JP3852188B2

JP3852188B2 - Method for manufacturing intermediate disk for toroidal continuously variable transmission

Info

Publication number: JP3852188B2
Application number: JP31039397A
Authority: JP
Inventors: 宏史石川; 伸夫後藤; 尚町田
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 1997-11-12
Filing date: 1997-11-12
Publication date: 2006-11-29
Anticipated expiration: 2017-11-12
Also published as: JPH11141637A

Description

【０００１】
【発明の属する技術分野】
この発明は、例えば自動車用の変速機として利用するトロイダル型無段変速機のうち、互いに並列な二つの動力の伝達経路を有する、ダブルキャビティ型のトロイダル型無段変速機を構成する中間ディスクの製造方法の改良に関する。
【０００２】
【従来の技術】
自動車用変速機として、図４〜５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ている。このトロイダル型無段変速機は、例えば実開昭６２−７１４６５号公報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、この入力軸１と同心に配置した出力軸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側には、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を中心として揺動する、それぞれが揺動部材であるトラニオン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面に上記枢軸５、５を、互いに同心に設けている。又、これら各トラニオン６、６の中間部には変位軸７、７の基端部を支持し、上記枢軸５、５を中心としてこれら各トラニオン６、６を揺動させる事により、上記各変位軸７、７の傾斜角度の調節を自在としている。上記各トラニオン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の、互いに対向する内側面２ａ、４ａ同士の間に挟持している。これら各内側面２ａ、４ａは、それぞれ断面が、上記枢軸５を中心とする円弧を上記入力軸１並びに出力軸３を中心に回転させて得られる、断面円弧状の凹面をなしている。そして、球状凸面に形成した上記各パワーローラ８、８の周面８ａ、８ａを、上記内側面２ａ、４ａに当接させている。
【０００４】
上記入力軸１と入力側ディスク２との間には、ローディ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、弾性的に押圧自在としている。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により転動自在に保持した複数個（例えば４個）のローラ１２、１２とから構成する。上記カム板１０の片側面（図４〜５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、上記入力側ディスク２の外側面（図４〜５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の中心に関し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が複数個のローラ１２、１２を、入力側ディスク２の外側面に形成したカム面１４に押圧する。この結果、上記入力側ディスク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、前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との回転速度比（変速比）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、前記各枢軸５、５を中心として前記各トラニオン６、６を所定方向に揺動させる。そして、上記各パワーローラ８、８の周面８ａ、８ａが図４に示す様に、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、上記各枢軸５、５を中心として上記各トラニオン６、６を反対方向に揺動させる。そして、上記各パワーローラ８、８の周面８ａ、８ａが図５に示す様に、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４と図５との中間にすれば、入力軸１と出力軸３との間で、中間の変速比を得られる。
【０００７】
又、図６〜７は、実願昭６３−６９２９３号（実開平１−１７３５５２号）のマイクロフィルムに記載された、より具体化されたトロイダル型無段変速機の１例を示している。入力側ディスク２と出力側ディスク４とは円管状の入力軸１５の周囲に、それぞれニードル軸受１６、１６を介して回転自在に支持している。又、カム板１０は上記入力軸１５の端部（図６の左端部）外周面にスプライン係合させ、鍔部１７により上記入力側ディスク２から離れる方向への移動を阻止している。そして、このカム板１０とローラ１２、１２とにより、押圧装置９を構成している。上記出力側ディスク４には、出力部材である出力歯車１８を、キー１９、１９により結合し、これら出力側ディスク４と出力歯車１８とが同期して回転する様にしている。
【０００８】
１対のトラニオン６、６の両端部は１対の支持板２０、２０に、揺動並びに軸方向（図６の表裏方向、図７の左右方向）に亙る変位自在に支持している。そして、上記各トラニオン６、６の中間部に形成した円孔２３、２３部分に、変位軸７、７を支持している。これら各変位軸７、７は、互いに平行で且つ偏心した支持軸部２１、２１と枢支軸部２２、２２とを、それぞれ有する。このうちの各支持軸部２１、２１を上記各円孔２３、２３の内側に、ラジアルニードル軸受２４、２４を介して、回転自在に支持している。又、上記各枢支軸部２２、２２の周囲にパワーローラ８、８を、ラジアルニードル軸受２５、２５を介して、回転自在に支持している。
【０００９】
尚、上記１対の変位軸７、７は、上記入力軸１５に対して１８０度反対側位置に設けている。又、これら各変位軸７、７の各枢支軸部２２、２２が各支持軸部２１、２１に対し偏心している方向は、上記入力側、出力側両ディスク２、４の回転方向に関し同方向（図７で左右逆方向）としている。又、偏心方向は、上記入力軸１５の配設方向に対しほぼ直交する方向としている。従って、上記各パワーローラ８、８は、上記入力軸１５の配設方向に亙る若干の変位自在に支持される。この結果、回転力の伝達状態で構成各部材に加わる大きな荷重に基づく、これら構成各部材の弾性変形に起因して、上記各パワーローラ８、８が上記入力軸１５の軸方向（図６の左右方向、図７の表裏方向）に変位する傾向となった場合でも、上記構成各部品に無理な力を加える事なく、この変位を吸収できる。
【００１０】
又、上記各パワーローラ８、８の外側面と上記各トラニオン６、６の中間部内側面との間には、パワーローラ８、８の外側面の側から順に、スラスト玉軸受２６、２６と、これら各スラスト玉軸受２６、２６を構成する外輪２７、２７に加わるスラスト荷重を支承するスラストニードル軸受２８、２８とを設けている。このうちのスラスト玉軸受２６、２６は、上記各パワーローラ８、８に加わるスラスト方向の荷重を支承しつつ、これら各パワーローラ８、８の回転を許容するものである。又、上記各スラストニードル軸受２８、２８は、上記各パワーローラ８、８から上記各外輪２７、２７に加わるスラスト荷重を支承しつつ、前記各枢支軸部２２、２２及び上記外輪２７、２７が、前記支持軸部２１、２１を中心に揺動する事を許容する。更に、上記各トラニオン６、６の一端部（図７の左端部）にはそれぞれ駆動ロッド２９、２９を結合し、これら各駆動ロッド２９、２９の中間部外周面に駆動ピストン３０、３０を固設している。そして、これら各駆動ピストン３０、３０を、それぞれ駆動シリンダ３１、３１内に油密に嵌装している。
【００１１】
上述の様に構成されるトロイダル型無段変速機の場合には、入力軸１５の回転は、押圧装置９を介して入力側ディスク２に伝わる。そして、この入力側ディスク２の回転が、１対のパワーローラ８、８を介して出力側ディスク４に伝わり、更にこの出力側ディスク４の回転が、出力歯車１８より取り出される。入力軸１５と出力歯車１８との間の回転速度比を変える場合には、上記１対の駆動ピストン３０、３０を互いに逆方向に変位させる。これら各駆動ピストン３０、３０の変位に伴って上記１対のトラニオン６、６が、それぞれ逆方向に変位し、例えば図７の下側のパワーローラ８が同図の右側に、同図の上側のパワーローラ８が同図の左側に、それぞれ変位する。この結果、これら各パワーローラ８、８の周面８ａ、８ａと上記入力側ディスク２及び出力側ディスク４の内側面２ａ、４ａとの当接部に作用する、接線方向の力の向きが変化する。そして、この力の向きの変化に伴って上記各トラニオン６、６が、支持板２０、２０に枢支された枢軸５、５を中心として、互いに逆方向に揺動する。この結果、前述の図４〜５に示した様に、上記各パワーローラ８、８の周面８ａ、８ａと上記各内側面２ａ、４ａとの当接位置が変化し、上記入力軸１５と出力歯車１８との間の回転速度比が変化する。
【００１２】
尚、この様に上記入力軸１５と出力歯車１８との間で回転力の伝達を行なう際には、構成各部材の弾性変形に基づいて上記各パワーローラ８、８が、上記入力軸１５の軸方向に変位し、これら各パワーローラ８、８を枢支している前記各変位軸７、７が前記各支持軸部２１、２１を中心として僅かに回動する。この回動の結果、前記各スラスト玉軸受２６、２６の外輪２７、２７の外側面と上記各トラニオン６、６の内側面とが相対変位する。これら外側面と内側面との間には、前記各スラストニードル軸受２８、２８が存在する為、この相対変位に要する力は小さい。従って、上述の様に各変位軸７、７の傾斜角度を変化させる為の力が小さくて済む。
