power roller 8 serves as a lubricating oil flow path. Then, a sufficient amount of lubricating oil flows through the concave grooves 40, 40 into the pockets 36 holding the balls 33. As a result, it is possible to prevent the lubricating oil existing in the contact portion between the raceway surface formed on the outer end surface of the power roller 8 and the rolling surface of the ball 33 from running short, and to reduce a part of the thrust ball bearing 32a. The risk of significant wear or seizure can be reduced.
[0017]
Furthermore, Patent Document 4 discloses that by optimizing the cross-sectional shape of each of the concave grooves 40, 40 while keeping the bending stress generated in the retainer 34a constant, in other words, without increasing the bending stress. A structure is described in which the cross-sectional area of each of the concave grooves 40, 40 is increased to increase the flow rate of the lubricating oil flowing in the pocket 36, thereby improving lubricity. That is, in the case of the structure described in Patent Literature 4, the shape of each of the grooves 40, 40, which are the lubricating oil flow paths, is set such that the axial depth of the retainer 34a is H, and the circumferential direction is H. When the width is set to 2 L, the width satisfies 0.29 ≦ H / L ≦ 0.88. With this configuration, it is possible to increase the flow rate of the lubricating oil flowing through each of the concave grooves 40, 40 while preventing the cross-sectional area of each of the concave grooves 40, 40 from becoming unnecessarily large and easily damaging the retainer 34a. Thus, the lubricity is improved.
[0018]
[Patent Document 1]
Japanese Utility Model Publication No. Sho 62-71465
[Patent Document 2]
Microfilm of Japanese Utility Model Application No. 61-87523 (Japanese Utility Model Application Laid-Open No. 62-199557)
[Patent Document 3]
Utility Model Registration No. 2603559
[Patent Document 4]
JP-A-2002-89646
[0019]
[Problems to be solved by the invention]
The retainers 34, 34a incorporated in the thrust ball bearings 32, 32a for supporting the power rollers 8, 8 with respect to the trunnions 6, 6 rotate at a high speed during operation of the toroidal type continuously variable transmission and a part of the power. However, the cages 34 and 34a themselves do not particularly contribute to power transmission. For this reason, in order to improve the transmission efficiency of the toroidal type continuously variable transmission, it is desired that the retainers 34 and 34a be as small and lightweight as possible. However, if the retainers 34, 34a are reduced in size unnecessarily, the distance between the outer peripheral edge of the retainers 34, 34a and the inner peripheral surface of each of the pockets 36, 36 is shortened. The retainers 34, 34a are likely to be damaged such as cracks.
[0020]
For example, as shown in FIG. 10, the case where the cage 34 a is eccentric with respect to the pitch circle of each ball 33 and a radial load F acts on the inner surface of the pocket 36 from any of the balls 33 will be considered. . In this case, it is considered that the portion 41 between the outer peripheral edge of the retainer 34a and the inner surface of the pocket 36 where the concave grooves 40 and 40 are formed can be approximated to a support beam fixed at both ends. Accordingly, the maximum bending stress σ generated in the intermediate portion 41 when the intermediate portion 41 is pressed with a force (load) F is expressed by the following equation (1) in terms of material mechanics.
σ = 3FL / ｛4b ² (T−H)｝ −−− (1)
[0021]
In the formula (1), L is の of the circumferential width of each of the grooves 40, 40, b is the length of the inter-portion 41 in the diametrical direction of the retainer 34a, and H is Represents the depth of each of the grooves 40, 40 in the axial direction of the retainer 34a. In addition, t is の of the thickness of the retainer 34a in the axial direction at a portion deviating from each of the concave grooves 40, 40. From such an equation (1), it can be seen that, when the length b of the inter-portion 41 decreases, the bending stress σ applied to the inter-portion 41 increases, and the cage 34a is easily damaged.
In view of such circumstances, the present invention has been made to reduce the bending stress generated in the inter-portion 41 so that the cage 34a is hardly damaged, and to improve the durability and reliability of the toroidal type continuously variable transmission. It was invented.
