JP2004251385A - Power transmitting chain and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmitting chain having great power transmitting performance without giving surface damage to the end faces of pins and sheave surfaces for a long period even when used in slide contact in a boundary lubricated state under the conditions of high torque and high contact pressure. <P>SOLUTION: The power transmitting chain 1 comprises a plurality of links 2 and the plurality of pins 3 connecting these to one another. The chain 1 is bridged between first and second pulleys and has slide contact between end faces 3a, 3b of the pins 3 and the sheave surfaces of the first and second pulleys. For this purpose, the contour line of each pin 3 on the side of the end faces 3a, 3b is a logarithmic curve in the axially sectional view thereof. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【数５】

【数６】

【００１２】
本発明の第２の動力伝達チェーンは、複数のリンクと、これらを相互に連結する複数のピンとを備え、円錐面状のシーブ面を有する第１のプーリと、円錐面状のシーブ面を有する第２のプーリとの間に架け渡されて用いられ、前記ピンの端面と前記第１および第２のプーリのシーブ面との間で滑り接触をする動力伝達チェーンであって、前記ピンは、その軸方向断面視において端面側の外形線が対数曲線に近似した曲線になっていることを特徴としている。
【００１３】
上記の構成のように、ピン端面の外形線が対数曲線に近似した曲線になっていても（ピン端面が擬似的な複合クラウニング形状になっていても）、上記第１の動力伝達チェーンと同様、高トルクおよび高面圧条件下において、境界潤滑状態で滑り接触させて使用しても、長期にわたって、ピン端面やシーブ面に表面損傷を生じることなく、大きな動力伝達を行うことができるものとなる。また、大きなミスアライメントを許容することができる。さらに、この場合、加工しやすいという利点がある。
ここで、本発明において「対数曲線に近似した曲線」とは、ピン端面の外形線が完全な対数曲線とはいえないが、例えば、曲率半径の異なる複数の円弧を連結することで対数曲線に近似するようにした曲線のように、上記した対数曲線と同様の作用効果を奏する曲線をいう。
【００１４】
本発明の第１の動力伝達装置は、円錐面状のシーブ面を有する第１のプーリと、円錐面状のシーブ面を有する第２のプーリと、両者の間に架け渡され、前記第１および第２のプーリのシーブ面と滑り接触をする端面を有する複数のピンと、これらピンによって相互に連結された複数のリンクとを有するチェーンと、を備えた動力伝達装置であって、前記チェーンが、上記した第１または第２の動力伝達チェーンであることを特徴としている。
上記の構成によれば、高トルクおよび高面圧下において境界潤滑状態で接触させて使用するという過酷な使用条件に耐えうる動力伝達チェーンを用いているので、長期にわたって安定して所定の伝達比で動力伝達を行うことが可能なものとなる。
【００１５】
本発明の第２の動力伝達装置は、円錐面状のシーブ面を有する第１のプーリと、円錐面状のシーブ面を有する第２のプーリと、両者の間に架け渡され、前記第１および第２のプーリのシーブ面と滑り接触をする端面を有する複数のピンと、これらピンによって相互に連結された複数のリンクとを有するチェーンと、を備えた動力伝達装置であって、前記ピンの端面とプーリのシーブ面の無負荷接触における面間隙間の値をＹ（ｘ）としたとき、無負荷で前記ピン端面とシーブ面が接触する場合の接触点とプーリの回転軸を含む断面視においてＹ（ｘ）は対数曲線または対数曲線に近似した曲線になっていることを特徴としている。
上記の構成によれば、高トルクおよび高面圧下において境界潤滑状態で接触させて使用するという過酷な使用条件に耐えうる動力伝達チェーンを用いているので、長期にわたって安定して所定の伝達比で動力伝達を行うことが可能なものとなる。
【００１６】
【発明の実施の形態】
つぎに、本発明の好ましい実施形態について図面を参照しながら説明する。まず、本発明の動力伝達チェーンについて説明する。
図１は本発明の動力伝達チェーンの一実施形態に係るいわゆるチェーン式無段変速機用のチェーン（以下単に「チェーン」ともいう）の要部構成を模式的に示す斜視図である。図１において、Ｘ，Ｙ，Ｚを互いに直交する３方向とする。
本形態に係るチェーン１は、無端状であって、複数の金属（軸受鋼等）製リンク２と、これらリンク２を相互に連結するための複数の金属（軸受鋼等）製ピン３とから構成される。
【００１７】
リンク２は、直方体状であって、１枚につき貫通孔４が２つずつ設けられており、貫通孔４毎にそれぞれピン３が２つずつ圧入できるようになっている。そして、リンク２は、チェーン１の幅方向（Ｚ方向）に平行に配列され、１列おきに貫通孔４が１つ分ずれるよう、さらにチェーン１の長手方向（Ｘ方向）に屈曲可能なように連結されている。
【００１８】
ピン３は、貫通孔４内周面に沿う側面を有する棒状体であり、その側面をリンク２の貫通孔４の内周面に沿わせて、周方向に摺動可能に圧入されている。
そして、ピン３は、図２に示すように、ピン３の軸方向（長手方向、図１のＺ方向）断面視において端面３ａ，３ｂ側の外形線がそれぞれ対数曲線になっている。具体的には、下記の数式（１）で表される対数曲線になっている。
【００１９】
【数７】

