JP2004156686A

JP2004156686A - Belt nip diameter/nip pressure serial control type continuously variable transmission

Info

Publication number: JP2004156686A
Application number: JP2002322132A
Authority: JP
Inventors: Kunihiro Iwatsuki; 邦裕岩月; Yasunori Nakawaki; 康則中脇; Masami Sugaya; 正美菅谷
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2002-11-06
Filing date: 2002-11-06
Publication date: 2004-06-03
Anticipated expiration: 2022-11-06
Also published as: JP4158491B2

Abstract

<P>PROBLEM TO BE SOLVED: To improve a continuously variable transmission in which an endless belt is laid between pulley pairs so as to appropriately maintain nip pressure of the pulley pair to the endless belt even during transmission ratio change. <P>SOLUTION: In endless belt laying type continuously variable transmission between pulling pairs a belt nip diameter adjusting means for reciprocally varying the belt nip diameters of a driving pulley pair and driven pulley pair adjusts the belt nip diameter through the medium of a belt nip pressure generation means for acting belt nip pressure which is increased by the pulley pair according to increase of transmission torque to the endless belt. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、無段変速装置、特にＶ型ベルト挟み溝のベルト挟み径を可変に調節できる駆動プーリ対と、同ベルト挟み径を可変に調節できる被動プーリ対と、かかる駆動プーリ対と被動プーリ対との間に掛け渡された無端ベルトとを有し、これら駆動プーリ対と被動プーリ対のベルト挟み径を相反的に変更させることにより両ベルト対間に伝達される回転力の変速比が無段に変更されるようになった無段変速装置に係る。
【０００２】
【従来の技術】
この種の無段変速装置に於いては、駆動プーリ対と被駆動プーリ対の間に伝達される回転力の変速比を設定すべく駆動プーリ対のベルト挟み径と被動プーリ対のベルト挟み径とを相反的に変更させるベルト挟み径調節手段が必要であると共に、無端ベルトと駆動プーリ対および被動プーリ対の間に両者の摩擦係合により回転力が伝達されるよう、駆動および被動の各プーリ対に於いて無端ベルトをプーリ対間に押し挟む挟み圧を作用させるベルト挟み圧生成手段が必要である。
【０００３】
上記の挟み径調節手段としては、ねじによる送り手段と歯車による連動手段とを組み合わせた機械式の装置、シリンダ／ピストンによる送り手段と油圧経路による連動手段とを組み合わせた油圧式の装置等が、下記の特許文献にも記載されている如く知られている。
【０００４】
上記のベルト挟み圧生成手段としては、駆動プーリ対または被動プーリ対の少なくとも一方に於いて、軸線方向可動プーリを軸線方向不動プーリへ向けて軸線方向に付勢するばねや、プーリ対に作用するトルクによって相対的に回転偏倚される二つの部材の間に環状カムを設け、両部材間に生ずる回転偏倚を両部材間の軸線方向偏倚に変換する偏倚変換手段が知られている。
【０００５】
例えば、下記の特許文献１には、この種の無段変速装置に於いて、前記ベルト挟み径調節手段が、駆動プーリ対および被動プーリ対の各々に於いて、軸線方向不動プーリとその軸の回りにスプラインにより回転方向には相対回転不能にまた軸線方向には相対移動可能に装着された軸線方向可動プーリの間に作用するねじ式送り装置として構成され、前記ベルト挟み圧生成手段は、プーリ対に作用するトルクによって相対的に回転偏倚される二つの部材の間にカムを設け、両部材間に生ずる回転偏倚を両部材間の軸線方向偏倚に変換する偏倚変換手段として構成されることが記載されており、また下記の特許文献２には、前記ベルト挟み径調節手段が、シリンダ／ピストンによる送り手段と油圧経路による連動手段とを組み合わせた油圧式の装置として構成され、且つそれが特に被動プーリ対の側に設けられることを特徴とし、前記無端ベルトをプーリ対間に押し挟む挟み圧を作用させるベルト挟み圧生成手段は、ばね要素として構成され、且つそれが特に駆動プーリ対の側に設けられることを特徴とすることが記載されている。
【特許文献１】
特開平６−５８３８５号公報
【特許文献２】
特開平１１−２２７９８号公報
【０００６】
【発明が解決しようとする課題】
上記特許文献１および２の装置を含む従来のこの種の無段変速装置に於いては、前記ベルト挟み径調節手段と前記ベルト挟み圧生成手段とは、それぞれが個別にプーリ対に対して並列に作用するようになっている。即ち、ベルト挟み径調節手段は、変速制御装置からの変速指令に応じて独自に作動してプーリ対間の隔置距離を所定の値に設定する作動を行い、一方、ベルト挟み圧生成手段は、油圧による場合等ではベルト挟み圧制御装置からのベルト挟み圧制御指令に応じてベルト挟み圧を目標制御し、またカム等によりベルト挟み圧を生成する場合には、ベルト挟み圧の不足により無端ベルトとプーリの間に生ずる相対滑りを利用してカムを作動させ、軸線方向可動プーリまたは軸線方向不動プーリを他方へ向けて押圧することが、それぞれ個別に行われるようになっている。
【０００７】
しかし、ベルト挟み径調節手段とベルト挟み圧生成手段の作動とが個別に行われるようになっていると、ベルト挟み径調節手段によりベルト挟み径が変更されるとき、ベルト挟み径調節手段によりベルト挟み径が実際に変化し、その結果、無端ベルトに対するプーリ対の有効挟み幅が変化し、その結果、ベルト挟み圧生成手段に作用する無端ベルトの反作用が変化して、初めてベルト挟み圧生成手段は、ベルト挟み径調節手段の作動に追従するようその作動を変化させるので、ベルト挟み径調節の変化に対するベルト挟み圧の変化に追従遅れが生じ、変速比の変更中にベルト挟み圧が適正値に維持されない状態が生ずることがあるという問題がある。
【０００８】
本発明は、上記の問題に鑑み、上記の型の無段変速装置に於いて、変速比の変更中にも無端ベルトに対する挟み圧が適正に維持されるよう、これを改良することを課題としている。
【０００９】
【課題を解決するための手段】
上記の課題を解決するものとして、本発明は、Ｖ型ベルト挟み溝のベルト挟み径を可変に調節できる駆動プーリ対と、前記ベルト挟み径を可変に調節できる被動プーリ対と、前記駆動プーリ対と前記被動プーリ対との間に掛け渡された無端ベルトと、前記駆動プーリ対のベルト挟み径と前記被動プーリ対のベルト挟み径とを相反的に変更させるベルト挟み径調節手段と、前記駆動プーリ対と前記被動プーリ対の少なくとも一方に於いて該プーリ対間に挟まれた前記無端ベルトに対し該プーリ対と該無端ベルトの間に伝達されるトルクの増大に応じて増大する挟み圧を作用させるベルト挟み圧生成手段とを有する無段変速装置にして、前記ベルト挟み径調節手段は前記ベルト挟み圧生成手段を介してベルト挟み径を調節するよう構成されていることを特徴とする無段変速装置を提案するものである。
