JP2017062177A - Quality assurance method and device for machine element material - Google Patents

Quality assurance method and device for machine element material Download PDF

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JP2017062177A
JP2017062177A JP2015187602A JP2015187602A JP2017062177A JP 2017062177 A JP2017062177 A JP 2017062177A JP 2015187602 A JP2015187602 A JP 2015187602A JP 2015187602 A JP2015187602 A JP 2015187602A JP 2017062177 A JP2017062177 A JP 2017062177A
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JP6587880B2 (en
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良典 杉崎
Yoshinori Sugisaki
良典 杉崎
和寛 八木田
Kazuhiro Yakida
和寛 八木田
工 藤田
Takumi Fujita
工 藤田
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NTN Corp
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NTN Toyo Bearing Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a quality assurance method and device for a machine element material capable of discriminating whether a rolling fatigue lifetime reaches a fixed level by assuring an existence probability of an interposing object which is positioned in fixed depth from a raceway surface and in which a crack may progress, at a predetermined value or less by performing an interposing object inspection in a steel material state.SOLUTION: The method includes the steps of: acquiring information relating to an interposing object of a steel material (S1); simulating casting and acquiring information about a direction of a fiber flow after the casting (S2); investigating a distribution state of the interposing object positioned in fixed depth from a surface of a rolling plane in a state where the steel material is productized into a machine element based on the information relating to the interposing object acquired in the interposing object inspection step and the information about the direction of the fiber flow acquired in the casting simulation step (S3); and calculating an existence probability of the interposing object which is positioned in fixed depth from a raceway surface and in which a crack may progress, based on stored information in a database relating to the interposing object in which a crack may progress, and the distribution state of the interposing object (S6).SELECTED DRAWING: Figure 1

Description

この発明は、転がり軸受の軌道輪等の転動により疲労する機械要素の材料の転動疲労寿命が一定の水準に達していることを保証する機械要素材料の品質保証方法および装置に関する。   The present invention relates to a quality assurance method and apparatus for machine element material that guarantees that the rolling fatigue life of a material of a machine element that fatigues due to rolling of a bearing or the like of a rolling bearing has reached a certain level.

軸受の軌道面表面および軌道面直下の非金属介在物が、転がり軸受の転動疲労寿命に影響を及ぼすことがよく知られている。例えば、非特許文献1に記載の論文「軸受鋼の転動疲労寿命における非金属介在物の大きさの影響」では、同じ材質、硬さにおけるL10寿命は、介在物の種類によらず転動面直下の危険体積中に存在する最大の介在物の大きさに支配されるとしている。近年、鋼中の酸素濃度の低減などにより、転動疲労寿命に影響を及ぼす巨大な非金属介在物の存在確率は減少してきてはいるものの、全く零にすることはできない。そのような軌道面近傍の不可避に含まれる巨大な非金属介在物を検出し、寿命を保証する方法が提案されている。例えば、特許文献1では、超音波探査法を用いて軌道面における非金属介在物を長さ500μm 未満、好ましくは100μm 未満に規制することにより、安定的な転動疲労寿命を保証できるとしている。   It is well known that the bearing surface of the bearing and non-metallic inclusions directly under the raceway affect the rolling fatigue life of the rolling bearing. For example, in the paper “Non-Patent Document 1” “Effect of Non-Metallic Inclusion Size on Rolling Fatigue Life of Bearing Steel”, the L10 life of the same material and hardness depends on the type of inclusion. It is said that it is governed by the size of the largest inclusion existing in the dangerous volume directly below the surface. In recent years, the existence probability of huge non-metallic inclusions affecting the rolling fatigue life has been reduced by reducing the oxygen concentration in steel, but it cannot be made zero at all. There has been proposed a method for detecting the enormous non-metallic inclusions inevitable in the vicinity of the raceway surface and guaranteeing the lifetime. For example, in Patent Document 1, a stable rolling fatigue life can be guaranteed by regulating the non-metallic inclusions on the raceway surface to a length of less than 500 μm, preferably less than 100 μm, using an ultrasonic exploration method.

また、製鋼、鍛造工程において導入されるファイバーフローの方向についても転動疲労寿命に影響を及ぼすことが報告されている。特許文献2では、鋼中の合金成分量、具体的にはCuとAL量を閾値以下に規定することにより、寿命に対するファイバーフローの影響を取り除くことができるとしている。特許文献3のように、鍛造の方法を工夫することによりファイバーフローの影響を是正する技術も開示されている。   It has also been reported that the direction of fiber flow introduced in steelmaking and forging processes also affects the rolling fatigue life. Patent Document 2 states that the influence of the fiber flow on the life can be removed by defining the alloy component amount in the steel, specifically, the Cu and AL amounts below the threshold value. As disclosed in Patent Document 3, a technique for correcting the influence of fiber flow by devising a forging method is also disclosed.

特許文献4では、超音波探査法を用いて軌道面における非金属介在物を長さ300μm 未満、かつ軌道面に対するファイバーフローを15°未満に規制することで、長寿命化を図ることができるとしている。   According to Patent Document 4, it is possible to extend the life by regulating the non-metallic inclusions on the raceway surface to a length of less than 300 μm and the fiber flow to the raceway surface to less than 15 ° using an ultrasonic exploration method. Yes.

特開2000−130447号公報JP 2000-130447 A 特許第2969232号公報Japanese Patent No. 2969232 特開平5−277615号公報Japanese Patent Laid-Open No. 5-277615 特開2003−301850号公報JP 2003-301850 A

「軸受鋼の転動疲労寿命における非金属介在物の大きさの影響」Sanyo Technical Report Vol.12 (2005) No.1 p38"Effect of nonmetallic inclusion size on rolling fatigue life of bearing steel" Sanyo Technical Report Vol.12 (2005) No.1 p38 「鋼硬度鋼のモード・疲労き裂進展特性を求めるための新試験法」NTN Technical Review No.69 (2001) p53“New Test Method for Determining Mode / Fatigue Crack Propagation Properties of Hard Steel” NTN Technical Review No.69 (2001) p53

上述した超音波探傷法は、軸受軌道面全体を検査できるという利点はあるものの、不感帯ができるため、表面近傍の検出に難がある。周波数の高い超音波探傷を実施することにより数十μm サイズの非金属介在物の検出も可能ではあるが、工業的な利用を考えた場合、100μm 未満のサイズの検出は困難である。非特許文献2では、実験から求めたJIS−SUJ2のモード・下限界応力拡大係数ΔKth 条件におけるき裂が進展する円盤状き裂の臨界直径の計算結果を提示している。これによると、最大面圧が2.5GPa の場合、き裂の臨界直径は50μm であり、特許文献1の規制値である100μm 未満は、転動疲労寿命を充分に確保できるとは言えない。   Although the ultrasonic flaw detection method described above has an advantage that the entire bearing raceway surface can be inspected, a dead zone is formed, so that it is difficult to detect the vicinity of the surface. Although it is possible to detect non-metallic inclusions with a size of several tens of μm by performing ultrasonic flaw detection with a high frequency, it is difficult to detect a size of less than 100 μm when considering industrial use. Non-Patent Document 2 presents the calculation result of the critical diameter of a disk-shaped crack in which the crack propagates under the JIS-SUJ2 mode / lower limit stress intensity factor ΔKth condition obtained from experiments. According to this, when the maximum surface pressure is 2.5 GPa, the critical diameter of the crack is 50 μm, and if it is less than 100 μm, which is the regulation value of Patent Document 1, it cannot be said that sufficient rolling fatigue life can be secured.

