JPS6334423B2 - - Google Patents
Info
- Publication number
- JPS6334423B2 JPS6334423B2 JP3429079A JP3429079A JPS6334423B2 JP S6334423 B2 JPS6334423 B2 JP S6334423B2 JP 3429079 A JP3429079 A JP 3429079A JP 3429079 A JP3429079 A JP 3429079A JP S6334423 B2 JPS6334423 B2 JP S6334423B2
- Authority
- JP
- Japan
- Prior art keywords
- fatigue
- amount
- rolling
- width
- retained austenite
- 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.)
- Expired
Links
- 238000005096 rolling process Methods 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 17
- 229910000734 martensite Inorganic materials 0.000 claims description 16
- 238000005259 measurement Methods 0.000 claims description 14
- 229910001566 austenite Inorganic materials 0.000 claims description 12
- 230000000717 retained effect Effects 0.000 claims description 10
- 238000002441 X-ray diffraction Methods 0.000 claims description 8
- 239000007769 metal material Substances 0.000 claims description 5
- 238000011156 evaluation Methods 0.000 claims 2
- 239000002184 metal Substances 0.000 claims 1
- 206010016256 fatigue Diseases 0.000 description 48
- 238000012360 testing method Methods 0.000 description 6
- 230000009466 transformation Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005461 lubrication Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000009510 drug design Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000005381 potential energy Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Landscapes
- Analysing Materials By The Use Of Radiation (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Description
本発明は軸受、歯車、カム等の転動部に生じる
転がり疲れの疲労度測定方法に関する。本明細書
中で用いられる転がり疲れは、多少の滑りを伴な
う場合も含めて転がり接触による材料の疲労を意
味する。従つて、ヘルツの転がり接触応力、表面
の摩擦力、異物噛み込み時の応力等の繰り返しに
よる疲労を具体的には指す。
従来、軸受等の転がり疲れの程度を定量的に表
わす方法はなく、例えば視覚的観察で判定したり
或いはより科学的には転がり疲れによつて生じる
転動部の材質の変化をＸ線装置によつて測定して
求められた物理量でおおよその目安をつけるとい
つた程度であつた。特に、後者の物理量で目安を
つける方法についてここで述べると、公知なこと
は以下の如きことである。即ち、マルテンサイト
相のＸ線の回折線半価幅（単位mm）（以下半価幅
という）と転がり疲労度、及び残留オーステナイ
ト量（単位Vol％）（以下γR量という）と転がり
疲労度が何らかの関係を持つことは知られてお
り、当然上記半価幅やγR量の測定法についても知
られている。しかし、半価幅或いはγR量だけでは
各測定対象についてバラツキが大き過ぎて疲労度
のおおよその目安さえつけ難いと共に、同一対象
についても各部位（具体的には転動部の表面、或
る深さの内部）において求められた半価幅とγR量
をそれぞれどう処理して疲労度判定に用いるかは
明瞭になつていない。
従つて、本発明は、各対象の各部位について求
まつた半価幅とγR量をそれぞれ区別して適当に処
理し各対象の各部位の転がり疲れによる疲労度を
測定する方法を提供することを目的としている。
このことは、本発明においては疲労の程度が表面
付近で最大になる場合と、内部の最大せん断応力
位置付近の深さで最大になる場合とでＸ線装置に
よる測定値から求まる疲労度パラメータによる疲
労進行度判定の規準をかえて各測定対象の残存寿
命が推定されるということをも意味する。これ
は、内部疲労の方が様々な環境条件に晒される表
面疲労より破損するまでの疲労の蓄積が大きい傾
向があるからである。
以下、本発明の具体的な実施例について説明す
る。
第１図は疲労の程度が測定対象の表面付近で最
大になつている場合の例を示し、具体的には表１
に示す各測定対象の表面疲労に関する各種のフラ
グを示している。第１ａ図は表面疲労の進行につ
れての半価幅の変化を示し、第１ｂ図は同じくγR
量減少のようすを示している。半価幅は及びγR減
少量はＸ線回折装置の測定から得られるもので、
ここでは前者についてはmm単位そして後者につい
ては体積パーセント（Vol％）で示されている。
また、疲労の進行度は、最終的に転がり疲れ破損
に至るまでの時間を100としてそれまで経過した
耐久試験時間の相対的な量（相対的耐久試験時間
Ｌ）で示されている。この２つのグラフから明ら
かなように、同じ金属材料の種類かつ同じ表面疲
労の場合であつても軸受の形式、潤滑条件等によ
りＬに対する半価幅の変化具合及びγR減少量が相
当大きく異なることがわかる。従つて、測定対象
の測定値をばらばらに見ただけでは疲労度が推定
できないことになる。しかし、第１ｃ図のような
各ＬにおけるγR減少量（△Ｒ）に対する半価幅の
減少量（△Ｂ）のグラフを見ればわかるように、
Ｆ＝ｋ・△Ｒ＋△Ｂ（ただしｋ＝ｂ／ａでこれは金属
材料の種類により決定される）なる量は軸受の形
式、潤滑条件等に係わりなくＬとほぼ一対一に対
応している。従つて、各測定対象の△Ｒと△Ｂが
わかればそれからＦが計算でき、さらにはＬがわ
かることになる。こうしたことから、第１ｄ図の
如き表面疲労におけるＬに対するＦ即ち疲労度パ
ラメータのグラフを予め作成しておけば、各測定
対象の半価幅の減少量とγR減少量を測定すること
により疲労度パラメータＦを算出し、このパラメ
ータの値をもとに上記グラフからその対象のＬが
求められて疲労進行度が相当確実に推定できるこ
とになる。
次に、第２図は内部疲労の場合の例を示し、具
体的には表２に示す各測定対象の内部疲労に関す
る各種のグラフを示している。内部疲の場合につ
いても表面疲の場合と同じことが言えて、第２
ａ，ｂ図から△Ｒ、△Ｂがわかり、金属材料の種
類に応じて変わるｋがわかつているからＦが計算
できて第２ｃ図が作成できる。ただ、表面疲労と
の相違点は、疲労度パラメータＦが表面疲労と内
部疲労とで同じであつてもＬは異なると言うこと
である。このことの理由は前に述べてある。転動
部の内部の疲労を測定する場合には、転がり疲労
前及び転がり疲労後の転動部を電解研削のような
加工荷重のかからないような方法で除去して測定
したい面を露出させ、前記のようにＸ線回折装置
により半価幅、残留オーステナイト量を測定す
る。後は表面の疲労度を測定する場合と同じであ
る。
ここで、疲労していない時のγR量や半価幅の求
め方について触れると、それは同種類の新品のも
のについて測定したり、疲労の影響を受けない内
部の測定値から外挿したり、同一対象の転動面以
外の部分を測定したりして求められる。
ところで、第１図、第２図に見られるように、
γR減少量と半価幅減少量の間に一定の関係が認め
られる理由は次のように考えられる。
くり返し応力によるγRの減少は、応力誘起変態
によるγRのマルテンサイト変態によるものとみら
れる。この疲労過程の途中で生じたマルテンサイ
トは新しく生成された相であるからまだ疲労して