【００１０】
前記ベルト挟み径調節手段は軸線方向に不動のプーリに対し回転可能で且つ軸線方向に可動のプーリの前記軸線方向不動プーリに対する軸線方向隔置距離を制御された所定値以下に制限する第一の部材を含み、前記ベルト挟み圧生成手段は前記第一の部材により軸線方向位置を制限された状態で前記軸線方向不動プーリと共に回転する第二の部材と、前記軸線方向可動プーリの回転に伴ってそれより可撓的回転トルクを及ぼされる第三の部材と、前記可撓的回転トルクにより前記第三の部材が前記第二の部材に対し回転偏倚されるにつれて前記第三の部材を前記第二の部材より軸線方向に遠ざけ、これによって前記軸線方向可動プーリを前記軸線方向不動プーリへ向けて軸線方向に偏倚させる偏倚変換手段とを有していてよい。
【００１１】
或いはまた、前記ベルト挟み径調節手段は軸線方向に不動のプーリに対し相対回転を係止されていて軸線方向に可動のプーリの前記軸線方向不動プーリに対する軸線方向隔置距離を制御された所定値以下に制限する第一の部材を含み、前記ベルト挟み圧生成手段は前記第一の部材により軸線方向位置を制限された状態で前記第一の部材により可撓的制動トルクを及ぼされつつ前記軸線方向可動プーリに追随して回転することができる第二の部材と、前記軸線方向可動プーリの回転に伴ってそれより可撓的回転トルクを及ぼされる第三の部材と、前記可撓的回転トルクにより前記第三の部材が前記第二の部材に対し回転偏倚されるにつれて前記第三の部材を前記第二の部材より軸線方向に遠ざけ、これによって前記軸線方向可動プーリを前記軸線方向不動プーリへ向けて軸線方向に偏倚させる偏倚変換手段とを有していてもよい。
【００１２】
上記いずれの場合にも、前記偏倚変換手段は前記第二の部材と前記第三の部材の環状対向面の間に組み込まれた環状カム手段であってよい。
【００１３】
また、前記ベルト挟み圧生成手段は前記第三の部材を前記第二の部材に対しそれより軸線方向に遠ざかる方向に可撓的に付勢するばね要素を含んでいてよい。
【００１４】
更にまた、前記第二の部材はボール型スラスト軸受を介して前記第一の部材に対し軸線方向に当接していてよく、また、前記軸線方向可動プーリはボール型スラスト軸受を介して前記第三の部材に対し軸線方向に当接していてよい。
【００１５】
【発明の作用及び効果】
上記の如くＶ型ベルト挟み溝のベルト挟み径を可変に調節できる駆動プーリ対と、前記ベルト挟み径を可変に調節できる被動プーリ対と、前記駆動プーリ対と前記被動プーリ対との間に掛け渡された無端ベルトとを有する無段変速装置に於いて、前記駆動プーリ対のベルト挟み径と前記被動プーリ対のベルト挟み径とを相反的に変更させるベルト挟み径調節手段と、前記駆動プーリ対と前記被動プーリ対の少なくとも一方に於いて該プーリ対間に挟まれた前記無端ベルトに対し該プーリ対と該無端ベルトの間に伝達されるトルクの増大に応じて増大する挟み圧を作用させるベルト挟み圧生成手段とが設けられている場合に、前記ベルト挟み径調節手段が前記ベルト挟み圧生成手段を介してベルト挟み径を調節するようこれらが直列の関係に構成されていれば、無段変速装置の変速比を変更すべく前記ベルト挟み径調節手段によりベルト挟み径が変更されるとき、ベルト挟み径の変化により生ずるベルト挟み圧の変化はそのまま直ちに前記ベルト挟み圧生成手段に伝わるので、前記ベルト挟み径調節手段の作動に対する前記ベルト挟み圧生成手段の作動には何らの追従遅れが生じず、変速比変更の途中に於いてもベルト挟み圧は無端ベルトとプーリ対の間に伝達すべきトルクの大きさに応じて常時連続して適正な値に維持される。
【００１６】
この場合、前記ベルト挟み径調節手段が軸線方向に不動のプーリに対し回転可能で且つ軸線方向に可動のプーリの軸線方向隔置距離を制御された所定値以下に制限する第一の部材を含み、前記ベルト挟み圧生成手段が前記第一の部材により軸線方向位置を制限された状態で前記軸線方向不動プーリと共に回転する第二の部材と、前記軸線方向可動プーリの回転に伴ってそれより可撓的回転トルクを及ぼされる第三の部材と、前記可撓的回転トルクにより前記第三の部材が前記第二の部材に対し回転偏倚されるにつれて前記第三の部材を前記第二の部材より軸線方向に遠ざけ、これによって前記軸線方向可動プーリを前記軸線方向不動プーリへ向けて軸線方向に偏倚させる偏倚変換手段とを有していれば、前記ベルト挟み径調節手段によりプーリ対間の隔置距離が変更されるとき、プーリ対間隔置距離の変化によってベルト挟み圧が不足すると、駆動トルクまたは負荷トルクが掛かるプーリに対して自由に回転するプーリが無端ベルトにより駆動されて回転偏倚し、これによって前記第三の部材が前記第二の部材に対し回転偏倚し、それに伴って前記第三の部材は前記第二の部材より軸線方向に遠ざけられ、軸線方向可動プーリを軸線方向不動プーリへ向けて押しやるのでベルト挟み圧を上げる作動が直ちに行なわれ、またベルト挟み圧が大き過ぎると、軸線方向可動プーリが軸線方向不動プーリより離れる方向に押されることにより前記第三の部材は前記第二の部材へ向けて押しつけられて該第二の部材に対し回転偏倚し、軸線方向可動プーリを軸線方向不動プーリより離れる方向に偏倚させる作動が直ちに行なわれるので、ベルト挟み径調節手段の作動にベルト挟み圧生成手段の作動を遅れなく追従させることができる。
【００１７】
また、前記ベルト挟み径調節手段が軸線方向に不動のプーリに対し相対回転を係止されていて軸線方向に可動のプーリの軸線方向隔置距離を制御された所定値以下に制限する第一の部材を含み、前記ベルト挟み圧生成手段が前記第一の部材により軸線方向位置を制限された状態で前記第一の部材により可撓的制動トルクを及ぼされつつ前記軸線方向可動プーリに追随して回転することができる第二の部材と、前記軸線方向可動プーリの回転に伴ってそれより可撓的回転トルクを及ぼされる第三の部材と、前記可撓的回転トルクにより前記第三の部材が前記第二の部材に対し回転偏倚されるにつれて前記第三の部材を前記第二の部材より軸線方向に遠ざけ、これによって前記軸線方向可動プーリを前記軸線方向不動プーリへ向けて軸線方向に偏倚させる偏倚変換手段とを有していれば、前記第二の部材と前記第三の部材の間には常にプーリ対に作用するトルクを摩擦係合的に薄めたトルクが作用し、それが常時前記第二の部材に対する前記第三の部材の軸線方向偏倚に変換されているので、ベルト挟み圧が無端ベルトとプーリ対間の伝達トルクの変化に対応して適正に変化するようベルト挟み径調節手段の作動に対しベルト挟み圧生成手段の作動を遅れなく追従させることができる。
【００１８】
上記いずれの場合にも、前記偏倚変換手段が前記第二の部材と前記第三の部材の環状対向面の間に組み込まれた環状カム手段であれば、無端ベルトとプーリ対の間に伝達すべきトルクの大きさに応じて比例的に増大する挟み圧を無端ベルトとプーリ対の間に作用させることができ、プーリ対に生成させるべき無端ベルト挟み圧を無端ベルトとプーリ対の間に伝達すべきトルクの大きさに応じて適正値に制御することができる。
【００１９】
また、前記ベルト挟み圧生成手段が前記第三の部材を前記第二の部材に対しそれより軸線方向に遠ざかる方向に可撓的に付勢するばね要素を含んでいれば、前記第一の部材と前記第二の部材とを常時接触状態に維持し、また前記第三の部材と軸線方向可動プーリとを常時接触状態に維持し、無段変速装置が回転を開始したときには前記第二の部材と前記第三の部材の間の回転偏倚を確実に生じさせ、前記ベルト挟み圧生成手段を確実に作動させることができる。
【００２０】
また、前記第二の部材がボール型スラスト軸受を介して前記第一の部材に対し軸線方向に当接し、また、前記軸線方向可動プーリがボール型スラスト軸受を介して前記第三の部材に対し軸線方向に当接していれば、無段変速装置の作動中にこれらのスラスト軸受部に於いて熱が発生しても、それをより効果的に発散させることができ、装置の耐久性を高めることができる。
【００２１】
【発明の実施の形態】
