JP2019207157A - Method for evaluating performance of rolling component - Google Patents

Abstract

To provide a method for evaluating performance of a rolling component which allows for highly accurate evaluation of the performance of the rolling component using a fatigue degree or a remaining life.SOLUTION: The method for evaluating performance of a rolling component comprises the steps of: estimating a fatigue degree of the rolling component; and evaluating the performance of the rolling component. In the step of evaluating the performance of the rolling component, the performance of the rolling component is evaluated on the basis of a relationship between load frequencies in a plurality of states and the fatigue degree being evaluation data corresponding to the load frequencies. The step of estimating the fatigue degree includes a step (S10) of acquiring measurement data, and a step (S11) of estimating the fatigue degree. In the step (S10) of acquiring the measurement data, the measurement data of an X-ray analysis value related to the rolling component are acquired by irradiating a fatigue part of the rolling component with X-ray. In the step (S11) of estimating the fatigue degree, the fatigue degree of the rolling component is estimated from the measurement data on the basis of a relationship between the X-ray analysis value and the fatigue degree of the rolling component.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for evaluating the performance of a rolling component, and more specifically, the performance of a rolling component that evaluates the performance of the rolling component by estimating the fatigue level and remaining life of the rolling component in use. It relates to the evaluation method.

  It is known that the life of rolling bearings (hereinafter also referred to as bearings) depends on operating conditions such as load and lubrication conditions and material properties such as hardness, structure and residual stress of the rolling parts that make up the bearings. Yes. Therefore, the life of the bearing is estimated using a life calculation formula that can be calculated from the operating conditions and material characteristics of the bearing. This formula is used to estimate how long a bearing can be used under certain conditions, or under what conditions it should be used so that the bearing will not break during the required period of use. Is used.

  In general, a bearing is used under a use condition set based on a life calculation formula. Therefore, the life should not be a problem when the bearing is used under the assumed conditions. However, bearing life is often a problem in the market. This is presumably because the bearing life may be shortened unexpectedly in actual bearings due to disturbances such as the use environment. Therefore, in bearings, there is a need to estimate the actual fatigue level of a bearing based on some analysis result and to manage the risk of damage to the bearing from the fatigue level. There is also a need to estimate the remaining life based on the degree of fatigue from the fatigue level and to quantitatively predict the bearing replacement time from the remaining life. Furthermore, if the fatigue level and remaining life estimation of the rolling parts are applied to the rolling parts during the rolling fatigue test, the rolling parts are not tested until they reach the end of their life, i.e., until separation occurs. The fatigue characteristics of rolling parts can be evaluated from the speed of progress of the fatigue level. As a result, it can also contribute to speeding up the development of rolling parts.

  For example, Japanese Patent Application Laid-Open No. 2014-167421 describes a method for predicting damage forms such as peeling, flaking, wear, and smearing from a plasticity index obtained from a contact pressure of a bearing and a protrusion shape of surface roughness. Has been. Furthermore, a method for predicting the life of peeling, which is a type of surface-origin damage, from conditions such as contact pressure, plasticity index, and slip ratio is described.

  The method of estimating the remaining life for peeling is described by Zenyuki Tsushima et al., “Application of X-ray stress measurement to bearing failure analysis”, Bearing Engineer No. 49 (1984), pp. 25-34. In this paper, the degree of fatigue when peeling occurs is estimated from the amount of change in residual stress and half width measured by X-ray, and the remaining life is estimated from the degree of fatigue.

  In Japanese Patent Application Laid-Open No. 2014-13188, various X-ray analysis values (for example, stress, residual austenite amount, annular diffraction X) obtained from annular diffraction X-rays generated when X-rays are applied to the rolling parts of bearing parts are disclosed. (Diffraction intensity distribution with respect to the center angle of the line, half width with respect to the center angle, etc.) and various usage conditions (number of loads, load, lubrication conditions, etc.) of the rolling parts are made into a database. A method for estimating and estimating the life of a bearing from its use conditions is disclosed.

JP 2014-167421 A JP 2014-13188 A

Zenji Tsushima et al., “Application of X-ray stress measurement to bearing failure analysis”, Bearing Engineer No. 49 (1984), pp. 25-34

  The method disclosed in Japanese Patent Application Laid-Open No. 2014-167421 described above is based on the surface pressure-induced damage mode and life if the use conditions such as the contact pressure, the plasticity index indicating the severity of contact with the surface roughness, and the slip rate are known. Can be predicted. However, there is no means for predicting the use conditions of the bearing and how much the bearing is fatigued, that is, the degree of fatigue of the bearing, and it is difficult to estimate the remaining life.

  The method disclosed in the above-mentioned paper “Application of X-ray stress measurement to bearing failure analysis” assumes that the product of the increase in compressive residual stress and the decrease in half-value width is a parameter corresponding to the degree of fatigue. The remaining life of the rolling parts is estimated from the relationship between the parameters and the life of the rolling parts obtained under specific test conditions. The basis for the assumption that the product of the increase in compressive residual stress and the decrease in half-value width is a parameter that corresponds to the degree of fatigue corresponds to the life of the rolling part obtained under the specified test conditions The relationship is seen. However, this relationship is not theoretically obtained, and is a correspondence relationship between the degree of fatigue and the X-ray analysis value under a specific experimental condition. Therefore, since the relationship can vary greatly depending on the test conditions, there is a problem in the estimation accuracy of the fatigue level and the remaining life.

  The method disclosed in Japanese Patent Application Laid-Open No. 2014-13188 uses an X-ray diffraction ring analyzer that provides more information on rolling fatigue than conventional devices, and uses various X-ray analysis results and various rolling conditions (use This is a method for constructing a database of surface pressure, lubrication conditions, slip conditions, etc.), estimating bearing use conditions from the database, and estimating the remaining life. In this method, if the life can be estimated from the estimated use conditions by the method of Japanese Patent Application Laid-Open No. 2014-167421, the degree of fatigue becomes clear under the condition that the use time up to now is known. Further, assuming that the subsequent use conditions are equivalent to the use conditions up to now, the remaining life of the bearing parts can be estimated. However, this method is also assumed to have a large error in remaining life estimation because assumptions are made in subsequent use conditions. Furthermore, in this method, use conditions (for example, the number of loads, load, lubrication conditions, slip, etc.) of complicated rolling parts are statistically estimated from the X-ray analysis values. For this reason, if there is no database based on an enormous amount of experiments, the estimation accuracy of the use conditions is lowered, and as a result, the estimation accuracy of the remaining life is deteriorated.

  Here, the inventor is considering performing the performance evaluation of the rolling part using the above-described fatigue degree or remaining life of the rolling part. However, as described above, the conventional method uses the fatigue degree and remaining life. Therefore, it was difficult to evaluate the performance of rolling parts with high accuracy by using the fatigue level or remaining life.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to use the fatigue level or remaining life by estimating the fatigue level and remaining life with high accuracy. Another object of the present invention is to provide a rolling component performance evaluation method capable of performing the rolling component performance evaluation with high accuracy.

