JPH0979336A - Rolling body for toroidal type continuously variable transmission having excellent rolling fatigue strength - Google Patents
Rolling body for toroidal type continuously variable transmission having excellent rolling fatigue strengthInfo
- Publication number
- JPH0979336A JPH0979336A JP23572495A JP23572495A JPH0979336A JP H0979336 A JPH0979336 A JP H0979336A JP 23572495 A JP23572495 A JP 23572495A JP 23572495 A JP23572495 A JP 23572495A JP H0979336 A JPH0979336 A JP H0979336A
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- amount
- depth
- continuously variable
- variable transmission
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H15/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members
- F16H15/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members without members having orbital motion
- F16H15/04—Gearings providing a continuous range of gear ratios
- F16H15/06—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B
- F16H15/32—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a curved friction surface formed as a surface of a body of revolution generated by a curve which is neither a circular arc centered on its axis of revolution nor a straight line
- F16H15/36—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a curved friction surface formed as a surface of a body of revolution generated by a curve which is neither a circular arc centered on its axis of revolution nor a straight line with concave friction surface, e.g. a hollow toroid surface
- F16H15/38—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a curved friction surface formed as a surface of a body of revolution generated by a curve which is neither a circular arc centered on its axis of revolution nor a straight line with concave friction surface, e.g. a hollow toroid surface with two members B having hollow toroid surfaces opposite to each other, the member or members A being adjustably mounted between the surfaces
- F16H2015/383—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a curved friction surface formed as a surface of a body of revolution generated by a curve which is neither a circular arc centered on its axis of revolution nor a straight line with concave friction surface, e.g. a hollow toroid surface with two members B having hollow toroid surfaces opposite to each other, the member or members A being adjustably mounted between the surfaces with two or more sets of toroid gearings arranged in parallel
Landscapes
- Friction Gearing (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、自動車などの車両
や回転動力源等において、無段変速機として使用可能な
トロイダル式（転がり式）無段変速機に関し、とくに、
トロイダル式無段変速機を構成する転動体に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toroidal type (rolling type) continuously variable transmission that can be used as a continuously variable transmission in vehicles such as automobiles and rotary power sources.
The present invention relates to a rolling element that constitutes a toroidal type continuously variable transmission.
【０００２】[0002]
【従来の技術】自動車などの車両において使用される変
速機としては、歯車列における噛み合わせ状態を手動や
自動で切り替える有段変速機が多く用いられているが、
無段変速機を採用する試みもなされている。2. Description of the Related Art As a transmission used in a vehicle such as an automobile, a stepped transmission that switches the meshing state of a gear train manually or automatically is often used.
Attempts have also been made to adopt a continuously variable transmission.
【０００３】この無段変速機は、連続的に変速するた
め、燃費が向上すること、変速ショックが無いこと等の
特徴をもっているが、その構造によって、ベルト式とト
ロイダル式の２つに大別される。Since the continuously variable transmission continuously shifts gears, it is characterized by improved fuel economy and no shift shock, but it is roughly classified into a belt type and a toroidal type according to its structure. To be done.
【０００４】その中で、トロイダル式（転がり式）の無
段変速機は、図１に示すように、潤滑油を介して接触す
る金属製転動体を用いた構造を有するものであって、こ
のトロイダル式無段変速機１は、入力軸２に接続したロ
ーディングカム３および連結軸４を介して一体で回転す
る入力ディスク５，５を備えていると共に、歯車６，７
を介して出力軸８を回転させる出力ディスク９，９をそ
なえ、入力ディスク５，５と出力ディスク９，９との間
にパワーローラー１０，１０，１０，１０を設け、各パ
ワーローラー１０はボールベアリング１１を介して各々
支持体１２により支持された構造を有するものである。Among them, a toroidal type (rolling type) continuously variable transmission has a structure using metal rolling elements that come into contact with each other through lubricating oil, as shown in FIG. The toroidal type continuously variable transmission 1 includes input disks 5 and 5 that rotate integrally via a loading cam 3 and a connecting shaft 4 connected to an input shaft 2, and gears 6 and 7.
It is equipped with output disks 9 and 9 for rotating the output shaft 8 via, and power rollers 10, 10, 10 and 10 are provided between the input disks 5 and 5 and the output disks 9 and 9, and each power roller 10 is a ball. The structure is such that each is supported by a support 12 via a bearing 11.
【０００５】そして、このトロイダル式無段変速機１で
は、入力ディスク５と出力ディスク９との間で挟まれた
パワーローラー１０の傾きを変化させ、入出力ディスク
５，９の相対回転速度を変えて変速しつつ、入力軸２か
ら出力軸８へと動力を伝達する仕組みになっている（特
開平１−２２９１５８号公報など）。In the toroidal type continuously variable transmission 1, the inclination of the power roller 10 sandwiched between the input disk 5 and the output disk 9 is changed to change the relative rotation speed of the input / output disks 5, 9. The mechanism is such that power is transmitted from the input shaft 2 to the output shaft 8 while shifting gears (Japanese Patent Laid-Open No. 1-229158, etc.).