添付の図１は本発明による無段変速装置の第一の実施の形態を示す解図的縦断面図である。図示の実施の形態の於いては、駆動プーリ対として作動するプーリ対１０に於ける軸線方向不動プーリ１２が前後進切換装置１４を経て図には示されていない駆動源より２つの回転方向のいずれかの方向に選択的に駆動されるようになっている。１６は軸線方向可動プーリであり、軸線方向不動プーリ１２の軸１８は軸線方向可動プーリの中心軸線Ｎ１に沿って明けられた中心孔２０を潜って延在している。軸線方向不動プーリ１２はラジアル−スラスト軸受２２および２４により図にその一部が示されているハウジング２６よりそれに対して定まった軸線方向位置にて回転可能に支持されている。軸線方向可動プーリ１６は軸線方向不動プーリの軸１８によりその周りに回転可能にまた該軸に沿って軸線方向に移動可能に支持されている。
【００２２】
ハウジング２６からは他の一つのラジアル−スラスト軸受２８により中空ハブ３０が軸線方向不動プーリ軸１８の周りにこれと同心で所定の軸線方向位置にて回転可能に支持されている。この中空ハブには歯車３２が装着されており、またその図にて歯車３２より右方に延在する部分は外周に沿ってねじを切られたねじ筒３４として構成されている。このねじ筒３４の部分には、これとねじ係合するねじ孔３６を備えた円板部材３８が該ねじ孔にて中空ハブ３０のねじ筒３４にねじ係合した状態に装着されている。円板部材３８は、その外周の一部に設けられたエッジ４０がハウジング２６に設けられたガイドレール４２に沿って摺動するよう案内されていることによって、軸線方向には移動できるがその回転は阻止されており、従って中空ハブ３０が歯車３２により回転されると、円板部材３８は中心軸線Ｎ１に沿って図にて左右に移動する。
【００２３】
円板部材３８の図に於ける右側の面には中心軸線Ｎ１に対し同心の円軌跡に沿って円弧状断面の環状溝４４が形成されており、該環状溝に一部嵌合した状態にて一連のボール４６が円環状に配列されている。これらのボールは環状のボールリテーナ４８により環状溝４４に沿って等間隔に保持されており、円板部材３８と図示の如きＷ型縦断面形状を有する輪形部材５０との間に作用するスラスト軸受を構成している。輪形部材５０には円板部材３８に対向する面に環状溝４４に対応して一連のボール４６の一部を受け入れる環状溝５２が形成されている。
【００２４】
輪形部材５０はその中央部にスプライン孔５４を備えており、このスプライン孔にて軸方向不動プーリ軸１８の対応する部分に設けられたスプライン５６に係合し、これによって輪形部材５０は該スプラインが設けられている範囲内にて軸線方向不動プーリ軸１８に沿って移動可能な状態にて軸線方向不動プーリ１２と共に回転するようになっている。輪形部材５０の図に於ける右端の外周部には図示の如く両回転方向に対し斜面を呈するカム部が複数個周方向に配列された環状カム５８が形成されている。そしてこれら一連のカム部の各々には各１個のボール６０が嵌め込まれ、更にこれら一連のボール６０を挟んで環状カム５８に対向する環状カム６２を備えた円環部材６４が設けられている。円環部材６４の環状カム６２も輪形部材５０の環状カム５８と同様に両回転方向に対し斜面を呈するカム部が複数個周方向に配列された形状に作られている。かかる環状カム５８および６２とその間に挟まれたボール６０とにより、輪形部材５０と円環部材６４の間に生ずる回転偏倚を両者間の軸線方向偏倚に変換する偏倚変換機構が構成されている。輪形部材５０と円環部材６４の間には、両者を互いに離れる方向に付勢する圧縮コイルばね６６が設けられている。
【００２５】
円環部材６４の図に於ける右側の面には中心軸線Ｎ１に対し同心の円軌跡に沿って円弧状断面の環状溝６８が形成されており、該環状溝に一部嵌合した状態にて一連のボール７０が円環状に配列されている。これらのボールは環状のボールリテーナ７２により環状溝６８に沿って等間隔に保持されており、円環部材６４と軸線方向可動プーリ１６との間に作用するスラスト軸受を構成している。軸線方向可動プーリ１６には円環部材６４に対向する面に環状溝６８に対応して一連のボール７０の一部を受け入れる環状溝７４が形成されている。
【００２６】
かかる構成によれば、軸線方向不動プーリ１２に対する軸線方向可動プーリ１６の軸線方向隔置距離の大きさは、従って駆動プーリ対に於けるベルト挟み径の大きさは、ハウジング２６に対する中空ハブ３０の回転によって円板部材３８が軸線方向不動プーリ軸１８に沿ってどの位置に設定されるかによって調節され、その上で駆動プーリ対に掛け渡された後述の無端ベルトに対するベルト挟み圧は、軸線方向可動プーリ１６が軸線方向不動プーリ１２に対し相対的に回転変位し、それに一連のボール７０を介して作用する摩擦力によって円環部材６４がつられて回転しようとし、輪形部材５０と円環部材６４との間に回転偏倚が生じ、それが環状カム５８および６２とその間に挟まれた一連のボール６０とによる偏倚変換手段により円環部材６４が輪形部材５０より遠ざけられる軸線方向偏倚に変換されることにより発生される。
【００２７】
一方、図示の実施の形態の於いては被動プーリ対として作動するプーリ対７６は、軸線方向不動プーリ７８と軸線方向可動プーリ８０とを含んでいる。軸線方向不動プーリ７８はその軸８２の部分にてラジアル−スラスト軸受８４および８６によりハウジング２６に対し所定の軸線方向位置にて中心軸線Ｎ２の周りに回転するよう支持されている。軸線方向可動プーリ８０はその中心部にスプライン孔８８を形成されており、このスプライン孔にて軸線方向不動プーリの軸８２の対応する部分に設けられたスプライン９０に係合し、該スプラインが設けられている範囲内にて軸線方向不動プーリ７８に対し軸線方向に偏倚可能な状態で共に回転するようになっている。
【００２８】
ハウジング２６からは他の一つのラジアル−スラスト軸受９２により中空ハブ９４が軸線方向不動プーリ軸８２の周りにこれと同心で所定の軸線方向位置にて回転可能に支持されている。この中空ハブには歯車９６が装着されており、またその図にて歯車９６より左方に延在する部分は外周に沿ってねじを切られたねじ筒９８として構成されている。このねじ筒９８の部分には、これとねじ係合するねじ孔１００を備えた円板部材１０２が該ねじ孔にて中空ハブ９４のねじ筒９８にねじ係合した状態に装着されている。円板部材１０２は、その外周の一部に設けられたエッジ１０４がハウジング２６に設けられたガイドレール１０６に沿って摺動するよう案内されていることによって、軸線方向には移動できるがその回転は阻止されており、従って中空ハブ９４が歯車９６により回転されると、中心軸線Ｎ２に沿って図にて左右に移動する。
【００２９】
円板部材１０２の図に於ける左側の面には中心軸線Ｎ２に対し同心の円軌跡に沿って円弧状断面の環状溝１０８が形成されており、該環状溝に一部嵌合した状態にて一連のボール１１０が円環状に配列されている。これらのボールは環状のボールリテーナ１１２により環状溝１０８に沿って等間隔に保持されており、円板部材１０２と軸線方向可動プーリ８０との間に作用するスラスト軸受を構成している。軸線方向可動プーリ８０には円板部材１０２に対向する面に環状溝１０８に対応して一連のボール１１０の一部を受け入れる環状溝１１４が形成されている
【００３０】
歯車３２にはピニオン１１６が噛み合っており、歯車は９６にはピニオン１１８が噛み合っている。ピニオン１１６および１１８は軸１２０により担持されており、軸１２０はハウジング２６より軸受１２２および１２４を介して回転可能に支持されている。ピニオン１１６には更に電動アクチュエータ１２６により回転駆動されるピニオン１２８が噛み合わされている。電動アクチュエータ１２６によるピニオン１２８の回転は変速制御装置１３０により制御され、ピニオン１２８の回転により歯車３２と９６とが互いに同期して反対方向に回転されることに応じて、円板部材３８と１０２とは中空ハブ３０と９４により中心軸線Ｎ１とＮ２に沿って互いに反対方向に移動され、駆動プーリ対１０に於ける軸線方向不動プーリ１２と軸線方向可動プーリ１６との間の隔置距離と被動プーリ対７６に於ける軸線方向不動プーリ７８と軸線方向可動プーリ８０との間の隔置距離とを相反的に変化させる。
【００３１】
駆動プーリ対１０の軸線方向不動プーリ１２と軸線方向可動プーリ１６との間に形成されたＶ型溝と被動プーリ対７６の軸線方向不動プーリ７８と軸線方向可動プーリ８０との間に形成されたＶ型溝の間には無端ベルト１３２が掛け渡されている。図示の状態では、駆動プーリ対１０に於ける軸線方向可動プーリ１６は軸線方向不動プーリ１２より最も大きく引き離され、駆動プーリ対に於ける無端ベルト挟み径が最も小さくされており、これに対応して被動プーリ対に於ける軸線方向可動プーリ８０は軸線方向不動プーリ７８に最も近づけられ、被動プーリ対に於ける無端ベルト挟み径が最も大きくされており、変速装置は減速比最大の状態にある。これに対し各プーリ対に於ける軸線方向可動プーリおよび無端ベルトが図中二点鎖線にて示す位置にあるときには、無段変速装置は変速比最小の状態である。