  The rolling component performance evaluation method according to the present disclosure includes a step of estimating a fatigue level of the rolling component and a step of evaluating the performance of the rolling component. In the step of estimating the fatigue level, the fatigue level of the rolling component is estimated for each of the rolling components to which the repeated load is applied, with respect to a plurality of states in which the number of loads of the repeated load on the rolling component is different from each other. . In the step of evaluating the performance of the rolling component, the performance of the rolling component is evaluated based on the relationship between the number of loads in a plurality of states and the degree of fatigue corresponding to the number of loads. The step of estimating the fatigue level includes a step of obtaining measurement data and a step of estimating the fatigue level. In the step of acquiring measurement data, X-ray analysis value measurement data relating to the rolling part is acquired by irradiating the fatigued part of the rolling part with X-rays. In the step of estimating the fatigue level, the fatigue level of the rolling component is estimated from the measurement data based on the relationship between the X-ray analysis value and the fatigue level of the rolling component.

  The rolling component performance evaluation method according to the present disclosure includes a step of estimating a remaining life and a step of evaluating the performance of the rolling component. In the step of estimating the remaining life, the remaining life of the rolling component is estimated for each of a plurality of states in which the number of times of the repeated load on the rolling component is different from each other. In the step of evaluating the performance, the performance of the rolling component is evaluated based on the relationship between the number of loads and the remaining life in a plurality of states. The step of estimating the remaining life includes a step of acquiring measurement data of X-ray analysis values, a step of acquiring surface shape measurement data, a step of deriving residual stress data, and a step of estimating repetitive stress data And a step of estimating a life, a step of estimating a fatigue level, and a step of estimating a remaining life. In the step of acquiring the measurement data of the X-ray analysis value, the measurement data of the X-ray analysis value relating to the rolling part is acquired by irradiating the fatigue part of the rolling part with X-rays. In the step of acquiring the measurement data of the surface shape, the fatigue data of the rolling part is measured to acquire the measurement data of the surface shape. In the step of deriving the residual stress data, the residual stress data in the fatigue part of the rolling part is derived based on the measurement data of the X-ray analysis values. In the step of estimating the repeated stress data, the repeated stress data acting on the fatigue portion is estimated based on the residual stress data and the surface shape measurement data. In the step of estimating the life, the life of the rolling component is estimated from the repeated stress data. In the step of estimating the fatigue level, the fatigue level of the rolling part is estimated from the measurement data of the X-ray analysis value based on the relationship between the X-ray analysis value and the fatigue level of the rolling part. In the step of estimating the remaining life, the remaining life of the rolling part is estimated based on the life and fatigue level of the rolling part.

  Based on the above, it is possible to obtain a rolling component performance evaluation method capable of performing the performance evaluation of the rolling component with high accuracy using the degree of fatigue or the remaining life.

It is a flowchart for demonstrating the performance evaluation method of rolling components which concerns on this embodiment. It is a flowchart for demonstrating the modification of the performance evaluation method of rolling components which concerns on this embodiment. It is a graph for demonstrating the performance evaluation method of rolling components which concerns on this embodiment. It is a flowchart for demonstrating the process of calculating | requiring the remaining life of rolling components. It is a flowchart for demonstrating the process which creates the database which shows the relationship between a X-ray analysis value and the fatigue degree of rolling components. It is a schematic diagram which shows the structural example of the measuring apparatus of a X-ray-analysis value. It is a schematic diagram for demonstrating the micro unevenness | corrugation of the rolling surface of rolling components. It is a graph for demonstrating the relationship between SN diagram and a fatigue degree. It is a graph which shows typically the relation between the history of equivalent stress, and the remaining life. It is a graph which shows the relationship between the frequency | count of a load, and the dispersion | variation in diffraction intensity. It is the schematic which shows the structure of a two-cylinder testing machine. It is a graph which shows the change of the residual stress (equivalent stress) in an Example. It is a graph which shows the change of the root mean square inclination _{Rdq in} an Example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

<Outline of performance evaluation method for rolling parts>
FIG. 1 is a flowchart for explaining a rolling component performance evaluation method according to the present embodiment. FIG. 2 is a flowchart for explaining a modification of the rolling component performance evaluation method according to the present embodiment. FIG. 3 is a graph for explaining the performance evaluation method for rolling parts according to the present embodiment. The outline of the rolling component performance evaluation method according to this embodiment will be described below.

  As shown in FIG. 1, the rolling component performance evaluation method according to the present disclosure includes a step (S1) of estimating a fatigue level of the rolling component and a step (S2) of evaluating the performance of the rolling component. . In the step of estimating the degree of fatigue (S1), for example, a rolling part to which a repeated load is applied as in a rolling fatigue test, for a plurality of states in which the number of repeated loads in the rolling part is different from each other, Estimate the fatigue level of rolling parts. For example, the step (S1) of estimating the degree of fatigue is performed for every certain number of loads. Details of the step (S1) of estimating the fatigue level will be described later. In the step (S2) of evaluating the performance of the rolling component, as shown in FIG. 3, based on the relationship between the number of loads in a plurality of states and the degree of fatigue that is evaluation data corresponding to the number of loads, Evaluate performance. In FIG. 3, the horizontal axis indicates the period of use, that is, the number of loads, and the vertical axis indicates the value of the evaluation data. Here, fatigue values are shown as evaluation data. As shown in FIG. 3, when data indicating the relationship between the number of loads and the degree of fatigue is plotted for rolling parts, the rolling parts that are in a normal use state become a data group as shown in the first group 10. . On the other hand, it can be seen that the rolling parts showing the data 11 out of the first group 10 are fatigued faster than the rolling parts included in the first group 10. Moreover, about the rolling components which show the data 12 which deviated from the 1st group 10, the way of progress of fatigue is slower than the rolling components contained in the 1st group 10, and it is used on the conditions which become long life. I understand.

  2 includes a step (S3) of estimating the remaining life and a step (S2) of evaluating the performance of the rolling component. In the step (S3) of estimating the remaining life, the remaining life of the rolling parts is respectively calculated for a plurality of states in which the number of repeated loads on the rolling parts is different from each other. presume. In the step of evaluating performance (S2), the performance of the rolling component is evaluated based on the relationship between the number of loads and the remaining life in a plurality of states. Details of the step of estimating the remaining life (S3) will be described later. In the step of evaluating performance (S2), similar to the performance evaluation method shown in FIG. 1, the remaining life estimated in the above step (S3) is plotted on the graph with the horizontal axis representing the number of loads and the vertical axis representing the remaining life. By plotting this data, it is possible to evaluate the performance of the rolling component from the change in the remaining life of the rolling component with respect to the number of loads.