【００１３】
更に、伝達可能なトルクを増大すべく、図８に示す様に、回転軸である入力軸１５の周囲に、それぞれが外側ディスクである入力側ディスク２Ａ、２Ｂと、それぞれが中間ディスクである出力側ディスク４、４とを２個ずつ設け、これら２個ずつの入力側ディスク２Ａ、２Ｂと出力側ディスク４、４とを動力の伝達方向に関して互いに並列に配置する、所謂ダブルキャビティ型のトロイダル型無段変速機の構造も、従来から考えられている。この図８に示した構造では、上記入力軸１５の中間部周囲に出力歯車１８ａを、この入力軸１５に対する回転を自在として支持し、この出力歯車１８ａの両端部に上記各出力側ディスク４、４を、スプライン係合させている。そして、これら各出力側ディスク４、４の内周面と上記入力軸１５の外周面との間にニードル軸受１６、１６を設け、これら各出力側ディスク４、４を上記入力軸１５の周囲に、この入力軸１５に対する回転、並びにこの入力軸１５の軸方向に亙る変位を自在に支持している。又、上記各入力側ディスク２Ａ、２Ｂは、上記入力軸１５の両端部に、この入力軸１５と共に回転自在に支持している。
【００１４】
但し、一方（図８の左方）の入力側ディスク２Ａは、背面（図８の左面）をローディングナット３２に突き当てて、上記入力軸１５に対する軸方向（図８の左右方向）の変位を阻止している。これに対して、カム板１０に対向する入力側ディスク２Ｂは、ボールスプライン３３により上記入力軸１５に、軸方向に亙る変位自在に支持している。そして、この入力側ディスク２Ｂの背面（図８の右面）とカム板１０の前面（図８の左面）との間に皿板ばね３４とスラストニードル軸受３５とを、互いに直列に設けている。このうちの皿板ばね３４は、上記各ディスク２Ａ、２Ｂ、４の内側面２ａ、４ａとパワーローラ８、８の周面８ａ、８ａとの当接部に予圧を付与する為の予圧装置としての役目を果たす。
【００１５】
上述の様に構成するダブルキャビティ型のトロイダル型無段変速機の運転時には、上記入力軸１５の回転が、１対の入力側ディスク２Ａ、２Ｂから１対の出力側ディスク４、４に、それぞれ複数個ずつ（図示の例では２個ずつ合計４個であるが、３個ずつ合計６個の場合もある）のパワーローラ８、８を介して伝達される。そして、上記１対の出力側ディスク４、４に伝達された回転動力は、１個の出力歯車１８ａに伝わり、この出力歯車１８ａが噛合した別の歯車（図示せず）を介して取り出される。この様に、上記入力軸１５から出力歯車１８ａへの回転力の伝達を、互いに並列に配置した２系統に分けて行なう為、大きな回転力（トルク）の伝達が可能になる。尚、上記入力軸１５と出力歯車１８ａとの間での変速比を変える為には、上記各パワーローラ８、８を支承した変位軸７、７を傾斜させるべく、これら各変位軸７、７を支承した各トラニオン６、６を平行移動させる。この様に各トラニオン６、６を平行移動させる為の構造は、前述の図６〜７に示した、シングルキャビティ型のトロイダル型無段変速機の場合と同様である。但し、ダブルキャビティ型のトロイダル型無段変速機の場合には、上記各トラニオン６、６の移動量並びに移動方向を互いに同期させるべく、各駆動シリンダ３１、３１（図７参照）への圧油の給排状態を切り換える様にしている。
【００１６】
【発明が解決しようとする課題】
図８に示した従来のダブルキャビティ型のトロイダル型無段変速機の場合には、それぞれが中間ディスクである１対の出力側ディスク４、４と出力歯車１８ａとを別体とし、この出力歯車１８ａの中心部に設けたスリーブ部３６の両端部に、上記１対の出力側ディスク４、４をスプライン係合させている。この為、構成部品の数が多くなり、部品製作、部品管理、組立作業が何れも面倒になるだけでなく、これら１対の出力側ディスク４、４及び出力歯車１８ａの設置部分の軸方向寸法が嵩む事が避けられない。
【００１７】
この様に上記設置部分の軸方向寸法が嵩むと、その分、入力軸１５の軸方向長さが大きくなり、この入力軸１５の両端部に支持した、１対の入力側ディスク２Ａ、２Ｂ同士の間隔が大きくなる。この様に、これら１対の入力側ディスク２Ａ、２Ｂ同士の間隔が大きくなると、回転伝達時にこれら両入力側ディスク２Ａ、２Ｂ間での、上記入力軸１５の捩り変形量が多くなり、これら両入力側ディスク２Ａ、２Ｂ間の回転方向に関する位相差が大きくなる。この結果、一方のキャビティ側の入力側ディスク２Ａと出力側ディスク４との間での回転伝達と、他方のキャビティ側の入力側ディスク２Ｂと出力側ディスク４との間での回転伝達との間で回転力伝達を同期させる制御が難しくなり、ダブルキャビティ型のトロイダル型無段変速機の効率確保が難しくなる。
【００１８】
米国特許第２１４００１２号明細書には、中間ディスクに相当する１個の出力側ディスクの軸方向両側面をそれぞれ断面円弧形の凹面とし、これら両凹面にパワーローラの周面を当接させる構造が記載されている。ところが、この米国特許明細書に記載された構造の場合には、上記出力側ディスクの回転を、この出力側ディスクにその一端開口部を結合固定し、一方の入力側ディスクを内部に包み込む、有底円筒状のドラムにより取り出す様にしている。この為、上記一方の入力側ディスクと中間ディスクとの間に設けるパワーローラの支持が非常に難しくなり、構造が非常に複雑になるだけでなく、当該パワーローラの支持構造を上記ドラムの内側に配置する必要がある。この為、この支持構造を含むパワーローラ部分を小型化せざるを得ない。しかも、上記ドラムで伝達可能な動力は限られるので、上記パワーローラ部分を小型化せざるを得ない事と相まって、伝達可能な回転力を、必ずしも十分に大きくできない。
本発明のトロイダル型無段変速機用中間ディスクの製造方法は、上述の様な不都合を何れも解消すべく発明したものである。
【００１９】
【課題を解決するための手段】
本発明の製造方法の対象となる中間ディスクを組み込むトロイダル型無段変速機は、回転軸と、それぞれが断面円弧状の凹面である内側面を互いに対向させた状態で上記回転軸の両端部に、この回転軸と同期した回転を自在に支持した１対の外側ディスクと、軸方向両側面を断面円弧状の凹面とし、上記回転軸の周囲に、この回転軸に対する相対回転を自在として支持した中間ディスクと、この中間ディスクの外周面に直接形成した、上記回転軸と同心のギヤと、この回転軸の軸方向に関して上記各外側ディスクと中間ディスクとの中間部に位置し、上記回転軸の軸方向に対し直角方向で且つこの回転軸に対し捻れの位置にある枢軸を中心として揺動する複数の揺動部材と、これら各揺動部材の内側面から突出した複数本の変位軸と、上記各揺動部材の内側面で上記各変位軸の周囲に回転自在に支持された状態で、上記各外側ディスクの内側面と上記中間ディスクの両側面との間に挟持された複数個のパワーローラとを備える。
そして、上記中間ディスクの両側面でこれら各パワーローラの周面と当接する部分に第一の硬化層を、上記中間ディスクの外周面で上記ギヤを形成した部分に第二の硬化層を、それぞれ形成すると共に、上記第一の硬化層の有効深さを上記第二の硬化層の有効深さよりも深くしている。
【００２０】
この為に本発明の製造方法では、上述の様な中間ディスクを、請求項１〜３に記載した様な工程を経て造る。
このうち、請求項１に記載した発明の場合には上記中間ディスクを、次の(1) 〜(7) の工程を経て造る。
(1) 金属材料に鍛造若しくは削り出し加工を施して、前加工用素材を造る第一工程。
(2) 上記前加工用素材のうち、軸方向両側面部分に前加工を施して断面円弧状の凹面を形成し、完成後の中間ディスクよりも大きな形状を有する第一素材とする第二工程。
(3) 上記第一素材に浸炭処理又は浸炭窒化処理を施し、表面部分を硬化して第二素材とする第三工程。
(4) 上記第二素材のうち、上記ギヤを形成すべき外周寄り部分の表面部分に存在する浸炭層を除去して第三素材とする第四工程。
(5) 上記第三素材の外周縁部にギヤを形成して第四素材とする第五工程。
(6) 上記第四素材に浸炭クエンチ処理又は浸炭窒化クエンチ処理を施して第五素材とする第六工程。
(7) 上記第五素材の軸方向両側面と外周縁に形成したギヤ部分とを仕上げ加工して上記中間ディスクとする第七工程。
尚、上記(3) の第三工程と上記(4) の第四工程との間で、第二素材の少なくとも外周寄り部分に軟化焼鈍を行なう場合もある。
【００２１】
又、請求項２に記載した発明の場合には上記中間ディスクを、次の(1) 〜(7) の工程を経て造る。
(1) 金属材料に鍛造若しくは削り出し加工を施して、前加工用素材を造る第一工程。
(2) 上記前加工用素材のうち、軸方向両側面部分に前加工を施して断面円弧状の凹面を形成し、完成後の中間ディスクよりも大きな形状を有する第一素材とする第二工程。
(3) 上記第一素材の外周寄り部分で上記ギヤを形成すべき部分の表面部分に防炭処理を施す第三工程。
(4) 防炭処理を施した上記第一素材に浸炭処理又は浸炭窒化処理を施し、表面部分を硬化して第二素材とする第四工程。
(5) 上記第二素材の外周縁部にギヤを形成して第三素材とする第五工程。
(6) 上記第三素材に浸炭クエンチ処理又は浸炭窒化クエンチ処理を施して第四素材とする第六工程。
(7) 上記第四素材の軸方向両側面と外周縁に形成したギヤ部分とを仕上げ加工して上記中間ディスクとする第七工程。
【００２２】
又、請求項３に記載した発明の場合には上記中間ディスクを、次の(1) 〜(5) の工程を経て造る。
(1) 金属材料に鍛造若しくは削り出し加工を施して、前加工用素材を造る第一工程。
(2) 上記前加工用素材のうち、軸方向両側面部分に断面円弧状の凹面を形成すると共に外周面に上記ギヤを形成する前加工を施して、完成後の中間ディスクよりも大きな形状を有する第一素材とする第二工程。
(3) 上記第一素材の外周寄り部分で上記ギヤを形成した部分の表面部分に半防炭処理を施す第三工程。
(4) 上記第一素材に浸炭クエンチ処理又は浸炭窒化クエンチ処理を施して第二素材とする第四工程。
(5) 上記第二素材の軸方向両側面と外周縁に形成したギヤ部分とを仕上げ加工して上記中間ディスクとする第五工程。
【００２４】
【作用】
