JP2020027069A - Estimation method of x-ray parameter of metal component and fatigue level acquisition method of metal component - Google Patents

Abstract

To provide an estimation method which can accurately estimate an initial value of an X-ray parameter of a metal component.SOLUTION: An estimation method includes: (a) a step for acquiring a range of a depth at which material quality is homogenized by using a metal component 2 which has not been subjected to a surface treatment yet; (b) a step for acquiring a depth at which X-ray parameters of second surfaces 2b, 2c which are not fatigued by a use receive influence of the surface treatment by using an unused metal component 2 which has been subjected to the surface treatment; (c) a step for acquiring a variation amount of an X-ray parameter of a first surface 2a which is influenced by the surface treatment by using the unused metal component 2 which has been subjected to the surface treatment; (d) a step for measuring an X-ray parameter of a deep region deeper than a depth which is acquired in the step (b) within a range which is acquired in the step (a) at the second surfaces 2b, 2c of a used metal component 2; and (e) a step for estimating an initial value of the X-ray parameter of the first surface 2a by reflecting the variation amount acquired in the step (c) to the X-ray parameter which is measured in the step (d).SELECTED DRAWING: Figure 8

Description

  The present invention relates to a method for estimating an X-ray parameter in a metal part and a method for obtaining a fatigue degree of the metal part.

For metal parts that come into rolling contact with rolling elements, such as the outer ring and inner ring of rolling bearings, it is possible to predict the remaining life and identify the replacement time by using the fatigue degree that quantitatively indicates the degree of rolling fatigue. Have been done.
For example, in Patent Document 1, X-ray parameters such as a half width of diffracted X-rays obtained by irradiating a metal part with X-rays and residual stress and residual austenite amount obtained from the diffracted X-rays are measured. It is disclosed that the fatigue level is obtained by comparing the X-ray parameters with a previously created fatigue level database.

  Specifically, in Patent Document 1, when the degree of fatigue of the raceway surface of the bearing ring is measured using the half-width, the half-width reduction in the raceway after use is obtained, and this half-width reduction is calculated. The fatigue level is obtained by collating with the fatigue level database. The degree of reduction in half width is obtained by “(internal half width−half width of raceway surface) / inner half width” using the inner half width and raceway half width of the used bearing ring. Value. The internal half-width of the raceway is the half-width measured at a deep part that is not affected by rolling contact, such as the axial end face and shoulder of the raceway, and is substituted as the initial value of the half-width of the raceway. You.

JP 2000-304710 A

  Generally, the hardness of a metal component used for a rolling bearing is increased by heat treatment such as quenching, but the depth of hardening varies depending on the type of the heat treatment. For example, ordinary quenching hardens to the deep part of a metal part, but surface quenching such as carburizing hardens the hardening to a shallow depth. Therefore, when the above-mentioned half-width width reduction degree is obtained, the internal half-width width substituted as the initial value of the half-width width of the track surface varies, and it becomes difficult to obtain the accurate half-width width reduction degree. . For this reason, the accuracy of the obtained degree of fatigue also decreases.

  An object of the present invention is to provide an estimation method capable of accurately estimating an initial value of an X-ray parameter of a metal part, and a method of obtaining a fatigue degree of the metal part.

(1) The present invention is a method for estimating an initial value of an X-ray parameter of a first surface that is fatigued by use in a metal part having been subjected to surface processing, and (a) the metal part before the surface processing. Obtaining a range of the depth at which the material becomes uniform using (b), using the unused metal parts after the surface processing, the X-ray parameters of the second surface that are not fatigued by use are determined by the surface processing. Obtaining a depth affected by the surface processing; and (c) obtaining an amount of change in the X-ray parameter of the first surface due to the surface processing using an unused metal part after the surface processing. (D) X-rays in an area within the range obtained in step (a) and deeper than the depth obtained in step (b) on the second surface of the used or unused metal part. Measuring parameters And (e) reflecting the variation obtained in step (c) on the X-ray parameter measured in step (d) to thereby obtain an initial value of the X-ray parameter of the first surface. Estimating.