【００３２】
かくして図示の如き実施の形態によれば、Ｖ型ベルト挟み溝のベルト挟み径を可変に調節できる駆動プーリ対（１０）と、ベルト挟み径を可変に調節できる被動プーリ対（７６）と、駆動プーリ対と被動プーリ対との間に掛け渡された無端ベルト（１３２）と、駆動プーリ対のベルト挟み径と被動プーリ対のベルト挟み径とを相反的に変更させるベルト挟み径調節手段（３０〜４２）と、駆動プーリ対と被動プーリ対の少なくとも一方（この実施の形態では駆動プーリ対のみ）に於いてプーリ対間に挟まれた無端ベルトに対しプーリ対と無端ベルトの間に伝達されるトルクの増大に応じて増大する挟み圧を作用させるベルト挟み圧生成手段（５８，６０，６２）とを有する無段変速装置に於いて、ベルト挟み径調節手段（３０〜４２）がベルト挟み圧生成手段（５８，６０，６２）を介してベルト挟み径を調節する構成が得られる。尚、プーリ対間に無端ベルトを挟む挟み圧は、プーリ対に於けるベルト挟み径を増大させようとする作用によってプーリ対間に掛け渡された無端ベルトに対し緊張作用を与えるので、ベルト挟み圧生成手段は駆動プーリ対または被動プーリ対の何れか一方に設けられていれば、他方のプーリ対に於いてもベルト挟み圧を発生させることができる。
【００３３】
図２は、本発明による無段変速装置の第二の実施の形態を示す解図的縦断面図である。この実施の形態は、図１に示した第一の実施の形態に比して、駆動側プーリ対の中空ハブ３０と被動プーリ対の中空ハブ９４とを連動させる機構を変更したである。従って、図２に於いては、図１に示した構成と同じ部分は図１に於ける符号と同じ符号により示されている。
【００３４】
この第二の実施の形態の於いては、第一の実施の形態に於ける歯車３２と９６に対応する歯車３３と９７とは、それぞれに噛み合うピニオン１３４と１３６を備えた個別のアクチュエータ１３８と１４０により駆動されるようになっており、歯車３２と９６の駆動に於ける連動は、変速制御装置１３０によるアクチュエータ１３８と１４０の電気的駆動制御の段階に於いて行われるようになっている。かかる電気的連動制御によっても、駆動プーリ対と被動プーリ対に於けるベルト挟み径調節手段の相反的制御が図１について説明した要領と同様に行えることは明らかであろう。
【００３５】
図３は、本発明による無段変速装置の第三の実施の形態を示す解図的断面図である。この実施の形態は、図１に示した第一の実施の形態に比して、プーリ対１０に於いて、軸線方向可動プーリ１６が軸線方向不動プーリ１２に対し係止されて共に回転するようになっており、一方、輪形部材５０が軸線方向不動プーリ軸１８に対し回転を係止されない部材とされている点に於いて異なっている。
【００３６】
この第三の実施の形態に於いては、軸線方向不動プーリ軸１８の軸線方向可動プーリ１６の中心孔２０を貫通する部分はスプライン５７が形成されておりが形成されており、軸線方向可動プーリ１６の中心孔２０はスプライン５７とスプライン係合するスプライン孔として形成されている。そして、円環部材５０は円環部材６４と同様の環状カムとしてのみ作用する部材となっている。
【００３７】
かかる構成によれば、円環部材５０と６４の間には常にプーリ対に作用するトルクを一連のボール４６と７０とによる可撓的摩擦係合手段により一定の割合に薄めたトルクが作用し、それが常時円環部材５０に対する円環部材６４の軸線方向偏倚に変換されるので、環状カムを５８および６２の傾斜角を適当に設定しておくことにより、ベルト挟み径調節手段の作動に応じて、追従に遅れを来たすことなく、ベルト挟み圧を無端ベルトとプーリ対間の伝達トルクの変化に対応させてた適正値に変化させることができる。
【００３８】
図４は、本発明による無段変速装置の第四の実施の形態を示す同様の解図的断面図である。この第四の実施の形態は、上記第二の実施の形態が上記第一の実施の形態に対しなす関係と同じ関係を上記第三の実施の形態に対しなすものである。図４に於いては、図３に示す部分に対応する部分は図３に於けると同じ符号により示されており、また図２に示す部分に対応する部分は図２に於けると同じ符号により示されている。この第四の実施の形態がその作動の一部に於いては第三の実施の形態の作動と同じであり、その作動の残りの部分に於いては第二の実施が形態の作動と同じであることは明らかであろう。
【００３９】
以上に於いては本発明を四つの実施の形態について詳細に説明したが、これらの実施の形態について本発明の範囲内にて種々の変更が可能であることは当業者にとって明らかであろう。
【図面の簡単な説明】
【図１】本発明による無段変速装置の第一の実施の形態を示す解図的断面図。
【図２】本発明による無段変速装置の第二の実施の形態を示す解図的断面図。
【図３】本発明による無段変速装置の第三の実施の形態を示す解図的断面図。
【図４】本発明による無段変速装置の第四の実施の形態を示す解図的断面図。
【符号の説明】
１０…プーリ対、１２…軸線方向不動プーリ、１４…前後進切換装置、１６…軸線方向可動プーリ、１８…軸線方向不動プーリ軸、２０…中心孔、２２，２４…ラジアル−スラスト軸受、２６…ハウジング、２８…ラジアル−スラスト軸受、３０…中空ハブ、３２，３３…歯車、３４…ねじ筒、３６…ねじ孔、３８…円板部材、４０…エッジ、４２…ガイドレール、４４…環状溝、４６…ボール、４８…ボールリテーナ、５０…輪形部材、５２…環状溝、５４…スプライン孔、５６，５７…スプライン、５８…環状カム、６０…ボール、６２…環状カム、６４…円環部材、６６…圧縮コイルばね、６８…環状溝、７０…ボール、７２…ボールリテーナ、７４…環状溝、７６…プーリ対、７８…軸線方向不動プーリ、８０…軸線方向可動プーリ、８２…軸線方向不動プーリ軸、８４，８６…ラジアル−スラスト軸受、８８…スプライン孔、９０…スプライン、９２…ラジアル−スラスト軸受、９４…中空ハブ、９６，９７…歯車、９８…ねじ筒、１００…ねじ孔、１０２…円板部材、１０４…エッジ、１０６…ガイドレール、１０８…環状溝、１１０…ボール、１１２…ボールリテーナ、１１４…環状溝、１１６，１１８…ピニオン、１２０…軸、１２２，１２４…軸受、１２６…電動アクチュエータ、１２８…ピニオン、１３０…変速制御装置、１３２…無端ベルト、１３４，１３６…ピニオン、１３８，１４０…電動アクチュエータ、[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a continuously variable transmission, in particular, a drive pulley pair capable of variably adjusting a belt pinching diameter of a V-shaped belt pinching groove, a driven pulley pair capable of variably adjusting the belt pinching diameter, such a drive pulley pair and a driven pulley. An endless belt is stretched between the pair and the pair of driving pulleys and the pair of driven pulleys is reciprocally changed in belt diameter, so that the transmission ratio of the rotational force transmitted between the pair of belts is changed. The present invention relates to a continuously variable transmission that is continuously changed.