また、製品の複雑形状化や製造工程上、鍛造による軌道面に対するファイバーフロー方向の制御が困難である場合がある。併せて、鋼材の多様化、グローバル調達化が進む中、閾値以上の合金成分量の鋼材を使用する場合もあることから、新たな転動疲労寿命を確保する手法が必要である。   Further, it may be difficult to control the fiber flow direction with respect to the raceway surface by forging due to the complicated shape of the product and the manufacturing process. Along with the diversification of steel materials and global procurement, steel materials with alloy component amounts that exceed the threshold may be used, so a new method for ensuring a rolling fatigue life is required.

この発明の目的は、鋼材の状態で介在物検査を行うことで、機械要素として製品化された場合における、軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を所定値以下に保証し、転動疲労寿命が一定の水準に達しているかの判定が行える機械要素材料の品質保証方法および装置を提供することである。   The object of the present invention is to perform the inclusion inspection in the state of the steel material, and to determine the existence probability of the inclusion that can be cracked and located at a certain depth from the raceway surface when it is commercialized as a machine element. It is intended to provide a quality assurance method and apparatus for a machine element material that guarantees a predetermined value or less and can determine whether or not the rolling fatigue life has reached a certain level.

この発明の機械要素材料の品質保証方法は、転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を行う機械要素材料の品質保証方法であって、
前記鋼材の介在物に係る情報を取得する介在物検査過程(ステップS1)と、
前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する鍛造シミュレーション過程(ステップS2)と、
前記介在物検査過程で得た介在物に係る情報と前記鍛造シミュレーション過程で得たファイバーフロ−の方向の情報とから、前記鋼材が前記機械要素に製品化された状態における前記転動面の表面から一定の深さに位置する前記介在物の分布状態を調べる分布状態シミュレーション過程(ステップS3)と、
前記転動面で転動が行われた場合に前記機械要素にき裂が進展し得る介在物に係るデータベースの蓄積情報、および前記分布状態シミュレーション(ステップS3)で得られた介在物の分布状態から、前記製品の軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を求めるき裂進展介在物存在確率推定過程(ステップS6)と、
この求められた存在確率が一定値以下であるか否かを判定する転動疲労寿命確保過程(ステップ8)とを含む。
According to the quality assurance method for machine element material of the present invention, when a steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging, the rolling fatigue life reaches a certain level. A quality assurance method for machine element material for determining whether or not
Inclusion inspection process (step S1) for acquiring information related to inclusions in the steel material;
A forging simulation process (step S2) for obtaining information on the direction of fiber flow after the forging by performing a forging simulation for processing the steel material into the shape of the machine element;
From the information on the inclusions obtained in the inclusion inspection process and the information on the direction of the fiber flow obtained in the forging simulation process, the surface of the rolling surface in a state where the steel material is commercialized into the machine element. A distribution state simulation process (step S3) for examining the distribution state of the inclusions located at a certain depth from
Accumulated information of inclusions related to inclusions that can crack in the machine element when rolling is performed on the rolling surface, and the distribution state of inclusions obtained in the distribution state simulation (step S3) From the crack propagation inclusion existence probability estimation process (step S6) for obtaining the existence probability of an inclusion that is located at a certain depth from the raceway surface of the product and that can propagate a crack;
And a rolling fatigue life securing step (step 8) for judging whether or not the obtained existence probability is a predetermined value or less.

この方法によると、まず鋼材の介在物検査を実施し(ステップ1)、鍛造シミュレーション(ステップ2)を介して製品形状における非金属介在物の分布状態を模擬する(ステップ3)。さらに、例えば有限要素法により求めデータベース化したき裂の進展し得る介在物サイズとの比較により、軌道面からの一定深さに位置するき裂が進展し得る介在物の存在確率を求める(ステップ6)。なお、鋼材がどのように鍛造されて製品形状の機械要素とされるかにつき、鍛造時の素材である鋼材の寸法形状およびファイバーフロ−の方向は常に定まっているとする。
このように、鋼材の介在物検査を実施することにより、製品の軌道面からの一定深さに位置するき裂が進展し得る非金属介在物の存在確率を一定値以下に保証することにより、安定的な転動疲労寿命を確保することができる。
According to this method, first, an inclusion inspection of a steel material is performed (step 1), and a distribution state of nonmetallic inclusions in a product shape is simulated through a forging simulation (step 2) (step 3). Furthermore, for example, the existence probability of inclusions where a crack located at a fixed depth from the raceway surface can be determined by comparing with the inclusion size that can be propagated by a crack obtained by a finite element method and database (step) 6). It is assumed that the dimensional shape and the direction of fiber flow of the steel material, which is the material at the time of forging, are always determined according to how the steel material is forged into a product-shaped machine element.
In this way, by performing the inclusion inclusion inspection of the steel material, by assuring the existence probability of the nonmetallic inclusion that the crack located at a certain depth from the raceway surface of the product can propagate to a certain value or less, A stable rolling fatigue life can be secured.

なお、前記介在物は、例えば非金属介在物である。また、この明細書において、「一定の」とは、任意に定められる値であり、設計やシミュレーション、試験等の結果に基づき、任意に定めれば良い。   In addition, the said inclusion is a nonmetallic inclusion, for example. Further, in this specification, “constant” is a value that is arbitrarily determined, and may be arbitrarily determined based on results of design, simulation, test, and the like.

この発明方法において、前記分布状態シミュレーション過程(ステップ3)では、乱数を用いた複数回の試行により、前記転動面の表面から一定の深さに位置する前記介在物の分布状態を定めるようにしても良い。
これにより、き裂が進展し得る介在物の存在確率を、より一層精度良く求め、転動疲労寿命の推定の精度を高めることができる。
In the method of the present invention, in the distribution state simulation process (step 3), the distribution state of the inclusions located at a certain depth from the surface of the rolling surface is determined by a plurality of trials using random numbers. May be.
As a result, the existence probability of inclusions through which cracks can propagate can be determined with higher accuracy, and the accuracy of estimating the rolling fatigue life can be increased.