【００２０】
上記数式（１）において、Ｆはピン端面にかかる全体荷重であり、Ｌはピン端面の外形線の有効長さであり、πは円周率である。また、Ｅ′は等価ヤング率であって、ピンのヤング率Ｅ_１およびポアソン比ν_１、ピン端面と接触する相手部材であるプーリのヤング率Ｅ_２およびポアソン比ν_２の各数値を用い、Ｅ′＝２／〔（１−ν_１ ^２）／Ｅ_１＋（１−ν_２ ^２）／Ｅ_２〕により算出される値である。さらに、ｋ_１は下記の数式（２）で表される係数であり、ｋ_２は下記の数式（３）で表される係数である。
【００２１】
【数８】

【数９】

【００２２】
このようなピン３は、例えば軸受鋼からなる素材に対し、鍛造、旋削、切削等を施して所定形状に形成された棒状の中間素材を形成した後、ピン端面３ａ，３ｂ側の外形線が上記数式（１）で表される対数曲線になるよう研削加工などを行うことにより製造することができる。
【００２３】
本形態に係るチェーン１は、ピン端面３ａ，３ｂの外形線が対数曲線になっているので、ピン３の軸方向断面視において直線状のプーリのシーブ面と接触して、高トルク（３００Ｎ・ｍ以上）および高面圧（４００ＭＰａ以上）条件下において、境界潤滑状態で滑り接触させて使用しても、局所的に接触圧力の高い部分が発生しない。さらに、上記数式（１）で表される対数曲線としているため、接触部材料内部のダメージが均一に分布する効果もある。このため、ピン端面３ａ，３ｂやシーブ面に局部的に摩耗、圧痕などの表面損傷が早期に発生してしまうといったことなく、大きな動力伝達を行うことが可能となる。また、大きなミスアライメントを許容することが可能となる。なお、本発明者らは、ピン端面３ａ，３ｂの外形線を上記数式（１）で表される対数曲線としたもの（対数クラウニング形状、実施例品）が、ピン端面の外形線を円弧にしたもの（フルクラウニング形状、比較例品）と比べ、１．５倍程度の接触面圧に耐えつつ動力伝達を行えたことを確認している。
【００２４】
なお、本発明のチェーンは、上記数式（１）で表される対数曲線に限定されるものではない。例えば、ピン３の材料がフォンミーゼス（ｖｏｎ Ｍｉｓｅｓ）の降伏条件に従う場合には、下記の数式（４）に示す対数曲線になっていることが好ましく、またピン３の材料がトレスカ（Ｔｒｅｓｃａ）の降伏条件に従う場合には、下記の数式（５）に示す対数曲線になっていることが好ましい。これらの数式（４）（５）で表される対数曲線の場合には、材料の強度限界まで表面損傷を生じることなく、大きな動力伝達を行うことができる。
【００２５】
【数１０】