上述の様な本発明の製造方法により造られる中間ディスクを組み込んだトロイダル型無段変速機の場合には、１個の中間ディスクにより、１対の外側ディスクとの間での回転力伝達を行なえる。従って、この中間ディスク設置部分の軸方向寸法を小さくして、この中間ディスクを挿通する状態で設けた、回転軸の軸方向長さを短くできる。又、上記ギヤを中間ディスクの外周縁部に直接形成しているので、これらギヤと中間ディスクとの結合強度を十分に大きくできる。従って、これらギヤと中間ディスクとの結合部の強度が、トロイダル型無段変速機で伝達可能な動力の大きさを制限する事はない。
又、上述の様に、回転軸の軸方向長さを短くできるので、この回転軸の両端部に支持した１対の外側ディスクの回転方向に亙る位相差を小さくして、トロイダル型無段変速機の伝達効率の向上を図れる。
更に、上記中間ディスクの軸方向両側面部分と、この中間ディスクの外周縁に形成するギヤ部分とでは、必要な硬化層の深さが異なるが、本発明の製造方法によれば、上記中間ディスクの各部の硬化層の深さを、それぞれの部分に関して最適値にできる。即ち、上記軸方向両側面部分はパワーローラの周面との接触楕円が大きい為、最大剪断応力を生じる深さが深くなって、必要とする硬化層の深さが深くなる。これに対してギヤ部分では、硬化層の深さが深過ぎると、歯元部分の強度（靱性）が低くなる。従って、上記ギヤの表面部分に形成する硬化層は、上記両側面部分に設ける硬化層よりも薄く（浅く）する事が好ましい。本発明の製造方法によれば、前述の様な工程で上記中間ディスクを製造する為、上記軸方向両側面部分とギヤ部分との耐久性を、何れも十分に確保できる。
【００２５】
【発明の実施の形態】
図１〜３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、１対の出力側ディスク４、４（図８参照）を、１個の中間ディスク３７にまとめると共に、この中間ディスク３７の外周面に、ギヤである出力歯車１８ｂを直接形成した点にある。その他の部分の構造及び作用は、前述の図８に示した様な、従来から考えられていたダブルキャビティ型のトロイダル型無段変速機の場合と同様である為、同等部分には同一符号を付して、重複する説明を省略若しくは簡略にし、以下、本例の特徴部分と図８に示した構造と異なる部分とを中心に説明する。尚、図１と図８とは、切断位置が、入力軸１５の円周方向に関して９０度異なっている。
【００２６】
回転軸である入力軸１５の両端部には、それぞれが外側ディスクである１対の入力側ディスク２Ａ、２Ｂを、それぞれボールスプライン３３、３３を介して支持している。図示の例の場合には、一方（図１の左方）の入力側ディスク２Ａの背面（図１の左面）をローディングナット３２に、大きな弾力を有する皿ばね３８を介して突き当てて、上記入力軸１５に対する軸方向（図１の左右方向）の変位を実質的に阻止している。この様に上記入力側ディスク２Ａとローディングナット３２との間に皿ばね３８を介在させたのは、トロイダル型無段変速機で伝達すべき回転力（トルク）が急に増大した際に、上記ローディングナット３２に加わる衝撃力を緩和する為である。又、上記入力軸１５の周囲には上記中間ディスク３７を、１対のニードル軸受１６、１６により、この入力軸１５に対する相対回転を自在に支持している。この中間ディスク３７の外周面には、上記出力歯車１８ｂを直接形成している。
【００２７】
上記中間ディスク３７の両側面で各パワーローラ８、８の周面８ａ、８ａ（図８）と当接する部分には、図２に斜格子で示す様に第一の硬化層４２、４２を、上記中間ディスク３７の外周面で上記出力歯車１８ｂを形成した部分には第二の硬化層４３を、それぞれ形成している。そして、これら第一、第二の硬化層４２、４３のうち、第一の硬化層４２の有効深さＨ₄₂を第二の硬化層４３の有効深さＨ₄₃よりも深く（Ｈ₄₂＞Ｈ₄₃）している。
【００２８】
上述の様に、外周面に出力歯車１８ｂを直接形成し、且つ、互いに深さの異なる第一、第二の硬化層４２、４３を形成した上記中間ディスク３７は、次の(1) 〜 (7) の工程を経て造る。
(1) 炭素鋼等の金属材料に鍛造若しくは削り出し加工を施して、前加工用素材を造る第一工程。
(2) この前加工用素材に前加工を施して、図３（Ａ）に示す様に、完成後の中間ディスク３７｛図１及び図３（Ｃ）参照｝よりも大きな形状を有する第一素材３９とする第二工程。即ち、この第二工程では、上記前加工用素材に鍛造等の前加工を施す事により、軸方向両側面に断面円弧状の凹面を形成する等して、図３（Ａ）に示す様な第一素材３９を造る。この第一素材３９は、上記中間ディスク３７に比べて全体的に厚肉に形成している。特に、この第一素材３９の外周部分は、上記中間ディスク３７の外周縁部に形成する出力歯車１８ｂ｛図１及び図３（Ｃ）参照｝よりも十分に厚肉の、厚肉部４０としている。
(3) 第二工程で造った第一素材３９に浸炭処理又は浸炭窒化処理を施し、表面部分を硬化して第二素材とする第三工程。即ち、この第三工程では、上記第一素材３９に浸炭処理又は浸炭窒化処理を施す事により、この第一素材３９の表面に、比較的深い浸炭層を形成して、表面が硬化した第二素材とする。この第二素材の形状は、図３（Ａ）に示した第一素材３９の形状と同じである。
(4) 上記第二素材のうち、上記出力歯車１８ｂを形成すべき外周寄り部分の表面部分に存在する浸炭層を除去して第三素材とする第四工程。尚、この第四工程を実施する際、必要に応じて上記第二素材のうち、上記出力歯車１８ｂを形成すべき外周寄り部分を軟化焼鈍する。この様に軟化焼鈍すれば、上記浸炭層の除去作業を容易に行なえる。この様に浸炭層を除去する第四工程は、続く第五工程で、この第三素材の外周寄り部分の肉を除去する為に行なう。この第四工程により、上記第三工程を経過する事により硬化した、上記厚肉部４０の表面層部分を除去し、次述する第五工程で、外周部分に上記出力歯車１８ｂを形成する作業を容易に行なえる様になる。
(5) 上記第三素材の外周縁部に上記出力歯車１８ｂを形成して第四素材４１とする第五工程。即ち、この第五工程では、上記第三素材の一部で上記厚肉部４０の軸方向両側部分を、旋削等の切削加工により除去して、この部分の肉厚を上記出力歯車１８ｂの肉厚と同じか、この出力歯車１８ｂの肉厚よりも僅かに大きな程度にする。又、上記第三素材の外周縁部分に、間欠的に切削加工を施す事により、上記出力歯車１８ｂを形成し、上記第四素材４１とする。
(6) 上記第四素材４１に浸炭クエンチ処理又は浸炭窒化クエンチ処理を施して第五素材とする第六工程。この第六工程では、上記第四工程で表面層部分を除去した為、表面に軟質の金属層が露出した、上記出力歯車１８ｂの表面部分に硬化層を形成して、この出力歯車１８ｂの表面部分を硬くする。尚、この第六工程で第五素材の表面に形成する浸炭層の深さ（厚さ）は、上記第三工程で第二素材の表面に形成する浸炭層の深さよりも小さくする。
(7) 上記第五素材の両側面と外周縁に形成した出力歯車１８ｂとを仕上げ加工して、上記中間ディスク３７とする第七工程。この第七工程では、上記第五素材の両側面と上記出力歯車１８ｂの表面部分とに、研削等の仕上げ加工を施して、これら各面を、所望形状を有する平滑面とする。
【００２９】
上述の様にして造る中間ディスク３７を組み込んだ、本例のトロイダル型無段変速機の場合には、１対の出力側ディスクとして機能する１個の中間ディスク３７により、１対の入力側ディスク２Ａ、２Ｂとの間での回転力伝達を行なえる。即ち、本例のトロイダル型無段変速機の運転時には、前記入力軸１５の回転が、１対の入力側ディスク２Ａ、２Ｂから１個の中間ディスク３７に、それぞれ複数個ずつのパワーローラ８、８（図８参照）を介して伝達される。そして、上記中間ディスク３７に伝達された回転動力は、この中間ディスク３７の外周縁部に設けた出力歯車１８ｂに伝わり、この出力歯車１８ｂが噛合した別の歯車（図示せず）を介して取り出される。
【００３０】
本発明の製造方法により造られる中間ディスク３７を組み込んだトロイダル型無段変速機の場合には、１個の中間ディスク３７が１対の出力側ディスクとしての役目を果たすので、中間ディスク３７設置部分の軸方向寸法を小さくして入力軸１５の軸方向長さを短くできる。又、上記出力歯車１８ｂを中間ディスク３７の外周縁部に直接形成しているので、これら出力歯車１８ｂと中間ディスク３７との結合強度を十分に大きくできる。従って、これら出力歯車１８ｂと中間ディスク３７との結合部の強度が、トロイダル型無段変速機で伝達可能な動力の大きさを制限する事はない。即ち、このトロイダル型無段変速機で伝達可能な動力の大きさは、上記パワーローラ８、８の数や大きさ等、出力歯車１８ｂと中間ディスク３７との結合部以外の他の要素で定まる。従って、この他の要素を工夫すれば、上記伝達可能な動力を大きくできる。
【００３１】
又、上記中間ディスク３７設置部分の軸方向寸法を小さくする事により、この中間ディスク３７の内側に挿通した入力軸１５の軸方向長さを短くできる。従って、トロイダル型無段変速機の運転時、上記入力軸１５に捩り方向の力が加わっても、この入力軸１５の両端部に支持した１対の入力側ディスク２Ａ、２Ｂの回転方向に亙る位相差を小さくして、トロイダル型無段変速機の伝達効率の向上を図れる。
【００３２】
更に、上記中間ディスク３７の軸方向両側面部分と、この中間ディスク３７の外周縁に形成する出力歯車１８ｂ部分とでは、必要な浸炭深さ等、必要とする硬化層の厚さが異なるが、本発明の製造方法によれば、上記中間ディスク３７の各部の浸炭深さを、それぞれの部分に関して最適値にできる。即ち、上記各パワーローラ８、８の周面８ａ、８ａ（図８参照）が強く押し付けられる、上記中間ディスク３７の軸方向両側面は、前述の様に接触楕円が大きく、十分な転がり疲れ寿命を確保する為、上記浸炭深さを大きくする必要がある。これに対して、上記出力歯車１８ｂは、他の歯車との噛合に基づく摩耗を抑えるべく、表面を硬くすると共に、十分な靱性を確保すべく、中心部には（浸炭されていない）生の層を残留させる必要がある。本発明の製造方法によれば、上記両側面部分に浸炭層を形成する際には、上記出力歯車１８ｂを形成する部分に厚肉部４０を設けているので、前記第三工程で、上記出力歯車１８ｂの中心部に対応する部分に生の層を残留させつつ、上記軸方向両側面部分に、十分に深い浸炭層を形成できる。又、上記出力歯車１８ｂの表面には、前記第五工程で、必要とする深さの浸炭層を形成できる。従って、上記両側面部分と出力歯車１８ｂ部分とのそれぞれに、最適な深さを有する浸炭層を形成して、これら各部分の耐久性を、何れも十分に確保できる。
【００３３】