  According to the above estimation method, the X-ray parameters in the second surface of the used or unused metal part within the range where the material becomes uniform and deeper than the depth affected by the surface processing Is measured, and the amount of variation of the X-ray parameter due to the influence of the surface processing is reflected on this X-ray parameter, whereby the initial value of the X-ray parameter of the first surface that is fatigued by use is estimated. The initial values of the parameters can be accurately estimated, and the initial values can be used to accurately acquire the degree of fatigue.

(2) In the above estimation method, preferably, the metal component is subjected to a surface hardening heat treatment. When the surface hardening heat treatment is performed on the metal component, the X-ray parameters inside the second surface used for estimating the initial value of the half-value width of the first surface are likely to vary. It is possible to estimate the initial value of the X-ray parameter of the first surface by using the X-ray parameter in the region within the depth where the material becomes uniform and deeper than the depth affected by the surface processing. Will be more useful.

(3) In the above estimation method, preferably, the X-ray parameter is a half width of a diffracted X-ray. Since the half width of the diffracted X-ray has a high correlation with the degree of fatigue, it is possible to obtain the degree of fatigue more accurately by measuring the half-width of the diffracted X-ray as an X-ray parameter. Becomes

(4) The present invention relates to a method for acquiring a degree of fatigue of a first surface which is fatigued by use after use of a metal part subjected to surface processing, wherein (f) the metal part after use is used. Measuring an X-ray parameter of the first surface of the component; (g) estimating an initial value of the X-ray parameter of the first surface by the estimation method of (1) to (3) above; And (h) acquiring the degree of fatigue of the first surface based on the X-ray parameters measured in the step (f) and the initial values of the X-ray parameters estimated in the step (g). Step.

  According to the above-described method for acquiring the degree of fatigue, the degree of fatigue can be accurately acquired using the more accurately estimated initial value.

  According to the X parameter estimation method of the present invention, the initial value of the X-ray parameter of the metal component can be accurately estimated. ADVANTAGE OF THE INVENTION According to the fatigue-degree acquisition method of this invention, a fatigue-degree can be acquired accurately using the initial value of the X-ray parameter estimated correctly.

It is sectional drawing which shows the rolling bearing which concerns on embodiment. It is a schematic structure figure showing a fatigue level acquisition device. It is a graph which shows the relationship between a fatigue degree and the half value width reduction degree. It is a graph which shows the distribution of the hardness of the inner ring in the depth direction after the completion of heat treatment. It is a graph which shows the average value and standard deviation of the hardness of the inner ring after completion of heat treatment. It is explanatory drawing which shows the uniform depth area of an inner ring. It is a graph which shows the distribution of the half value width of the inner ring in the depth direction after polishing is completed. It is a flowchart which shows the procedure of the pre-processing for fatigue degree acquisition. It is a flowchart which shows the procedure of the acquisition process of a fatigue degree.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Overall configuration of tapered roller bearings]
FIG. 1 is a cross-sectional view illustrating a rolling bearing according to the embodiment. The rolling bearing of the present embodiment is a tapered roller bearing 1, which includes races 2 and 3, a plurality of tapered rollers 4, and a retainer 7. The bearing rings 2 and 3 include an inner ring 2 and an outer ring 3 provided radially outside the inner ring 2. The plurality of tapered rollers 4 are disposed so as to roll freely between the inner ring 2 and the outer ring 3 in the radial direction. The retainer 7 holds a plurality of tapered rollers 4 in the circumferential direction.

  The inner ring 2 is an annular member formed using bearing steel, steel for machine structural use, or the like, and has a tapered raceway surface 2a (hereinafter referred to as an inner race raceway surface) on which a plurality of tapered rollers 4 roll on its outer periphery. 2a) is formed. The inner ring 2 is provided on one axial side of the raceway surface 2a (the right side in FIG. 1) and protrudes radially outward, and on the other axial side of the raceway surface 2a (the left side in FIG. 1). A large flange portion 6 that is provided and protrudes radially outward.