【０００６】そのため、このような金属製転動体よりな
る入力ディスク５，出力ディスク９およびパワーローラ
ー１０は、エンジントルクの入力によって、転動面にお
いては面圧入力を受けることとなるので、面疲労強度
（転動疲労強度）に優れていることが要求され、高い表
面硬度と深い硬化層深さを有していることが必要となる
（例えば、特開平７−７１５５５号等）。Therefore, the input disk 5, the output disk 9 and the power roller 10 made of such metal rolling elements receive a surface pressure input on the rolling surface due to the input of the engine torque, so that the surface fatigue occurs. It is required to have excellent strength (rolling fatigue strength), and it is necessary to have a high surface hardness and a deep hardened layer depth (for example, JP-A-7-71555).
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、このよ
うな従来のトロイダル式無段変速機１の転動体（５，
９，１０）においては、トルクを伝達するために入力デ
ィスク５にローディングカム３にて荷重をかけ、転動面
に高い面圧を負荷する必要があるため、転動体内部に高
い剪断応力が発生し、最大剪断応力の発生深さ付近を起
点とする亀裂が生成され、ピッティング剥離に至る故障
が生じることがあった。また、剥離に至らない場合で
も、内部の塑性変形に伴い転動面が陥没し、変速性能が
損なわれることがあった。However, the rolling element (5, 5 of the conventional toroidal type continuously variable transmission 1 as described above is provided.
9 and 10), it is necessary to apply a load to the input disk 5 by the loading cam 3 in order to transmit the torque and to apply a high surface pressure to the rolling surface, so that a high shear stress is generated inside the rolling element. However, a crack having a starting point near the maximum shear stress generation depth may be generated, resulting in a failure leading to pitting separation. Further, even if the peeling does not occur, the rolling surface may be depressed due to the plastic deformation of the inside, and the shifting performance may be impaired.
【０００８】更に、使用中のトロイダル式無段変速機１
の潤滑油中には、種々の摺動部品から生じる夾雑物があ
り、このような夾雑物が転動面に噛み込むと圧痕が出
来、その周囲に形成される応力集中により、表面起点の
亀裂が発生し、ピッティング剥離に至ることがあった。Further, the toroidal type continuously variable transmission 1 in use
In the lubricating oil of, there are contaminants that are generated from various sliding parts.When such contaminants are caught in the rolling surface, indentations are created, and the stress concentration around them creates a crack at the surface starting point. May occur and lead to pitting peeling.
【０００９】そして、パワーローラー１０の背面は、ボ
ールベアリング１１を介して各々支持体１２により支持
されているが、入力ディスク５に荷重が負荷される際
に、やはり高い面圧が発生するため、夾雑物を噛み込む
と表面起点の亀裂および剥離が発生することがあった。The back surface of the power roller 10 is respectively supported by the support 12 via the ball bearings 11. However, when a load is applied to the input disk 5, a high surface pressure is also generated. Occurrence of cracks and delamination at the surface origin sometimes occurred when foreign matter was caught.
【００１０】したがって、このような内部起点の亀裂お
よび剥離が生じがたく、また、表面起点の亀裂および剥
離が発生しがたいものとすることが課題であった。[0010] Therefore, it has been a problem to prevent such cracks and peeling originating from the inside, and to prevent cracks and peeling originating from the surface.
【００１１】[0011]
【発明の目的】本発明は、上記の課題にかんがみてなさ
れたものであって、Ｃｒを含有する機械構造用鋼を用い
たトロイダル式無段変速機用転動体において、耐ピッテ
ィング性および転動疲労強度に優れ、内部起点の亀裂お
よび剥離が生じがたいと共に、表面起点の亀裂および剥
離も生じがたく、長寿命のものにできるようにすること
を目的としている。SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a rolling element for a toroidal-type continuously variable transmission using a Cr-containing steel for machine structural use, which is resistant to pitting and rolling. The object of the present invention is to provide a material with excellent dynamic fatigue strength, which is unlikely to be cracked and peeled from an internal origin, and which is unlikely to be cracked and peeled from a surface origin to have a long life.
【００１２】[0012]
【課題を解決するための手段】上記課題を解決すること
のできた本発明に係わるトロイダル式無段変速機用転動
体の構成は、以下の通りである。The structure of the rolling element for a toroidal type continuously variable transmission according to the present invention, which can solve the above-mentioned problems, is as follows.