尚、上述の様に、中間ディスク３７の両側面部分と、この中間ディスク３７の外周縁に形成する出力歯車１８ｂ部分とで、硬化層の深さを変える事は、前述の請求項１に記載した発明以外でも、請求項２、３に記載した発明によっても実現できる。そして、これら請求項２、３に記載した発明により得た中間ディスク３７によっても、上述したのと同様の作用・効果を得られる。
【００３４】
【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、小型で大きな回転力を伝達する事ができると共に、所望の変速比を正確に実現でき、しかも優れた耐久性を有するダブルキャビティ型のトロイダル型無段変速機を実現できる。
【図面の簡単な説明】
【図１】本発明の実施の形態の１例を、部分的に切断位置を変えて示す要部断面図。
【図２】中間ディスクの硬化層の深さを説明する為の半部断面図。
【図３】中間ディスクの製造方法を工程順に示す半部断面図。
【図４】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側面図。
【図５】同じく最大増速時の状態で示す側面図。
【図６】従来の具体的構造の第１例を示す断面図。
【図７】図６のＡ−Ａ断面図。
【図８】従来から考えられているダブルキャビティ型のトロイダル型無段変速機の１例を示す、図１のＢ−Ｂ断面に相当する要部断面図。
【符号の説明】
１入力軸
２、２Ａ、２Ｂ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入力軸
１６ニードル軸受
１７鍔部
１８、１８ａ、１８ｂ出力歯車
１９キー
２０支持板
２１支持軸部
２２枢支軸部
２３円孔
２４、２５ラジアルニードル軸受
２６スラスト玉軸受
２７外輪
２８スラストニードル軸受
２９駆動ロッド
３０駆動ピストン
３１駆動シリンダ
３２ローディングナット
３３ポールスプライン
３４皿ばね
３５スラストニードル軸受
３６スリーブ部
３７中間ディスク
３８皿ばね
３９第一素材
４０厚肉部
４１第四素材
４２第一の硬化層
４３第二の硬化層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intermediate disk constituting a double-cavity toroidal continuously variable transmission having two power transmission paths parallel to each other among toroidal continuously variable transmissions used as a transmission for an automobile, for example . The present invention relates to an improvement of a manufacturing method .
[0002]
[Prior art]
The use of a toroidal continuously variable transmission as schematically shown in FIGS. 4 to 5 has been studied as a transmission for automobiles. This toroidal continuously variable transmission, for example, as disclosed in Japanese Utility Model Laid-Open No. 62-71465, supports an input side disk 2 concentrically with an input shaft 1, and outputs arranged concentrically with the input shaft 1. An output side disk 4 is fixed to the end of the shaft 3. Inside the casing containing the toroidal-type continuously variable transmission, there is a trunnion that swings around pivots 5 and 5 that are twisted with respect to the input shaft 1 and the output shaft 3. 6 and 6 are provided.
[0003]
That is, these trunnions 6 and 6 are provided with the pivots 5 and 5 concentrically with each other on the outer surfaces of both ends. In addition, the base ends of the displacement shafts 7 and 7 are supported at intermediate portions of the trunnions 6 and 6, and the trunnions 6 and 6 are swung around the pivot shafts 5 and 5 so that the respective displacements are displaced. The inclination angle of the shafts 7 and 7 can be freely adjusted. Power rollers 8 and 8 are rotatably supported around the displacement shafts 7 and 7 supported by the trunnions 6 and 6, respectively. Each of these power rollers 8 and 8 is sandwiched between inner surfaces 2a and 4a of the input side and output side disks 2 and 4 facing each other. Each of the inner side surfaces 2a, 4a has a concave surface with a circular arc section obtained by rotating a cross section around the pivot shaft 5 around the input shaft 1 and the output shaft 3. And the peripheral surfaces 8a and 8a of each said power roller 8 and 8 formed in the spherical convex surface are made to contact | abut to the said inner surface 2a and 4a.
[0004]
A loading cam type pressing device 9 is provided between the input shaft 1 and the input side disc 2, and the pressing device 9 makes the input side disc 2 toward the output side disc 4 elastically pressable. Yes. The pressing device 9 includes a cam plate 10 that rotates together with the input shaft 1 and a plurality of (for example, four) rollers 12 and 12 that are rotatably held by a cage 11. A cam surface 13 that is an uneven surface extending in the circumferential direction is formed on one side surface (left side surface in FIGS. 4 to 5) of the cam plate 10, and the outer side surface (right side in FIGS. 4 to 5) of the input side disk 2 is formed. The same cam surface 14 is also formed on the surface). The plurality of rollers 12 and 12 are supported so as to be rotatable about the 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 cam surface 13 moves the rollers 12, 12 to the outside of the input side disk 2. The cam surface 14 formed on the side surface is pressed. As a result, the input side disk 2 is pressed by the plurality of power rollers 8 and 8 and at the same time, based on the pressing of the pair of cam surfaces 13 and 14 and the plurality of rollers 12 and 12, The input side disk 2 rotates. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 through the plurality of power rollers 8, 8, and the output shaft 3 fixed to the output side disk 4 rotates.