[0022]
[Means for Solving the Problems]
The toroidal-type continuously variable transmission according to the present invention includes first and second disks which are concentrically arranged with their inner surfaces facing each other, similarly to the aforementioned conventional toroidal-type continuously variable transmission. A trunnion that swings about a pivot that is twisted with respect to the center axis of the first and second discs, a displacement shaft supported by the trunnion, and a rotatable support around the displacement axis. In this state, a power roller sandwiched between the inner surfaces of the first and second disks and a load in the thrust direction provided between the power roller and the trunnion and applied to the power roller. And a thrust ball bearing for supporting the bearing. The inner surface of each of the first and second disks is a concave surface having an arc-shaped cross section, and the peripheral surface of the power roller is a spherical convex surface. This peripheral surface and each of the inner surfaces correspond to each other. The above-mentioned thrust ball bearing is provided with a plurality of balls and a retainer which holds the plurality of balls in a freely rolling manner. The retainer has a ring-shaped main body, a plurality of pockets each formed at a diametrically intermediate portion of the main body, and holding therein each of the balls one by one in a freely rolling manner, A plurality of lubricating oil flow paths provided between the inner peripheral edge and the outer peripheral edge of the main body in a state of crossing the pocket.
In particular, in the toroidal type continuously variable transmission of the present invention, the thickness of the cage in the axial direction is set to 2t, and each of the pockets and the outer peripheral edge of the cage in the respective lubricating oil flow paths. When the length in the radial direction of the retainer is b, the depth in the axial direction is H, the width in the circumferential direction is 2L, and the diameter of each ball is Da, (Da ² / B ² Satisfies the relationship of {L / (t−H)} ≦ 146.17.
[0023]
[Action]
The toroidal-type continuously variable transmission according to the present invention configured as described above adjusts the operation of transmitting power between the first and second disks and the ratio of the rotational speeds of the first and second disks. The operation performed is the same as that of the conventional toroidal-type continuously variable transmission shown in FIGS. In addition, by flowing lubricating oil into the pocket of the cage through a plurality of lubricating oil passages provided in the main body constituting the cage, even when the cage is displaced in the axial direction, the lubrication can be performed in the pocket. The operation of supplying oil is the same as that of the conventional toroidal-type continuously variable transmission shown in FIGS.
[0024]
In particular, in the toroidal-type continuously variable transmission of the present invention, the shape (b, L, H, t) of the portion of each lubricating oil flow path existing between each pocket and the outer peripheral edge of the cage. And the diameter Da of the ball constituting the thrust ball bearing is represented by (Da ² / B ² ) Since {L / (t−H)} ≦ 146.17, the cage can be prevented from becoming smaller than the limit and becoming easily damaged. For this reason, the transmission efficiency of the toroidal type continuously variable transmission incorporating the retainer can be improved while ensuring durability and reliability.
[0025]
Next, (Da ² / B ² The reason why the cage can be prevented from being broken by setting {L / (t−H)} ≦ 146.17 will be described. Similarly to the above-mentioned equation (1), the maximum bending stress σ generated in the portion between each pocket and the outer peripheral edge of the cage in each lubricating oil flow path is expressed by the following equation (1) in terms of material mechanics. It is represented by an equation. The meaning of each code is as described above.
σ = 3FL / ｛4b ² (T−H)｝ −−− (1)
In the equation (1), the load F by which the ball pushes the cage toward the outer diameter side is F = C · Da according to the analysis similar to the method described in “Advanced Dynamics of Rolling Elements”. ² By substituting this into the above equation (1), the following equation (2) is obtained.