<Method for estimating remaining life>
About remaining life:
The remaining life of the bearing is determined by how much the bearing is currently fatigued (fatigue level) and subsequent use conditions. The degree of fatigue and the remaining life are easily confused, but the difference is easy to understand by looking at the following equation representing the linear cumulative damage law (hereinafter, the minor law).

  The above equation (1) indicates that when the life at a certain stress amplitude is L1, L2... Li... Ln, N1, N2,. Is an empirical formula in which the life is reached when the linear sum of the ratios of the load to the respective life reaches 1. In this equation, the inside of the broken-line square on the left side is the degree of fatigue representing “how long it has been used under a certain use condition”. In addition, Nn in the last term on the left side of the above formula (1) is a remaining life representing “how long can it be used thereafter”. As is clear from this equation (1), the remaining life cannot be estimated unless the fatigue level (that is, within the broken line square in the equation (1)) and the life Ln determined by subsequent use conditions are known. Therefore, in the fatigue level estimation, it is a problem to devise an analysis method for accurately estimating the fatigue level in the broken-line square of the equation (1). Further, in the remaining life estimation, in addition to accurate fatigue level estimation, it becomes an issue to devise a method for predicting the future life from the usage conditions.

Specific method for estimating remaining life:
FIG. 4 is a flowchart for explaining a process for obtaining the remaining life of the rolling component. As shown in FIG. 4, in the method for estimating the remaining life of the rolling component, first, a surface shape measuring step (S20) of the rolling component is performed. Next, the oil film parameter is estimated from the data obtained in the step (S20) and the operating condition data of the rolling parts, specifically the rotational speed, operating temperature, load, lubricating oil condition, etc. (S21). To implement. When the oil film parameter is 3 or less, it is possible to directly contact the tip of the minute irregularities on the surface of the rolling part of the rolling component and the tip of the minute irregularities on the surface of the rotating member that contacts the rolling surface. There is sex. In this case, stress concentration (hereinafter referred to as “micro stress”) occurs on the minute unevenness on the surface of the rolling component. Surface-origin damage is due to this microstress. In the performance evaluation method according to the present embodiment, performance evaluation is performed by focusing on surface-origin damage (for example, peeling). Therefore, it can be confirmed that the performance evaluation method according to the present embodiment can be applied by confirming that the oil film parameter is 3 or less in the step (S21). Whether or not rolling parts such as bearings in use cause surface-origin separation will depend on the surface shape. Therefore, in the remaining life estimation process in the performance evaluation method according to the present embodiment, the step of calculating the stress state of the rolling surface (S22) is performed.

Hereinafter, an example of a specific method for calculating the stress state in step (S22) will be described.
First, the root mean square slope shown by Ioannides et al. (E. Ioannides, G. Bergling, A. Gabelli, "An Analytical Formulation for the Life of Rolling Bearings", ACTA POLYTECHNICA SCANDINAVICA, MECHANICAL ENGINEERING SERIES No. 137) Is assumed to be proportional to the micro-stress, as shown in the following equation (2).

  The roughness produced by grinding is directional, and long and narrow protrusions are present on the ground surface along the grinding direction as shown in FIG. Here, FIG. 7 is a schematic diagram for explaining minute irregularities on the rolling surface of the rolling component. In FIG. 7, the direction indicated by the arrow 31 is the grinding direction. The micro-concave convex portion 30 is formed so as to extend along the grinding direction indicated by the arrow 31. Here, if the cross-sectional shape of the object is uniform and has a sufficient length, it can be regarded as a plane strain state except for both ends thereof. Accordingly, it is possible to assume a plane strain stress state at the contact portion with minute irregularities, and the internal stress under the micro contact portion on the surface can be calculated by the following equations (3) to (6). It should be noted that an approximate value under the boundary lubrication condition, for example, an appropriate value such as 0.1 may be substituted for the friction coefficient μ. In the following formula, the xyz coordinate may be defined as follows, for example. That is, when a test piece in a two-cylinder test is considered as a rolling part, the z-axis is an axis extending in the radial direction from the outer peripheral surface of the test piece, and the x-axis is along the rotation direction of the test piece and tangential from the outer peripheral surface. The y-axis is an axis extending in the direction along the rotation axis from the outer peripheral surface of the test piece. When considering the inner ring of a rolling bearing as a rolling component, the z-axis is an axis extending in the radial direction from the outer peripheral surface (rolling surface) of the inner ring, and the x-axis is along the rotational direction of the inner ring and tangent from the outer peripheral surface. The y-axis is an axis extending in the direction along the rotation axis from the outer peripheral surface of the inner ring.

  The equivalent stress can be calculated by the following equation.

From the above, when the root mean square slope R _dq is measured, the triaxial stress immediately below the micro contact portion is calculated by using the equations (2) to (7), leaving the unknown constant a in the equation (2). it can.

  On the other hand, when a high stress is generated on the raceway surface of the rolling component, a high residual stress is gradually generated on the raceway surface due to repeated plastic deformation. For this reason, the residual stress is superimposed on the above-described micro stress when the rolling component rolls. Therefore, it is necessary to predict the repetitive stress of the surface layer, which determines the life due to the surface-origin type delamination, in consideration of both microstress and residual stress due to unevenness. Therefore, in the remaining life estimation process shown in FIG. 4, the residual stress is calculated from the result of the X-ray diffraction ring analysis on the surface (rolling surface) of the rolling part, and the microstress obtained in step (S22) is superimposed. In addition, the equivalent stress (repetitive stress) immediately below the contact portion is calculated. Specifically, after performing the X-ray diffraction ring analysis step (S10) of the rolling parts, the step (S12) of calculating the residual stress of the rolling surface is performed to obtain the residual stress, and then the rolling surface is obtained. The repetitive stress calculation step (S30) taking into account the residual stress is performed.

  In step (S10), the X-ray diffraction ring is measured using a measuring device as shown in FIG. 6, for example. FIG. 6 is a schematic diagram illustrating a configuration example of an X-ray analysis value measurement apparatus. As shown in FIG. 6, the measurement apparatus includes an irradiation unit 21 that irradiates a measurement target 90 such as a rolling part with X-rays, and a detector 22 that detects annular X-rays diffracted by the measurement target 90. A control calculation unit 23 connected to the detector 22 for calculating a predetermined X-ray analysis value based on the detection data of the annular X-ray detected by the detector 22 and storing the detection data; The display unit 24 is connected to the unit 23 and displays a calculation result in the control calculation unit 23 and the detection data.

  The irradiation unit 21 includes an X-ray tube installed so as to be opposed to the measurement object 90. The detector 22 includes a planar detection unit 22 </ b> A that can be opposed to the measurement object 90 and a hole formed in a central part through which X-rays irradiated from the irradiation unit 21 pass. An X-ray CCD may be adopted as the detection unit 22A of the detector 22. The control calculation unit 23 calculates an X-ray analysis value of the measurement object 90 based on a database stored in advance in a storage unit (not shown) and annular X-ray detection data detected by the detector 22. May be. The calculated X-ray analysis value and detection data are displayed on the display unit 24.