【００２６】
また、本発明のチェーン１において、ピン３は、ピン３の軸方向（長手方向、図１のＺ方向）断面視において端面３ａ，３ｂ側の外形線がそれぞれ実質的に対数曲線に近似した曲線になっていてもよい。例えば、大きな曲率半径を有する円弧の両端に小さな曲率半径を有する円弧をそれぞれ連結してなる曲線になっていてもよい。このような複合クラウニング形状であれば、対数曲線の場合と比較して機械加工しやすいという利点がある。
【００２７】
さらに、本発明のチェーン１は、ピン３の端面３ａ，３ｂの外形線が上記したようになっておれば、ピン３やリンク２について適宜の形状に変更してもよい。また、ピン３側面や貫通孔４内周面には、摩耗や摺動抵抗を減少させるために、二硫化モリブデン、フッ素等の固体潤滑材を塗布したり、あるいはショットピーニング処理やバレル処理等の粗面化処理を施して潤滑油溜まりのための凹部を形成したりしてもよい。
【００２８】
つぎに、本発明の動力伝達装置について説明する。
図３は、本発明の動力伝達装置の一実施形態に係るいわゆるチェーン式無段変速機（以下単に「無段変速機」ともいう）の要部構成を示す模式的な斜視図である。本形態に係る無段変速機は、例えば自動車に搭載され、第１のプーリとしての金属（構造用鋼等）製ドライブプーリ１０と、第２のプーリとしての金属（構造用鋼等）製ドリブンプーリ２０と、その間に架け渡された無端状のチェーン１とを備えている。なお、図３中のチェーン１は理解を容易にするために一部断面を明示している。
【００２９】
図４も参照して、ドライブプーリ１０は、エンジン側に接続された入力軸１１に一体回転可能に取り付けられたものであり、円錐面状の傾斜面１２ａを有する固定シーブ１２と、その傾斜面１２ａに対向して配置される円錐面状の傾斜面１３ａを有する可動シーブ１３とを備えている。よって、ピン端面とシーブ面は略線接触の状態にある。また、これら傾斜面は図４の断面内（無負荷でピン端面とシーブ面が接触する場合の接触点とプーリの回転軸を含む断面内）で直線状となるよう形成されている。そして、これらシーブの傾斜面１２ａ、１３ａにより溝を形成し、この溝によってチェーン１を強圧で挟んで保持するようになっている。また、可動シーブ１３には、溝幅を変更するための油圧アクチュエータ（図示せず）が接続されており、変速時に、図４の左右方向に可動シーブ１３を移動させることにより溝幅を変化させ、それにより図４の上下方向にチェーン１を移動させて入力軸１１に対するチェーン１の巻掛け半径を変化できるようになっている。
【００３０】
一方、ドリブンプーリ２０は、駆動輪側に接続された出力軸２１に一体回転可能に取り付けられており、ドライブプーリ１０と同様に、チェーン１を強圧で挟む溝を形成するための傾斜面を有する固定シーブ２２と可動シーブ２３とを備えている。また、このプーリ２０の可動シーブ２３には、ドライブプーリ１０の可動シーブ１３と同様に、油圧アクチュエータ（図示せず）が接続されており、変速時に、可動シーブ１３を移動させることにより、溝幅を変化させ、それによりチェーン１を移動させて出力軸２１に対するチェーン１の巻掛け半径を変化できるようになっている。
【００３１】
上記ドライブプーリ１０とドリブンプーリ２０との間に架け渡されるチェーン１は、上述した、図１および図２に示すものである。すなわち、チェーン１を構成するピン３は、その軸方向断面視において端面３ａ，３ｂ側の外形線が対数曲線になっているものである。また、対数曲線に近似した曲線になっていてもよい。なお、詳細については、上述したとおりであるので、その説明は省略する。
【００３２】
上記のように構成された本形態に係る無段変速機では、例えば、以下のようにして無段階の変速を行うことができる。
出力軸２１の回転を減速する場合、ドライブプーリ１０側の溝幅を可動シーブ１３の移動によって拡大させ、チェーン１のピン端面３ａ，３ｂを円錐面状のシーブ面１２ａ，１３ａの内側方向（図４の下方向）に向けて境界潤滑条件下で滑り接触させながらチェーン１の入力軸１１に対する巻き掛け径を小さくする一方、ドリブンプーリ２０側では可動シーブ２３の移動によって溝幅を縮小させ、チェーン１のピン端面３ａ，３ｂを円錐面状のシーブ面２２ａ，２３ａの外側方向に向けて境界潤滑条件下で滑り接触させながらチェーン１の出力軸２１に対する巻き掛け径を大きくする。こうすることで、出力軸２１の回転を減速することができる。
出力軸２１の回転を増速する場合、ドライブプーリ１０側の溝幅を可動シーブ１３の移動によって縮小させ、チェーン１のピン端面３ａ，３ｂを円錐面状のシーブ面１２ａ，１３ａの外側方向（図４の上方向）に向けて境界潤滑条件下で滑り接触させながらチェーン１の入力軸１１に対する巻き掛け径を大きくする一方、ドリブンプーリ２０側では可動シーブ２３の移動によって溝幅を拡大させ、チェーン１のピン端面３ａ，３ｂを円錐面状のシーブ面２２ａ，２３ａの内側方向に向けて境界潤滑条件下で滑り接触させながらチェーン１の出力軸２１に対する巻き掛け径を小さくする。こうすることで、出力軸２１の回転を増速することができる。
【００３３】
以上のように、本形態に係る無段変速機では、変速時にはピン端面３ａ，３ｂと円錐面状のシーブ面１２ａ，１３ａ（２２ａ，２３ａ）とがシーブ面１２ａ，１３ａ（２２ａ，２３ａ）の内外方向に境界潤滑条件下で滑り接触するとともにシーブ面１２ａ，１３ａ（２２ａ，２３ａ）の周方向にも境界潤滑条件下で若干の滑り接触し、また一定の伝達比に固定して動力伝達を行う時にはシーブ面１２ａ，１３ａ（２２ａ，２３ａ）の周方向に境界潤滑条件下で若干の滑り接触を生じながら、動力伝達が行われるが、上記したようなチェーン１を用いているので、高トルク（３００Ｎ・ｍ以上）および高面圧（４００ＭＰａ以上）条件下で使用しても、長期にわたって安定して所定の伝達比で動力伝達を行うことが可能なものとなる。
【００３４】
なお、上記実施形態では、図４の断面視で、対数曲線状のピン端面と直線状のプーリのシーブ面が接触する例を示したが、前記局所的接触応力増大抑制や、ダメージ均一化効果は、ピン端面とシーブ面の接触部形状が相対的に対数曲線等になっていればよい。すなわち、この断面視において、ピン端面とシーブ面の両方に曲線形状を施し、両者が接触した場合、あるいはピン端面を直線状にシーブ面に対数曲線形状を施し、両者が接触した場合の接触部の（無負荷接触における）両面間の隙間の値が対数曲線あるいは対数曲線に近似した曲線となっていても、同様の効果を得ることができる。つまり、無負荷でピン端面とシーブ面とが接触する場合の接触点とプーリの回転軸を含む断面視において、前記隙間の値をＹ（ｘ）（ｘ：前記断面においてｙと垂直方向の座標）とした時、曲線Ｙ（ｘ）が対数曲線あるいは対数曲線に近似していればよい。対数曲線の場合は前記数式（１）が好ましいのは前述と同様である。
【００３５】
本発明の動力伝達装置は、ドライブプーリおよびドリブンプーリの両方の溝幅が変動する態様に限定されるものではなく、いずれか一方の溝幅のみが変動し、他方が変動しない固定幅にした態様であってもよい。また、上記では溝幅が連続的（無段階）に変動する無段変速機について説明したが、有段的に変動したり、固定式（無変速）である等の他の動力伝達装置に適用してもよい。
【００３６】
【発明の効果】
以上のように、本発明の第１の動力伝達チェーンによれば、高トルクおよび高面圧条件下において、境界潤滑状態で滑り接触させて使用しても、長期にわたって、ピン端面やシーブ面に表面損傷を発生させることなく、大きな動力伝達を行うことができるものとなる。
また、本発明の第２の動力伝達チェーンによれば、上記第１の動力伝達チェーンと同様に、高トルクおよび高面圧で、しかも境界潤滑状態の接触という過酷な使用条件に耐え、大きな動力伝達を行うことができるものとなる。また、加工しやすいという利点がある。
さらに、本発明の動力伝達装置によれば、長期にわたって安定して所定の伝達比で動力を伝達することが可能となる。
【図面の簡単な説明】
【図１】本発明の動力伝達チェーンの一実施形態に係るチェーン式無段変速機用チェーンの要部構成を模式的に示す斜視図である。
【図２】図１に示すチェーン式無段変速機用チェーンのピン、リンクのＺ方向の断面図である。
【図３】本発明の動力伝達装置の一実施形態に係るチェーン式無段変速機の要部構成を模式的に示す斜視図である。
【図４】図３に示すチェーン式無段変速機のドライブプーリ（ドリブンプーリ）、チェーンの部分的な拡大断面図である。
【図５】ピン端面形状を曲率半径の小さい円弧面にした場合を模式的に示す断面図である。
【図６】ピン端面形状を曲率半径の大きい円弧面にした場合を模式的に示す断面図である。
【符号の説明】
１ チェーン式無段変速機用チェーン（動力伝達チェーン）
２ リンク
３ ピン
３ａ，３ｂ ピンの端面
４ 貫通孔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power transmission chain used for a so-called chain-type continuously variable transmission employed in a vehicle and the like, and a power transmission device using the same.
[0002]
[Prior art]
As a continuously variable transmission (CVT: Continuously Variable Transmission) of an automobile, for example, a drive pulley provided on an engine side, a driven pulley provided on a drive wheel side, and an endless chain bridged therebetween. Some are provided with In such a chain type continuously variable transmission, the conical sheave surface of each pulley and the pin end surface of the chain are in a boundary lubrication state (a part of the contact surface is in direct contact with minute projections, and the rest is lubricated. Traction is generated by making a slight sliding contact in the circumferential direction of the sheave surface in a lubricating state in which the sheave surface comes into contact with the oil film, and traction is generated, and power is transmitted by the traction force. Then, by continuously changing the groove width (distance between sheave surfaces) of at least one of the drive pulley and the driven pulley, a stepless speed change can be performed with a smooth motion different from the conventional gear type. .
[0003]