【００１３】すなわち、潤滑油を介して接触する複数個
の金属製転動体を用いたトロイダル式無段変速機におい
て、前記転動体の素材としてＣｒを含有する機械構造用
鋼を用い、浸炭窒化処理により、転動面におけるＮ量が
重量％で０．２％以上０．６％以下、面接触により転動
体内部に発生する最大剪断応力の発生深さをＺｓｔとし
たときに深さｄ≦０．２Ｚｓｔの位置においてＣ＋Ｎ量
が重量％で０．９％以上１．３％以下、残留オーステナ
イト量が体積％で２０％以上４５％以下、硬さがＨＶ５
００以上であり、かつ、深さ０．５Ｚｓｔ≦ｄ≦１．４
Ｚｓｔの位置においてＣおよびＮ量が重量％で０．６％
≦Ｃ＋Ｎ≦１．２％、硬さがＨＶ７００以上であるトロ
イダル式無段変速機用転動体の構成としたことを特徴と
している。That is, in a toroidal type continuously variable transmission using a plurality of metallic rolling elements that come into contact with each other through lubricating oil, carbon steel is used for the mechanical structural steel containing Cr as the raw material of the rolling elements, and carbonitriding treatment is performed. As a result, when the amount of N in the rolling surface is 0.2% or more and 0.6% or less in weight%, and the maximum shear stress generated inside the rolling element due to surface contact is Zst, the depth d ≦ 0. At the position of 2Zst, the C + N amount is 0.9% or more and 1.3% or less by weight%, the retained austenite amount is 20% or more and 45% or less by volume%, and the hardness is HV5.
00 or more and a depth of 0.5 Zst ≦ d ≦ 1.4
0.6% by weight of C and N at Zst position
It is characterized in that it has a structure of a rolling element for a toroidal-type continuously variable transmission having ≦ C + N ≦ 1.2% and a hardness of HV 700 or more.
【００１４】本発明に係わるトロイダル式無段変速機用
転動体は、Ｃｒを含有する機械構造用鋼を素材として用
いるものであるが、この場合、Ｃｒは、焼き入れ性，浸
炭窒化性を向上させる作用を有すると共に、炭窒化物を
形成して軟化抵抗を向上させる作用を有している。そし
て、この場合のＣｒ含有量は０．２〜５．０％程度とす
ることが好ましく、このようなＣｒを含有する機械構造
用鋼としては、例えば、ＪＩＳに制定するニッケルクロ
ム鋼（ＳＮＣ），ニッケルクロムモリブデン鋼（ＳＮＣ
Ｍ），クロム鋼（ＳＣｒ），クロムモリブデン鋼（ＳＣ
Ｍ），マンガンクロム鋼（ＳＭｎＣ）等があり、その他
適宜に成分調整したものが用いられる。The rolling element for a toroidal type continuously variable transmission according to the present invention uses Cr-containing machine structural steel as a raw material. In this case, Cr improves hardenability and carbonitriding property. In addition to having the effect of making it soften, it has the effect of forming carbonitrides and improving the softening resistance. And, in this case, the Cr content is preferably about 0.2 to 5.0%, and as the steel for mechanical structure containing such Cr, for example, nickel chrome steel (SNC) defined in JIS is used. , Nickel chrome molybdenum steel (SNC
M), chrome steel (SCr), chrome molybdenum steel (SC
M), manganese chrome steel (SMnC), and the like, and those whose components are appropriately adjusted are used.
【００１５】[0015]
【発明の作用】以下に、本発明によるトロイダル式無段
変速機用転動体の浸炭窒化処理によるＣおよびＮ量、残
留オーステナイト量、硬さを定めた理由を各々の作用と
共に順次説明するが、以下の説明において、Ｚｓｔは転
動面における荷重により転動体内部に発生する最大剪断
応力の発生深さであり、ＣおよびＮ量は重量％、残留オ
ーステナイト量は体積％にて表わす。The reasons for determining the amounts of C and N, the amount of retained austenite, and the hardness by carbonitriding of the rolling element for a toroidal type continuously variable transmission according to the present invention will be sequentially described below together with the respective actions. In the following description, Zst is the depth of maximum shear stress generated inside the rolling element due to the load on the rolling surface, the C and N contents are expressed in weight%, and the residual austenite amount is expressed in volume%.
【００１６】転動面におけるＮ量：重量％で０．２％以
上０．６％以下 潤滑油中の夾雑物が転動面に噛み込むと、表面に微小な
陥没が生じ、陥没周囲の応力集中部に亀裂が生成する。
この亀裂生成を阻止するためには、応力集中を緩和する
とともに、金属組織を強化する必要がある。応力集中の
緩和には延性に優れる残留オーステナイトが必要である
が、Ｎ量が０．２％未満では、その量が不十分で、か
つ、残留オーステナイトに固溶しているＮ量が不足して
強度不足となるため、容易に亀裂が生成するので、０．
２％以上とした。しかし、Ｎ量が０．６％を超えると、
残留オーステナイトが多すぎ、硬度が低下するため、亀
裂生成が容易となる。また、Ｎ量が０．６％を超える
と、焼き入れ時にベイナイトが生成され、所望の残留オ
ーステナイト量が得られないこともあるので、０．６％
以下とした。N content in rolling surface: 0.2% or more and 0.6% or less by weight% When foreign matter in the lubricating oil is caught in the rolling surface, a minute depression is generated on the surface and stress around the depression is generated. A crack is generated in the concentrated portion.