  In the X-ray diffraction ring analysis step (S10) using the measurement apparatus shown in FIG. 6, first, the measurement object 90 is prepared, and the step (S101) of irradiating the fatigue portion of the measurement object 90 with X-rays is performed. To be implemented. In this step (S101), the measuring object 90 which is a rolling part is set at a predetermined position, and the measuring object 90 is irradiated with X-rays from the irradiation unit 21. At this time, as shown in FIG. 6, the X-rays are irradiated along the arrow α so as to enter the measurement object 90 at a predetermined incident angle.

   Next, a step (S102) in which an X-ray diffraction ring is detected is performed. In this step (S102), as shown in FIG. 6, the X-rays incident on the measuring object 90 along the arrow α are diffracted so as to form the conical surface β and reach the detection unit 22A. In the detection unit 22A, which is, for example, an X-ray CCD, an annular diffraction X-ray (X-ray diffraction ring) is detected based on an intensity signal corresponding to the intensity of the X-ray output from each pixel. An X-ray analysis value is obtained from the measurement data of the annular diffraction X-ray described above. The X-ray analysis value is data indicating variation between the central angle and diffraction intensity of the annular diffracted X-ray diffracted at the fatigue portion of the measurement object 90 that is a rolling part, and the X-ray analysis value of the measurement object 90 that is a rolling part. It consists of six-component residual stress data in the fatigue part, half-width data of the diffraction X-ray peak diffracted in the fatigue part of the measurement object 90, and residual austenite amount data in the fatigue part of the measurement object 90. One data selected from the group may be used, or a combination of at least two data selected from the group may be used. The six-component residual stress data described above includes, for example, the vertical stress σx in the direction along the x-axis direction, the vertical stress σy in the direction along the y-axis direction, the vertical stress σz in the direction along the z-axis direction, and the xy plane. Shear stress τxy generated in the plane, shear stress τxz generated in the xz plane, shear stress τyz generated in the yz plane, and the like.

  After the step (S10), a step (S11) of estimating the fatigue level from the relationship between the fatigue level and the X-ray analysis value is performed, and the fatigue level D is specified (step (S13)). The relationship between the fatigue level and the X-ray analysis value is specified based on the data of the X-ray analysis and surface shape measurement of the rolling part. An example of how to obtain the relationship will be described later. The obtained fatigue level D is used for estimating the remaining life as will be described later.

  In addition, after the step (S10), a step (S12) of calculating the residual stress on the rolling surface based on the data obtained in the step (S10) is performed. The obtained residual stress value is used in the repeated stress calculation in step (S30).

Here, the value of the triaxial residual stress is required for the calculation of the repeated stress. As a method for calculating the triaxial residual stress, an X-ray stress measurement method capable of measuring the triaxial residual stress is applied. Any method can be used as such an X-ray stress measurement method. For example, Dolle et al. (“The Influence of Stress States, Stress Gradients and Elastic Anisotropy on the Evaluation of (Residual) Stresses by X- rays ”, J. Appl. Crysr., 12 (1979) 489-501), Toshihiko Sasaki et al.,“ Study on improvement of X-ray triaxial stress measurement method using area detector ”, Japan Society of Mechanical Engineers, A, 75 , 750, (2009) 219-227, etc., can be applied. As a result, the normal stress, shear stress and equivalent stress directly under the contact portion are obtained from the results of the residual stress measurement and the surface roughness measurement, so the relationship between these stress S and life L (repetitive stress S and life stress). If the relationship with L) is known, the step of obtaining the life (S40) based on the relationship can be performed to obtain the life L (step (S50)). Further, if it is possible to determine the degree of fatigue D from the relationship between fatigue and X-ray analysis as described above, it is possible to obtain the remaining life N _R from the following relation by using the Miner's rule (step (S60)) .

  Hereinafter, an example of a method for obtaining the SN diagram showing the relationship between the stress S and the life L and the relationship between the X-ray analysis value and the fatigue level from the experimental results will be described.

Method for determining SN diagram showing relationship between stress S and life L:
In the following, focusing on the equivalent stress as one of the stresses S, a procedure for obtaining the relationship between the equivalent stress and the life will be described. FIG. 8 is a graph for explaining the relationship between the SN diagram and the degree of fatigue. FIG. 9 is a graph schematically showing the relationship between the history of equivalent stress and the remaining life. 8 and 9, the horizontal axis indicates the number of loads corresponding to the life, and the vertical axis indicates the equivalent stress. SN diagram of FIG. 8 (hereinafter, also referred to as a SN curve) in, if the life of the case conditions the rolling equivalent stress S ₁ is acting as L _1, N ₁ iterations fatigue given equivalent stress S ₁ The degree of fatigue is expressed as N ₁ / L ₁ . In rolling contact in a rolling test, the surface roughness decreases with use, stress concentration at the protrusion contact portion is reduced, and compressive residual stress is generated. For this reason, the equivalent stress S decreases as the number of loads increases, and the fatigue level accumulates as the number of loads increases, as is apparent from Equation (1). In order to experimentally obtain the change in the equivalent stress indicated by the broken line in FIG. 8 from the results of the rolling test, the measurement of the surface roughness of the rolling part undergoing the rolling test and the measurement of the X-ray diffraction ring Is performed for each load. For this reason, the change of the stress S obtained by actual calculation is stepped as shown by S1, S2, S3, etc. in FIG.

  Next, for example, the following formula (9) is used as the formula of the SN curve specific to the material shown in FIGS.

Here, N indicates the load number, S is shown an equivalent stress acting on the contact surface, S _f represents the yield stress of the material after work-hardening due to repeated stress, A, B denotes a constant. The yield stress _Sf is a material constant and can be specified according to the material of the rolling part.

  A rolling test is performed on the rolling component, and the surface roughness and the X-ray diffraction ring of the rolling surface (fatigue surface) of the rolling component are measured every predetermined number of loads. The test is continued until separation occurs while calculating the fatigue level of the solid line. If this rolling test is performed a plurality of times, a plurality of rolling component life data can be plotted in FIG. The unknowns of Equation (2) and Equation (9) are obtained so as to fit this plot and the SN curve equation of Equation (9). In this way, an SN diagram based on the experimental result is obtained. Since there are a total of four unknowns, a, A, B, and S, in Equation (2) and Equation (9), the SN diagram can be determined from the experimental results of four levels or more, but a more accurate SN diagram can be obtained. It is desirable to experiment with as many levels as possible.