In the above-mentioned chain type continuously variable transmission, in order to be applicable to a large vehicle, a chain capable of withstanding the use conditions of high torque (300 Nm or more) and high surface pressure (400 MPa or more) has been developed. I have. In detail, the chain transmits power in a state where it is sandwiched between pulleys that rotate with high torque from both end faces of the pin with high force, so that both ends of the pin have large vertical load and shear. A large load in the direction acts. For this reason, compared to rolling bearings in which a large load acts mainly in the vertical direction, it has specific severe contact conditions, and the development of a chain with a pin end face that can withstand this specific severe contact condition has been developed. Is underway.
[0004]
Under such circumstances, there has been proposed a chain in which an edge layer containing nitrogen such as a carbonitrided layer is formed on the end face of a pin, and the outer shape of the end face of the pin is straight in an axial cross-sectional view (see FIG. 1). For example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-2002-147542 (pages 4 to 5, FIG. 1 and FIG. 3)
[0006]
[Problems to be solved by the invention]
The conventional chain has a carbonitrided layer on the contact surface with the pulley, so that the wear resistance has been improved to some extent.However, it is not sufficient under the conditions of high surface pressure and high torque. I can't say. In addition, when a misalignment occurs such that the axial direction of the pin is not parallel to the axial center of the sheave surface, the edge of the pin comes into strong contact with the sheave surface because the pin end surface is linear. As a result, there is a problem that an edge load (a local increase in contact stress near the edge) occurs and surface damage such as abrasion and indentation occurs.
[0007]
To cope with such a problem, a method of forming the pin end surface into a circular arc surface (full crowning shape) is conceivable. However, in this method, the following problem occurs. For example, as shown in FIG. 5, when the end surface 33a of the pin 33 constituting the chain 31 is an arc surface having a small radius of curvature, it is difficult to transmit a large power because the contact area with the pulley 34 is small. There is a problem in that the contact pressure with the contact surface 34 becomes extremely high, and the pin end face and the sheave face may be damaged early, such as abrasion and indentation. On the other hand, for example, as shown in FIG. 6, when the end surface 33b of the pin 33 constituting the chain 31 is an arc surface having a large radius of curvature, similarly to the case where the pin end surface 33b is linear, if the pin 33 Edge load occurs in the edge portion 33c, and a problem occurs that surface damage such as abrasion and indentation occurs.
[0008]
The present invention has been made in view of such circumstances, and even when used in sliding contact in a boundary lubrication state under high torque and high surface pressure conditions, surface damage to the pin end surface and the sheave surface is caused for a long time. It is an object of the present invention to provide a power transmission chain capable of performing large power transmission without generating power and a power transmission device using the same.
[0009]
[Means for Solving the Problems]
A first power transmission chain of the present invention includes a plurality of links, a plurality of pins interconnecting the links, a first pulley having a conical sheave surface, and a conical sheave surface. A power transmission chain which is used to be bridged between a second pulley and a sliding contact between an end surface of the pin and a sheave surface of the first and second pulleys, wherein the pin is It is characterized in that the outer shape line on the end face side is a logarithmic curve in a sectional view in the axial direction.
[0010]
According to the above configuration, since the outer shape of the pin end surface has a logarithmic curve (the pin end surface has a logarithmic crowning shape), the contact area with the sheave surface becomes appropriate, and the contact pressure is distributed substantially uniformly. Can be done. Therefore, even when the pin is used in sliding contact in a boundary lubrication state under high torque and high surface pressure conditions, a substantially uniform pressure acts on the entire contact portion between the pin end surface and the sheave surface. It is possible to prevent surface damage such as abrasion and dents from being locally generated on the surface at an early stage, thereby prolonging the life as a whole and enabling large power transmission. Further, since the occurrence of edge load can be prevented even if misalignment occurs, a large misalignment can be tolerated. Therefore, large power transmission can be performed for a long time without causing surface damage to the pin end surface or the sheave surface.
[0011]
In the above power transmission chain, it is preferable that the logarithmic curve is a logarithmic curve represented by the following equation (1). In this case, the contact pressure can be very uniformly distributed, and the damage of the material in the contact portion after the contact between the chain and the pulley (after the operation) can be uniformly distributed. For this reason, even when used in sliding contact in a boundary lubrication state under high torque and high surface pressure conditions, local damage in the contact part can be prevented, and surface damage on the pin end surface and sheave surface reliably occurs for a long period of time Without this, large power transmission can be performed.
(Equation 4)