Similarly to the inner ring 2, the outer ring 3 is an annular member formed using bearing steel, steel for machine structural use, and the like, and a plurality of tapered rollers 4 rolling on the inner periphery thereof are opposed to the inner ring raceway surface 2a. A tapered raceway surface 3a (hereinafter, also referred to as an outer raceway surface 3a) is formed.
The inner ring 2 and the outer ring 3 are subjected to a surface hardening heat treatment such as carburizing and tempering (hereinafter also referred to as “carburizing and quenching”).

  The tapered rollers 4 are members formed using bearing steel or the like, and roll on the inner raceway surface 2a and the outer raceway surface 3a. That is, when the inner ring 2 or the outer ring 3 rotates together with a shaft (not shown), each tapered roller 4 revolves around the center line of the bearing while rotating around the roller center line along the inner ring raceway surface 2a and the outer ring raceway surface 3a. I do. The tapered roller 4 has a small end face 4a having a small diameter on one side in the axial direction and a large end face 4b having a large diameter on the other side in the axial direction.

  In the tapered roller bearing 1, since the tapered rollers 4 roll on the inner raceway surface 2a and the outer raceway surface 3a, rolling fatigue occurs on each raceway surface 2a, 3a. The degree of such rolling fatigue can be evaluated using an index called “fatigue degree”. The fatigue degree is an index indicating the degree to which the fatigue has progressed, assuming that the time until damage due to rolling fatigue is 100%. By using this degree of fatigue, it is possible to predict the remaining life of the tapered roller bearing 1 and specify a replacement time.

  The above-mentioned fatigue degree can be acquired by a fatigue degree acquisition device described below. In the following description, an example in which the fatigue degree of the inner raceway surface 2a of the inner ring 2 is acquired as the fatigue degree acquisition target will be described. However, the fatigue degree of other metal parts can be acquired by the same method. .

[Configuration of fatigue acquisition device]
FIG. 2 is a schematic configuration diagram showing the fatigue degree acquiring device.
The fatigue degree acquisition device 10 includes an X-ray diffraction device 11 and a processing device 12. The fatigue degree acquisition device 10 acquires an X-ray parameter on the raceway surface 2a of the inner race 2 by the X-ray diffraction device 11, and acquires a fatigue degree of the raceway surface 2a by using the X-ray parameter by the processing device 12.

(Configuration of X-ray diffractometer 11)
As shown in FIG. 2, the X-ray diffraction apparatus 11 includes a holding unit 21 that holds the inner ring 2 to be measured, a measurement unit 22 that irradiates the inner ring 2 with X-rays to measure information on diffracted X-rays, And a moving unit 23 for moving the holding unit 21.
The holding portion 21 includes a chuck portion 21a formed of, for example, a three-jaw chuck, and inserts the chuck portion 21a into the inner peripheral surface of the inner ring 2 and expands the diameter of the inner ring 2 so that the inner ring 2 is gripped from the inside. It is configured.

  The measurement unit 22 is fixed to a certain position in the X-ray diffraction device 11. The measurement unit 22 includes an irradiation unit 22a that irradiates the inner ring 2 that is a measurement target with X-rays, and a detection unit 22b that detects a diffracted X-ray generated from the measurement target and measures a predetermined X-ray parameter. I have. The irradiating unit 22a irradiates an X-ray with a specific point of a measurement target as a measurement point P. The X-ray parameters measured by the detection unit 22b are transmitted to the processing device 12, and stored in the storage unit 32 described later. As the X-ray parameter, for example, the half width of the diffracted X-ray, residual stress, residual austenite amount and the like can be adopted.