σ = 3C · Da ² ・ L / $ 4b ² (T−H)｝ −−− (2)
[0026]
In the equation (2), C is a constant, and it has been found that this value is about 1.39 even in the case of the maximum load by performing the same analysis as the method described in the above-mentioned document. On the other hand, assuming that the fatigue strength of the cage material is σw, σ / σw and (Da ² / B ² ) {L / (t−H)} is as shown in FIG. Here, brass (HB) is used as a material for forming a cage of a thrust ball bearing of a toroidal type continuously variable transmission. _S C1) or an iron-based metal material is generally used. Among them, the fatigue limit σw of brass is about 150 MPa, and therefore, as can be seen from FIG. ² / B ² ) {L / (t−H)} = 146.17, and σ / σw = 1. As can be seen from FIG. 14, when σw changes (Da ² / B ² ) {L / (t−H)} changes, but the brass (HB _S If the design is performed in consideration of the value of C1), fatigue fracture can be prevented. Accordingly, from the viewpoint of preventing the cage from being damaged and securing the durability and reliability of the toroidal type continuously variable transmission incorporating the cage, the above (Da) ² / B ² It is understood that it is preferable to set the value of {L / (t−H)} to 146.17 or less.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
FIGS. 1 to 3 show, as a first example of an embodiment of the present invention, a case where concave grooves 40a and 40b each having a rectangular cross section are provided as a lubricating oil flow path. It should be noted that a feature of the present invention is that the shape (b, b) of the inter-portion 41 provided with the concave grooves 40b, 40b existing between each pocket 36 and the outer peripheral edge of the retainer 34b among the concave grooves 40a, 40b. By regulating the relationship between (L, H, t) and the diameter Da of the ball 33, it is possible to prevent the outer diameter of the retainer 34b from becoming smaller than the limit, thereby preventing the retainer 34b from being easily broken. On the point. Since the structure and operation of the other parts are the same as those of the above-described conventional structure, the illustration and description of the equivalent parts are omitted or simplified, and the following description will focus on the characteristic parts of the present invention.
[0028]
A plurality of pockets 36 are formed at regular intervals in the circumferential direction at a radially intermediate portion of the annular main body 39 constituting the retainer 34b. A plurality of concave grooves 40a and 40b are formed on both the inner and outer surfaces (both axial surfaces) of the main body 39 so as to cross each pocket 36. These concave grooves 40a and 40b constitute a plurality of lubricating oil channels provided between the inner peripheral edge and the outer peripheral edge of the main body 39. When the toroidal type continuously variable transmission is operated, each of the grooves 40a and 40b serving as the lubricating oil flow path is provided with the above-described oil supply hole 38 (FIG. 8, FIG. 8) from the inner peripheral side to the outer peripheral side of the main body 39. 9 and 13). During this time, the lubricating oil lubricates the contact portion between the rolling surface of the ball 33 held in each pocket 36 and the mating raceway surface.
[0029]
In the case of the present example, the inner surface of each of the pockets 36 and the outer peripheral edge of the retainer 34b are communicated with each other among the concave grooves 40a and 40b, and the lubricating oil fed into each of the pockets 36 is used as the above. The shape of the inter-portion 41 in which the concave grooves 40b, 40b (downstream portion) to be discharged around the retainer 34b are formed is regulated in relation to the diameter Da of the ball 33. That is, the axial thickness of the retainer 34b is 2t, the length of the inter-portion 41 in the diametric direction of the retainer 34b is b, the depth in the axial direction is H, and the circumferential width is In the case of 2L, (Da ² / B ² ) {L / (t−H)} ≦ 146.17. As described above, the relationship between the shape of the space portion 41 and the diameter Da of the ball 33 is represented by (Da ² / B ² ) Since {L / (t−H)} ≦ 146.17 is set, the cage 34b can be prevented from becoming smaller than the limit and easily broken. For this reason, the transmission efficiency of the toroidal-type continuously variable transmission incorporating the retainer 34b can be improved while ensuring durability and reliability.
[0030]
Next, FIG. 4 shows a second example of the embodiment of the present invention. In the case of this example, the cross-sectional shapes of the concave grooves 40c, 40c, which are the lubricating oil flow paths, are arc-shaped. Also in the case of the present example in which the concave grooves 40c, 40c having the arcuate cross-section are formed, based on the same concept as in the case of the above-described first example in which the cross-sectional shape is rectangular, the above-described radial direction of the retainer 34c is used. The relationship between the shape (b, L, H, t) of the portion 41 between the grooves 40c, 40c and the diameter Da of the ball 33 (see FIG. 1) is expressed by (Da ² / B ² ) {L / (t−H)} ≦ 146.17. With this configuration, the outer diameter of the retainer 34c is reduced while ensuring the strength, and the transmission efficiency of the toroidal type continuously variable transmission incorporating the retainer 34c is improved in durability and reliability. It has been improved while ensuring the quality. As described above, the cross-sectional shape of the concave groove serving as the lubricating oil flow path can be an arbitrary shape such as a rectangular shape or an arc shape.