(Equation 5)

(Equation 6)

[0012]
A second power transmission chain according to the present invention includes a plurality of links, a plurality of pins interconnecting the links, a first pulley having a conical sheave surface, and a conical sheave surface. A power transmission chain which is used to be bridged between a second pulley and a sliding contact between an end surface of the pin and a sheave surface of the first and second pulleys, wherein the pin is It is characterized in that the outer shape line on the end face side in the axial sectional view is a curve approximating a logarithmic curve.
[0013]
Like the above-described configuration, even if the outer shape of the pin end face is a curve approximating a logarithmic curve (even if the pin end face has a pseudo composite crowning shape), the same as in the first power transmission chain. Under the conditions of high torque and high surface pressure, even when used in sliding contact with boundary lubrication, large power transmission can be performed for a long time without causing surface damage to the pin end surface or sheave surface. Become. Also, large misalignment can be tolerated. Further, in this case, there is an advantage that processing is easy.
Here, in the present invention, the `` curve approximated to a logarithmic curve '' is not a complete logarithmic curve in the outline of the pin end face, but for example, by connecting a plurality of arcs having different radii of curvature to a logarithmic curve. Like an approximated curve, a curve having the same operation and effect as the logarithmic curve described above.
[0014]
The first power transmission device of the present invention is provided with a first pulley having a conical sheave surface and a second pulley having a conical sheave surface. And a chain having a plurality of pins having end faces in sliding contact with a sheave surface of the second pulley, and a plurality of links interconnected by the pins, wherein the chain is , Or the first or second power transmission chain described above.
According to the above configuration, since the power transmission chain that can withstand the harsh use conditions of being used in contact with the boundary lubrication state under a high torque and a high surface pressure is used, the power transmission chain is stably provided at a predetermined transmission ratio for a long time. Power transmission can be performed.
[0015]
A second power transmission device according to the present invention includes a first pulley having a conical sheave surface and a second pulley having a conical sheave surface. And a chain having a plurality of pins having an end surface in sliding contact with the sheave surface of the second pulley, and a chain having a plurality of links interconnected by the pins. Assuming that the value of the gap between the end face and the sheave face of the pulley in the no-load contact is Y (x), a cross-sectional view including the contact point and the rotation axis of the pulley when the pin end face and the sheave face contact with no load. Is characterized in that Y (x) is a logarithmic curve or a curve approximating the logarithmic curve.
According to the above configuration, since the power transmission chain that can withstand the harsh use conditions of being used in contact with the boundary lubrication state under a high torque and a high surface pressure is used, the power transmission chain is stably provided at a predetermined transmission ratio for a long time. Power transmission can be performed.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a preferred embodiment of the present invention will be described with reference to the drawings. First, the power transmission chain of the present invention will be described.
FIG. 1 is a perspective view schematically showing a main part configuration of a chain for a so-called chain type continuously variable transmission (hereinafter also simply referred to as “chain”) according to an embodiment of the power transmission chain of the present invention. In FIG. 1, X, Y, and Z are three directions orthogonal to each other.
The chain 1 according to this embodiment is endless and includes a plurality of metal (bearing steel or the like) links 2 and a plurality of metal (bearing steel or the like) pins 3 for interconnecting the links 2. Be composed.
[0017]
The link 2 has a rectangular parallelepiped shape, and is provided with two through-holes 4 for each one, so that two pins 3 can be pressed into each of the through-holes 4. The links 2 are arranged in parallel to the width direction (Z direction) of the chain 1 so that the through holes 4 are shifted by one every other row and can be bent in the longitudinal direction of the chain 1 (X direction). It is connected to.
[0018]
The pin 3 is a rod-shaped body having a side surface extending along the inner peripheral surface of the through hole 4, and is press-fit slidably in the circumferential direction along the inner peripheral surface of the through hole 4 of the link 2.
As shown in FIG. 2, the outer shape of the end face 3a, 3b side of the pin 3 in the axial direction (longitudinal direction, Z direction in FIG. 1) is a logarithmic curve. Specifically, it is a logarithmic curve represented by the following equation (1).
[0019]
(Equation 7)