  The moving unit 23 includes an actuator such as a motor, a linear guide, and an air cylinder, and a support member such as a rail, a link, and a shaft for movably supporting the holding unit 21. The moving unit 23 moves the inner ring 2 held by the holding unit 21 three-dimensionally, for example, on xyz coordinate axes. In addition, the moving unit 23 rotates the inner ring 2 held by the holding unit 21 around the axis O to adjust the angle θ of the axis O. The moving unit 23 moves the inner ring 2 held by the holding unit 21 to move the measurement point P by the measuring unit 22 to the inner ring raceway surface (measured surface) 2a, the axial end surface (the large end surface 2b, It is moved to the small end surface 2c), the outer peripheral surface of the flanges 5 and 6, and the like. The moving unit 23 includes a method of automatically moving the measurement point P three-dimensionally using, for example, NC control.

[Configuration of the processing device 12]
The processing device 12 includes a control unit 31, a storage unit 32, and a calculation unit 33.
The control unit 31 controls operations of the holding unit 21, the measuring unit 22, and the moving unit 23 in the X-ray diffraction device 11. Specifically, the control unit 31 controls the holding operation of the inner ring 2 by the holding unit 21, the X-ray irradiation and diffraction X-ray detection operation by the measurement unit 22, and the movement operation of the holding unit 21 by the moving unit 23.

  The storage unit 32 stores various types of information necessary for acquiring the degree of fatigue. For example, as described above, the X-ray parameters measured by the measurement unit 22 of the X-ray diffraction apparatus 11, the fatigue degree database DB used for acquiring the degree of fatigue, hardness data measured in a preliminary process described later, and the like are stored. Has been saved. The storage unit 32 stores shape data of the inner race 2 input from outside. The shape data includes three-dimensional model data and the like representing the outer shape of the inner ring 2.

  The shape data of the inner ring 2 stored in the storage unit 32 is used, for example, for controlling the moving unit 23 by the control unit 31. Specifically, the control unit 31 controls the moving unit 23 to move the inner ring 2 based on the shape data of the inner ring 2 and move the measurement point P by the measuring unit 22 on the inner ring raceway surface 2a. This enables measurement of X-ray parameters at a plurality of locations on the outer surface of the inner ring 2.

The fatigue level database DB stored in the storage unit 32 associates X-ray parameters acquired by diffracted X-rays with the fatigue level of the inner ring 2.
FIG. 3 is a graph showing the relationship between the degree of fatigue and the degree of decrease in half width. As described above, the degree of fatigue is an index indicating the degree to which fatigue has progressed, assuming that the time until damage due to rolling fatigue is 100%. The half width is one of the X-ray parameters acquired by the diffracted X-ray, and is the width at half the peak value of the width of the diffraction pattern of the diffracted X-ray.

The half value width reduction degree is an index indicating how much the half value width has decreased before and after use of the rolling bearing. This degree of decrease is calculated from the half-width of the inner raceway surface 2a before use (hereinafter, also referred to as “half-width before use”), that is, the half-width of the inner raceway surface 2a after use (the initial half-width). Hereinafter, it is also obtained by subtracting the “half price width in use”) and dividing the value by the half price width before use. That is, the half width width reduction degree is obtained by the following equation (1).
Degree of decrease in half-value width = (half-value width before use-second-half value width before use) / half-value width before use ... (1)

  As shown in FIG. 3, the degree of fatigue increases as the degree of reduction in half width increases. That is, there is a correlation between the degree of reduction in half width and the degree of fatigue. The relationship between the half-value width decrease degree and the fatigue degree as shown in FIG. 3 is accumulated in the fatigue degree database DB.

  The calculation unit 33 of the processing device 12 obtains the half width width reduction degree using the half width width information measured by the X-ray diffraction apparatus 11, and compares the half width width reduction degree with the fatigue degree database DB. To get the degree of fatigue.

  In the present embodiment, the “half-width before use” used to determine the degree of decrease in the half-value width is used as a “half-width before use” of a portion of the inner ring 2 after use where rolling fatigue does not occur, for example, the axial end faces 2 b and 2 c of the inner ring 2. What is “estimated” from the half-width measured inside (hereinafter, also referred to as “end surface half-width”) is used.