In order to prevent this crack formation, it is necessary to relieve stress concentration and strengthen the metal structure. Retained austenite with excellent ductility is required to relax stress concentration, but if the N content is less than 0.2%, the amount is insufficient and the amount of N dissolved in the retained austenite is insufficient. Since the strength is insufficient, cracks are easily generated.
2% or more. However, if the N content exceeds 0.6%,
Since the amount of retained austenite is too large and the hardness is lowered, crack formation is facilitated. On the other hand, if the N content exceeds 0.6%, bainite may be formed during quenching, and the desired residual austenite content may not be obtained.
Below.
【００１７】深さｄ≦０．２Ｚｓｔの位置におけるＣ＋
Ｎ量：重量％で０．９％以上１．３％以下 この部分は、潤滑油中の夾雑物が転動面に噛み込み、転
動表面で生成したクラックが伝播しやすい。それを阻止
するためには、転動体の金属組織が十分な靭性を有する
ことが必要であるが、Ｃ＋Ｎ量が０．９％未満では亀裂
の生成および伝播を阻止するのに十分な高い靭性を有す
る残留オーステナイトが得られないので、０．９％以上
とした。しかし、Ｃ＋Ｎ量が１．３％を超えると結晶粒
界に網状に炭（窒）化物が生成し、かえって亀裂の生成
および伝播を助長するので、１．３％以下とした。C + at the position of depth d≤0.2Zst
N content: 0.9% or more and 1.3% or less in weight% In this portion, impurities in the lubricating oil are caught in the rolling surface, and cracks generated on the rolling surface easily propagate. In order to prevent this, it is necessary that the metal structure of the rolling element has sufficient toughness, but if the C + N content is less than 0.9%, a sufficiently high toughness to prevent the generation and propagation of cracks is required. Since the retained austenite which it has cannot be obtained, it was set to 0.9% or more. However, when the amount of C + N exceeds 1.3%, carbon (nitride) nitrides are formed in the crystal grain boundaries in a net-like manner, which rather promotes the generation and propagation of cracks, so the content was made 1.3% or less.
【００１８】深さｄ≦０．２Ｚｓｔの位置における残留
オーステナイト量：体積％で２０％以上４５％以下 残留オーステナイトは靭性に優れた組織であって、亀裂
先端の応力を緩和し、その伝播を阻止する作用がある。
しかし、この深さの部分においてその量が２０％未満で
は、亀裂の伝播を阻止するには不十分であるので、２０
％以上とした。一方、その量が４５％を超えると、硬度
が低下し大きな陥没が生じるので、４５％以下とした。Amount of retained austenite at a position of depth d ≦ 0.2 Zst: 20% or more and 45% or less in volume% Retained austenite is a structure having excellent toughness and relaxes the stress at the crack tip and prevents its propagation. There is an action.
However, if the amount is less than 20% in this depth portion, it is not enough to prevent the propagation of cracks.
% And above. On the other hand, if the amount exceeds 45%, the hardness decreases and a large depression occurs, so the amount was made 45% or less.
【００１９】深さｄ≦０．２Ｚｓｔの位置における硬
さ：ビッカース硬さでＨＶ５００以上 この深さの部分における硬さがＨＶ５００を下回ると繰
り返し荷重による亀裂の生成および伝播が容易となるの
で、ＨＶ５００以上とした。Hardness at a depth d ≦ 0.2 Zst: Vickers hardness of HV500 or more If the hardness at this depth is less than HV500, cracks are easily generated and propagated by repeated load, and thus HV500. That's it.
【００２０】０．５Ｚｓｔ≦ｄ≦１．４Ｚｓｔの位置に
おけるＣ＋Ｎ量：重量％で０．６％≦Ｃ＋Ｎ≦１．２％ この深さの部位は、大きな剪断応力の繰り返しを受ける
ため、内部亀裂の起点となることが多く、また、塑性変
形が生じて転動面が大きく陥没する原因ともなる。そし
て、この部位でＣ＋Ｎ量が０．６％未満であると、マル
テンサイトの硬さが低下し、大きな陥没が生じるので、
０．６％以上とした。また、Ｃ＋Ｎ量が１．２％を超え
ると、炭窒化物が析出することに伴い、その周囲に不完
全焼き入れ組織が形成され、そこを起点とする亀裂が生
成するので１．２％以下とした。C + N content at a position of 0.5 Zst ≦ d ≦ 1.4 Zst: 0.6% by weight% ≦ C + N ≦ 1.2% Since a portion of this depth is repeatedly subjected to a large shear stress, an internal crack is generated. Often becomes the starting point, and also causes plastic deformation to cause a large depression of the rolling surface. If the C + N amount is less than 0.6% at this portion, the hardness of martensite decreases and a large depression occurs.