この発明方法において、前記データベースの構築については、任意の使用条件における、任意の緒元の介在物周りの応力拡大係数振幅を有限要素法により算出し、算出された応力拡大係数振幅と、既知の下限界応力拡大係数との比較により、前記応力拡大係数振幅が大きい場合に、転動によりき裂が進展し得る介在物であると判断し、この検討を、使用条件、介在物緒元毎に実施し、き裂が進展し得る介在物の前記データベースを構築しても良い。
この方法の場合、き裂が進展し得る介在物の前記データベースを、使用条件、介在物緒元毎に検索可能に構築でき、き裂が進展し得る介在物の存在確率、しいては転動疲労寿命を、さらに一層精度良く求めることができる。
In the method of the present invention, regarding the construction of the database, the stress intensity factor amplitude around an arbitrary inclusion is calculated by a finite element method under an arbitrary use condition, and the calculated stress intensity factor amplitude and a known By comparison with the lower limit stress intensity factor, when the stress intensity factor amplitude is large, it is determined that the inclusion can be cracked by rolling. It is possible to construct the database of inclusions that can be implemented and cracks can propagate.
In the case of this method, the database of inclusions through which cracks can propagate can be constructed so as to be searchable according to usage conditions and specifications of the inclusions, the existence probability of inclusions through which cracks can propagate, and rolling The fatigue life can be determined with higher accuracy.

この発明方法において、転動疲労寿命試験の実施によって、き裂が進展し得る介在物の存在確率と転動疲労寿命との関係のデータベースを構築し、このデータベースと、前記き裂進展介在物存在確率推定過程で求めた前記き裂が進展し得る介在物の存在確率とを照合することにより、転動疲労寿命が一定水準に達しているかを判定する過程を含むようにしても良い。
この場合、任意の鋼材を用いて任意の製品を加工した場合の転動疲労寿命が一定水準に達しているかを判定することができるため、安定的な転動疲労寿命を確保することができる。
In the method of the present invention, by performing a rolling fatigue life test, a database of the relationship between the existence probability of inclusions that can propagate cracks and the rolling fatigue life is constructed, and this database and the existence of the crack propagation inclusions You may make it include the process of determining whether the rolling fatigue life has reached a fixed level by collating with the existence probability of the inclusion which the crack can progress calculated | required in the probability estimation process.
In this case, since it is possible to determine whether the rolling fatigue life has reached a certain level when an arbitrary product is processed using an arbitrary steel material, a stable rolling fatigue life can be ensured.

この発明方法において、前記機械要素が転がり軸受の軌道輪または転動体であっても良い。
この発明方法は、転動面を有する機械要素の材料であれば適用することができ、軸受部品の他に、等速ジョイントの継手部材等にも適用できるが、前記機械要素が転がり軸受の軌道輪または転動体である場合に、転動疲労寿命を推定することが強く求められ、その要求に良好に対応することができる。
In the method of the present invention, the mechanical element may be a bearing ring or a rolling element of a rolling bearing.
The method of the present invention can be applied as long as it is a material of a machine element having a rolling surface, and can be applied to a joint member of a constant velocity joint in addition to a bearing component. In the case of a wheel or a rolling element, it is strongly required to estimate the rolling fatigue life, and the request can be satisfactorily met.

この発明の機械要素材料の品質保証装置20は、転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を行う機械要素材料の品質保証装置であって、
前記鋼材の介在物に係る情報を記憶する介在物検査情報記憶手段21と、
前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する鍛造シミュレーション手段22と、
前記介在物検査情報記憶手段21に記憶された介在物に係る情報と前記鍛造シミュレーション手段22で得たファイバーフロ−の方向の情報とから、前記鋼材が前記機械要素に製品化された状態における前記転動面の表面から一定の深さに位置する前記介在物の分布状態を調べる分布状態シミュレーション手段23と、
前記転動面で転動が行われた場合に前記機械要素にき裂が進展し得る介在物に係るデータベース25の蓄積情報、および前記分布状態シミュレーションで得られた介在物の分布状態から、前記製品の軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を求めるき裂進展介在物存在確率推定手段26と、
この求められた存在確率が一定値以下であるか否かを判定する転動疲労寿命確保手段28、とを含む。
In the machine element material quality assurance device 20 according to the present invention, when a steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging, the rolling fatigue life is maintained at a certain level. A machine element material quality assurance device for determining whether or not
Inclusion inspection information storage means 21 for storing information relating to the inclusions of the steel material;
Forging simulation means 22 for performing simulation of forging for processing the steel material into the shape of the machine element to obtain information on the direction of fiber flow after the forging;
From the information on the inclusions stored in the inclusion inspection information storage means 21 and the information on the direction of the fiber flow obtained by the forging simulation means 22, the steel material in the state of being commercialized into the machine element. A distribution state simulation means 23 for examining the distribution state of the inclusions located at a certain depth from the surface of the rolling surface;
From the accumulated information of the database 25 relating to the inclusions that can crack in the machine element when rolling is performed on the rolling surface, and the distribution state of the inclusions obtained by the distribution state simulation, Crack propagation inclusion existence probability estimation means 26 for determining the existence probability of an inclusion that can be propagated by a crack located at a certain depth from the track surface of the product;
Rolling fatigue life securing means 28 for judging whether or not the obtained existence probability is a certain value or less.

この構成の機械要素材料の品質保証装置によると、この発明の機械要素材料の品質保証方法につき前述したと同様に、鋼材状態で介在物検査を行うことで、機械要素として製品化された場合における、軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を所定値以下に保証し、転動疲労寿命が一定の水準に達しているかの判定が行える。   According to the machine element material quality assurance apparatus of this configuration, as described above with respect to the machine element material quality assurance method of the present invention, the inclusion inspection is performed in the steel material state, so that the machine element material is commercialized as a machine element. In addition, it is possible to guarantee that the existence probability of inclusions, which are located at a certain depth from the raceway surface, and in which cracks can propagate, is below a predetermined value, and to determine whether the rolling fatigue life has reached a certain level.

この発明の機械要素材料の品質保証方法は、転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を行う機械要素材料の品質保証方法であって、前記鋼材の介在物に係る情報を取得する介在物検査過程と、前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する鍛造シミュレーション過程と、前記介在物検査過程で得た介在物に係る情報と前記鍛造シミュレーション過程で得たファイバーフロ−の方向の情報とから、前記鋼材が前記機械要素に製品化された状態における前記転動面の表面から一定の深さに位置する前記介在物の分布状態を調べる分布状態シミュレーション過程と、前記転動面で転動が行われた場合に前記機械要素にき裂が進展し得る介在物に係るデータベースの蓄積情報、および前記分布状態シミュレーションで得られた介在物の分布状態から、前記製品の軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を求めるき裂進展介在物存在確率推定過程と、この求められた存在確率が一定値以下であるか否かを判定する転動疲労寿命確保過程とを含むため、鋼材状態で介在物検査を行うことで、機械要素として製品化された場合における、軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を所定値以下に保証し、転動疲労寿命が一定の水準に達しているかの判定が行える。   According to the quality assurance method for machine element material of the present invention, when a steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging, the rolling fatigue life reaches a certain level. It is a quality assurance method for machine element material to determine whether or not it is an inclusion inspection process for obtaining information on inclusions in the steel material, and forging simulation for processing the steel material into the shape of the machine element Forging simulation process for obtaining information on the direction of fiber flow after forging, information on inclusions obtained in the inclusion inspection process, and information on the direction of fiber flow obtained in the forging simulation process. From the information, a distribution state simulation for examining a distribution state of the inclusions located at a certain depth from the surface of the rolling surface in a state where the steel material is commercialized into the machine element. Process, accumulated information in a database relating to inclusions that can crack in the machine element when rolling occurs on the rolling surface, and the distribution state of inclusions obtained by the distribution state simulation From the crack propagation inclusion existence probability estimation process for obtaining the existence probability of an inclusion that can be propagated by a crack located at a certain depth from the raceway surface of the product, and the obtained existence probability is less than a certain value. The rolling fatigue life ensuring process to determine whether or not there is, the inclusion is inspected in the steel material state, and when it is commercialized as a machine element, it is located at a certain depth from the raceway surface. It is possible to guarantee that the existence probability of inclusions that can develop cracks is below a predetermined value, and to determine whether the rolling fatigue life has reached a certain level.