About the relationship between life and number of loads:
Consider a case where the equivalent stress acts on the rolling surface with a history as shown in FIG. The contact surface equivalent stresses at the time indicated by circles 1, 2, and 3 in FIG. 9 are S ₁ , S ₂ , and S ₃ , respectively, and the peeling life when these equivalent stresses are repeatedly applied is shown. Let L ₁ , L ₂ , and L ₃ . In order to calculate the equivalent stresses S ₁ , S ₂ , and S ₃ during the experiment, it is necessary to measure the roughness each time.

First, equivalent N ₁ times under conditions of stress S1, assume that underwent rolling fatigue N ₂ times with appreciable stress S ₂ condition. Further assume that the load number _(N 1 ₊ N ₂₎ times thereafter continued to receive the contact surface equivalent stress S _3, peeling occurs after N ₃ times the load. At this time, the remaining life at the number of times of load (N ₁ + N ₂ ) is N ₃ , and the relationship between the life and the number of loads can be expressed by the following equation based on the minor rule.

When formula (10) is rearranged, the remaining life N under the assumption that (N ₁ + N ₂ ) times of load is applied and fatigue progresses with the surface roughness and residual stress at the time of (N ₁ + N ₂ ) times. ₃ is represented by the following equation (11).

  Further, generalizing equation (11) yields the following equation (12).

About the relationship between X-ray analysis and fatigue level:
In the rolling test carried out in the above-described SN diagram determination method, the fatigue level is obtained for each predetermined number of loads, and X-ray analysis is also performed each time. Therefore, a database indicating the relationship between the degree of fatigue and the X-ray analysis value that is the X-ray analysis result can also be created. A method of creating the database will be described with reference to FIG. X-ray analysis values include stress, residual austenite amount, variation in diffraction intensity with respect to the central angle of the annular diffraction X-ray, half width with respect to the central angle, average value of diffraction intensity, and difference between minimum and maximum values. , Integral width (product of half width and diffraction intensity at a certain position), and the like.

<How to build a database of fatigue levels and X-ray analysis values>
FIG. 5 is a flowchart for explaining a process of creating a database indicating the relationship between the X-ray analysis value and the fatigue level of rolling parts. As shown in FIG. 5, in the process of creating a database indicating the relationship between the fatigue level and the X-ray analysis value, a step (S110) of performing a rolling fatigue test is performed. In the rolling fatigue test, an X-ray analysis step (S120) and a rolling component surface shape measurement step (S130) are performed when a certain number of loads have elapsed. In step (S120), the X-ray diffraction ring is measured in the same manner as the process for obtaining the SN diagram described above. Also in step (S130), the surface roughness of the rolling surface of the rolling component is measured in the same manner as the process for obtaining the SN diagram described above.

  Next, a step (S121) of obtaining a residual stress on the rolling surface of the rolling component based on the result of the X-ray analysis step (S120) is performed. In this step (S121), the residual stress is calculated using the same method as in step (S12) of FIG.

  Further, the step (S131) of estimating the oil film parameter from the data obtained in step (S20) and the rotational speed, operating temperature, load, lubricating oil conditions, etc., which are the operating condition data of the rolling parts, The stress state calculation step (S132) and the repetitive stress calculation step (S140) in consideration of the residual stress on the raceway are the same as step (S21), step (S22) and step (S30) shown in FIG. 4, respectively. Implement the process. If separation has not occurred in the rolling component when step (S140) is performed, the process returns to step (S110) again, and after applying a certain number of loads to the rolling component again, the above steps are performed. To do. If the rolling part has peeled when step (S140) is performed, the process proceeds to step (S15) for obtaining life data (peeling time) and stopping the rolling fatigue test. And 4 or more pieces of lifetime data are acquired by repeating the step (S110)-step (S150) mentioned above 4 times or more. Then, the step (S160) of determining the unknown number of a SN diagram is implemented so that the cyclic stress S of a rolling surface and the lifetime data N may correspond. In this step (S160), a process similar to the process of obtaining the unknowns of the equations (2) and (9) can be applied in the process of obtaining the SN diagram.

  Then, the step (S170) which calculates the fatigue degree for every load frequency of each rolling test from the SN diagram using the minor side is performed. As a result, since it is possible to acquire the data of the fatigue level and the X-ray analysis value for each of a plurality of loads, a step of constructing a database indicating the relationship between the fatigue level and the X-ray analysis value using these data ( S180) is performed. In this way, the database can be obtained. This database can be used to estimate the fatigue level based on the X-ray analysis value in step (S11) of FIG.

  Here, in step (S1) in the performance evaluation method shown in FIG. 1, step (S10), step (S11), and step (S13) shown in FIG. 4 are performed, and an X-ray diffraction value that is an X-ray analysis value is obtained. The degree of fatigue can be estimated from the ring analysis results. In this case, as shown in FIG. 5, since the database used for estimating the fatigue level is created based on the results of X-ray analysis and surface shape measurement measured in the rolling fatigue test, the fatigue level is highly accurate. Can be estimated. In the performance evaluation method shown in FIG. 2, the remaining life can be estimated using the process shown in FIG. As can be seen from the process shown in Fig. 4, the remaining life is estimated with high accuracy because the results of X-ray analysis and surface shape measurement in the rolling fatigue test of rolling parts are used to estimate the remaining life. it can.

  In the performance evaluation method described above, the performance of the rolling component can be evaluated. The performance of the rolling part includes, for example, the performance of a surface treatment part (for example, a plastic processing part such as shot peening, a chemical conversion treatment part such as black dyeing, a film forming part) applied to the rolling surface of the rolling part. . Moreover, you may evaluate the quality of the lubrication state of rolling components as a performance of rolling components. Specifically, the viscosity and life of the lubricant used during the operation of the rolling parts are considered as evaluation targets. For example, for two types of lubricants applied to the same rolling component, if there is a difference in remaining life at the same number of loads, a lubricant with a relatively longer remaining life is superior from the viewpoint of lubrication performance. It is thought that there is.

<Effect>
The rolling component performance evaluation method according to the present disclosure includes a step (S1) of estimating the fatigue level of the rolling component and a step (S2) of evaluating the performance of the rolling component as shown in FIG. In the step (S1) of estimating the degree of fatigue, the rolling parts are subjected to fatigue levels for a plurality of states in which the number of repeated loads applied to the rolling parts is different from each other. presume. In the step (S2) of evaluating the performance of the rolling component, as shown in FIG. 3, based on the relationship between the number of loads in a plurality of states and the degree of fatigue that is evaluation data corresponding to the number of loads, Evaluate performance. The step of estimating the fatigue level (S1) includes a step of acquiring measurement data (S10) and a step of estimating the fatigue level (S11). In the step (S10) of acquiring measurement data, X-ray analysis value measurement data relating to the rolling part is acquired by irradiating the fatigue part of the rolling part with X-rays. In the step of estimating the fatigue level (S11), the fatigue level of the rolling part is estimated from the measurement data based on the relationship between the X-ray analysis value and the fatigue level of the rolling part. The relationship between the measurement data of the X-ray analysis value and the fatigue level may be determined using the measurement result of the surface shape of the rolling part and the analysis result of X-ray diffraction as described above. Further, in the step (S2) of evaluating the performance of the rolling parts, the relational data between the number of repeated loads and the fatigue degree is compared for a plurality of rolling parts, and a reference data group (shown in FIG. 3) showing standard performance is compared. After specifying the first group 10), the performance of the rolling component may be evaluated based on the degree of separation from the reference data group in the fatigue degree data of the target rolling component.