[0031]
【The invention's effect】
The toroidal type continuously variable transmission according to the present invention is configured and operated as described above, and without reducing the strength of the retainer incorporated in the thrust ball bearing attached to the power roller, the lubrication of the thrust ball bearing can be improved. The size and weight of the cage can be further improved. Therefore, the transmission efficiency of the toroidal-type continuously variable transmission incorporating the thrust ball bearing can be improved while ensuring reliability and durability.
[Brief description of the drawings]
FIG. 1 is a partial plan view of a retainer, showing a first example of an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, showing a ball omitted;
FIG. 3 is a view seen from the left side of FIG. 2;
FIG. 4 is a view similar to FIG. 3, showing a second example of the embodiment of the present invention;
FIG. 5 is a schematic side view showing a basic configuration of a conventionally known toroidal-type continuously variable transmission in a state of maximum deceleration.
FIG. 6 is a schematic side view similarly showing a state at the time of maximum speed increase.
FIG. 7 is a sectional view showing an example of a conventional specific structure.
FIG. 8 is a sectional view of a thrust ball bearing and a lubricating device thereof.
9 is an enlarged view of a portion B in FIG. 8 showing a state in which lubrication is favorably performed and a state in which lubrication is poor in the apparatus shown in FIG. 8;
FIG. 10 is a partial plan view of a cage, showing an example of a conventional structure for improving lubricity.
FIG. 11 is a cross-sectional view taken along the line CC of FIG. 10, showing a ball omitted;
FIG. 12 is a view seen from the left side of FIG. 11;
FIG. 13 is a view corresponding to a portion B in FIG. 8, showing a thrust ball bearing portion incorporating the cage shown in FIGS.
FIG. 14 shows the relationship between the shape (b, L, H, t) of the portion between the lubricating oil flow paths and the diameter (Da) of the ball, and the ratio between the stress σ applied to this portion and the fatigue strength σw. FIG.
[Explanation of symbols]
1 input shaft
2 Input side disk
2a Inside surface
3 Output shaft
4 Output side disk
4a Inner surface
5 Axis
6 trunnion
7 Displacement axis
8 Power roller
8a Peripheral surface
9 Pressing device
10 Cam plate
11 cage
12 rollers
13, 14 Cam surface
15 clutch
16 input shaft
17 Needle bearing
18 Output shaft
19 Housing
20 ball bearings
21 Roller bearing
22 Ball bearing
23 sleeve
24 Drive-side forward gear
25 Reverse gear on drive side
26 Transmission gear
27 Take-out shaft
28 Driven forward gear
29 Driven reverse gear
30 nuts
31 Stop Ring
32, 32a thrust ball bearing
33 balls
34, 34a, 34b, 34c Cage
35 Outer ring
36 pockets
37 Thrust bearing
38 Oil supply hole
39 subject
40, 40a, 40b, 40c Groove
41 Intersection

Claims

First and second disks arranged concentrically with their inner surfaces facing each other, and swinging about a pivot axis which is twisted with respect to the center axis of the first and second disks. A moving trunnion, a displacement shaft supported by the trunnion, and a power pinched between inner surfaces of the first and second disks in a state of being rotatably supported around the displacement axis. Roller, a thrust ball bearing provided between the power roller and the trunnion and supporting a load in the thrust direction applied to the power roller, and the inner surfaces of the first and second disks have respective cross sections. An arcuate concave surface, the peripheral surface of the power roller is a spherical convex surface, and the peripheral surface and each of the inner surfaces are in contact with each other. The thrust ball bearing includes a plurality of balls and a plurality of balls. Roll the ball The cage is provided with a ring-shaped main body, each of which is formed at a diametrically intermediate portion of the main body, and the balls are rolled one by one inside the main body. In a toroidal-type continuously variable transmission having a plurality of pockets movably held and a plurality of lubricating oil passages provided between an inner peripheral edge and an outer peripheral edge of the main body in a state of traversing each pocket. The thickness of the cage in the axial direction is 2t, and the length of the portion of the lubricating oil flow path between each pocket and the outer peripheral edge of the cage in the radial direction of the cage. Where b is the depth in the axial direction, H is the width in the circumferential direction, 2 L is the width in the circumferential direction, and Da is the diameter of each of the above balls. (Da ² / b ² ) ｛L / (t−H) A toroidal type continuously variable transmission characterized by satisfying a relationship of｝ ≦ 146.17.