この発明の機械要素材料の品質保証装置は、転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を行う機械要素材料の品質保証装置であって、前記鋼材の介在物に係る情報を記憶する介在物検査情報記憶手段と、前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する鍛造シミュレーション手段と、前記介在物検査情報記憶手段に記憶された介在物に係る情報と前記鍛造シミュレーション手段で得たファイバーフロ−の方向の情報とから、前記鋼材が前記機械要素に製品化された状態における前記転動面の表面から一定の深さに位置する前記介在物の分布状態を調べる分布状態シミュレーション手段と、前記転動面で転動が行われた場合に前記機械要素にき裂が進展し得る介在物に係るデータベースの蓄積情報、および前記分布状態シミュレーションで得られた介在物の分布状態から、前記製品の軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を求めるき裂進展介在物存在確率推定手段と、この求められた存在確率が一定値以下であるか否かを判定する転動疲労寿命確保手段とを備えるため、鋼材状態で介在物検査を行うことで、機械要素として製品化された場合における、軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を所定値以下に保証し、転動疲労寿命が一定の水準に達しているかの判定が行える。   In the machine element material quality assurance device according to the present invention, when a steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging, the rolling fatigue life reaches a certain level. A machine element material quality assurance device for determining whether or not a steel element includes inclusion inspection information storage means for storing information relating to the inclusion of the steel material, and forging that processes the steel material into the shape of the machine element. Forging simulation means for obtaining information on the direction of fiber flow after forging by performing simulation of the above, information on inclusions stored in the inclusion inspection information storage means, and fiber obtained by the forging simulation means From the information on the flow direction, the distribution state of the inclusions located at a certain depth from the surface of the rolling surface in a state where the steel material is commercialized into the machine element is examined. Distribution state simulation means, stored information in a database relating to inclusions that can crack in the machine element when rolling is performed on the rolling surface, and inclusions obtained in the distribution state simulation A crack propagation inclusion existence probability estimating means for obtaining an existence probability of an inclusion which can be propagated from a distribution state and located at a certain depth from the raceway surface of the product, and the obtained existence probability is a constant value. It is located at a certain depth from the raceway surface when it is commercialized as a machine element by conducting inclusions inspection in the steel material state, because it is provided with rolling fatigue life securing means for judging whether or not In addition, the existence probability of inclusions that can develop cracks is guaranteed to be a predetermined value or less, and it can be determined whether the rolling fatigue life has reached a certain level.

この発明の一実施形態に係る機械要素材料の品質保証方法を示す流れ図である。It is a flowchart which shows the quality assurance method of the machine element material which concerns on one Embodiment of this invention. 同品質保証方法で行ったシミュレーション結果の一例である。It is an example of the simulation result performed by the same quality assurance method. この発明の一実施形態に係る機械要素材料の品質保証装置を示す概念構成のブロック図である。It is a block diagram of a conceptual structure which shows the quality assurance apparatus of the machine element material which concerns on one Embodiment of this invention. この発明の対象とする機械要素の一例を有する機械要素である車輪用軸受の断面図である。It is sectional drawing of the bearing for wheels which is a machine element which has an example of the machine element made into the object of this invention. 同車輪用軸受における外輪のファイバーフロ−の説明図である。It is explanatory drawing of the fiber flow of the outer ring | wheel in the wheel bearing. 転がり軸受の外輪の製造過程の説明図である。It is explanatory drawing of the manufacturing process of the outer ring | wheel of a rolling bearing.

この発明の一実施形態を図面と共に説明する。この品質保証方法は、転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を、鋼材の状態で行う機械要素材料の品質保証方法であって、図1にその各過程の流れ図を示す。前記転動面を有する機械要素は、例えば、転がり軸受の軌道輪もしくは転動体、または等速ジョイントの一対の継手部材もしくはトルク伝達ボール等の転がり接触を行う機械要素であり、この実施形態では転がり軸受の軌道輪を対象としている。   An embodiment of the present invention will be described with reference to the drawings. This quality assurance method determines whether or not the rolling fatigue life has reached a certain level when a steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging. Is a quality assurance method for machine element material in the state of a steel material, and FIG. 1 shows a flowchart of each process. The machine element having the rolling surface is, for example, a machine element that makes rolling contact with a bearing ring or rolling element of a rolling bearing, a pair of joint members of a constant velocity joint, or a torque transmission ball. In this embodiment, the rolling element is a rolling element. It is intended for bearing rings.

図1と共に、同図の各ステップ毎の処理を説明する。
「鋼材の介在物検査過程」(ステップS1)分布介在物情報の取得
前記鋼材の介在物に係る情報を取得する過程である。この過程では、検査対象の鋼材を、検査面が鋼材軸方向に対して平行、すなわちファイバーフロー方向と平行になるように切断して、試料を作製する。試料の硬度を確保するために、焼入を実施する。検査面を研磨および琢磨工程により、観察可能な鏡面に仕上げる。光学顕微鏡もしくはSEM−EDX(走査電子顕微鏡)を用いて、試料検査面を観察し、任意検査面積における種類、大きさ、アスペクト比、分布密度などの介在物情報を取得する。光学顕微鏡を用いた際の介在物の種類の決定は、介在物の色味による識別で実施する。一方、SEM−EDXを用いた際は、EDXによる元素分析を実施し識別する。
The process for each step in FIG. 1 will be described with FIG.
“Steel Inclusion Inspection Process” (Step S1) Acquisition of Distributed Inclusion Information This is a process of acquiring information relating to the inclusion of steel. In this process, the steel material to be inspected is cut so that the inspection surface is parallel to the steel material axial direction, that is, parallel to the fiber flow direction, to prepare a sample. Quenching is performed to ensure the hardness of the sample. The inspection surface is finished to an observable mirror surface by polishing and polishing processes. The specimen inspection surface is observed using an optical microscope or SEM-EDX (scanning electron microscope), and inclusion information such as the type, size, aspect ratio, distribution density, etc. in an arbitrary inspection area is acquired. Determination of the type of inclusions when using an optical microscope is carried out by identification based on the color of the inclusions. On the other hand, when SEM-EDX is used, elemental analysis using EDX is performed for identification.