  If it does in this way, the fatigue degree of the rolling components in use can be estimated with high accuracy using the relation between the measurement data of the X-ray analysis value and the fatigue degree, for example. Therefore, in the step (S2) of evaluating the performance of the rolling component, the transition of the fatigue level according to the number of times of the repeated load can be estimated with high accuracy. Therefore, based on the transition of the fatigue level, the performance of the rolling component, or It is possible to accurately evaluate the performance of the lubricant used during the operation of the rolling component.

  In the step (S2) of evaluating the performance of the rolling component, the relationship between the number of loads and the degree of fatigue includes the ratio of the amount of change in fatigue to the amount of change in the number of loads. In this case, the rate of change in the degree of fatigue accompanying the increase in the number of loads can be used for performance evaluation.

  The rolling component performance evaluation method according to the present disclosure includes a step (S3) of estimating the remaining life as shown in FIG. 2 and a step (S2) of evaluating the performance of the rolling component. In the step (S3) of estimating the remaining life, the remaining life of the rolling parts is respectively calculated for a plurality of states in which the number of repeated loads on the rolling parts is different from each other. presume. In the step of evaluating performance (S2), the performance of the rolling component is evaluated based on the relationship between the number of loads and the remaining life in a plurality of states. As shown in FIG. 4, the step of estimating the remaining life (S3) includes a step of obtaining measurement data of X-ray analysis values (S10), a step of obtaining measurement data of surface shape (S20), and residual stress. A step of deriving data (S12), a step of estimating data of repetitive stress (S30), a step of estimating life (S40), a step of estimating fatigue (S11), and estimating the remaining life Step (S60). In the step (S10) of acquiring the measurement data of the X-ray analysis value, the measurement data of the X-ray analysis value relating to the rolling part is acquired by irradiating the fatigue part of the rolling part with X-rays. In the step (S20) of acquiring the surface shape measurement data, the fatigue portion of the rolling part is measured to acquire the surface shape measurement data. In the step of deriving the residual stress data (S12), the residual stress data in the fatigue part of the rolling part is derived based on the measurement data of the X-ray analysis values. In the step of estimating repetitive stress data (S30), repetitive stress data acting on the fatigue portion is estimated based on the residual stress data and the surface shape measurement data. In the step of estimating the life (S40), the life of the rolling component is estimated from the data of repeated stress. In the step of estimating the fatigue level (S11), the fatigue level of the rolling part is estimated from the measurement data of the X-ray analysis value based on the relationship between the X-ray analysis value and the fatigue level of the rolling part. In the step of estimating the remaining life (S60), the remaining life of the rolling component is estimated based on the life and fatigue level of the rolling component. In the step (S2) of evaluating the performance of the rolling parts, the relationship data between the number of repeated loads and the remaining life is compared for a plurality of rolling parts, and a reference data group indicating standard performance is specified. The performance of the rolling component may be evaluated based on the degree of separation from the reference data group in the remaining life data of the rolling component as a target.

  In this way, the relationship between the measurement data of the X-ray analysis value and the fatigue level is determined using the measurement result of the surface shape of the rolling part and the analysis result of the X-ray diffraction as described above. Since the measurement result of the surface shape of the rolling component and the analysis result of X-ray diffraction are also used for estimating the life of the moving component, for example, the remaining life of the rolling component in use can be estimated with high accuracy. Therefore, in the step (S2) for evaluating the performance of the rolling parts, the transition of the remaining life corresponding to the number of times of repeated load can be estimated with high accuracy. Therefore, based on the transition of the remaining life, It is possible to accurately evaluate the performance of the lubricant used during the operation of the rolling component.

  In the rolling component performance evaluation method, as shown in FIG. 3 and FIG. 4, in the step of estimating the repeated stress data (S 30), the data used to estimate the repeated stress data is the oil film of the rolling component. Contains parameters.

  In this case, by estimating the oil film parameter, it is possible to confirm whether or not the surface-initiated peeling that is focused in the rolling component performance evaluation method according to the present embodiment can occur. Therefore, it can be confirmed in advance whether the performance evaluation method according to the present embodiment is effective.

  In the above-described performance evaluation method for rolling parts, the relationship between the X-ray analysis value and the fatigue level of the rolling parts is implemented using a plurality of rolling part samples to which repeated loads are applied as shown in FIG. The relationship between the plurality of X-ray analysis values and the plurality of fatigue levels obtained by the relationship deriving step (S110 to S180). The relationship deriving step (S110 to S180) includes a step of obtaining life data and data of repetitive stress (S110 to S150), a step of estimating an SN diagram (S160), and a step of obtaining a fatigue level (S170). Including. In the steps (S110 to S150) of obtaining life data and cyclic stress data, the first measurement data of the X-ray analysis value for the rolling part sample is obtained by irradiating the fatigue part of the rolling part sample with X-rays. A step (S120), a step (S121) of deriving residual stress data in the fatigue part of the rolling part sample based on the first measurement data, a second part of the surface shape by measuring the fatigue part of the rolling part sample A step of obtaining measurement data (S130) and a step of estimating data of repetitive stress acting on the fatigue part based on the residual stress data and the second measurement data (S140), Repeatedly in which the rolling part sample was damaged by carrying out the test until the rolling part sample was damaged in multiple states with different loads. Obtaining the data of life data and repeated stress is the load number of the load. In the step of estimating the SN diagram (S160), the SN diagram of the rolling part sample is estimated from the life data and the cyclic stress data. In the step of obtaining the fatigue level (S170), the fatigue level for each of a plurality of states in the rolling part sample is obtained using the SN diagram.

  In this case, since a highly accurate database of the relationship between the fatigue level and the X-ray analysis value can be created, it is possible to accurately estimate the fatigue level using the database.

  In the performance evaluation method for a rolling part, the X-ray analysis value includes data indicating variations in the central angle and diffraction intensity of the annular diffraction X-ray diffracted at the fatigue part of the rolling part. In this case, the annular diffracted X-ray (X-ray diffracting ring) contains more information than can be obtained at one time by the conventional X-ray diffraction method, so that the rolling is performed by the information obtained by one measurement. It is possible to accurately estimate the fatigue level or remaining life of a part.

  In the rolling part performance evaluation method, the X-ray analysis value includes data of residual stresses of six components in the fatigue part of the rolling part.

  In the rolling component performance evaluation method, the X-ray analysis value includes half-width data of the peak of the diffracted X-ray diffracted at the fatigue part of the rolling component.