[0006]
When changing the rotational speed ratio (transmission ratio) between the input shaft 1 and the output shaft 3, and when first decelerating between the input shaft 1 and the output shaft 3, the pivots 5 and 5 are used as the centers. Each trunnion 6, 6 is swung in a predetermined direction. As shown in FIG. 4, the peripheral surfaces 8a and 8a of the power rollers 8 and 8 are formed on a portion near the center of the inner surface 2a of the input side disk 2 and a portion near the outer periphery of the inner surface 4a of the output side disk 4. The displacement shafts 7 and 7 are inclined so as to contact each other. On the contrary, when the speed is increased, the trunnions 6 and 6 are swung in the opposite directions around the pivots 5 and 5. As shown in FIG. 5, the peripheral surfaces 8a and 8a of the power rollers 8 and 8 are formed on the outer peripheral portion of the inner side surface 2a of the input side disc 2 and the central portion of the inner side surface 4a of the output side disc 4, respectively. The displacement shafts 7 and 7 are inclined so as to contact each other. If the inclination angle of each of the displacement shafts 7 and 7 is set intermediate between those shown in FIGS. 4 and 5, an intermediate gear ratio can be obtained between the input shaft 1 and the output shaft 3.
[0007]
6 to 7 show an example of a more specific toroidal type continuously variable transmission described in the microfilm of Japanese Utility Model Application No. 63-69293 (Japanese Utility Model Laid-Open No. 1-173352). The input side disk 2 and the output side disk 4 are rotatably supported around needle-shaped input shafts 15 via needle bearings 16 and 16, respectively. Further, the cam plate 10 is spline-engaged with the outer peripheral surface of the end portion (left end portion in FIG. 6) of the input shaft 15 and the movement of the cam plate 10 in the direction away from the input side disk 2 is prevented by the flange portion 17. The cam plate 10 and the rollers 12 and 12 constitute a pressing device 9. An output gear 18 that is an output member is coupled to the output side disk 4 by keys 19 and 19 so that the output side disk 4 and the output gear 18 rotate in synchronization.
[0008]
Both ends of the pair of trunnions 6 and 6 are supported on the pair of support plates 20 and 20 so as to be swingable and displaceable in the axial direction (front and back direction in FIG. 6, left and right direction in FIG. 7). The displacement shafts 7 and 7 are supported in the circular holes 23 and 23 formed in the intermediate portions of the trunnions 6 and 6. Each of these displacement shafts 7 and 7 has support shaft portions 21 and 21 and pivot shaft portions 22 and 22 that are parallel to each other and eccentric, respectively. Of these, the support shaft portions 21 and 21 are rotatably supported inside the circular holes 23 and 23 via radial needle bearings 24 and 24. Further, power rollers 8 and 8 are rotatably supported around the pivot shaft portions 22 and 22 via radial needle bearings 25 and 25, respectively.
[0009]
The pair of displacement shafts 7 and 7 are provided at positions opposite to the input shaft 15 by 180 degrees. Further, the directions in which the pivot shafts 22 and 22 of the displacement shafts 7 and 7 are eccentric with respect to the support shafts 21 and 21 are the same with respect to the rotational directions of the input side and output side disks 2 and 4. It is set as the direction (left-right reverse direction in FIG. 7). The eccentric direction is a direction substantially perpendicular to the direction in which the input shaft 15 is disposed. Accordingly, the power rollers 8 and 8 are supported so as to be slightly displaceable in the direction in which the input shaft 15 is disposed. As a result, due to the elastic deformation of the constituent members based on the large load applied to the constituent members in the state of transmission of the rotational force, the power rollers 8 and 8 are moved in the axial direction of the input shaft 15 (see FIG. 6). Even when it tends to be displaced in the left-right direction (the front-back direction in FIG. 7), this displacement can be absorbed without applying an excessive force to each component.
[0010]
In addition, between the outer surface of each of the power rollers 8 and 8 and the inner surface of the intermediate portion of each of the trunnions 6 and 6, thrust ball bearings 26 and 26, in order from the outer surface of the power rollers 8 and 8, Thrust needle bearings 28 and 28 for supporting a thrust load applied to the outer rings 27 and 27 constituting the thrust ball bearings 26 and 26 are provided. Of these, the thrust ball bearings 26, 26 allow the power rollers 8, 8 to rotate while supporting a load in the thrust direction applied to the power rollers 8, 8. The thrust needle bearings 28 and 28 support the thrust shafts 22 and 22 and the outer rings 27 and 27 while supporting a thrust load applied to the outer rings 27 and 27 from the power rollers 8 and 8. However, it is allowed to swing around the support shaft portions 21 and 21. Further, driving rods 29 and 29 are coupled to one end portions (left end portions in FIG. 7) of the trunnions 6 and 6, respectively, and the driving pistons 30 and 30 are fixed to the outer peripheral surfaces of the intermediate portions of the driving rods 29 and 29, respectively. Has been established. The drive pistons 30 and 30 are oil-tightly fitted in the drive cylinders 31 and 31, respectively.
[0011]
In the case of the toroidal type continuously variable transmission configured as described above, the rotation of the input shaft 15 is transmitted to the input side disk 2 via the pressing device 9. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 through a pair of power rollers 8, 8, and the rotation of the output side disk 4 is taken out from the output gear 18. When changing the rotational speed ratio between the input shaft 15 and the output gear 18, the pair of drive pistons 30, 30 are displaced in opposite directions. As the drive pistons 30 and 30 are displaced, the pair of trunnions 6 and 6 are displaced in the opposite directions. For example, the lower power roller 8 in FIG. The power rollers 8 are displaced to the left in the figure. As a result, the direction of the tangential force acting on the contact portion between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner side surfaces 2a, 4a of the input side disk 2 and the output side disk 4 changes. To do. The trunnions 6 and 6 swing in opposite directions around the pivots 5 and 5 pivotally supported by the support plates 20 and 20 in accordance with the change in the direction of the force. As a result, as shown in FIGS. 4 to 5 described above, the contact position between the peripheral surfaces 8a and 8a of the power rollers 8 and 8 and the inner surfaces 2a and 4a changes, and the input shaft 15 and The rotational speed ratio with the output gear 18 changes.
[0012]
When the rotational force is transmitted between the input shaft 15 and the output gear 18 in this way, the power rollers 8 and 8 are connected to the input shaft 15 based on the elastic deformation of the constituent members. The displacement shafts 7 and 7 which are displaced in the axial direction and pivotally support the power rollers 8 and 8 are slightly rotated around the support shaft portions 21 and 21. As a result of this rotation, the outer surfaces of the outer rings 27, 27 of the thrust ball bearings 26, 26 and the inner surfaces of the trunnions 6, 6 are relatively displaced. Since the thrust needle bearings 28, 28 exist between the outer surface and the inner surface, the force required for this relative displacement is small. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 7, 7 can be small.
[0013]
Further, in order to increase the torque that can be transmitted, as shown in FIG. 8, the input side disks 2A and 2B, which are outer disks, and the output, each of which is an intermediate disk, are arranged around the input shaft 15 which is a rotating shaft. So-called double cavity type toroidal type in which two side disks 4 and 4 are provided, and each of these two input side disks 2A and 2B and output side disks 4 and 4 are arranged in parallel with each other in the power transmission direction. A structure of a continuously variable transmission has also been conventionally considered. In the structure shown in FIG. 8, an output gear 18a is supported around the intermediate portion of the input shaft 15 so as to be freely rotatable with respect to the input shaft 15. The output side disks 4, 4 is in spline engagement. Needle bearings 16 and 16 are provided between the inner peripheral surface of each of the output side disks 4 and 4 and the outer peripheral surface of the input shaft 15, and the output side disks 4 and 4 are disposed around the input shaft 15. The rotation of the input shaft 15 and the displacement of the input shaft 15 in the axial direction are supported freely. Each of the input side disks 2A, 2B is rotatably supported at both ends of the input shaft 15 together with the input shaft 15.
[0014]
However, the input side disk 2A on the one side (left side in FIG. 8) abuts the back surface (left side in FIG. 8) against the loading nut 32 so that the displacement in the axial direction (left and right direction in FIG. 8) relative to the input shaft 15 is changed. Blocking. On the other hand, the input side disk 2B facing the cam plate 10 is supported by the ball spline 33 on the input shaft 15 so as to be displaceable in the axial direction. A disc spring 34 and a thrust needle bearing 35 are provided in series between the back surface (right surface in FIG. 8) of the input side disk 2B and the front surface (left surface in FIG. 8) of the cam plate 10. Of these, the disc spring 34 is a preload device for applying preload to the contact portion between the inner surfaces 2a, 4a of the disks 2A, 2B, 4 and the peripheral surfaces 8a, 8a of the power rollers 8, 8. To fulfill the role of
[0015]
During operation of the double cavity type toroidal continuously variable transmission configured as described above, the rotation of the input shaft 15 is transferred from the pair of input side disks 2A, 2B to the pair of output side disks 4, 4 respectively. The power is transmitted through a plurality of power rollers 8 and 8 (two in the example shown in the figure, a total of four in some cases, but there may be a total of six in three). The rotational power transmitted to the pair of output side disks 4 and 4 is transmitted to one output gear 18a, and is taken out via another gear (not shown) with which the output gear 18a is engaged. As described above, since the transmission of the rotational force from the input shaft 15 to the output gear 18a is performed in two systems arranged in parallel with each other, a large rotational force (torque) can be transmitted. In order to change the gear ratio between the input shaft 15 and the output gear 18a, the displacement shafts 7, 7 supporting the power rollers 8, 8 are inclined so that the displacement shafts 7, 7 are supported. The trunnions 6 and 6 that are supported are translated. The structure for translating the trunnions 6 and 6 in this way is the same as that of the single cavity type toroidal continuously variable transmission shown in FIGS. However, in the case of a double cavity type toroidal continuously variable transmission, the pressure oil to each drive cylinder 31, 31 (see FIG. 7) in order to synchronize the movement amount and the movement direction of each trunnion 6, 6 with each other. The supply / discharge state is switched.