「鍛造シミュレーション過程」(ステップS2)製品形状におけるファイバーフロー方向情報の取得
前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する過程である。
鋼材状態から鍛造を経て、製品形状におけるファイバーフローがどのように変化するかを、DEFORM(総合加工シミュレーションシステム)をはじめとするCAE(computer aided engineering)ソフトを用いてシミュレーションを実施する。シミュレーション結果から軌道面直下のファイバーフロー方向情報を取得する。図2に鍛造シミュレーション結果の一例を示す。同図は、車輪用軸受における外輪を鍛造する場合の例であり、製品状態で突出している箇所は、外輪の外周のフランジとなる部分である。鍛造シミュレーションが困難な場合は、鋼材ではなく、鍛造後の製品形状の介在物検査を実施することにより得られる介在物の角度情報を代替情報として採用する。
"Forging simulation process" (step S2) Acquisition of fiber flow direction information in product shape Performs forging simulation for processing the steel material into the shape of the machine element to acquire information on the direction of fiber flow after forging It is a process.
A simulation is carried out using CAE (computer aided engineering) software such as DEFORM (Comprehensive Processing Simulation System) to see how the fiber flow in the product shape changes after forging from the steel material state. Obtain fiber flow direction information just below the raceway surface from the simulation results. FIG. 2 shows an example of the forging simulation result. The figure is an example in the case of forging the outer ring in the wheel bearing, and the part protruding in the product state is a part that becomes the outer peripheral flange of the outer ring. When forging simulation is difficult, the angle information of the inclusions obtained by carrying out the inclusion inspection of the product shape after forging rather than the steel material is adopted as alternative information.

「軌道面直下の介在物の分布状態のシミュレーション過程」(ステップS3)
鋼材の介在物検査から得られた種類、大きさ、アスペクト比、分布密度と、鍛造シミュレーションから得られたファイバーフロー方向の情報とを用いて、前記鋼材が機械要素に製品化された状態における、軌道面直下の一定の深さに位置する介在物の分布状態のシミュレーションを実施する。
介在物の分布状態シミュレーションとして、モンテカルロ法を用いた乱数シミュレーションなどがあげられる。この場合、乱数を用いた複数回の試行により、前記転動面の表面から一定の深さに位置する前記介在物の分布状態を定める。続けて、機械要素の製品形状において介在物検査を実施することにより、鋼材状態の介在物情報から得られた介在物の分布状態のシミュレーション結果の精度を確認することも可能である。
“Simulation process of the distribution of inclusions directly under the raceway” (step S3)
Using the type, size, aspect ratio, distribution density obtained from the inclusion inspection of the steel material, and information on the fiber flow direction obtained from the forging simulation, the steel material has been commercialized into a machine element. A simulation of the distribution of inclusions located at a certain depth just below the raceway surface is performed.
Examples of inclusion distribution state simulation include random number simulation using the Monte Carlo method. In this case, the distribution state of the inclusions located at a certain depth from the surface of the rolling surface is determined by a plurality of trials using random numbers. Subsequently, by performing the inclusion inspection on the product shape of the machine element, it is also possible to confirm the accuracy of the simulation result of the inclusion distribution state obtained from the inclusion information in the steel material state.

「介在物からのき裂進展有無の検討過程」(ステップS4,S5)
任意の使用条件(荷重や摩擦係数など) における、任意の緒元の介在物周りの応力拡大係数振幅を有限要素法により算出する。算出された応力拡大係数振幅と、論文などで報告されている既知の下限界応力拡大係数の比較により、き裂の進展の有無を判断する。例えばモードIIの場合、非特許文献2で報告されている実験から求めたJIS−SUJ2のモードII下限界応力拡大係数(ΔKth=3MPa√m)と比較して、算出された応力拡大係数振幅が大きい場合に、転動によりき裂が進展し得る介在物であると判断する。
この検討を、使用条件、介在物緒元毎に実施し、この使用条件、介在物緒元毎に、き裂が進展し得る介在物のデータベースを構築する。(ステップS5)
"Examination process of crack growth from inclusions" (Steps S4 and S5)
Calculates the stress intensity factor amplitude around the inclusion of any given specification under any use condition (load, friction coefficient, etc.) by the finite element method. The presence or absence of crack growth is determined by comparing the calculated stress intensity factor amplitude with the known lower stress intensity factor reported in the paper. For example, in the case of mode II, compared with the JIS-SUJ2 mode II lower limit stress intensity factor (ΔKth = 3 MPa√m) obtained from the experiment reported in Non-Patent Document 2, the calculated stress intensity factor amplitude is When it is large, it is determined that the crack can be propagated by rolling.
This examination is carried out for each use condition and inclusion specification, and a database of inclusions in which cracks can develop is constructed for each use condition and inclusion specification. (Step S5)

「き裂が進展し得る介在物の存在確率」(ステップ6)
軌道面直下の介在物の分布状態のシミュレーション結果と、き裂が進展し得る介在物のデータベースを練成、つまり照合して検討することにより、き裂が進展し得る介在物の存在確率を導出することができる。そのため、軌道面からの一定深さに位置するき裂が進展し得る介在物の存在確率を保証することができる。
“Existence probability of inclusion that can crack” (Step 6)
Deriving the probability of existence of inclusions where cracks can be developed by studying the results of simulation of the distribution of inclusions directly under the raceway and the database of inclusions where cracks can propagate can do. Therefore, it is possible to guarantee the existence probability of inclusions in which a crack located at a certain depth from the raceway surface can propagate.

「寿命試験結果」(ステップS7,S8)
荷重などの試験条件や鍛流線方向をパラメータとして、転動疲労寿命試験を実施し、き裂が進展し得る介在物の存在確率と転動疲労寿命との関係のデータベースを構築する。(ステップS7)
そのデータベースと照合することにより、任意の鋼材を用いて任意の製品を加工した場合の転動疲労寿命が一定水準に達しているかを判定することができるため、安定的な転動疲労寿命を確保することができる。(ステップS8)
"Life test result" (steps S7, S8)
A rolling fatigue life test is conducted using the test conditions such as load and the direction of the forging line as parameters, and a database of the relationship between the existence probability of inclusions that can propagate cracks and the rolling fatigue life is constructed. (Step S7)
By collating with the database, it is possible to determine whether the rolling fatigue life has reached a certain level when processing any product using any steel material, ensuring a stable rolling fatigue life can do. (Step S8)

このように、この実施形態の機械要素材料の品質保証方法を用いれば、鋼材状態で介在物検査を実施することにより、製品形状における軌道面から一定深さに位置する、転動によりき裂が進展し得る介在物の存在確率を求めることができ、介在物の存在確率を一定値以下に保証することにより、転動疲労寿命が一定の水準に達しているかの判定ができる。   As described above, if the quality assurance method for machine element material according to this embodiment is used, by performing inclusion inspection in the steel material state, a crack is caused by rolling, which is located at a certain depth from the raceway surface in the product shape. The existence probability of inclusions that can progress can be obtained, and it can be determined whether or not the rolling fatigue life has reached a certain level by guaranteeing the existence probability of inclusions to a certain value or less.