  In the above-described performance evaluation method for rolling parts, the X-ray analysis value includes data on the amount of retained austenite in the fatigue part of the rolling parts.

  Since there is a strong correlation between the above-described data and the usage conditions of the rolling parts, the fatigue level or remaining life of the rolling parts can be estimated with high accuracy using the above-described data.

  In the above-described performance evaluation method for rolling parts, the X-ray analysis value is data indicating variation in the central angle and diffraction intensity of the annular diffraction X-ray diffracted at the fatigue part of the rolling part, and the fatigue part of the rolling part. Selected from the group consisting of six-component residual stress data, half-width data of diffraction X-ray peaks diffracted at the fatigue part of the rolling part, and residual austenite amount data at the fatigue part of the rolling part. A combination of at least two data. In this case, since the fatigue level or the remaining life is estimated by combining a plurality of data, the fatigue level or the remaining life can be estimated with higher accuracy.

(Example)
An example in which a rolling fatigue test using a two-cylinder tester was performed and the fatigue level was estimated for a rolling part as a test piece will be described below.

<Test equipment>
FIG. 11 is a schematic diagram showing the configuration of a two-cylinder testing machine. The two-cylinder testing machine 2 shown in FIG. 11 has a drive side rotation axis D1 and a driven side rotation axis F1. The drive-side rotation shaft D1 is a member extending in the left-right direction in FIG. 11, and a motor M is connected to the left end portion in FIG. By this motor M, the drive side rotation axis D1 is rotatable with respect to a central axis C1 extending in the left-right direction in FIG. A drive side test piece D2 is attached to the right end portion of the drive side rotation axis D1 in FIG. The driving side test piece D2 was fixed to the right end portion of the driving side rotating shaft D1 so as to be rotatable around the central axis C1 with the rotation of the driving side rotating shaft D1.

  On the other hand, the driven-side rotation shaft F1 is a member extending in the left-right direction in FIG. 11 and is rotatable with respect to the central axis C2 extending in the left-right direction in FIG. In FIG. 11, the driven side rotation shaft F1 has a tip portion on the left side and a terminal portion on the right side, contrary to the drive side rotation shaft D1. A driven test piece F2 is attached to the left end portion of the driven rotation shaft F1 in FIG.

  The center axis C1 of the driving side rotation axis D1 and the center axis C2 of the driven side rotation axis F1 do not coincide with each other, and both are spaced in the vertical direction of FIG. For this reason, the outer diameter surfaces of the driving side test piece D2 fixed to the front end portion of the driving side rotation shaft D1 and the driven side test piece F2 fixed to the front end portion of the driven side rotation shaft F1 are the same. Are arranged so as to be in contact with each other at the outer surface contact portion DF. The driving side test piece D2 and the driven side test piece F2 arranged so as to be in contact with each other are in contact with the felt pad 3 for fuel supply, which is laid under these.

<Specimen>
The driving side test piece D1 and the driven side test piece F2 are made of JIS standard SUJ2, and have a cylindrical shape with an outer diameter of 40 mm and a width of 12 mm. Two types of surface finishing were prepared for each test piece: superfinishing (surface roughness Ra of about 0.01 μm) and grinding finishing (surface roughness Ra of about 0.5 μm). The radius of curvature of each test piece in the axial direction is ∞ (straight) when the surface finish is superfinished, and 60 mm (curved surface) when the surface finish is ground.

<Test method>
Before starting the test, the surface roughness and residual stress of each test piece are measured, and the test is started. Table 1 shows the test conditions.

  In Table 1, Pmax is the maximum contact pressure (unit: GPa) in the test piece. The test was conducted under two conditions, test A and test B.

  Next, Table 2 shows the residual stress measurement conditions.

The residual stress was measured with an X-ray residual stress measuring device μ-X360 manufactured by Pulstec Industrial. During the rolling fatigue test, the test was interrupted every certain time, and the surface roughness and residual stress of each specimen were measured each time. Changes in residual stress (equivalent stress) and root mean square slope R _dq are shown in FIGS. 12 and 13. The horizontal axis in FIGS. 12 and 13 indicates the number of loads. The vertical axis in FIG. 12 represents equivalent stress (unit: MPa). The vertical axis in FIG. 13 represents the root mean square slope R _dq .

Here, it is known that the residual stress (equivalent stress) decreases as the peeling increases (that is, stress release occurs due to the occurrence of peeling). In the test of Condition A shown in FIG. 12, stress release due to the occurrence of peeling occurred at the load number of 3 × 10 ⁵ times. Further, in the test under the condition B shown in FIG. 12, stress release occurred at the load number of 3 × 10 ⁵ times. That is, in these tests, the peeling life is 3 × 10 ⁵ times and 3 × 10 ⁵ times, respectively.

From the above test results, the constants in the equations (2) and (9) were determined as follows.
First, the unknown number a in Equation (2) is determined. Here, in line contact, the maximum contact pressure Pmax can be calculated by the following equation.

P _Lmax in Expression (2) is a local maximum contact pressure generated between the roughness protrusion (for example, the rolling element) and the other side (for example, the raceway) shown in FIG. In this case, the other party is regarded as a plane. In the above equation (13), P _Lmax can be calculated by making the following assumptions.
<Assumption>
1) The curvature radius of the tip of the roughness protrusion is 0.02 mm (= R ₁ ).
2) The radius of curvature of the opponent (object 2) is ∞ (= R ₂ ). (That is, contact with a plane is assumed.)
3) The force generated per roughness protrusion is 2.41 N (= F).
4) The length of the roughness protrusion in the rolling direction (= l) is almost equal to the minor axis radius of the macro contact ellipse. (In the case of the above-described two-cylinder test, about 1 mm.)
Of the assumptions described above, 1) and 3) are based on measured values.

Using the above assumptions and the physical property values of steel, P _Lmax = 3281 MPa. Moreover, R _dq (average value of three rough surface side test pieces) immediately before the occurrence of the actually measured damage was 0.1875. Substituting these into equation (2) yields a = 1.75 × 10 ⁴ .

Thereafter, the process shown in FIG. 5 is performed to obtain a plurality of life data (the number of loads when damage occurs) and the stress Seq at that time, thereby obtaining a plot constituting the SN curve. By fitting the plot to equation (9), unknown constants A and B are obtained. As a result, A = 4.336 and B = −2.381 × 10 ⁻³ . These constants were determined using the convergence calculation function of spreadsheet software. It should be noted that, in this time of calculation, was 2000MPa the yield stress _{S f} after the work-hardening of JIS standard SUJ2.

  The SN curve was determined as described above. Thereafter, the fatigue level and the remaining life of the condition A were calculated based on the formula (11). Table 3 shows the relationship between the number of loads under condition A, the degree of fatigue, and the remaining life.