おらず、当然その半価幅は大きいと考えなければ
ならない。このように半価幅値の大きい回折線が
疲労したマルテンサイトの小さい半価幅の回折線
に重なることによつて、回折線半価幅は大きくな
るものと考えられる。この効果はオーステナイト
の量と一定の関係をもつと予測される。また、材
料によつて応力誘起変態で生ずる新しいマルテン
サイトの内部歪が異なり、そのためその半価幅値
が異なるということもあり得る。
もう一つの要因として、γRのマルテンサイト変
態のために外部エネルギーが消費され、その分、
マルテンサイトの疲労が遅延して半価幅減少が遅
れるという効果も考えられる。
しかし、もともとγRは常温できわめて不安定な
相であり瞬間的なすべり変形でマルテンサイト化
するので、マルテンサイト変態過程そのものに要
するエネルギーの消費は、転がり接触応力のエネ
ルギーを消費するより、γR自身がもともと有して
いたポテンシヤル・エネルギーを消費する方がは
るかに多いと考えられる。
したがつて、疲労によつて非常に大きな内部歪
を有するに至つたγRがある状態とその結果そのオ
ーステナイトがマルテンサイト変態してしまつた
状態を考えると、この両状態の間でマルテンサイ
トが疲労を軽減されたエネルギーは比較的小さい
ものにすぎず、この第２の要因による半価幅の影
響は第１の要因（新しいマルテンサイトの大きな
半価幅の影響）に比べると無視し得るほど小さい
と考えられる。よつて、主として第１の要因に基
づいて半価幅の補正を考えるべきであろう。
尚、以上の測定方法を具体化して測定装置を作
ることは容易である。それにはＸ線回折装置、計
算記録装置、マイコン等を結合させればよい。
以上、このような本発明による測定方法にする
と次のような有利な結果が招来される。
実用機械中に使用された軸受などの疲労損傷
の進行即ち疲労度が相当な確実性をもつて判
り、信頼性が高く合理的な設計や保全が可能と
なる。
従来はあたりを目で見て判定していた荷重の
傾きや局部応力集中などの異常を確実に知るこ
とができる。
耐久試験を最後の破損まで行なう必要がなく
なり、途中打切りによつて大幅に試験時間の短
縮と試験機台数の削減ができる。
航空機や鉄道車両などの安全性を強く要求さ
れる分野において、残存寿命を定期的に測定す
ることによりきわめて安全度高くこれらが使用
できる。
The present invention relates to a method for measuring the degree of rolling fatigue occurring in rolling parts such as bearings, gears, cams, etc. As used herein, rolling fatigue refers to fatigue of materials due to rolling contact, even when accompanied by some slippage. Therefore, it specifically refers to fatigue due to repeated Hertzian rolling contact stress, surface friction force, stress when foreign objects are caught, etc. Until now, there has been no method to quantitatively express the degree of rolling fatigue in bearings, etc.; for example, it can be determined by visual observation, or more scientifically, changes in the material of rolling parts caused by rolling fatigue can be detected using an X-ray machine. Therefore, it was only possible to use the physical quantities obtained by measurement as a rough guide. In particular, the latter method of determining the physical quantity as a guideline will be described here, and the known methods are as follows. That is, the X-ray diffraction line half-width (unit: mm) of the martensitic phase (unit: mm) (hereinafter referred to as half-width) and rolling fatigue degree, and the amount of retained austenite (unit: Vol%) (hereinafter referred to as γ R amount) and rolling fatigue degree. It is known that there is some kind of relationship between the two, and of course, the method for measuring the half width and the amount of γ R is also known. However, using only the half-width width or the γ R amount, there are too many variations for each measurement target, making it difficult to even approximate the degree of fatigue. It is not clear how to process the half-width and γ R amount determined at the depth (inside the depth) and use them to determine the degree of fatigue. Therefore, the present invention provides a method for measuring the degree of fatigue due to rolling fatigue of each part of each object by separately processing the half-width and γ R amount determined for each part of each object separately. It is an object.
In the present invention, this is determined by the fatigue degree parameter determined from the measurement value by an This also means that the remaining life of each measurement object is estimated by changing the criteria for determining the degree of fatigue progression. This is because internal fatigue tends to accumulate more before failure than surface fatigue, which is exposed to various environmental conditions. Hereinafter, specific examples of the present invention will be described. Figure 1 shows an example where the degree of fatigue is maximum near the surface of the measurement target.
Various flags related to surface fatigue of each measurement target shown in are shown. Figure 1a shows the change in half-width as surface fatigue progresses, and Figure 1b shows the same γ R
This shows a decrease in quantity. The half width and the amount of γ R reduction are obtained from measurements using an X-ray diffraction device.