[0002]
[Prior art]
In this type of continuously variable transmission, a belt clamping diameter of the driving pulley pair and a belt clamping diameter of the driven pulley pair are set in order to set a speed ratio of a rotational force transmitted between the driving pulley pair and the driven pulley pair. Is required, and the driving and driven members are driven so that the rotational force is transmitted by frictional engagement between the endless belt and the driving pulley pair and the driven pulley pair. Belt pinching pressure generating means for applying a pinching pressure for pressing the endless belt between the pair of pulleys in the pulley pair is required.
[0003]
As the above-mentioned pinching diameter adjusting means, a mechanical device combining a screw feeding means and a gear interlocking means, a hydraulic device combining a cylinder / piston feeding means and a hydraulic path interlocking means, and the like, It is known as described in the following patent documents.
[0004]
The belt clamping pressure generating means acts on a spring or a pulley pair that urges the axially movable pulley toward the axially stationary pulley in at least one of the driving pulley pair and the driven pulley pair. 2. Description of the Related Art There is known a bias conversion means for providing an annular cam between two members relatively rotated and biased by a torque, and converting a rotation bias generated between the two members into an axial bias between the two members.
[0005]
For example, in the following Patent Document 1, in this type of continuously variable transmission, the belt pinching diameter adjusting means includes an axially stationary pulley and a shaft thereof in each of a driving pulley pair and a driven pulley pair. A belt-type pinching pressure generating means that acts between an axially movable pulley mounted so as to be relatively non-rotatable in a rotational direction and relatively movable in an axial direction by a spline; A cam may be provided between two members that are relatively rotationally biased by the torque acting on the pair, and the cam may be configured as a bias converting means for converting the rotational bias generated between the two members into an axial bias between the two members. Patent Literature 2 below discloses a hydraulic device in which the belt pinching diameter adjusting means combines a feeding means using a cylinder / piston and an interlocking means using a hydraulic path. And it is provided particularly on the side of the driven pulley pair, wherein the belt pinching pressure generating means for applying a pinching pressure for pressing the endless belt between the pair of pulleys is configured as a spring element, and It is stated that it is provided in particular on the side of the drive pulley pair.
[Patent Document 1]
JP-A-6-58385
[Patent Document 2]
JP-A-11-22798
[0006]
[Problems to be solved by the invention]
In a conventional continuously variable transmission of this type including the devices of Patent Documents 1 and 2, the belt pinching diameter adjusting means and the belt pinching pressure generating means are individually arranged in parallel with the pulley pair. To act on. That is, the belt pinching diameter adjusting means independently operates in response to a shift command from the shift control device to set the separation distance between the pair of pulleys to a predetermined value, while the belt pinching pressure generating means performs In the case of hydraulic pressure, etc., the belt pinching pressure is target-controlled in accordance with the belt pinching pressure control command from the belt pinching pressure control device, and when the belt pinching pressure is generated by a cam or the like, it is endless due to insufficient belt pinching pressure. The cam is operated by using the relative slip generated between the belt and the pulley, and the axially movable pulley or the axially stationary pulley is pressed toward the other individually.
[0007]
However, if the operation of the belt pinching diameter adjusting means and the operation of the belt pinching pressure generating means are performed separately, when the belt pinching diameter is changed by the belt pinching diameter adjusting means, the belt pinching diameter adjusting means changes the belt. The pinching diameter actually changes, as a result, the effective pinching width of the pulley pair with respect to the endless belt changes, and as a result, the reaction of the endless belt acting on the belt pinching pressure generating means changes, and the belt pinching pressure generating means Changes the operation so as to follow the operation of the belt pinching diameter adjusting means.Therefore, there is a delay in following the change in the belt pinching pressure with respect to the change in the belt pinching diameter adjustment. However, there is a problem that a state may not be maintained.
[0008]
The present invention has been made in view of the above problems, and has an object to improve a continuously variable transmission of the above-described type so that the pinching pressure on the endless belt is appropriately maintained even during a change in a gear ratio. I have.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a drive pulley pair capable of variably adjusting a belt holding diameter of a V-shaped belt holding groove, a driven pulley pair capable of variably adjusting the belt holding diameter, and a drive pulley pair. And an endless belt stretched between the driven pulley pair; a belt pinching diameter adjusting means for reciprocally changing a belt pinching diameter of the driving pulley pair and a belt pinching diameter of the driven pulley pair; In at least one of the pulley pair and the driven pulley pair, a pinching pressure that increases in accordance with an increase in torque transmitted between the pulley pair and the endless belt is applied to the endless belt sandwiched between the pair of pulleys. And a belt-clamping-diameter adjusting means for adjusting the belt-clamping diameter via the belt-clamping-pressure generating means. It proposes a continuously variable transmission, wherein the door.
[0010]
The belt pinching diameter adjusting means is configured to limit the axial separation distance of the pulley that is rotatable with respect to the axially immovable pulley and that is axially movable with respect to the axially immovable pulley to a controlled predetermined value or less. A second member that rotates together with the axially stationary pulley in a state where the belt pinching pressure generating means is restricted in the axial position by the first member, with the rotation of the axially movable pulley. A third member that is subjected to a more flexible rotational torque; and the third member is moved to the second member as the third member is rotationally biased relative to the second member by the flexible rotational torque. And a bias converting means for axially moving the axially movable pulley toward the axially stationary pulley by moving the axially movable pulley toward the axially stationary pulley.
[0011]
Alternatively, the belt pinching diameter adjusting means is locked to a relative rotation with respect to an axially immovable pulley, and a predetermined value in which an axially movable distance between the axially movable pulley and the axially immovable pulley is controlled. The belt clamping pressure generating means includes a first member which is restricted below, and wherein the belt member is subjected to a flexible braking torque by the first member in a state where an axial position is restricted by the first member. A second member that can rotate following the directional movable pulley, a third member that receives more flexible rotational torque as the axially movable pulley rotates, and the flexible rotational torque. Thereby moving the third member axially away from the second member as the third member is rotationally biased relative to the second member, thereby moving the axially movable pulley to the shaft. It may have a biasing converting means for biasing axially toward the direction immovable pulley.
[0012]
In any of the above cases, the displacement converting means may be an annular cam means incorporated between the annular facing surfaces of the second member and the third member.
[0013]
The belt pinching pressure generating means may include a spring element that flexibly urges the third member toward the second member in a direction away from the second member in the axial direction.