[0020]
In the above formula (1), F is the total load applied to the pin end face, L is the effective length of the outline of the pin end face, and π is the pi. Furthermore, E 'is an equivalent Young's modulus, the Young's modulus E ₁ and Poisson's ratio [nu _{1 pin,} the respective numerical values of the pulley of the Young's modulus E ₂ and Poisson's ratio [nu ₂ is a mating member in contact with the pin end face with, E '= 2 / ^{_{[(1-ν 1 2) /}} E 1 + (1-ν 2 2) / E 2 ] is a value calculated by. Further, k ₁ is a coefficient expressed by the following equation (2), k ₂ is a coefficient expressed by the following equation (3).
[0021]
(Equation 8)

(Equation 9)

[0022]
Such a pin 3 is formed, for example, by forging, turning, cutting, or the like on a material made of bearing steel to form a rod-shaped intermediate material having a predetermined shape, and then the outer shape of the pin end surface 3a, 3b side is changed. It can be manufactured by performing a grinding process or the like so as to obtain a logarithmic curve represented by the above formula (1).
[0023]
In the chain 1 according to the present embodiment, since the outer shape of the pin end faces 3a and 3b is a logarithmic curve, the chain 1 comes into contact with the sheave surface of the linear pulley in the axial cross-sectional view of the pin 3 and has a high torque (300 N · m or more) and a high surface pressure (400 MPa or more), even when used in sliding contact in a boundary lubrication state, a locally high contact pressure portion does not occur. Further, since the logarithmic curve represented by the above equation (1) is used, there is an effect that the damage inside the contact portion material is evenly distributed. For this reason, large power transmission can be performed without the surface damage such as abrasion and indentation occurring locally on the pin end surfaces 3a and 3b and the sheave surface at an early stage. Also, large misalignment can be tolerated. Note that the present inventors have made the outer shape of the pin end faces 3a and 3b into a logarithmic curve represented by the above formula (1) (logarithmic crowning shape, product of the embodiment), but the outer shape of the pin end face is an arc. It was confirmed that power transmission was possible while withstanding a contact surface pressure of about 1.5 times as compared with a conventional one (full crowning shape, comparative example product).
[0024]
Note that the chain of the present invention is not limited to the logarithmic curve represented by the above equation (1). For example, when the material of the pin 3 complies with the yield condition of von Mises, it is preferable that the material of the pin 3 has a logarithmic curve represented by the following equation (4), and the material of the pin 3 is Tresca. When the yield condition is followed, it is preferable that the logarithmic curve shown by the following equation (5) is obtained. In the case of the logarithmic curves represented by these equations (4) and (5), large power transmission can be performed without causing surface damage up to the strength limit of the material.
[0025]
(Equation 10)