図3は、上記実施形態に係る機械要素材料の品質保証方法を実施する機械要素材料の品質保証装置の概念構成を示すブロック図である。
この機械要素材料の品質保証装置20は、転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を行う装置であって、介在物検査情報記憶手段21、鍛造シミュレーション手段22、分布状態シミュレーション手段23、データベース25、き裂進展介在物存在確率推定手段26、寿命試験結果記憶手段27、および転動疲労寿命確保手段28を備える。
FIG. 3 is a block diagram showing a conceptual configuration of a machine element material quality assurance apparatus for performing the machine element material quality assurance method according to the embodiment.
This machine element material quality assurance device 20 has a rolling fatigue life that reaches a certain level when steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging. An inclusion inspection information storage means 21, forging simulation means 22, distribution state simulation means 23, database 25, crack growth inclusion existence probability estimation means 26, life test result storage means 27, and rolling fatigue life securing means 28.

前記品質保証装置20は、鋼材の介在物に係る情報を記憶する手段であり、図1のステップS1で行った介在物検査の結果を記憶する。
前記鍛造シミュレーション手段22は、前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する手段であり、図1のステップS2の処理を行う。
The quality assurance device 20 is means for storing information relating to steel inclusions, and stores the results of the inclusion inspection performed in step S1 of FIG.
The forging simulation means 22 is means for obtaining information on the direction of fiber flow after the forging by performing a forging simulation for processing the steel material into the shape of the machine element, and the process of step S2 in FIG. I do.

前記分布状態シミュレーション手段23は、前記介在物検査情報記憶手段21に記憶された介在物に係る情報と前記鍛造シミュレーション手段22で得たファイバーフロ−の方向の情報とから、前記鋼材が前記機械要素に製品化された状態における前記転動面の表面から一定の深さに位置する前記介在物の分布状態を調べる手段である。この分布状態シミュレーション手段23は、図1のステップS3の処理を行う。   The distribution state simulation means 23 uses the information on the inclusions stored in the inclusion inspection information storage means 21 and the information on the fiber flow direction obtained by the forging simulation means 22 to make the steel material the machine element. Means for examining the distribution of the inclusions located at a certain depth from the surface of the rolling surface in the state of being commercialized. The distribution state simulation means 23 performs the process of step S3 in FIG.

前記データベース25は、機械要素の使用条件、介在物緒元毎に、前記転動面で転動が行われた場合にき裂が進展し得る介在物の情報を記憶した手段であり、例えば図1のステップS4で行った検討結果の情報が記憶される。   The database 25 is a means for storing information on inclusions that can develop cracks when rolling is performed on the rolling surface for each use condition of machine elements and specifications of inclusions. The information of the examination result performed in step S4 of 1 is stored.

前記き裂進展介在物存在確率推定手段26は、前記データベース25の蓄積情報である前記転動面で転動が行われた場合に前記機械要素にき裂が進展し得る介在物に係る情報、および前記分布状態シミュレーション手段23で得られた介在物の分布状態から、前記製品の軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を求める手段である。このき裂進展介在物存在確率推定手段26は、図1のステップS6の処理を行う。   The crack propagation inclusion existence probability estimation means 26 is information related to inclusions in which a crack can propagate to the machine element when rolling is performed on the rolling surface, which is stored information in the database 25. And means for determining the existence probability of inclusions that are located at a certain depth from the raceway surface of the product and can propagate cracks from the distribution state of inclusions obtained by the distribution state simulation means 23. The crack growth inclusion existence probability estimation unit 26 performs the process of step S6 in FIG.

寿命試験結果記憶手段27は、き裂が進展し得る介在物の存在確率と転動疲労寿命との関係の情報を記憶したデータベースであり、荷重などの試験条件や鍛流線方向をパラメータとして実施された転動疲労寿命試験の情報を記憶している。すなわち、図1のステップS7で行った寿命試験の結果を記憶させてある。   The life test result storage means 27 is a database that stores information on the relationship between the existence probability of inclusions through which cracks can propagate and the rolling fatigue life, and is implemented using test conditions such as load and forging line direction as parameters. Information on the rolling fatigue life test performed is stored. That is, the result of the life test performed in step S7 in FIG. 1 is stored.

前記転動疲労寿命確保手段28は、前記き裂進展介在物存在確率推定手段26で求められた存在確率が一定値以下であるか否かを判定する手段である。   The rolling fatigue life securing means 28 is means for determining whether or not the existence probability obtained by the crack propagation inclusion existence probability estimating means 26 is equal to or less than a certain value.

前記機械要素材料の品質保証装置20は、上記各手段の他に、入力処理手段29および出力処理手段30を備える。入力処理手段29は、キーボードやマウス等の入力機器31からオペレータの操作入力を受け付けたり、機外の記憶装置や他のコンピュータから入力を受け付けたりして記憶する。前記各手段で必要な入力は、この入力処理手段29を介して行われる。出力処理手段30は、液晶表示装置等の画像表示装置やプリンタ等の出力機器32に対して出力を行う手段であり、前記各手段で得た事項は出力処理手段30を介して出力機器32に表示される。
なお、この機械要素材料の品質保証装置20は、1台のパーソナルコンピュータ等のコンピュータで構成されていても、互いにネットワークで接続された複数台のコンピュータで構成されていても良い。
The machine element material quality assurance apparatus 20 includes an input processing means 29 and an output processing means 30 in addition to the above-described means. The input processing means 29 receives and stores an operator's operation input from an input device 31 such as a keyboard or a mouse, or receives an input from an external storage device or another computer. Input necessary for each means is performed through the input processing means 29. The output processing means 30 is means for outputting to an image display device such as a liquid crystal display device or an output device 32 such as a printer, and items obtained by each means are sent to the output device 32 via the output processing means 30. Is displayed.
The machine element material quality assurance device 20 may be composed of one computer such as a personal computer, or may be composed of a plurality of computers connected to each other via a network.

この構成の機械要素材料の品質保証装置20によると、鋼材状態で介在物検査を行うことで、機械要素として製品化された場合における、軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を所定値以下に保証し、転動疲労寿命が一定の水準に達しているかの判定が行える。   According to the quality assurance device 20 for the machine element material having this configuration, cracks located at a certain depth from the raceway surface when the product is commercialized as a machine element are developed by performing the inclusion inspection in the steel material state. The existence probability of the inclusions to be obtained can be guaranteed below a predetermined value, and it can be determined whether the rolling fatigue life has reached a certain level.