[0016]
[Problems to be solved by the invention]
In the case of the conventional double-cavity toroidal-type continuously variable transmission shown in FIG. 8, a pair of output-side disks 4 and 4 and an output gear 18a, each of which is an intermediate disk, are separated, and this output gear. The pair of output side disks 4 and 4 are spline-engaged with both ends of a sleeve portion 36 provided at the center of 18a. For this reason, the number of component parts increases, and not only parts production, parts management, and assembly work become troublesome, but also the axial dimensions of the installed portions of the pair of output disks 4 and 4 and the output gear 18a. It is inevitable that the volume increases.
[0017]
Thus, when the axial dimension of the installation portion increases, the axial length of the input shaft 15 increases correspondingly, and the pair of input side disks 2A, 2B supported at both ends of the input shaft 15 are equivalent to each other. The interval of becomes larger. Thus, when the distance between the pair of input side disks 2A, 2B increases, the amount of torsional deformation of the input shaft 15 between the input side disks 2A, 2B increases during rotation transmission. The phase difference regarding the rotation direction between the input side disks 2A and 2B becomes large. As a result, the rotation transmission between the input disk 2A and the output disk 4 on one cavity side and the rotation transmission between the input disk 2B and the output disk 4 on the other cavity side. As a result, it becomes difficult to control the rotational force transmission, and it is difficult to ensure the efficiency of the double cavity type toroidal continuously variable transmission.
[0018]
U.S. Pat. No. 2140012 discloses a structure in which both side surfaces in the axial direction of one output side disk corresponding to the intermediate disk are concave surfaces each having an arc cross section, and the circumferential surface of the power roller is brought into contact with both concave surfaces. Is described. However, in the case of the structure described in this U.S. Patent Specification, the rotation of the output side disk is performed by fixing one end opening of the output side disk and enclosing one input side disk inside. It is made to take out with the bottom cylindrical drum. For this reason, it becomes very difficult to support the power roller provided between the one input side disk and the intermediate disk, and the structure becomes very complicated, and the support structure for the power roller is arranged inside the drum. Need to be placed. For this reason, the power roller part including this support structure must be reduced in size. In addition, since the power that can be transmitted by the drum is limited, it is not always possible to sufficiently increase the rotational force that can be transmitted in combination with the necessity of downsizing the power roller portion.
The method for producing an intermediate disk for a toroidal-type continuously variable transmission according to the present invention was invented to eliminate any of the above-mentioned disadvantages.
[0019]
[Means for Solving the Problems]
A toroidal-type continuously variable transmission incorporating an intermediate disk that is the object of the manufacturing method of the present invention has a rotary shaft and inner surfaces that are concave surfaces each having an arcuate cross section facing each other at both ends of the rotary shaft. A pair of outer disks that freely supports rotation in synchronization with the rotating shaft, and both axial side surfaces are concave surfaces having a circular arc cross section, and are supported around the rotating shaft so as to freely rotate relative to the rotating shaft. An intermediate disk, a gear concentrically formed with the rotating shaft, formed directly on the outer peripheral surface of the intermediate disk, and an intermediate portion of the outer disk and the intermediate disk with respect to the axial direction of the rotating shaft, A plurality of oscillating members that oscillate about a pivot that is perpendicular to the axial direction and twisted with respect to the rotational axis, and a plurality of displacement shafts that protrude from the inner surface of each oscillating member; Each of the above A plurality of power rollers sandwiched between the inner surface of each outer disk and both side surfaces of the intermediate disk in a state where the inner surface of the moving member is rotatably supported around each displacement shaft. Prepare.
Then, a first hardened layer is formed on a part of the both sides of the intermediate disk that contacts the peripheral surface of each of the power rollers, and a second hardened layer is formed on a part of the outer peripheral surface of the intermediate disk where the gear is formed. While forming, the effective depth of said 1st hardened layer is made deeper than the effective depth of said 2nd hardened layer.
[0020]
Therefore, in the manufacturing method of the present invention, the intermediate disk as described above is manufactured through the processes as described in claims 1 to 3.
Among these, in the case of the invention described in claim 1, the intermediate disk is manufactured through the following steps (1) to (7).
(1) The first step of making a pre-processing material by forging or machining a metal material.
(2) Of the above-mentioned pre-processing materials, the second step is to form a first material having a shape larger than that of the completed intermediate disk by pre-processing the axially opposite side surface portions to form a concave surface having a circular arc cross section. .
(3) A third step in which carburizing or carbonitriding is performed on the first material, and the surface portion is cured to form a second material.
(4) A fourth step of removing the carburized layer present on the surface portion near the outer periphery where the gear is to be formed from the second material to form a third material.
(5) A fifth step in which a gear is formed on the outer peripheral edge of the third material to form a fourth material.
(6) A sixth step in which the fourth material is subjected to a carburization quenching process or a carbonitriding quenching process to obtain a fifth material.
(7) A seventh step of finishing the axially opposite side surfaces of the fifth material and the gear portions formed on the outer peripheral edge to form the intermediate disk.
In some cases, at least a portion near the outer periphery of the second material is softened and annealed between the third step (3) and the fourth step (4).
[0021]
In the case of the invention described in claim 2 , the intermediate disk is manufactured through the following steps (1) to (7).
(1) The first step of making a pre-processing material by forging or machining a metal material.
(2) Of the above-mentioned pre-processing materials, the second step is to form a first material having a shape larger than that of the completed intermediate disk by pre-processing the axially opposite side surface portions to form a concave surface having a circular arc cross section. .
(3) A third step of applying a carbon-proof treatment to the surface portion of the portion where the gear is to be formed near the outer periphery of the first material.
(4) A fourth step in which the carburizing treatment or carbonitriding treatment is performed on the first material subjected to the carbon-proofing treatment, and the surface portion is cured to form the second material.
(5) A fifth step in which a gear is formed on the outer peripheral edge of the second material to form a third material.
(6) A sixth step in which the third material is subjected to a carburization quench process or a carbonitriding quench process to obtain a fourth material.
(7) A seventh step in which the intermediate disk is formed by finishing the axially opposite side surfaces of the fourth material and the gear portions formed on the outer peripheral edge.
[0022]
In the case of the invention described in claim 3 , the intermediate disk is manufactured through the following steps (1) to (5).
(1) The first step of making a pre-processing material by forging or machining a metal material.
(2) Of the above-mentioned pre-processing materials, a pre-processing for forming a concave surface having an arc-shaped cross section on both side portions in the axial direction and forming the gears on the outer peripheral surface is performed, so that the shape is larger than the completed intermediate disk. A second step with a first material.
(3) A third step of subjecting the surface portion of the portion where the gear is formed near the outer periphery of the first material to a semi-carbon-proofing treatment.
(4) A fourth step in which the first material is subjected to a carburization quench process or a carbonitriding quench process to obtain a second material.
(5) A fifth step in which the intermediate disk is finished by finishing the axially opposite side surfaces of the second material and the gear portions formed on the outer periphery.
[0024]
[Action]
In the case of a toroidal-type continuously variable transmission incorporating an intermediate disk manufactured by the manufacturing method of the present invention as described above, a rotational force can be transmitted between a pair of outer disks by one intermediate disk. The Accordingly, it is possible to reduce the axial dimension of the rotary shaft provided in a state in which the intermediate disk is inserted by reducing the axial dimension of the intermediate disk installation portion. Further, since the gear is formed directly on the outer peripheral edge of the intermediate disk, the coupling strength between the gear and the intermediate disk can be sufficiently increased. Therefore, the strength of the coupling portion between these gears and the intermediate disk does not limit the magnitude of power that can be transmitted by the toroidal type continuously variable transmission.
Further, as described above, since the axial length of the rotating shaft can be shortened, the phase difference over the rotating direction of the pair of outer disks supported at both ends of the rotating shaft is reduced, and the toroidal type continuously variable transmission is performed. The transmission efficiency of the machine can be improved.