[0014]
Furthermore, the second member may be in axial contact with the first member via a ball-type thrust bearing, and the axially movable pulley may be in contact with the third member via a ball-type thrust bearing. May be in contact with the member in the axial direction.
[0015]
Function and effect of the present invention
A drive pulley pair capable of variably adjusting the belt pinching diameter of the V-shaped belt pinching groove as described above, a driven pulley pair capable of variably adjusting the belt pinching diameter, and a hook between the drive pulley pair and the driven pulley pair. In the continuously variable transmission having the transferred endless belt, the belt pulling diameter adjusting means for reciprocally changing the belt pulling diameter of the driving pulley pair and the belt pulling diameter of the driven pulley pair, and the driving pulley At least one of the pair and the driven pulley pair acts on the endless belt sandwiched between the pair of pulleys with a pinching pressure that increases as the torque transmitted between the pair of pulleys and the endless belt increases. And a belt-clamping-pressure generating means for causing the belt-clamping-diameter adjusting means to adjust the belt-clamping diameter via the belt-clamping-pressure generating means. If the belt pinching diameter is changed by the belt pinching diameter adjusting means so as to change the speed ratio of the continuously variable transmission, the change in the belt pinching pressure caused by the change in the belt pinching diameter is immediately applied to the belt pinching. Since it is transmitted to the pressure generating means, there is no delay in the operation of the belt nipping pressure generating means with respect to the operation of the belt nipping diameter adjusting means, and even during the change of the speed ratio, the belt nipping pressure is equal to that of the endless belt. An appropriate value is continuously maintained at all times according to the magnitude of the torque to be transmitted between the pair of pulleys.
[0016]
In this case, the belt pinching diameter adjusting means includes a first member that is rotatable with respect to the pulley that is immovable in the axial direction and that limits the axial separation distance of the pulley that is movable in the axial direction to a controlled predetermined value or less. A second member that rotates together with the axially stationary pulley in a state where the belt pinching pressure generating means has an axial position restricted by the first member, and a second member that rotates with the rotation of the axially movable pulley. A third member subjected to a flexural rotational torque; and the third member is moved away from the second member as the third member is rotationally biased relative to the second member by the flexible rotational torque. Bias conversion means for moving the axially movable pulley in the axial direction toward the axially immovable pulley by moving the pulley in the axial direction. When the separation distance between the pairs is changed, if the belt pinching pressure is insufficient due to the change in the separation distance between the pulleys, the pulley that rotates freely with respect to the pulley to which the driving torque or the load torque is applied is driven by the endless belt. Rotationally biasing, whereby the third member is rotationally biased relative to the second member, whereby the third member is axially moved away from the second member and the axially movable pulley is axially displaced. Since the belt is pushed toward the direction-immobile pulley, the operation of increasing the belt-clamping pressure is performed immediately. If the belt-clamping pressure is too large, the axially movable pulley is pushed in a direction away from the axial-direction immovable pulley, so that the third member Is pressed against the second member and is rotationally biased against the second member to move the axially movable pulley away from the axially stationary pulley. Since working for biasing is immediately performed, it can follow without delay the operation of the belt sandwiching pressure generating means to the operation of the belt pinching diameter adjusting means.
[0017]
Further, the belt pinching diameter adjusting means is locked for relative rotation with respect to an axially immovable pulley, and limits the axial separation distance of the axially movable pulley to a controlled predetermined value or less. A member, wherein the belt pinching pressure generating means follows the axially movable pulley while being subjected to a flexible braking torque by the first member in a state where the axial position is restricted by the first member. A second member that can rotate, a third member that is subjected to a flexible rotational torque by the rotation of the axially movable pulley, and a third member that is subjected to the flexible rotational torque. The third member is axially further away from the second member as it is rotationally biased relative to the second member, thereby axially biasing the axially movable pulley toward the axially stationary pulley. And a bias converting means for causing the torque acting on the pulley pair to be reduced by frictional engagement always acts between the second member and the third member. Since it is converted to the axial deviation of the third member with respect to the second member, the belt clamping diameter is adjusted so that the belt clamping pressure changes appropriately in accordance with the change in the transmission torque between the endless belt and the pulley pair. The operation of the belt clamping pressure generating means can follow the operation of the means without delay.
[0018]
In any of the above cases, if the displacement converting means is an annular cam means incorporated between the annular facing surfaces of the second member and the third member, the transmission is performed between the endless belt and the pair of pulleys. The pinching pressure, which increases proportionally to the magnitude of the torque to be applied, can be applied between the endless belt and the pulley pair, and the endless belt pinching pressure to be generated by the pair of pulleys is transmitted between the endless belt and the pulley pair. It can be controlled to an appropriate value according to the magnitude of the torque to be performed.
[0019]
In addition, if the belt pinching pressure generating means includes a spring element that flexibly biases the third member in a direction away from the second member in the axial direction, the first member And the second member are always kept in contact with each other, and the third member and the axially movable pulley are always kept in contact with each other, and when the continuously variable transmission starts rotating, the second member And the third member can be reliably caused to rotate, and the belt pinching pressure generating means can be reliably operated.
[0020]
Further, the second member is axially abutted against the first member via a ball-type thrust bearing, and the axially movable pulley is connected to the third member via a ball-type thrust bearing. If the contact is made in the axial direction, even if heat is generated in these thrust bearings during operation of the continuously variable transmission, the heat can be dissipated more effectively, and the durability of the device is increased. be able to.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an illustrative longitudinal sectional view showing a first embodiment of a continuously variable transmission according to the present invention. In the illustrated embodiment, an axially stationary pulley 12 in a pulley pair 10 operating as a drive pulley pair is driven by a forward / reverse switching device 14 from a drive source (not shown) in two rotational directions. It is selectively driven in either direction. Reference numeral 16 denotes an axially movable pulley, and a shaft 18 of the axially stationary pulley 12 extends below a center hole 20 formed along a central axis N1 of the axially movable pulley. The axially stationary pulley 12 is rotatably supported by radial-thrust bearings 22 and 24 at a defined axial position relative to a housing 26, a portion of which is shown in the figure. The axially movable pulley 16 is supported by an axially stationary pulley shaft 18 so as to be rotatable thereabout and axially movable along the axis.
[0022]
A hollow hub 30 is rotatably supported by the other radial-thrust bearing 28 around the axially stationary pulley shaft 18 at a predetermined axial position from the housing 26. A gear 32 is mounted on the hollow hub, and a portion extending rightward from the gear 32 in the figure is formed as a screw cylinder 34 threaded along the outer periphery. A disk member 38 having a screw hole 36 for screw engagement with the screw cylinder 34 is mounted on the screw cylinder 34 in a state of being screw-engaged with the screw cylinder 34 of the hollow hub 30 through the screw hole. The disk member 38 can be moved in the axial direction by its edge 40 provided on a part of the outer circumference thereof being guided along a guide rail 42 provided on the housing 26, but its rotation is possible. Therefore, when the hollow hub 30 is rotated by the gear 32, the disk member 38 moves left and right in the figure along the central axis N1.
[0023]
An annular groove 44 having an arc-shaped cross section is formed on the right side surface of the disk member 38 in the drawing along a circular locus concentric with the center axis N1, and is partially fitted in the annular groove. A series of balls 46 are arranged in an annular shape. These balls are held at equal intervals along the annular groove 44 by an annular ball retainer 48, and a thrust bearing acting between the disk member 38 and a ring-shaped member 50 having a W-shaped vertical sectional shape as shown in the drawing. Is composed. An annular groove 52 for receiving a part of a series of balls 46 is formed on the surface of the ring-shaped member 50 corresponding to the annular groove 44 on a surface facing the disk member 38.