The former is shown here in mm and the latter in volume percent (Vol%).
Further, the degree of progress of fatigue is expressed as a relative amount of durability test time (relative durability test time L), with the time until the final rolling fatigue failure being 100. As is clear from these two graphs, even in the case of the same type of metal material and the same surface fatigue, the degree of change in the half-value width with respect to L and the amount of reduction in γ R vary considerably depending on the bearing type, lubrication conditions, etc. I understand that. Therefore, the degree of fatigue cannot be estimated just by looking at the measured values of the measurement target separately. However, as shown in Figure 1c, if you look at the graph of the amount of decrease in half-value width (△B) against the amount of decrease in γ R (△R) for each L,
The quantity F=k・△R+△B (k=b/a, which is determined by the type of metal material) corresponds almost one-to-one to L, regardless of the bearing type, lubrication conditions, etc. . Therefore, if ΔR and ΔB of each measurement object are known, then F can be calculated, and furthermore, L can be found. For this reason, if a graph of F, that is, the fatigue degree parameter, against L in surface fatigue as shown in Figure 1d is created in advance, fatigue fatigue can be measured by measuring the amount of decrease in the half-power width and the amount of decrease in γ R of each measurement target. The degree parameter F is calculated, and based on the value of this parameter, L of the subject is determined from the above graph, and the degree of fatigue progress can be estimated with considerable certainty. Next, FIG. 2 shows an example of internal fatigue, and specifically shows various graphs regarding internal fatigue of each measurement target shown in Table 2. The same thing can be said for internal fatigue as for surface fatigue, and the second
Since ΔR and ΔB are known from diagrams a and b, and k, which changes depending on the type of metal material, is known, F can be calculated and diagram 2c can be created. However, the difference from surface fatigue is that even if the fatigue degree parameter F is the same for surface fatigue and internal fatigue, L is different. The reason for this has been stated earlier. When measuring internal fatigue of a rolling part, remove the rolling part before and after rolling fatigue using a method such as electrolytic grinding that does not apply a processing load to expose the surface to be measured. The half width and amount of retained austenite are measured using an X-ray diffraction device as shown in the figure. The rest is the same as when measuring the degree of surface fatigue. Here, we will talk about how to calculate the γ R amount and half-value width when not fatigued.It is possible to measure it on a new product of the same type, or extrapolate it from an internal measurement value that is not affected by fatigue. It can be found by measuring parts other than the rolling surface of the same object. By the way, as seen in Figures 1 and 2,
The reason why a certain relationship is recognized between the amount of γ R reduction and the amount of half width reduction is considered as follows. The decrease in γ R due to repeated stress appears to be due to martensitic transformation of γ R due to stress-induced transformation. Since the martensite generated during this fatigue process is a newly generated phase, it is not yet fatigued, and it must be considered that its half-width is naturally large. It is thought that the half-width of the diffraction line becomes large because the diffraction line with a large half-width value overlaps the diffraction line with a small half-width of fatigued martensite. This effect is predicted to have a certain relationship with the amount of austenite. It is also possible that the internal strain of new martensite generated by stress-induced transformation differs depending on the material, and therefore the half-width value thereof differs. Another factor is that external energy is consumed for martensitic transformation of γ R , and