It was set to 0.6% or more. Further, when the amount of C + N exceeds 1.2%, an incompletely hardened structure is formed around the carbonitride due to the precipitation thereof, and a crack starting from that is formed, so 1.2% or less And
【００２１】０．５Ｚｓｔ≦ｄ≦１．４Ｚｓｔの位置に
おける硬さ：ビッカース硬さでＨＶ７００以上 この深さ範囲での硬さがＨＶ７００未満となると、この
部位の塑性変形に起因する転動面の陥没が大きくなり、
トロイダル式無段変速機用転動体としての変速性能を阻
害するので、硬さはＨＶ７００以上とする必要がある。Hardness at a position of 0.5 Zst ≦ d ≦ 1.4 Zst: Vickers hardness of HV 700 or more When the hardness in this depth range is less than HV 700, the rolling surface of the rolling surface due to plastic deformation of this portion The depression will be bigger,
Since the rolling performance for the toroidal type continuously variable transmission is impaired, the hardness needs to be HV 700 or more.
【００２２】[0022]
【実施例】この実施例においては、先に説明した図１に
示したトロイダル式無段変速機１に適用した場合につい
て述べる。すでに説明したように、図１に示すトロイダ
ル式無段変速機１は、金属製転動体である入力ディスク
５、出力ディスク９およびパワーローラー１０を１組と
し、動力伝達能力により１組ないしは複数組（本実施例
の場合は２組）から構成されている。EXAMPLE In this example, the case of application to the toroidal type continuously variable transmission 1 shown in FIG. 1 described above will be described. As described above, the toroidal type continuously variable transmission 1 shown in FIG. 1 has the input disc 5, the output disc 9 and the power roller 10 which are metal rolling elements as one set, and one set or a plurality of sets depending on the power transmission capability. (Two sets in the case of the present embodiment).
【００２３】これらの金属製転動体である入力ディスク
５，出力ディスク９およびパワーローラー１０におい
て、この実施例では、表１に示す化学成分のクロムを含
有する機械構造用低合金鋼、すなわち、クロムモリブデ
ン鋼（ＳＣＭ）を使用した。In these examples of the input disc 5, the output disc 9 and the power roller 10 which are metallic rolling elements, in this example, a low alloy steel for machine structural use containing chromium as a chemical component shown in Table 1, that is, chromium. Molybdenum steel (SCM) was used.
【００２４】そして、表１に示した鋼材を部品形状に機
械加工を行った後、図２および表２に示すように、浸炭
窒化（一部浸炭）条件を適宜選択して熱処理を行い、研
磨加工を行って、入出力ディスク５，９およびパワーロ
ーラー１０の作製を行った。Then, after the steel materials shown in Table 1 were machined into the shape of parts, as shown in FIG. 2 and Table 2, carbonitriding (partially carburizing) conditions were appropriately selected, heat treatment was performed, and polishing was performed. By processing, the input / output disks 5 and 9 and the power roller 10 were manufactured.
【００２５】次いで、ディスク５，９およびパワーロー
ラー１０の表面および特定の深さの位置におけるビッカ
ース硬さ、Ｃ量、Ｎ量、残留オーステナイト（γＲ）量
を測定したところ、表３ないし表６に示す結果であっ
た。なお、表３ないし表６中のＺｓｔは、Ｈｅｒｔｚ接
触（面接触）により転動体内部に発生する最大剪断応力
の発生深さ（ｍｍ）を示すものである。Next, the Vickers hardness, the C content, the N content, and the retained austenite (γR) content on the surfaces of the disks 5 and 9 and the power roller 10 and at the position of a specific depth were measured. It was the result shown. Zst in Tables 3 to 6 indicates the depth (mm) of maximum shear stress generated inside the rolling element due to Hertz contact (surface contact).
【００２６】次に、各実施例１〜７および比較例１〜５
に基づいて作製した各入力ディスク５，出力ディスク９
およびパワーローラー１０に対し、表７に示す条件下で
耐久試験を実施した。この結果を同じく表４および表６
に示す。Next, Examples 1 to 7 and Comparative Examples 1 to 5
Each input disk 5 and output disk 9 produced based on
A durability test was performed on the power roller 10 and the conditions shown in Table 7. The results are also shown in Table 4 and Table 6.