[0024]
The ring-shaped member 50 is provided with a spline hole 54 at the center thereof, and the spline hole engages with a spline 56 provided at a corresponding portion of the axially stationary pulley shaft 18 so that the ring-shaped member 50 can be connected to the spline hole. Are rotatable together with the axially stationary pulley 12 while being movable along the axially stationary pulley shaft 18 within the range in which is provided. An annular cam 58 in which a plurality of cam portions exhibiting inclined surfaces in both rotational directions are arranged in the circumferential direction is formed on the outer peripheral portion at the right end in the drawing of the ring-shaped member 50 as shown in the figure. Each of the series of cam portions is fitted with one ball 60, and further provided with an annular member 64 having an annular cam 62 opposed to the annular cam 58 with the series of balls 60 interposed therebetween. . Similarly to the annular cam 58 of the ring-shaped member 50, the annular cam 62 of the annular member 64 is formed in a shape in which a plurality of cam portions exhibiting inclined surfaces in both rotation directions are arranged in the circumferential direction. The annular cams 58 and 62 and the ball 60 sandwiched therebetween constitute a displacement conversion mechanism that converts the rotational displacement generated between the ring-shaped member 50 and the annular member 64 into an axial displacement therebetween. A compression coil spring 66 is provided between the ring-shaped member 50 and the ring member 64 to urge them in directions away from each other.
[0025]
An annular groove 68 having an arcuate cross section is formed on the right side surface of the annular member 64 in the drawing along a circular locus concentric with the central axis N1, and the annular groove 68 is partially fitted in the annular groove. A series of balls 70 are arranged in an annular shape. These balls are held at equal intervals along an annular groove 68 by an annular ball retainer 72, and constitute a thrust bearing acting between the annular member 64 and the axially movable pulley 16. An annular groove 74 for receiving a part of a series of balls 70 is formed on the surface of the axially movable pulley 16 corresponding to the annular groove 68 on a surface facing the annular member 64.
[0026]
According to such a configuration, the magnitude of the axial separation distance of the axially movable pulley 16 with respect to the axially immovable pulley 12, and thus the magnitude of the belt pinching diameter in the drive pulley pair, is determined by the size of the hollow hub 30 with respect to the housing 26. The rotation is adjusted depending on the position of the disk member 38 along the axially stationary pulley shaft 18, and the belt pinching pressure on the endless belt, which will be described later, which is stretched over the pair of drive pulleys, is adjusted in the axial direction. The movable pulley 16 is rotationally displaced relative to the axially immovable pulley 12, and the ring member 64 tries to rotate by the frictional force acting through a series of balls 70, and the ring member 50 and the ring member 64 are rotated. Between the annular cams 58 and 62 and a series of balls 60 sandwiched between the annular cams 58 and 62. 64 is generated by being converted axially biased to be moved away from the ring-shaped member 50.
[0027]
On the other hand, in the illustrated embodiment, the pulley pair 76 operating as a driven pulley pair includes an axially stationary pulley 78 and an axially movable pulley 80. The axially stationary pulley 78 is supported at its shaft 82 by radial-thrust bearings 84 and 86 relative to the housing 26 for rotation about the central axis N2 at a predetermined axial position. The axially movable pulley 80 has a spline hole 88 formed at the center thereof, and the spline hole is engaged with a spline 90 provided at a corresponding portion of the shaft 82 of the axially stationary pulley, and the spline hole is formed. Within the range, the pulley 78 rotates together with the axially immovable pulley 78 in a state where it can be deviated in the axial direction.
[0028]
A hollow hub 94 is supported from the housing 26 by another radial-thrust bearing 92 so as to be rotatable about an axially stationary pulley shaft 82 and concentric therewith at a predetermined axial position. A gear 96 is mounted on the hollow hub, and a portion extending leftward from the gear 96 in the figure is formed as a screw cylinder 98 which is threaded along the outer periphery. A disk member 102 having a screw hole 100 which is screw-engaged with the screw tube 98 is mounted on the screw tube 98 in a state of being screw-engaged with the screw tube 98 of the hollow hub 94 at the screw hole. The disk member 102 can move in the axial direction because the edge 104 provided on a part of the outer periphery thereof is guided to slide along the guide rail 106 provided on the housing 26. Therefore, when the hollow hub 94 is rotated by the gear 96, the hollow hub 94 moves right and left in the figure along the central axis N2.
[0029]
An annular groove 108 having an arc-shaped cross section is formed on the left side surface of the disk member 102 in the figure along a circular locus concentric with the center axis N2, and is partially fitted in the annular groove. A series of balls 110 are arranged in an annular shape. These balls are held at equal intervals along the annular groove 108 by an annular ball retainer 112, and constitute a thrust bearing acting between the disk member 102 and the axially movable pulley 80. An annular groove 114 for receiving a part of a series of balls 110 is formed in the axially movable pulley 80 on a surface facing the disk member 102 so as to correspond to the annular groove 108.
[0030]
The pinion 116 meshes with the gear 32, and the pinion 118 meshes with the gear 96. The pinions 116 and 118 are carried by a shaft 120, and the shaft 120 is rotatably supported by the housing 26 via bearings 122 and 124. The pinion 116 further meshes with a pinion 128 that is driven to rotate by an electric actuator 126. The rotation of the pinion 128 by the electric actuator 126 is controlled by the transmission control device 130, and the rotation of the pinion 128 causes the gears 32 and 96 to rotate in synchronization with each other in the opposite directions. Are moved in opposite directions along the central axes N1 and N2 by the hollow hubs 30 and 94, and the distance between the axially stationary pulley 12 and the axially movable pulley 16 in the drive pulley pair 10 and the driven pulley The separation distance between the axially stationary pulley 78 and the axially movable pulley 80 in the pair 76 is reciprocally changed.
[0031]
A V-shaped groove formed between the axially stationary pulley 12 of the driving pulley pair 10 and the axially movable pulley 16 and an axially stationary pulley 78 and the axially movable pulley 80 of the driven pulley pair 76 are formed. An endless belt 132 is stretched between the V-shaped grooves. In the state shown in the figure, the axially movable pulley 16 in the driving pulley pair 10 is separated most greatly than the axially stationary pulley 12, and the endless belt pinching diameter in the driving pulley pair is minimized. Thus, the axially movable pulley 80 in the driven pulley pair is closest to the axially stationary pulley 78, the endless belt clamping diameter in the driven pulley pair is the largest, and the transmission is in the state of the maximum reduction ratio. . On the other hand, when the axially movable pulley and the endless belt in each pulley pair are at the positions indicated by the two-dot chain line in the drawing, the continuously variable transmission is in the state of the minimum gear ratio.
[0032]
Thus, according to the illustrated embodiment, a pair of drive pulleys (10) capable of variably adjusting the belt clamping diameter of the V-shaped belt clamping groove, a pair of driven pulleys (76) capable of variably adjusting the belt clamping diameter, An endless belt (132) stretched between the pair of pulleys and the driven pulley, and a belt clamping diameter adjusting means (30) for reciprocally changing the belt clamping diameter of the driving pulley pair and the belt clamping diameter of the driven pulley pair. To 42), and at least one of the driving pulley pair and the driven pulley pair (only the driving pulley pair in this embodiment) is transmitted between the pair of endless belts and the endless belt. A belt pinching pressure generating means (58, 60, 62) for applying a pinching pressure that increases in accordance with an increase in torque, wherein the belt pinching diameter adjusting means (30 to 42) includes a bell pinching diameter adjusting means (30 to 42). Structure sandwiched via the pressure generating means (58, 60, 62) to adjust the belt scissors size is obtained. The pinching pressure for sandwiching the endless belt between the pair of pulleys exerts a tensioning action on the endless belt stretched between the pair of pulleys by an action of increasing the belt pinching diameter in the pair of pulleys. If the pressure generating means is provided on either the driving pulley pair or the driven pulley pair, the other pulley pair can also generate the belt clamping pressure.