  Originally, before using the inner ring 2 for which the fatigue degree is to be acquired, the initial value of the half-value width on the inner ring raceway surface 2a is measured in advance as “half-value width before use”, and measured after the use of the inner ring 2 It is preferable to determine the degree of decrease in the half-value width by using the half-value width before use and the half-value width before use measured in advance. However, this method is extremely difficult to manage because the management of the half-width before use measured in advance and the history management of the bearing between the manufacturer and the user become very complicated. It is also conceivable that the half-width of another inner ring 2 of the same model number is measured in advance as a representative value of “half-width before use” instead of the inner ring 2 actually used. It is difficult to adopt this method because the half bandwidth before use may be different due to differences in processing equipment and processing conditions.

  Therefore, in the present embodiment, in the used inner ring 2 for which the degree of fatigue is to be obtained, the portion (end faces 2b, 2c) other than the raceway surface 2a, which is considered to be less affected by rolling fatigue, is more internal than the surface. The half width of the part that has entered (the half width inside the end face) is used for “estimating” the half width before use. In addition, by measuring the internal half width of a portion other than the raceway surface 2a, the inner ring 2 can be reused after obtaining the degree of fatigue.

  Also, unlike the normal quenching and tempering treatment, the inner ring 2 of the present embodiment has a hardened surface by carburizing quenching and tempering treatment, so the material near the surface is uniform and the hardness is relatively stable, The more the material penetrates deeply from the surface into the inside, the greater the variation in hardness. Therefore, in order to obtain a more appropriate half-width inside the end face, it is required to measure at a depth at which the hardness is stable.

Further, the inner ring 2 is subjected to surface processing (surface finishing) such as polishing after carburizing and quenching, and the half-width of the surface is changed by the surface processing.
Then, in the case of the inner ring 2 which has been subjected to a surface hardening heat treatment such as carburizing and quenching, the relationship between the degree of fatigue and the degree of reduction in half width shown in FIG. The inclination of the straight line tends to be small. Therefore, the obtained fatigue degree is greatly affected by the error of the half width width reduction degree, and the fluctuation of the half width width due to the surface processing cannot be ignored. Therefore, it is necessary to consider not only the half width at the end face measured at the depth at which the hardness is stabilized but also the half width at the end of use, but also the fluctuation of the half width at the time of surface processing.

  As described above, in the present embodiment, before performing the fatigue degree acquisition processing, the “pre-processing” is performed to obtain the depth at which the hardness is stabilized (the depth of uniform material) and the variation of the half-value width due to surface processing. And use the result of this pre-processing to more accurately estimate the half bandwidth before use.

Hereinafter, the “pre-processing” and the “fatigue degree obtaining processing” will be described in detail.
[Pre-processing]
FIG. 8 is a flowchart illustrating the procedure of the pre-processing.
This pre-processing is performed on the inner ring 2 equivalent to the inner ring 2 for which the degree of fatigue is to be acquired (for example, the inner ring 2 of the same model number or the inner ring 2 of the same production lot) in the manufacturing process of the inner ring 2 or immediately after manufacturing. This process is performed in advance, and can be roughly divided into the following steps.
(I) Step of acquiring a uniform material depth (II) Step of acquiring a processing influence depth and a processing influence amount by surface processing

The process (I) is performed by steps S11 to S13 in FIG.
First, in step S11, the hardness distribution in the depth direction is measured at several places of the inner ring 2 after the completion of the heat treatment and before the surface processing. The fatigue degree acquisition device 10 of the present embodiment further includes a hardness measurement device 13 that measures the hardness of the inner ring 2. As the hardness measurement device 13, for example, a device that measures the Vickers hardness of the inner ring 2 is used. Data of the measured hardness is transmitted or input to the processing device 12 and stored in the storage unit 32.

  As shown in FIG. 4B, for example, as shown in FIG. 4B, the hardness measuring device 13 measures the depth of a plurality of measurement points A to G on the surface (track surface, end surface, flange top surface, shoulder portion, etc.) of the inner ring 2. Measure hardness each time. FIG. 4A shows an example of the measurement result. According to the graph of FIG. 4A, it is understood that the hardness of the inner ring 2 increases near the surface, and when the depth exceeds a certain depth, the hardness gradually decreases.