Shown in
【００２７】[0027]
【表１】 [Table 1]
【００２８】[0028]
【表２】 [Table 2]
【００２９】[0029]
【表３】 [Table 3]
【００３０】[0030]
【表４】 [Table 4]
【００３１】[0031]
【表５】 [Table 5]
【００３２】[0032]
【表６】 [Table 6]
【００３３】[0033]
【表７】 [Table 7]
【００３４】表３ないし表６に示すように、本発明実施
例１〜７によれば、比較例１〜５のものと比べて剥離寿
命回数が多く、転動疲労特性に優れたものとなっている
と共に、剥離形態がすべて内部となっていて、表面起点
の剥離がなく、かつまた転動面の陥没などの変形も生じ
ないものとなっていることが確かめられた。As shown in Tables 3 to 6, according to Examples 1 to 7 of the present invention, the number of peeling lives was greater than those of Comparative Examples 1 to 5 and the rolling fatigue characteristics were excellent. In addition, it was confirmed that the peeling morphology was all inside, and that there was no peeling at the surface origin and no deformation such as depression of the rolling surface.
【００３５】このように、本発明実施例において確認さ
れたところからもわかるように、 （１）表面におけるＮ量が０．２〜０．６％で、かつ、
深さｄ≦０．２Ｚｓｔの位置におけるＣ＋Ｎ量が０．９
〜１．３％、残留オーステナイト量が２０〜４５％の範
囲であると、Ｎの固溶により、微小陥没部の応力集中を
緩和する残留オーステナイトを強化し、表面からの亀裂
の生成を抑制するため、耐ピッチング性を向上する。Thus, as can be seen from the results confirmed in the examples of the present invention, (1) the amount of N on the surface is 0.2 to 0.6%, and
The amount of C + N at the position of depth d ≦ 0.2Zst is 0.9
.About.1.3% and the amount of retained austenite is in the range of 20 to 45%, the solid solution of N strengthens the retained austenite that alleviates the stress concentration in the micro depression and suppresses the generation of cracks from the surface. Therefore, the pitting resistance is improved.
【００３６】（２）深さｄ≦０．２Ｚｓｔの位置におけ
る硬さがＨＶ５００以上であると、繰り返し荷重による
亀裂伝播を抑制するため、耐ピッチング性を向上する。(2) When the hardness at the position of depth d ≦ 0.2Zst is HV500 or more, crack propagation due to repeated load is suppressed, and thus pitching resistance is improved.
【００３７】（３）深さ０．５Ｚｓｔ≦ｄ≦１．４Ｚｓ
ｔの位置においてＣ＋Ｎ量が０．６≦Ｃ＋Ｎ≦１．２％
でかつ、硬さがＨＶ７００以上であると、マルテンサイ
ト＋炭窒化物の析出により、内部の塑性変形による転動
面陥没を抑制し、最大剪断応力の発生深さＺｓｔ近傍で
の剪断応力の繰り返しによる亀裂の発生および伝播を抑
制するため、面疲労強度を向上する。(3) Depth 0.5 Zst≤d≤1.4 Zs
C + N amount is 0.6 ≦ C + N ≦ 1.2% at the position of t
When the hardness is HV 700 or more, the rolling surface depression due to the plastic deformation inside is suppressed by the precipitation of martensite + carbonitride, and the shear stress is repeated in the vicinity of the maximum shear stress occurrence depth Zst. The surface fatigue strength is improved by suppressing the generation and propagation of cracks caused by.
【００３８】など、それぞれ必要とする特性を兼ね備え
ていることから、転動疲労特性が改善され、耐久寿命が
向上した転動体となる。Each of the rolling elements has required characteristics, so that the rolling fatigue characteristics are improved and the rolling element has a longer life.
【００３９】さらに、実施例１，３，５，６のように、
浸炭拡散時に少量のＮＨ３ガスを流すような熱処理法
（表２に示したＨ／Ｔ Ｎｏ．１，３，５，６）である
と、Ｎが深くまで拡散していくため、より高い面疲労強
度（転動疲労強度）を得ることが出来る。Further, as in Examples 1, 3, 5, and 6,
In the case of the heat treatment method (H / T No. 1, 3, 5, 6 shown in Table 2) in which a small amount of NH 3 gas is caused to flow at the time of carburizing and diffusing, since N diffuses deeply, a higher surface is obtained. Fatigue strength (rolling fatigue strength) can be obtained.
【００４０】さらにまた、実施例３，６のように、深さ
ｄ＝Ｚｓｔの位置におけるＣ＋Ｎ量が０．７５〜０．８
５％であると、その位置でほぼ最高硬さがＨＶ７６０以
上となり、より高い転動疲労強度を得ることが出来る。Furthermore, as in Examples 3 and 6, the amount of C + N at the position of depth d = Zst is 0.75 to 0.8.
When it is 5%, the maximum hardness becomes HV760 or more at that position, and higher rolling contact fatigue strength can be obtained.