Another possible effect is that the fatigue of martensite is delayed and the decrease in half-value width is delayed. However, since γ R is originally an extremely unstable phase at room temperature and transforms into martensite through instantaneous sliding deformation, the energy consumption required for the martensitic transformation process itself is less than the energy of rolling contact stress. It is thought that much more of the potential energy originally possessed by R itself is consumed. Therefore, considering a state in which γ R has a very large internal strain due to fatigue and a state in which the austenite has transformed into martensite, martensite is The fatigue-reduced energy is only relatively small, and the influence of this second factor on the half-width is negligible compared to the first factor (the effect of the large half-width of new martensite). It is considered small. Therefore, correction of the half-value width should be considered mainly based on the first factor. Note that it is easy to make a measuring device by embodying the above measuring method. For this purpose, an X-ray diffraction device, calculation/recording device, microcomputer, etc. may be combined. As described above, the measurement method according to the present invention brings about the following advantageous results. The progress of fatigue damage, that is, the degree of fatigue, of bearings used in practical machines can be determined with considerable certainty, allowing highly reliable and rational design and maintenance. It is now possible to reliably detect abnormalities such as load inclinations and local stress concentrations, which were previously determined by visually inspecting the area. It is no longer necessary to carry out the durability test until the final failure, and by stopping the test in the middle, the test time can be significantly shortened and the number of test machines can be reduced. In fields where safety is strongly required, such as aircraft and railway vehicles, these can be used with an extremely high degree of safety by periodically measuring their remaining life.
【表】
ろ軸受 に鉄粉と
土砂を混
入
[Table] Filter bearing with iron powder
Mix earth and sand
Enter
第１図は表面疲労の場合の各種のグラフを示
し、そして第２図は内部疲労の場合の各種のグラ
フを示している。
FIG. 1 shows various graphs for surface fatigue, and FIG. 2 shows various graphs for internal fatigue.
Claims (1)
転がり疲れによる疲労度の測定方法において、前
記金属材料の転動部の転がり疲労前および疲労後
のマルテンサイト相のＸ線回折半価幅と残留オー
ステナイト量（Vol％）を測定し、金属部材の種
類によつて決まる定数をＫ、疲労していないとき
の残留オーステナイト量（Vol％）と疲労時のそ
れとの差を△Ｒ、疲労してない時のマルテンサイ
ト相のＸ線回折半価幅と疲労時のそれとの差を△
Ｂとするとき、疲労度パラメータＦ＝Ｋ△Ｒ＋△
Ｂなる式に、前記の測定値にもとづくマルテンサ
イト相のＸ線回折半価幅の減少量と残留オーステ
ナイト量（Vol％）の減少量を代入し、疲労度パ
ラメータを求め、この疲労度パラメータを予め作
成しておいた前記転動部の各部位に応じた基準に
より評価し、該各部位の疲労度を測定することを
特徴とする転がり疲れによる疲労度の測定方法。 ２ 特許請求の範囲第１項に記載の測定方法にお
いて、転動部表面における転がり疲労前および転
がり疲労後のマルテンサイト相のＸ線回折半価幅
と残留オーステナイト量（Vol％）を測定し、前
記測定値にもとづく半価幅の減少量と残留オース
テナイト量（Vol％）の減少量をＦ＝Ｋ△Ｒ＋△
Ｂなる式に代入して疲労度パラメータを求め、予
め作成しておいた表面疲労の規準により評価する
ことを特徴とする転がり疲れによる疲労度の測定
方法。 ３ 特許請求の範囲第１項に記載の測定方法にお
いて、転動部内部における転がり疲労前および転
がり疲労後のマルテンサイト相のＸ線回折半価幅
と残留オーステナイト量（Vol％）を測定し、前
記測定値にもとづく半価幅の減少量と残留オース
テナイト量（Vol％）の減少量をＦ＝Ｋ△Ｒ＋△
Ｂなる式に代入して疲労度パラメータを求め、予
め作成しておいた表面疲労の規準により評価する
ことを特徴とする転がり疲れによる疲労度の測定
方法。[Scope of Claims] 1. A method for measuring the degree of fatigue due to rolling fatigue of a metallic material having a retained austenite structure, comprising the X-ray diffraction half-width of a martensitic phase before and after rolling fatigue of a rolling part of the metallic material. The amount of retained austenite (Vol%) is measured, K is the constant determined by the type of metal member, and △R is the difference between the amount of retained austenite (Vol%) when not fatigued and that when fatigued. △