[0026]
In the chain 1 of the present invention, the pin 3 has a shape in which the outer shape of the end face 3a, 3b side substantially approximates a logarithmic curve in the axial direction (longitudinal direction, Z direction in FIG. 1) cross-sectional view of the pin 3. It may be. For example, the curve may be formed by connecting arcs having a small radius of curvature to both ends of an arc having a large radius of curvature. Such a composite crowning shape has the advantage that machining is easier than in the case of a logarithmic curve.
[0027]
Further, in the chain 1 of the present invention, the pins 3 and the links 2 may be changed to appropriate shapes as long as the outlines of the end surfaces 3a and 3b of the pins 3 are as described above. In order to reduce abrasion and sliding resistance, a solid lubricant such as molybdenum disulfide or fluorine is applied to the side surfaces of the pins 3 or the inner peripheral surface of the through holes 4, or a shot peening process or a barrel process is performed. A concave portion for storing the lubricating oil may be formed by performing a roughening process.
[0028]
Next, the power transmission device of the present invention will be described.
FIG. 3 is a schematic perspective view showing a main part configuration of a so-called chain-type continuously variable transmission (hereinafter, also simply referred to as “continuously variable transmission”) according to an embodiment of the power transmission device of the present invention. The continuously variable transmission according to this embodiment is mounted on, for example, an automobile, and has a metal (such as structural steel) drive pulley 10 as a first pulley and a metal (such as structural steel) driven as a second pulley. It has a pulley 20 and an endless chain 1 spanned therebetween. The cross section of the chain 1 in FIG. 3 is partially shown for easy understanding.
[0029]
Referring also to FIG. 4, the drive pulley 10 is attached to an input shaft 11 connected to the engine side so as to be integrally rotatable, and has a fixed sheave 12 having a conical inclined surface 12a, and an inclined surface thereof. And a movable sheave 13 having a conical inclined surface 13a arranged opposite to 12a. Therefore, the pin end surface and the sheave surface are in substantially line contact. These inclined surfaces are formed so as to be linear in the cross section of FIG. 4 (in the cross section including the rotation axis of the pulley and the contact point when the pin end surface and the sheave surface come into contact with no load). A groove is formed by the inclined surfaces 12a and 13a of these sheaves, and the chain 1 is held between the grooves by strong pressure. Also, a hydraulic actuator (not shown) for changing the groove width is connected to the movable sheave 13, and the groove width is changed by moving the movable sheave 13 in the left-right direction of FIG. Thereby, the chain 1 can be moved in the vertical direction in FIG. 4 to change the winding radius of the chain 1 around the input shaft 11.
[0030]
On the other hand, the driven pulley 20 is integrally rotatably attached to the output shaft 21 connected to the drive wheel side, and has an inclined surface for forming a groove for sandwiching the chain 1 with high pressure, similarly to the drive pulley 10. A fixed sheave 22 and a movable sheave 23 are provided. A hydraulic actuator (not shown) is connected to the movable sheave 23 of the pulley 20 in the same manner as the movable sheave 13 of the drive pulley 10. , And thereby the chain 1 can be moved to change the winding radius of the chain 1 around the output shaft 21.
[0031]
The chain 1 bridged between the drive pulley 10 and the driven pulley 20 is as shown in FIGS. 1 and 2 described above. In other words, the pin 3 constituting the chain 1 has a logarithmic outer shape on the side of the end faces 3a, 3b in an axial sectional view. In addition, it may be a curve approximating a logarithmic curve. Since the details are as described above, the description is omitted.
[0032]
In the continuously variable transmission according to the present embodiment configured as described above, for example, a stepless speed change can be performed as follows.
When the rotation of the output shaft 21 is decelerated, the groove width on the drive pulley 10 side is enlarged by moving the movable sheave 13, and the pin end surfaces 3a, 3b of the chain 1 are directed inwardly of the conical sheave surfaces 12a, 13a (see FIG. 4 (downward direction) under boundary lubrication conditions, while reducing the winding diameter of the chain 1 around the input shaft 11 while reducing the groove width by moving the movable sheave 23 on the driven pulley 20 side. While the pin end faces 3a and 3b are in sliding contact with the conical sheave faces 22a and 23a outwardly under boundary lubrication conditions, the winding diameter of the chain 1 around the output shaft 21 is increased. By doing so, the rotation of the output shaft 21 can be reduced.
When increasing the rotation of the output shaft 21, the groove width on the drive pulley 10 side is reduced by the movement of the movable sheave 13, and the pin end surfaces 3a, 3b of the chain 1 are directed outwardly of the conical sheave surfaces 12a, 13a ( 4 (upward in FIG. 4), while making the sliding contact under the boundary lubrication condition, the winding diameter of the chain 1 around the input shaft 11 is increased, while the groove width is enlarged by moving the movable sheave 23 on the driven pulley 20 side. The winding diameter of the chain 1 around the output shaft 21 is reduced while sliding the pin end surfaces 3a, 3b of the chain 1 toward the inside of the conical sheave surfaces 22a, 23a under boundary lubrication conditions. By doing so, the rotation of the output shaft 21 can be increased.
[0033]
As described above, in the continuously variable transmission according to the present embodiment, the pin end surfaces 3a, 3b and the conical sheave surfaces 12a, 13a (22a, 23a) are the sheave surfaces 12a, 13a (22a, 23a) at the time of gear shifting. Sliding contact in the inward and outward directions under boundary lubrication conditions, and slight sliding contact also in the circumferential direction of the sheave surfaces 12a, 13a (22a, 23a) under boundary lubrication conditions, and power transmission is fixed at a fixed transmission ratio. When the power is transmitted, power is transmitted while slightly sliding contact occurs in the circumferential direction of the sheave surfaces 12a and 13a (22a and 23a) under boundary lubrication conditions. However, since the above-described chain 1 is used, high torque is applied. (300 N · m or more) and high surface pressure (400 MPa or more), it is possible to stably transmit power at a predetermined transmission ratio over a long period of time.
[0034]
In the above-described embodiment, an example in which the log-curved pin end face and the sheave surface of the linear pulley are in contact with each other in the cross-sectional view of FIG. 4 has been described. It is sufficient that the shape of the contact portion between the pin end surface and the sheave surface is relatively a logarithmic curve or the like. That is, in this cross-sectional view, a contact portion is formed when both the pin end surface and the sheave surface are curved and both are in contact with each other, or when the pin end surface is linearly formed into a logarithmic curve on the sheave surface and both are in contact with each other. The same effect can be obtained even if the value of the gap between both surfaces (in the no-load contact) is a logarithmic curve or a curve approximating a logarithmic curve. That is, in a sectional view including the contact point and the rotation axis of the pulley when the pin end surface and the sheave surface come into contact with no load, the value of the gap is represented by Y (x) (x: coordinate in the perpendicular direction to y in the cross section) ), It is only necessary that the curve Y (x) approximates a logarithmic curve or a logarithmic curve. In the case of a logarithmic curve, the above equation (1) is preferable as described above.
[0035]
The power transmission device of the present invention is not limited to a mode in which the groove width of both the drive pulley and the driven pulley fluctuates, but a mode in which only one of the groove widths fluctuates and the other has a fixed width that does not fluctuate. It may be. In the above description, a continuously variable transmission in which the groove width continuously (steplessly) fluctuates has been described. May be.
[0036]
【The invention's effect】
As described above, according to the first power transmission chain of the present invention, even when used in sliding contact in a boundary lubrication state under high torque and high surface pressure conditions, the pin end surface or sheave surface can be used for a long time. Large power transmission can be performed without causing surface damage.
Further, according to the second power transmission chain of the present invention, similarly to the first power transmission chain, it can withstand the severe operating conditions of high torque and high surface pressure and contact in a boundary lubrication state, and can provide a large power transmission. Communication can be performed. In addition, there is an advantage that processing is easy.
Furthermore, according to the power transmission device of the present invention, it is possible to transmit power at a predetermined transmission ratio stably over a long period of time.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a main configuration of a chain for a chain-type continuously variable transmission according to an embodiment of a power transmission chain of the present invention.
FIG. 2 is a sectional view in the Z direction of pins and links of the chain-type continuously variable transmission chain shown in FIG.
FIG. 3 is a perspective view schematically showing a main part configuration of a chain-type continuously variable transmission according to an embodiment of the power transmission device of the present invention.
4 is a partially enlarged sectional view of a drive pulley (driven pulley) and a chain of the chain type continuously variable transmission shown in FIG.
FIG. 5 is a cross-sectional view schematically showing a case where a pin end surface shape is an arc surface having a small radius of curvature.
FIG. 6 is a cross-sectional view schematically showing a case where a pin end surface shape is an arc surface having a large radius of curvature.
[Explanation of symbols]
1 Chain type continuously variable transmission chain (power transmission chain)
2 Link 3 Pin 3a, 3b Pin end face 4 Through hole