次に、この機械要素材料の品質保証方法および装置を適用する機械要素の具体例を図4ないし図6と共に説明する。図4は、内輪回転型の車輪用軸受装置の断面図である。この車輪用軸受装置は、ハブ輪1およびそのインボード側端の外周に嵌合した内輪2からなる内方部材3と、外方部材4とを備え、車体に対して車輪を回転自在に支持する。上記外方部材4が、上記実施形態における品質保証対象の機械要素となる。   Next, specific examples of machine elements to which the machine element material quality assurance method and apparatus are applied will be described with reference to FIGS. FIG. 4 is a cross-sectional view of an inner ring rotating type wheel bearing device. This wheel bearing device includes an inner member 3 composed of an inner ring 2 fitted to the outer periphery of the hub wheel 1 and its inboard side end, and an outer member 4, and rotatably supports the wheel with respect to the vehicle body. To do. The outer member 4 is a machine element subject to quality assurance in the embodiment.

ハブ輪1は、アウトボード側端に車輪取付用のフランジ5を有しており、フランジ5の周方向複数箇所に形成されたボルト挿通孔7に、車輪取付用のボルト8が圧入されている。ハブ輪1は、中央孔1aが貫通した筒状の部材とされている。中央孔1aには、図示しない等速自在継手の外側継手部材の軸部が嵌合している。上記ハブ輪1および内輪2に、複列の転動面10,11の片方ずつが設けられている。転動面10,11は、軌道面または転走面と呼ばれることもある。外方部材4は、単独の外輪からなり、外周に車体への取付用のフランジ6を有している。このフランジ6の周方向複数箇所にボルト挿通孔9が形成されている。外方部材4は、ハブ輪1および内輪2の転動面10,11に対向する複列の転動面12,13を有し、両列の対向する転動面10,12間、および転動面11,13間に転動体14が介在している。転動体14は鋼球等のボールである。これら転動体14は、各列毎に保持器29により保持されている。内方部材3と外方部材4との間の軸受空間における両端は、密封装置15,16により密封されている。   The hub wheel 1 has a wheel mounting flange 5 at an end on the outboard side, and wheel mounting bolts 8 are press-fitted into bolt insertion holes 7 formed at a plurality of locations in the circumferential direction of the flange 5. . The hub wheel 1 is a cylindrical member through which the central hole 1a passes. A shaft portion of an outer joint member of a constant velocity universal joint (not shown) is fitted in the central hole 1a. The hub wheel 1 and the inner ring 2 are each provided with one of the double-row rolling surfaces 10 and 11. The rolling surfaces 10 and 11 may be called a raceway surface or a rolling surface. The outer member 4 is composed of a single outer ring, and has a flange 6 for attachment to the vehicle body on the outer periphery. Bolt insertion holes 9 are formed at a plurality of locations in the circumferential direction of the flange 6. The outer member 4 has double rows of rolling surfaces 12 and 13 facing the rolling surfaces 10 and 11 of the hub wheel 1 and the inner ring 2, and between the opposing rolling surfaces 10 and 12 of both rows and between the rolling surfaces. A rolling element 14 is interposed between the moving surfaces 11 and 13. The rolling element 14 is a ball such as a steel ball. These rolling elements 14 are held by a holder 29 for each row. Both ends of the bearing space between the inner member 3 and the outer member 4 are sealed by sealing devices 15 and 16.

ハブ輪1および外方部材4は、いずれも鍛造後に旋削加工して製造される。ハブ輪1および外方部材4の材質は、例えば軸受鋼、または浸炭鋼、または炭素含有量が0.4〜0.8%の炭素鋼とされる。鍛造工程では、外方部材4は、図6に示すように、上記材質の鋼材であるバー材Wを所定寸法に切断し、1100℃前後に加熱して、据え込み、荒成形、仕上成形、および内径抜きを行う。このような鍛造工程により、外方部材4は図5に示す形状に加工される。同図において、外方部材4の旋削後の仕上げ形状を破線で示した。また、ファイバーフローFを示す曲線を同図の断面中に示した。同図中の符号A,Bで示す箇所は、転動面を構成する箇所である。   Both the hub wheel 1 and the outer member 4 are manufactured by turning after forging. The material of the hub wheel 1 and the outer member 4 is, for example, bearing steel, carburized steel, or carbon steel having a carbon content of 0.4 to 0.8%. In the forging process, as shown in FIG. 6, the outer member 4 cuts the bar material W, which is a steel material of the above material, into a predetermined dimension, heats it to around 1100 ° C., and places it up, rough forming, finish forming, And the inner diameter is removed. The outer member 4 is processed into the shape shown in FIG. 5 by such a forging process. In the figure, the finished shape of the outer member 4 after turning is indicated by a broken line. Moreover, the curve which shows the fiber flow F was shown in the cross section of the same figure. The locations indicated by reference signs A and B in the figure are locations that constitute the rolling surface.

ファイバーフローFを調べるには、例えば、外方部材4を軸方向に沿って切断し、その切断した試料を、加熱した塩酸溶液に浸漬させることで切断面に析出させればよい。   In order to examine the fiber flow F, for example, the outer member 4 may be cut along the axial direction, and the cut sample may be immersed in a heated hydrochloric acid solution to be deposited on the cut surface.

なお、上記実施形態では機械要素が車輪用軸受装置の外方部材である場合につき説明したが、この発明は、品質保証の対象となる機械要素が転がり軸受の軌道輪である場合に限らず、転動体であっても良く、またその他、転がり接触を行う機械要素一般にこの発明を適用することができる。   In the above embodiment, the case where the mechanical element is an outer member of the wheel bearing device has been described.However, the present invention is not limited to the case where the mechanical element targeted for quality assurance is a bearing ring of a rolling bearing, The present invention can be applied to a machine element that performs rolling contact.

以上、実施形態に基づいてこの発明を実施するための形態を説明したが、今回開示された実施の形態はすべての点で例示であって制限的なものではない。この発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。   As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

4…外方部材(機械要素)
20…機械要素材料の品質保証装置
21…介在物検査情報記憶手段
22…鍛造シミュレーション手段
23…分布状態シミュレーション手段
25…データベース
26…き裂進展介在物存在確率推定手段
27…寿命試験結果記憶手段
28…転動疲労寿命確保手段
F…ファイバーフロ−
4 ... Outer member (machine element)
20 ... Machine element material quality assurance device 21 ... Inclusion inspection information storage means 22 ... Forging simulation means 23 ... Distribution state simulation means 25 ... Database 26 ... Crack growth inclusion existence probability estimation means 27 ... Life test result storage means 28 ... Rolling fatigue life securing means F ... Fiber flow

Claims (6)