【００４１】これに対して、比較例１，３のように、深
さｄ＝Ｚｓｔの位置における硬さがＨＶ７００未満であ
ると、硬さ不足によりＺｓｔ近傍で塑性変形を起こし、
転動面が陥没し、短寿命で剥離してしまう。On the other hand, as in Comparative Examples 1 and 3, when the hardness at the position of the depth d = Zst is less than HV700, plastic deformation occurs in the vicinity of Zst due to insufficient hardness,
The rolling surface is depressed and peels off with a short life.
【００４２】また、比較例２，４で示すように、表面の
残留オーステナイト量が５０％以上と多く、硬さがＨＶ
５００未満のものは、表面起点の剥離を生じ、寿命も短
くなってしまう。Further, as shown in Comparative Examples 2 and 4, the residual austenite amount on the surface is as high as 50% or more, and the hardness is HV.
If it is less than 500, peeling from the surface origin occurs and the life is shortened.
【００４３】さらに、比較例５のように、最表面でのＮ
量が０．２％未満で、残留オーステナイト量が２０％未
満のものは、残留オーステナイト量が少ないことによる
靭性不足のため、表面起点の亀裂を生じやすく、寿命も
短くなってしまう。Further, as in Comparative Example 5, N on the outermost surface
If the amount is less than 0.2% and the amount of retained austenite is less than 20%, the toughness is insufficient due to the small amount of retained austenite, and thus cracks tend to occur at the surface starting point and the life is shortened.
【００４４】以上のことから、本発明によると、転動疲
労強度に優れ、かつ転動面の陥没を抑制しうる転動体と
なる。From the above, according to the present invention, the rolling element is excellent in rolling fatigue strength and capable of suppressing the depression of the rolling surface.
【００４５】[0045]
【発明の効果】以上説明してきたように、本発明による
トロイダル式無段変速機用転動体は、潤滑油を介して接
触する複数個の金属製転動体を用いたトロイダル式無段
変速機において、前記転動体の素材としてＣｒを含有す
る機械構造用鋼を用い、浸炭窒化処理により、転動面に
おけるＮ量が重量％で０．２％以上０．６％以下、面接
触により転動体内部に発生する最大剪断応力の発生深さ
をＺｓｔとしたときに深さｄ≦０．２Ｚｓｔの位置にお
いてＣ＋Ｎ量が重量％で０．９％以上１．３％以下、残
留オーステナイト量が体積％で２０％以上４５％以下、
硬さがＨＶ５００以上であり、かつ、深さ０．５Ｚｓｔ
≦ｄ≦１．４Ｚｓｔの位置においてＣおよびＮ量が重量
％で０．６％≦Ｃ＋Ｎ≦１．２％、硬さがＨＶ７００以
上である構成としたから、トロイダル式無段変速機用転
動体において、耐ピッチング性に優れたものとなり、か
つまた転動面の陥没を抑制するため、転動疲労寿命がさ
らに向上したものとなり、転動面陥没により変速性能の
悪化を改善することが可能であって、内部および表面起
点の亀裂および剥離が発生しがたい長寿命のトロイダル
式無段変速機用転動体を提供することが可能であるとい
う著しく優れた効果がもたらされる。As described above, the rolling element for a toroidal type continuously variable transmission according to the present invention is a toroidal type continuously variable transmission using a plurality of metal rolling elements that are in contact with each other through lubricating oil. , A mechanical structural steel containing Cr as a material of the rolling element is used, and the carbon content in the rolling surface is 0.2% or more and 0.6% or less by weight N in the rolling surface. When the depth of the maximum shearing stress generated in Zst is Zst, the C + N amount is 0.9% or more and 1.3% or less by weight% and the retained austenite amount is% by volume at the position of depth d ≦ 0.2Zst. 20% or more and 45% or less,
Hardness is HV500 or more and depth is 0.5Zst
At the position of ≤d≤1.4Zst, the content of C and N is 0.6% by weight% ≤C + N≤1.2%, and the hardness is HV 700 or more. In the above, since it has excellent anti-pitting property and suppresses the depression of the rolling contact surface, the rolling contact fatigue life is further improved, and the deterioration of the shifting performance due to the depression of the rolling contact surface can be improved. Therefore, it is possible to provide a rolling element for a toroidal type continuously variable transmission, which has a long life in which cracks and peeling originating from the inside and the surface do not easily occur.
【図１】トロイダル式（転がり式）無段変速機の構造を
例示する断面説明図である。FIG. 1 is an explanatory cross-sectional view illustrating the structure of a toroidal (rolling) continuously variable transmission.
【図２】本発明の実施例において採用した熱処理条件を
示す説明図である。FIG. 2 is an explanatory diagram showing heat treatment conditions adopted in the examples of the present invention.