When B, fatigue level parameter F=K△R+△
Substitute the reduction in the X-ray diffraction half-width of the martensitic phase and the reduction in the amount of retained austenite (Vol%) based on the above-mentioned measured values into the equation B to obtain the fatigue parameter, and use this fatigue parameter as A method for measuring the degree of fatigue due to rolling fatigue, characterized in that the degree of fatigue of each part is measured by evaluating according to a standard created in advance according to each part of the rolling part. 2. In the measuring method described in claim 1, the X-ray diffraction half-width and the amount of retained austenite (Vol%) of the martensitic phase before and after rolling fatigue on the surface of the rolling part are measured, The amount of decrease in half width and the amount of decrease in retained austenite amount (Vol%) based on the above measurement values are calculated as F=K△R+△
A method for measuring fatigue level due to rolling fatigue, characterized in that the fatigue level parameter is obtained by substituting it into the equation B, and the evaluation is performed based on a pre-prepared surface fatigue standard. 3. In the measuring method described in claim 1, the X-ray diffraction half-width and the amount of retained austenite (Vol%) of the martensitic phase before and after rolling fatigue inside the rolling part are measured, The amount of decrease in half width and the amount of decrease in retained austenite amount (Vol%) based on the above measurement values are calculated as F=K△R+△
A method for measuring fatigue level due to rolling fatigue, characterized in that the fatigue level parameter is obtained by substituting it into the equation B, and the evaluation is performed based on a pre-prepared surface fatigue criterion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3429079A JPS55126846A (en) | 1979-03-26 | 1979-03-26 | Measuring method for fatigue degree of rolling fatigue |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3429079A JPS55126846A (en) | 1979-03-26 | 1979-03-26 | Measuring method for fatigue degree of rolling fatigue |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55126846A JPS55126846A (en) | 1980-10-01 |
| JPS6334423B2 true JPS6334423B2 (en) | 1988-07-11 |
Family
ID=12410016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3429079A Granted JPS55126846A (en) | 1979-03-26 | 1979-03-26 | Measuring method for fatigue degree of rolling fatigue |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55126846A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8593138B2 (en) | 2009-12-17 | 2013-11-26 | Nsk Ltd. | Bearing residual life prediction method, bearing residual life diagnostic apparatus and bearing diagnostic system |
| WO2020255476A1 (en) | 2019-06-17 | 2020-12-24 | 日本精工株式会社 | Rolling machine element fatigue diagnosis method and rolling machine element fatigue diagnosis system |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5076719B2 (en) * | 2007-08-07 | 2012-11-21 | 日本精工株式会社 | Predicting remaining life of rolling bearings |
-
1979
- 1979-03-26 JP JP3429079A patent/JPS55126846A/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8593138B2 (en) | 2009-12-17 | 2013-11-26 | Nsk Ltd. | Bearing residual life prediction method, bearing residual life diagnostic apparatus and bearing diagnostic system |
| DE112010000023B4 (en) | 2009-12-17 | 2021-09-30 | Nsk Ltd. | A method for predicting a remaining life of a bearing, an apparatus for diagnosing a remaining life of a bearing and a bearing diagnostic system |
| WO2020255476A1 (en) | 2019-06-17 | 2020-12-24 | 日本精工株式会社 | Rolling machine element fatigue diagnosis method and rolling machine element fatigue diagnosis system |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55126846A (en) | 1980-10-01 |
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