[0033]
FIG. 2 is an illustrative longitudinal sectional view showing a second embodiment of the continuously variable transmission according to the present invention. This embodiment is different from the first embodiment shown in FIG. 1 in that the mechanism for linking the hollow hub 30 of the driving pulley pair and the hollow hub 94 of the driven pulley pair is changed. Therefore, in FIG. 2, the same portions as those in the configuration shown in FIG. 1 are denoted by the same reference numerals as those in FIG.
[0034]
In the second embodiment, the gears 33 and 97 corresponding to the gears 32 and 96 in the first embodiment are separate actuators 138 having pinions 134 and 136 respectively meshing therewith. The gears 32 and 96 are driven in synchronization with each other at the stage of electric drive control of the actuators 138 and 140 by the transmission control device 130. It is apparent that reciprocal control of the belt pinching diameter adjusting means in the driving pulley pair and the driven pulley pair can be performed in the same manner as described with reference to FIG.
[0035]
FIG. 3 is an illustrative sectional view showing a third embodiment of the continuously variable transmission according to the present invention. This embodiment is different from the first embodiment shown in FIG. 1 in that in the pulley pair 10, the axially movable pulley 16 is locked to the axially stationary pulley 12 and rotates together. On the other hand, the difference is that the ring-shaped member 50 is a member that is not locked against rotation with respect to the axially stationary pulley shaft 18.
[0036]
In the third embodiment, a portion of the axially stationary pulley shaft 18 that penetrates through the center hole 20 of the axially movable pulley 16 is formed with a spline 57, and the axially movable pulley is formed. The 16 center holes 20 are formed as spline holes that spline-engage with the splines 57. The annular member 50 is a member that acts only as an annular cam similar to the annular member 64.
[0037]
According to this configuration, the torque acting on the pair of pulleys is always reduced between the annular members 50 and 64 by a fixed friction ratio by the flexible friction engagement means using the series of balls 46 and 70. Is always converted to the axial deviation of the annular member 64 with respect to the annular member 50. By appropriately setting the inclination angles of the annular cams 58 and 62, the operation of the belt pinching diameter adjusting means can be controlled. Accordingly, the belt clamping pressure can be changed to an appropriate value corresponding to the change in the transmission torque between the endless belt and the pulley pair without delay in following.
[0038]
FIG. 4 is a similar schematic cross-sectional view showing a fourth embodiment of the continuously variable transmission according to the present invention. In the fourth embodiment, the same relation as the second embodiment to the first embodiment is applied to the third embodiment. In FIG. 4, parts corresponding to the parts shown in FIG. 3 are denoted by the same reference numerals as those in FIG. 3, and parts corresponding to the parts shown in FIG. 2 are denoted by the same reference numerals as in FIG. Is indicated by The operation of the fourth embodiment is the same as the operation of the third embodiment in part of the operation, and the operation of the second embodiment is the same as the operation of the second embodiment in the rest of the operation. It should be clear that
[0039]
Although the present invention has been described in detail with reference to the four embodiments, it will be apparent to those skilled in the art that various modifications can be made to these embodiments within the scope of the present invention.
[Brief description of the drawings]
FIG. 1 is an illustrative sectional view showing a first embodiment of a continuously variable transmission according to the present invention.
FIG. 2 is an illustrative sectional view showing a second embodiment of the continuously variable transmission according to the present invention.
FIG. 3 is an illustrative sectional view showing a third embodiment of a continuously variable transmission according to the present invention.
FIG. 4 is an illustrative sectional view showing a fourth embodiment of a continuously variable transmission according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... pulley pair, 12 ... axial direction immovable pulley, 14 ... forward / backward switching device, 16 ... axial direction movable pulley, 18 ... axial direction immovable pulley shaft, 20 ... center hole, 22, 24 ... radial-thrust bearing, 26 ... Housing, 28 ... radial-thrust bearing, 30 ... hollow hub, 32, 33 ... gear, 34 ... screw cylinder, 36 ... screw hole, 38 ... disk member, 40 ... edge, 42 ... guide rail, 44 ... annular groove, 46 ... ball, 48 ... ball retainer, 50 ... ring member, 52 ... annular groove, 54 ... spline hole, 56, 57 ... spline, 58 ... annular cam, 60 ... ball, 62 ... annular cam, 64 ... annular member, 66 ... compression coil spring, 68 ... annular groove, 70 ... ball, 72 ... ball retainer, 74 ... annular groove, 76 ... pulley pair, 78 ... axially stationary pulley, 80 ... axially movable pulley 82: axially fixed pulley shaft, 84, 86: radial-thrust bearing, 88: spline hole, 90: spline, 92: radial-thrust bearing, 94: hollow hub, 96, 97: gear, 98: screw cylinder, 100 ... Screw hole, 102 ... Disc member, 104 ... Edge, 106 ... Guide rail, 108 ... Circular groove, 110 ... Ball, 112 ... Ball retainer, 114 ... Circular groove, 116, 118 ... Pinion, 120 ... Shaft, 122, 124 ... Bearing, 126 ... Electric actuator, 128 ... Pinion, 130 ... Shift control device, 132 ... Endless belt, 134,136 ... Pinion, 138,140 ... Electric actuator,

Claims

A pair of drive pulleys capable of variably adjusting the belt pinching diameter of the V-shaped belt pinching groove, a driven pulley pair capable of variably adjusting the belt pinching diameter, and a loop spanned between the drive pulley pair and the driven pulley pair. An endless belt, a belt pinching diameter adjusting means for reciprocally changing a belt pinching diameter of the driving pulley pair and a belt pinching diameter of the driven pulley pair, and at least one of the driving pulley pair and the driven pulley pair. Continuously variable transmission having belt clamping pressure generating means for applying a clamping pressure that increases with an increase in torque transmitted between the pair of endless belts and the endless belt sandwiched between the pair of pulleys. A continuously variable transmission, wherein the belt pinching diameter adjusting means is configured to adjust the belt pinching diameter via the belt pinching pressure generating means.

The belt pinching diameter adjusting means is configured to limit the axial separation distance of the pulley rotatable with respect to the axially immovable pulley and the axially movable pulley with respect to the axially immovable pulley to a controlled predetermined value or less. A second member that rotates together with the axially immovable pulley in a state where the belt pinching pressure generating means is restricted in the axial position by the first member, and with the rotation of the axially movable pulley, A third member that is subjected to a more flexible rotational torque; and the third member is moved to the second member as the third member is rotationally biased relative to the second member by the flexible rotational torque. A bias conversion means for axially moving said axially movable pulley toward said axially stationary pulley, said biasing means being axially further away from said member. Continuously variable transmission according to.

The belt pinching diameter adjusting means is locked for relative rotation with respect to the axially immovable pulley, and limits the axially movable distance between the axially movable pulley and the axially immovable pulley to a controlled predetermined value or less. The first movable member and the first movable member are provided with a flexible braking torque applied by the first member in a state where the axial position is restricted by the first member. A second member capable of rotating in accordance with the rotation of the axially movable pulley, a third member to which a flexible rotational torque is exerted with the rotation of the axially movable pulley, As the third member is rotationally biased relative to the second member, the third member is moved axially away from the second member, thereby moving the axially movable pulley to the axially stationary pulley. Continuously variable transmission according to claim 1, characterized in that it comprises a biasing converting means for biasing axially towards Li.

4. The continuously variable transmission according to claim 2, wherein the bias conversion unit is an annular cam unit incorporated between the annular opposing surfaces of the second member and the third member.

The belt clamping pressure generating means includes a spring element that flexibly biases the third member in a direction axially away from the second member. 5. The continuously variable transmission according to 3 or 4.

The continuously variable transmission according to any one of claims 2 to 5, wherein the second member is in axial contact with the first member via a ball-type thrust bearing.

The continuously variable transmission according to any one of claims 2 to 6, wherein the axially movable pulley is in axial contact with the third member via a ball-type thrust bearing.