１ トロイダル式（転がり式）無段変速機 ５ 入力ディスク（転動体） ９ 出力ディスク（転動体） １０ パワーローラー（転動体） 1 Toroidal type (rolling type) continuously variable transmission 5 Input disc (rolling element) 9 Output disc (rolling element) 10 Power roller (rolling element)
フロントページの続き (72)発明者 安 部 聡 兵庫県神戸市灘区灘浜東町２ 株式会社神 戸製鋼所神戸製鉄所内 (72)発明者 松 本 隆 神奈川県横浜市神奈川区宝町２番地 日産 自動車株式会社内 (72)発明者 木 野 伸 郎 神奈川県横浜市神奈川区宝町２番地 日産 自動車株式会社内 (72)発明者 内 山 典 子 神奈川県横浜市神奈川区宝町２番地 日産 自動車株式会社内 (72)発明者 梅 垣 俊 造 神奈川県横浜市神奈川区宝町２番地 日産 自動車株式会社内Front page continuation (72) Inventor Satoshi Abe 2 Nadahama Higashi-cho, Nada-ku, Kobe City, Hyogo Prefecture Inside the Kido Steel Works, Kobe Steel Works (72) Inventor Takashi Matsumoto 2 Takara-cho, Kanagawa-ku, Yokohama, Japan Nissan Motor Co., Ltd. In-company (72) Shinro Kino No. 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Noriko Uchiyama 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) ) Inventor Shun Umegaki 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd.
Claims (1)
転動体を用いたトロイダル式無段変速機において、前記
転動体の素材としてＣｒを含有する機械構造用鋼を用
い、浸炭窒化処理により、転動面におけるＮ量が重量％
で０．２％以上０．６％以下、面接触により転動体内部
に発生する最大剪断応力の発生深さをＺｓｔとしたとき
に深さｄ≦０．２Ｚｓｔの位置においてＣ＋Ｎ量が重量
％で０．９％以上１．３％以下、残留オーステナイト量
が体積％で２０％以上４５％以下、硬さがＨＶ５００以
上であり、かつ、深さ０．５Ｚｓｔ≦ｄ≦１．４Ｚｓｔ
の位置においてＣおよびＮ量が重量％で０．６％≦Ｃ＋
Ｎ≦１．２％、硬さがＨＶ７００以上であることを特徴
とするトロイダル式無段変速機用転動体。1. A toroidal type continuously variable transmission using a plurality of metal rolling elements that come into contact with each other through lubricating oil, wherein a carbon for mechanical structure containing Cr as a material of the rolling element is carbonitrided. The amount of N on the rolling surface is
Is 0.2% or more and 0.6% or less, and when the depth of maximum shearing stress generated inside the rolling element due to surface contact is Zst, the amount of C + N is% by weight at the position of depth d ≦ 0.2Zst. 0.9% or more and 1.3% or less, the amount of retained austenite is 20% or more and 45% or less in volume%, the hardness is HV500 or more, and the depth is 0.5Zst ≦ d ≦ 1.4Zst.
0.6% ≦ C + in% by weight of C and N at the position
A rolling element for a toroidal-type continuously variable transmission, characterized in that N ≦ 1.2% and a hardness of HV 700 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23572495A JP3637983B2 (en) | 1995-09-13 | 1995-09-13 | Rolling element for toroidal continuously variable transmission with excellent rolling fatigue strength |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23572495A JP3637983B2 (en) | 1995-09-13 | 1995-09-13 | Rolling element for toroidal continuously variable transmission with excellent rolling fatigue strength |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0979336A true JPH0979336A (en) | 1997-03-25 |
| JP3637983B2 JP3637983B2 (en) | 2005-04-13 |
Family
ID=16990292
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23572495A Expired - Fee Related JP3637983B2 (en) | 1995-09-13 | 1995-09-13 | Rolling element for toroidal continuously variable transmission with excellent rolling fatigue strength |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3637983B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6623400B2 (en) | 2000-10-20 | 2003-09-23 | Nsk Ltd. | Toroidal-type continuously variable transmission |
| US6666792B2 (en) | 2000-12-27 | 2003-12-23 | Nsk Ltd. | Toroidal continuously variable transmission |
| US6746365B2 (en) | 2000-11-14 | 2004-06-08 | Nsk Ltd. | Toroidal-type continuously variable transmission |
-
1995
- 1995-09-13 JP JP23572495A patent/JP3637983B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6623400B2 (en) | 2000-10-20 | 2003-09-23 | Nsk Ltd. | Toroidal-type continuously variable transmission |
| US6746365B2 (en) | 2000-11-14 | 2004-06-08 | Nsk Ltd. | Toroidal-type continuously variable transmission |
| DE10155574B4 (en) * | 2000-11-14 | 2010-07-29 | Nsk Ltd. | Continuously adjustable toroidal transmission |
| US6666792B2 (en) | 2000-12-27 | 2003-12-23 | Nsk Ltd. | Toroidal continuously variable transmission |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3637983B2 (en) | 2005-04-13 |
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