Furthermore, although the required depth of the hardened layer differs between the axially opposite side surface portions of the intermediate disc and the gear portion formed on the outer peripheral edge of the intermediate disc , according to the manufacturing method of the present invention, the intermediate disc The depth of the hardened layer in each part can be optimized for each part. That is, since the contact ellipse with the peripheral surface of the power roller is large on both side portions in the axial direction, the depth at which the maximum shear stress is generated becomes deep, and the required depth of the hardened layer becomes deep. On the other hand, in the gear part, if the depth of the hardened layer is too deep, the strength (toughness) of the tooth base part is lowered. Accordingly, the hardened layer formed on the surface portion of the gear is preferably thinner (shallow) than the hardened layer provided on the both side surface portions. According to the manufacturing method of the present invention, since the intermediate disk is manufactured through the above-described steps, it is possible to sufficiently ensure the durability between the axial side surfaces and the gear portion.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an example of an embodiment of the present invention. The feature of this example is that a pair of output side disks 4 and 4 (see FIG. 8) are combined into one intermediate disk 37, and an output gear 18b as a gear is provided on the outer peripheral surface of the intermediate disk 37. It is in the point formed directly. Since the structure and operation of the other parts are the same as those of the conventional double cavity type toroidal continuously variable transmission as shown in FIG. 8, the same reference numerals are used for the equivalent parts. In addition, overlapping description will be omitted or simplified, and the following description will focus on the characteristic part of the present example and parts different from the structure shown in FIG. 1 and FIG. 8 are different from each other in the cutting position by 90 degrees with respect to the circumferential direction of the input shaft 15.
[0026]
A pair of input side disks 2A and 2B, each of which is an outer disk, are supported at both ends of the input shaft 15 which is a rotating shaft via ball splines 33 and 33, respectively. In the case of the illustrated example, the back surface (left surface in FIG. 1) of one (left side in FIG. 1) of the input side disk 2A is abutted against the loading nut 32 via a disc spring 38 having a large elasticity, and A displacement in the axial direction (left-right direction in FIG. 1) with respect to the input shaft 15 is substantially prevented. The disc spring 38 is interposed between the input side disk 2A and the loading nut 32 in this manner when the rotational force (torque) to be transmitted by the toroidal continuously variable transmission suddenly increases. This is to alleviate the impact force applied to the loading nut 32. The intermediate disk 37 is supported around the input shaft 15 by a pair of needle bearings 16 and 16 so as to freely rotate relative to the input shaft 15. The output gear 18 b is directly formed on the outer peripheral surface of the intermediate disk 37.
[0027]
As shown by the diagonal grid in FIG. 2, the first hardened layers 42 and 42 are formed on the portions of the both sides of the intermediate disk 37 that are in contact with the peripheral surfaces 8a and 8a (FIG. 8) of the power rollers 8 and 8, respectively. A second hardened layer 43 is formed on the outer peripheral surface of the intermediate disk 37 where the output gear 18b is formed. Then, these first, of the second hardened layers 42 and 43, the effective depth H ₄₂ of the first cured layer 42 deeper than the effective depth H ₄₃ of the second hardened layer 43 (H _42> H ₄₃ ).
[0028]
As described above, the intermediate disk 37 in which the output gear 18b is directly formed on the outer peripheral surface and the first and second hardened layers 42 and 43 having different depths are formed has the following (1) to ( It is manufactured through the process of 7) .
(1) The first step of making a pre-processing material by forging or machining a metal material such as carbon steel.
(2) Pre-processing this pre-processed material, and as shown in FIG. 3 (A), the first intermediate disk 37 having a larger shape than the completed intermediate disk 37 {see FIG. 1 and FIG. 3 (C)} The second step of making the material 39. That is, in this second step, by performing pre-processing such as forging on the pre-processing material, concave surfaces having a circular arc shape in cross section are formed on both side surfaces in the axial direction, as shown in FIG. The first material 39 is made. The first material 39 is generally thicker than the intermediate disk 37. In particular, the outer peripheral portion of the first material 39 is a thick portion 40 that is sufficiently thicker than the output gear 18b {see FIGS. 1 and 3C) formed on the outer peripheral edge of the intermediate disk 37. Yes.
(3) A third step in which carburizing or carbonitriding is performed on the first material 39 produced in the second step, and the surface portion is cured to form the second material. That is, in this third step, the first material 39 is subjected to carburizing treatment or carbonitriding to form a relatively deep carburized layer on the surface of the first material 39, and the surface is hardened. The material. The shape of the second material is the same as the shape of the first material 39 shown in FIG.
(4) The 4th process which removes the carburized layer which exists in the surface part of the outer periphery part which should form the said output gearwheel 18b among said 2nd materials, and makes it a 3rd material. In addition, when implementing this 4th process, the part near the outer periphery which should form the said output gearwheel 18b among said 2nd materials is softened and annealed as needed. If soft annealing is performed in this way, the removal work of the carburized layer can be easily performed. The fourth step of removing the carburized layer in this way is performed in the following fifth step in order to remove the meat near the outer periphery of the third material. In the fourth step, the surface layer portion of the thick portion 40 that has been cured by passing through the third step is removed, and the output gear 18b is formed on the outer peripheral portion in the fifth step described below. Can be performed easily.
(5) A fifth process in which the output gear 18b is formed on the outer peripheral edge of the third material to form the fourth material 41. That is, in this fifth step, the axially opposite side portions of the thick portion 40 are removed by cutting such as turning in a part of the third material, and the thickness of this portion is reduced by the thickness of the output gear 18b. The thickness is the same as or slightly larger than the thickness of the output gear 18b. Further, the output gear 18b is formed by intermittently cutting the outer peripheral edge portion of the third material to form the fourth material 41.
(6) A sixth step in which the fourth material 41 is subjected to a carburization quenching process or a carbonitriding quenching process to obtain a fifth material. In the sixth step, since the surface layer portion is removed in the fourth step, a soft metal layer is exposed on the surface, a hardened layer is formed on the surface portion of the output gear 18b, and the surface of the output gear 18b Harden the part. Note that the depth (thickness) of the carburized layer formed on the surface of the fifth material in the sixth step is made smaller than the depth of the carburized layer formed on the surface of the second material in the third step.
(7) A seventh step of finishing the output gear 18b formed on both side surfaces and the outer peripheral edge of the fifth material to form the intermediate disk 37. In the seventh step, finish processing such as grinding is performed on both side surfaces of the fifth material and the surface portion of the output gear 18b, so that each surface becomes a smooth surface having a desired shape.
[0029]
In the case of the toroidal-type continuously variable transmission of this example incorporating the intermediate disk 37 manufactured as described above, a pair of input-side disks is provided by a single intermediate disk 37 that functions as a pair of output-side disks. The rotational force can be transmitted between 2A and 2B. That is, during operation of the toroidal-type continuously variable transmission of the present example , the rotation of the input shaft 15 is transferred from the pair of input side disks 2A, 2B to one intermediate disk 37, and a plurality of power rollers 8, 8 (see FIG. 8). The rotational power transmitted to the intermediate disk 37 is transmitted to an output gear 18b provided on the outer peripheral edge of the intermediate disk 37, and is taken out via another gear (not shown) engaged with the output gear 18b. It is.
[0030]
In the case of a toroidal-type continuously variable transmission incorporating an intermediate disk 37 manufactured by the manufacturing method of the present invention, one intermediate disk 37 serves as a pair of output side disks. Thus, the axial length of the input shaft 15 can be shortened. Further, since the output gear 18b is formed directly on the outer peripheral edge of the intermediate disk 37, the coupling strength between the output gear 18b and the intermediate disk 37 can be sufficiently increased. Therefore, the strength of the coupling portion between the output gear 18b and the intermediate disk 37 does not limit the magnitude of power that can be transmitted by the toroidal-type continuously variable transmission. In other words, the magnitude of the power that can be transmitted by the toroidal type continuously variable transmission is determined by factors other than the coupling portion between the output gear 18b and the intermediate disk 37, such as the number and size of the power rollers 8 and 8. . Therefore, if other elements are devised, the power that can be transmitted can be increased.
[0031]
Further, by reducing the axial dimension of the intermediate disk 37 installation portion, the axial length of the input shaft 15 inserted inside the intermediate disk 37 can be shortened. Therefore, even when a torsional force is applied to the input shaft 15 during operation of the toroidal-type continuously variable transmission, the pair of input-side disks 2A and 2B supported at both ends of the input shaft 15 are rotated. By reducing the phase difference, the transmission efficiency of the toroidal-type continuously variable transmission can be improved.