  On the other hand, when the relationship between the fatigue degree D obtained as described above and the variation I of the diffraction intensity with respect to the central angle of the annular diffraction X-ray was investigated, it was found that the following relationship could be approximated.

  Note that the diffraction intensity variation I in the above equation (14) is expressed by the following equation (15).

  Here, the reason why the relationship between the degree of fatigue D and the variation I of the diffraction intensity can be approximated as shown in Expression (14) is as follows. That is, it has been known by experiments so far that the variation I of the diffraction intensity with respect to the number of loadings changes as shown in FIG. Here, FIG. 10 is a graph showing the relationship between the number of loads and the variation in diffraction intensity. The horizontal axis in FIG. 10 indicates the number of loads, and the vertical axis indicates the variation I in diffraction intensity. Since the fatigue level D is a value obtained from the number of loads and the life, it can be expected that the relationship between the diffraction intensity and the fatigue level D will also be as shown in FIG. Therefore, when a parameter study was performed on the relationship between the degree of fatigue D and the diffraction intensity variation I assuming a power root function, it was found that the relationship can be approximated by the relational expression (14).

  Here, by fitting the relationship between the fatigue level D and the diffraction intensity variation I with respect to the central angle of the diffracted X-rays in the conditions A and B described above into the equation (14), the constants b, c, d was determined to be b = 10.07, c = 0.864, and d = 0.812, respectively.

If the above results are used, the fatigue level D can be obtained from the measurement results of the X-ray diffraction ring. And the life L of Formula (8) can be calculated | required from the measurement data of surface roughness and residual stress. As a result, it is possible to estimate the remaining life N _R. Even with an X-ray stress measurement device that cannot measure an X-ray diffraction ring (for example, a device that detects X-rays with a one-dimensional PSPC, a scintillation counter, etc.) Since the triaxial residual stress can be measured, the life L can be obtained. In addition, if the relationship between the analysis value obtained by the X-ray stress measuring device that cannot measure the X-ray diffraction ring and the fatigue level D is known, this embodiment can be used even if the X-ray stress measuring device that cannot measure the X-ray diffraction ring is used. It is possible to estimate the remaining life related to.

  As described above, in the performance evaluation method according to the present embodiment, the change (trend) of the rolling part in use and the remaining life with respect to the number of loads is measured by measuring the surface shape of the rolling part and the X-ray analysis. Find from the result. From this trend, the performance of rolling parts and lubricants can be evaluated.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. 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.

  2 Two-cylinder testing machine, 3 refueling felt pad, 10 first group, 11, 12 data, 21 irradiation unit, 22 detector, 22A detection unit, 23 control operation unit, 24 display unit, 30 convex portion, 31 arrow .

Claims (9)

Estimating the degree of fatigue of the rolling component with respect to a plurality of states in which the number of loads of the repeated load in the rolling component is different from each other with respect to the rolling component to which a repeated load is applied
And evaluating the performance of the rolling component based on the relationship between the number of loads in the plurality of states and the fatigue level corresponding to the number of loads.
The step of estimating the fatigue level includes:
Irradiating the fatigue part of the rolling part with X-rays to obtain measurement data of X-ray analysis values related to the rolling part;
Estimating the degree of fatigue of the rolling part from the measurement data based on the relationship between the X-ray analysis value and the degree of fatigue of the rolling part. Estimating the remaining life of the rolling parts with respect to a plurality of states in which the number of loads of the repeated loads in the rolling parts is different from each other with respect to the rolling parts to which a repeated load is applied;
Evaluating the performance of the rolling component based on the relationship between the number of loads and the remaining life in the plurality of states,
The step of estimating the remaining life includes
Irradiating the fatigue part of the rolling part with X-rays to obtain measurement data of X-ray analysis values related to the rolling part;
Measuring the fatigue part of the rolling part to obtain measurement data of the surface shape;
Deriving residual stress data in the fatigue part of the rolling part based on the measurement data of the X-ray analysis value;
Estimating repetitive stress data acting on the fatigue portion based on the data of the residual stress and the measurement data of the surface shape;
Estimating the life of the rolling component from the data of the cyclic stress;
Estimating the fatigue level of the rolling part from the measurement data of the X-ray analysis value based on the relationship between the X-ray analysis value and the fatigue level of the rolling part;
Estimating the remaining life of the rolling component based on the life and fatigue level of the rolling component.   The rolling part manufacturing method according to claim 2, wherein in the step of estimating the cyclic stress data, the data used to estimate the cyclic stress data includes an oil film parameter of the rolling part. The relationship between the X-ray analysis value and the fatigue level of the rolling component is a plurality of X-ray analysis values obtained by a relationship deriving step performed on a plurality of rolling component samples subjected to repeated loads. And a plurality of the fatigue levels,
The relationship derivation step includes:
Irradiating a fatigue part of the rolling part sample with X-rays to obtain first measurement data of the X-ray analysis value relating to the rolling part sample; and the rolling part based on the first measurement data Deriving residual stress data in the fatigue portion of the sample; measuring the fatigue portion of the rolling part sample to obtain second measurement data of a surface shape; and the residual stress data and the Estimating the data of the repeated stress acting on the fatigue part based on the second measurement data, in the plurality of states in which the number of times of the repeated load in the rolling part sample is different from each other, By carrying out each until it breaks, the life data that is the number of times of repeated load in which the rolling part sample is damaged and the data of the repeated stress are obtained. And the step that,
Estimating an SN diagram of the rolling part sample from the life data and the cyclic stress data;
The method for evaluating the performance of a rolling component according to any one of claims 1 to 3, further comprising a step of obtaining a degree of fatigue for each of the plurality of states in the rolling component sample using the SN diagram. .   5. The X-ray analysis value according to claim 1, wherein the X-ray analysis value includes data indicating variation between a central angle and diffraction intensity of an annular diffraction X-ray diffracted at the fatigue portion of the rolling part. The method for evaluating the performance of the described rolling parts.   5. The rolling component performance evaluation method according to claim 1, wherein the X-ray analysis value includes data of six component residual stresses in the fatigue portion of the rolling component.   The said X-ray analysis value contains the data of the half width of the peak of the diffraction X-ray diffracted in the said fatigue part of the said rolling component, The rolling component of any one of Claims 1-4 Performance evaluation method.   The said X-ray analysis value is a performance evaluation method of the rolling components of any one of Claims 1-4 containing the data of the amount of retained austenites in the said fatigue part of the said rolling components.   The X-ray analysis value is data indicating variation in the center angle and diffraction intensity of the annular diffracted X-ray diffracted at the fatigue part of the rolling part, and the remaining six components in the fatigue part of the rolling part Selected from the group consisting of stress data, half-value width data of diffraction X-ray peaks diffracted at the fatigue part of the rolling part, and data of retained austenite amount at the fatigue part of the rolling part The method for evaluating the performance of a rolling component according to any one of claims 1 to 4, comprising a combination of at least two data.

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