Claims (5)

A first pulley having a conical sheave surface and a second pulley having a conical sheave surface, comprising a plurality of links and a plurality of pins interconnecting the links; A power transmission chain for sliding contact between an end surface of the pin and a sheave surface of the first and second pulleys,
The power transmission chain according to claim 1, wherein the outer shape of the end face side of the pin in a cross-sectional view in the axial direction is a logarithmic curve. The power transmission chain according to claim 1, wherein the logarithmic curve is a logarithmic curve represented by the following equation (1).

A first pulley having a conical sheave surface and a second pulley having a conical sheave surface, comprising a plurality of links and a plurality of pins interconnecting the links; A power transmission chain for sliding contact between an end surface of the pin and a sheave surface of the first and second pulleys,
A power transmission chain, wherein the outer shape of the end face side of the pin in the axial sectional view is a curve approximating a logarithmic curve. A first pulley having a conical sheave surface;
A second pulley having a conical sheave surface;
A chain having a plurality of pins that are bridged between the two and have end faces that make sliding contact with the sheave surfaces of the first and second pulleys, and a plurality of links that are interconnected by the pins; Power transmission device,
A power transmission device, wherein the chain is the power transmission chain according to any one of claims 1 to 3. A first pulley having a conical sheave surface;
A second pulley having a conical sheave surface;
A chain having a plurality of pins that are bridged between the two and have end faces that make sliding contact with the sheave surfaces of the first and second pulleys, and a plurality of links that are interconnected by the pins; Power transmission device,
When the value of the gap between the end surface of the pin and the sheave surface of the pulley in the no-load contact is Y (x), the contact point when the end surface of the pin and the sheave surface contact with no load and the rotation axis of the pulley Wherein Y (x) is a logarithmic curve or a curve approximating a logarithmic curve in a cross-sectional view including:

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