転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を行う機械要素材料の品質保証方法であって、
前記鋼材の介在物に係る情報を取得する介在物検査過程と、
前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する鍛造シミュレーション過程と、
前記介在物検査過程で得た介在物に係る情報と前記鍛造シミュレーション過程で得たファイバーフロ−の方向の情報とから、前記鋼材が前記機械要素に製品化された状態における前記転動面の表面から一定の深さに位置する前記介在物の分布状態を調べる分布状態シミュレーション過程と、
前記転動面で転動が行われた場合に前記機械要素にき裂が進展し得る介在物に係るデータベースの蓄積情報、および前記分布状態シミュレーションで得られた介在物の分布状態から、前記製品の軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を求めるき裂進展介在物存在確率推定過程と、
この求められた存在確率が一定値以下であるか否かを判定する転動疲労寿命確保過程、 とを含む機械要素材料の品質保証方法。
When a steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging, it is determined whether or not the rolling fatigue life has reached a certain level. A quality assurance method,
Inclusion inspection process for obtaining information on inclusions in the steel material;
A forging simulation process of obtaining information on the direction of fiber flow after the forging by performing a forging simulation for processing the steel material into the shape of the machine element;
From the information on the inclusions obtained in the inclusion inspection process and the information on the direction of the fiber flow obtained in the forging simulation process, the surface of the rolling surface in a state where the steel material is commercialized into the machine element. A distribution state simulation process for examining the distribution state of the inclusion located at a certain depth from
From the accumulated information in the database related to inclusions that can crack in the machine element when rolling is performed on the rolling surface, and the distribution state of inclusions obtained by the distribution state simulation, the product A crack propagation inclusion existence probability estimation process for determining the existence probability of an inclusion that can propagate a crack, located at a certain depth from the orbital plane of
A quality assurance method for a machine element material, comprising: a rolling fatigue life securing process for determining whether or not the obtained existence probability is a predetermined value or less.
請求項1に記載の機械要素材料の品質保証方法において、前記分布状態シミュレーション過程では、乱数を用いた複数回の試行により、前記転動面の表面から一定の深さに位置する前記介在物の分布状態を定める機械要素材料の品質保証方法。   The quality assurance method for machine element material according to claim 1, wherein, in the distribution state simulation process, the inclusions located at a certain depth from the surface of the rolling surface are subjected to a plurality of trials using random numbers. Quality assurance method for machine element material that determines distribution status. 請求項1または請求項2に記載の機械要素材料の品質保証方法において、前記データベースの構築については、任意の使用条件における、任意の緒元の介在物周りの応力拡大係数振幅を有限要素法により算出し、算出された応力拡大係数振幅と、既知の下限界応力拡大係数との比較により、前記応力拡大係数振幅が大きい場合に、転動によりき裂が進展し得る介在物であると判断し、この検討を、使用条件、介在物緒元毎に実施し、き裂が進展し得る介在物の前記データベースを構築する機械要素材料の品質保証方法。   The quality assurance method for machine element material according to claim 1 or 2, wherein the database is constructed by using a finite element method to determine the stress intensity factor amplitude around an inclusion of an arbitrary specification under an arbitrary use condition. By calculating and comparing the calculated stress intensity factor amplitude with a known lower limit stress intensity factor, it is determined that the inclusion can cause a crack to develop by rolling when the amplitude of the stress intensity factor is large. The quality assurance method for machine element materials, in which this examination is performed for each use condition and inclusion specification, and the database of inclusions in which cracks can develop is constructed. 請求項1ないし請求項3のいずれか1項に記載の機械要素材料の品質保証方法において、転動疲労寿命試験の実施によって、き裂が進展し得る介在物の存在確率と転動疲労寿命との関係のデータベースを構築し、このデータベースと、前記き裂進展介在物存在確率推定過程で求めた前記き裂が進展し得る介在物の存在確率とを照合することにより、転動疲労寿命が一定水準に達しているかを判定する過程を含む機械要素材料の品質保証方法。   In the quality assurance method of the machine element material according to any one of claims 1 to 3, the existence probability of inclusions that can develop cracks and the rolling fatigue life are determined by performing a rolling fatigue life test. The rolling fatigue life is constant by collating this database with the existence probability of inclusions that can be propagated by the crack, which is obtained in the crack propagation inclusion existence probability estimation process. A quality assurance method for machine element materials, including a process for determining whether the level has been reached. 請求項1ないし請求項4のいずれか1項に記載の機械要素材料の品質保証方法において、前記機械要素が転がり軸受の軌道輪または転動体である機械要素材料の品質保証方法。   The quality assurance method for machine element material according to any one of claims 1 to 4, wherein the machine element is a bearing ring or a rolling element of a rolling bearing. 転動面を有する機械要素の材料である鋼材が、鍛造を経て前記機械要素に製品化された場合に、転動疲労寿命が一定の水準に達しているか否かの判定を行う機械要素材料の品質保証装置であって、
前記鋼材の介在物に係る情報を記憶する介在物検査情報記憶手段と、
前記鋼材を前記機械要素の形状に加工する鍛造のシミュレーションを行って前記鍛造の後のファイバーフロ−の方向の情報を取得する鍛造シミュレーション手段と、
前記介在物検査情報記憶手段に記憶された介在物に係る情報と前記鍛造シミュレーション手段で得たファイバーフロ−の方向の情報とから、前記鋼材が前記機械要素に製品化された状態における前記転動面の表面から一定の深さに位置する前記介在物の分布状態を調べる分布状態シミュレーション手段と、
前記転動面で転動が行われた場合に前記機械要素にき裂が進展し得る介在物に係るデータベースの蓄積情報、および前記分布状態シミュレーションで得られた介在物の分布状態から、前記製品の軌道面から一定深さに位置する、き裂が進展し得る介在物の存在確率を求めるき裂進展介在物存在確率推定手段と、
この求められた存在確率が一定値以下であるか否かを判定する転動疲労寿命確保手段、 とを備える機械要素材料の品質保証装置。
When a steel material, which is a material of a machine element having a rolling surface, is commercialized into the machine element through forging, it is determined whether or not the rolling fatigue life has reached a certain level. A quality assurance device,
Inclusion inspection information storage means for storing information relating to inclusions in the steel material;
Forging simulation means for obtaining information on the direction of fiber flow after the forging by performing a forging simulation for processing the steel material into the shape of the machine element;
The rolling in a state in which the steel material is commercialized into the machine element from the information related to the inclusion stored in the inclusion inspection information storage means and the information on the direction of the fiber flow obtained by the forging simulation means. A distribution state simulation means for examining the distribution state of the inclusions located at a certain depth from the surface of the surface;
From the accumulated information in the database related to inclusions that can crack in the machine element when rolling is performed on the rolling surface, and the distribution state of inclusions obtained by the distribution state simulation, the product A crack propagation inclusion existence probability estimating means for obtaining the existence probability of an inclusion that can be propagated by a crack located at a certain depth from the orbital plane of
A rolling element fatigue life securing means for judging whether or not the obtained existence probability is a predetermined value or less, and a quality assurance device for machine element material.
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