[0032]
Furthermore, the thickness of the hardened layer required, such as the required carburizing depth, differs between the axially opposite side surface portions of the intermediate disc 37 and the output gear 18b portion formed on the outer peripheral edge of the intermediate disc 37. According to the manufacturing method of the present invention, the carburization depth of each part of the intermediate disk 37 can be set to an optimum value for each part. That is, the circumferential surfaces 8a and 8a (see FIG. 8) of the power rollers 8 and 8 are strongly pressed, and the axially opposite side surfaces of the intermediate disk 37 have a large contact ellipse as described above, and a sufficient rolling fatigue life. Therefore, it is necessary to increase the carburization depth. On the other hand, the output gear 18b has a hard surface (not carburized) in the center so as to harden the surface and to secure sufficient toughness in order to suppress wear due to meshing with other gears. It is necessary to leave a layer. According to the manufacturing method of the present invention, when the carburized layer is formed on the both side surface portions, the thick portion 40 is provided in the portion where the output gear 18b is formed. A sufficiently deep carburized layer can be formed on both side portions in the axial direction while a raw layer remains in a portion corresponding to the central portion of the gear 18b. Further, a carburized layer having a required depth can be formed on the surface of the output gear 18b in the fifth step. Therefore, a carburized layer having an optimum depth is formed on each of the both side surface portions and the output gear 18b portion, and the durability of each of these portions can be sufficiently ensured.
[0033]
Note that, as described above, changing the depth of the hardened layer between the both side surface portions of the intermediate disk 37 and the output gear 18b portion formed on the outer peripheral edge of the intermediate disk 37 is described in claim 1 above. In addition to the inventions described above, the inventions described in claims 2 and 3 can also be realized. The same operation and effect as described above can be obtained by the intermediate disk 37 obtained by the invention described in claims 2 and 3 .
[0034]
【The invention's effect】
Since the present invention is constructed and operates as described above, it can transmit a large rotational force with a small size, can accurately realize a desired gear ratio, and has excellent durability. A type continuously variable transmission can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing an example of an embodiment of the present invention by partially changing a cutting position.
FIG. 2 is a half sectional view for explaining the depth of a hardened layer of an intermediate disc.
FIG. 3 is a half sectional view showing a method of manufacturing an intermediate disk in the order of steps.
FIG. 4 is a side view showing a basic configuration of a conventionally known toroidal type continuously variable transmission in a state of maximum deceleration.
FIG. 5 is a side view showing the state of the maximum speed increase.
FIG. 6 is a cross-sectional view showing a first example of a conventional concrete structure.
7 is a cross-sectional view taken along line AA in FIG.
8 is a cross-sectional view of an essential part corresponding to the BB cross section of FIG. 1, showing an example of a double cavity type toroidal continuously variable transmission that has been conventionally considered.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Input shaft 2, 2A, 2B Input side disk 2a Inner side surface 3 Output shaft 4 Output side disk 4a Inner side surface 5 Pivot 6 Trunnion 7 Displacement shaft 8 Power roller 8a Circumferential surface 9 Pressing device 10 Cam plate 11 Cage 12 Roller 13, 14 Cam surface 15 Input shaft 16 Needle bearing 17 Gutter portion 18, 18a, 18b Output gear 19 Key 20 Support plate 21 Support shaft portion 22 Pivot shaft portion 23 Circular hole 24, 25 Radial needle bearing 26 Thrust ball bearing 27 Outer ring 28 Thrust Needle bearing 29 Drive rod 30 Drive piston 31 Drive cylinder 32 Loading nut 33 Pole spline 34 Belleville spring 35 Thrust needle bearing 36 Sleeve portion 37 Intermediate disc 38 Belleville spring 39 First material 40 Thick portion 41 Fourth material 42 First curing Layer 43 second hardened layer

Claims

A pair of outer disks that freely support rotation synchronized with the rotation shaft at both ends of the rotation shaft in a state where the inner surfaces, each of which is a concave surface having an arcuate cross section, are opposed to each other; Concentric with the rotating shaft, which is formed directly on the outer peripheral surface of the intermediate disk, and an intermediate disk which is supported on the periphery of the rotating shaft so as to be freely rotatable relative to the rotating shaft. It is located in the middle part of the outer disk and the intermediate disk with respect to the axial direction of the gear and the rotating shaft, and is centered on a pivot that is perpendicular to the axial direction of the rotating shaft and twisted with respect to the rotating shaft. A plurality of oscillating members oscillating as follows, a plurality of displacement shafts projecting from the inner surface of each of the oscillating members, and an inner surface of each of the oscillating members are rotatably supported around each displacement shaft. Each outside The intermediate disk constituting the toroidal type continuously variable transmission that includes a plurality of power rollers interposed between the inner surface and both side surfaces of the intermediate disk disk, the following (1) to (7) building through the steps, the production method of the toroidal type continuously variable transmission for intermediate disc.
(1) The first step of making a pre-processing material by forging or machining a metal material.
(2) Of the above-mentioned pre-processing materials, the second step is to form a first material having a shape larger than that of the completed intermediate disk by pre-processing the axially opposite side surface portions to form a concave surface having a circular arc cross section. .
(3) A third step in which carburizing or carbonitriding is performed on the first material, and the surface portion is cured to form a second material.
(4) A fourth step of removing the carburized layer present on the surface portion near the outer periphery where the gear is to be formed from the second material to form a third material.
(5) A fifth step in which a gear is formed on the outer peripheral edge of the third material to form a fourth material.
(6) A sixth step in which the fourth material is subjected to a carburization quenching process or a carbonitriding quenching process to obtain a fifth material.
(7) A seventh step of finishing the axially opposite side surfaces of the fifth material and the gear portions formed on the outer peripheral edge to form the intermediate disk.

A pair of outer disks that freely support rotation synchronized with the rotation shaft at both ends of the rotation shaft in a state where the inner surfaces, each of which is a concave surface having an arcuate cross section, are opposed to each other; Concentric with the rotating shaft, which is formed directly on the outer peripheral surface of the intermediate disk, and an intermediate disk which is supported on the periphery of the rotating shaft so as to be freely rotatable relative to the rotating shaft. It is located in the middle part of the outer disk and the intermediate disk with respect to the axial direction of the gear and the rotating shaft, and is centered on a pivot that is perpendicular to the axial direction of the rotating shaft and twisted with respect to the rotating shaft. A plurality of oscillating members oscillating as follows, a plurality of displacement shafts projecting from the inner surface of each of the oscillating members, and an inner surface of each of the oscillating members are rotatably supported around each displacement shaft. Each outside The intermediate disk constituting the toroidal type continuously variable transmission that includes a plurality of power rollers interposed between the inner surface and both side surfaces of the intermediate disk disk, the following (1) to (7) building through the steps, the production method of the toroidal type continuously variable transmission for intermediate disc.
(1) The first step of making a pre-processing material by forging or machining a metal material.
(2) Of the above-mentioned pre-processing materials, the second step is to form a first material having a shape larger than that of the completed intermediate disk by pre-processing the axially opposite side surface portions to form a concave surface having a circular arc cross section. .
(3) A third step of applying a carbon-proof treatment to the surface portion of the portion where the gear is to be formed near the outer periphery of the first material.
(4) A fourth step in which the carburizing treatment or carbonitriding treatment is performed on the first material subjected to the carbon-proofing treatment, and the surface portion is cured to form the second material.
(5) A fifth step in which a gear is formed on the outer peripheral edge of the second material to form a third material.
(6) A sixth step in which the third material is subjected to a carburization quench process or a carbonitriding quench process to obtain a fourth material.
(7) A seventh step in which the intermediate disk is formed by finishing the axially opposite side surfaces of the fourth material and the gear portions formed on the outer peripheral edge.

A pair of outer disks that freely support rotation synchronized with the rotation shaft at both ends of the rotation shaft in a state where the inner surfaces, each of which is a concave surface having an arcuate cross section, are opposed to each other; Concentric with the rotating shaft, which is formed directly on the outer peripheral surface of the intermediate disk, and an intermediate disk which is supported on the periphery of the rotating shaft so as to be freely rotatable relative to the rotating shaft. It is located in the middle part of the outer disk and the intermediate disk with respect to the axial direction of the gear and the rotating shaft, and is centered on a pivot that is perpendicular to the axial direction of the rotating shaft and twisted with respect to the rotating shaft. A plurality of oscillating members oscillating as follows, a plurality of displacement shafts projecting from the inner surface of each of the oscillating members, and an inner surface of each of the oscillating members are rotatably supported around each displacement shaft. Each outside The intermediate disk constituting the toroidal type continuously variable transmission that includes a plurality of power rollers interposed between the inner surface and both side surfaces of the intermediate disk disk, the following (1) to (5) building through the steps, the production method of the toroidal type continuously variable transmission for intermediate disc.
(1) The first step of making a pre-processing material by forging or machining a metal material.
(2) Of the above-mentioned pre-processing materials, a pre-processing for forming a concave surface having an arc-shaped cross section on both side portions in the axial direction and forming the gears on the outer peripheral surface is performed, so that the shape is larger than the completed intermediate disk. A second step with a first material.
(3) A third step of subjecting the surface portion of the portion where the gear is formed near the outer periphery of the first material to a semi-carbon-proofing treatment.
(4) A fourth step in which the first material is subjected to a carburization quench process or a carbonitriding quench process to obtain a second material.
(5) A fifth step in which the intermediate disk is finished by finishing the axially opposite side surfaces of the second material and the gear portions formed on the outer periphery.