  In step S12, the processing device 12 calculates the average value and the standard deviation of the hardness measured in step S11 for each depth. FIG. 5 shows an example of the calculation result. In FIG. 5, the average value of the hardness is almost stably maintained at a high value in a predetermined range H2 close to the surface of the inner ring 2, and gradually decreases as the hardness increases beyond the range H2. Therefore, it is considered that the range H2 is sufficiently hardened by the surface hardening heat treatment. Further, the standard deviation of the hardness shows a stable low value in a predetermined range H3 close to the surface of the inner ring 2, and the standard deviation gradually increases as the depth goes beyond the range H3. Therefore, in the range H3, the variation in the hardness of the inner ring 2 is small, and it can be said that the material is uniform.

  In step S13, the processing device 12 acquires a "range of uniform depth of the material" from the range that can be hardened by the surface hardening heat treatment based on the calculation result illustrated in FIG. For example, as shown in FIG. 6, with reference to the large end face 2b of the inner ring 2, a range H1 of a uniform depth of material is a range H2 in which the average value of hardness is stable and a standard deviation of hardness is stable. This is a region obtained by subtracting the polishing amount (polishing allowance) H4 of the polishing process as the surface processing from the region where the range H3 overlaps.

  By the above steps S11 to S13, the range H1 of the uniform depth of the material of the inner ring 2 can be obtained. By measuring the internal half width in this range H1, the hardness due to the surface hardening heat treatment can be determined. It is possible to obtain the internal half width which is not affected by the variation. The hardness measurement device 13 and the processing device 12 function as an acquisition unit (first acquisition unit) that acquires the range of the depth at which the material of the inner ring 2 is uniform by executing the above steps.

The step (II) of acquiring the “processing influence depth” and the “processing influence amount” by the surface processing is performed by steps S14 and S15 in FIG.
First, in step S14, the distribution of the half width in the depth direction is measured by the X-ray diffraction device 11 for the track surface 2a and the end surfaces 2b and 2c of the unused inner ring 2 after the surface processing (polishing) is completed. FIG. 7 shows an example of the result. In this step S14, the half-value width of the raceway surface 2a and the end surfaces 2b, 2c is measured for each depth using a plurality (for example, three) of inner rings (N = 1 to 3). The measured half-value width data is stored in the storage unit 32 of the processing device 12.

  Next, in step S15, the processing device 12 obtains a “processing influence amount” and a “processing influence depth” for the raceway surface 2a and the end surfaces 2b, 2b. Specifically, as shown in FIG. 7, the processing device 12 analyzes the fluctuation amount of the half width at each depth on each of the raceway surface 2a and the end surfaces 2b and 2c, and obtains the minimum half width a1 to a3. And stable values b1 to b3 at which the fluctuation of the half width becomes small.

  The half width here indicates the minimum values a1 to a3 on the surface (depth 0). The half-value width gradually increases from the minimum values a1 to a3 as the depth from the surface increases, and takes a stable value b1 to b3 when the half-value width exceeds a predetermined depth d1 to d3. Such a change in the half width is considered to be caused by the influence of the surface processing. Therefore, the processing device 12 calculates the processing influence amount (fluctuation amount of the half width) of the surface processing by “(stable values b1 to b3) − (minimum values a1 to a3)” for each surface. Get by doing. Further, the processing device 12 acquires the depths d1 to d3 when the half-value width takes the stable values b1 to b3 as the depth affected by the surface processing (the processing influence depth).

  Therefore, the X-ray diffraction apparatus 11 and the processing apparatus 12 execute the above steps to obtain the processing influence depth (second obtaining part) and the processing influence amount obtaining part (second obtaining part). 3 acquisition unit).

  Since the degree of surface processing (surface roughness after processing) differs between the raceway surface 2a and the end surfaces 2b and 2c of the inner race 2, the processing influence amount and the processing influence depths d1 to d3 are different from each other. However, the stable values b1 to b3 of the half-value width are half-value widths in a region that is not affected by the processing, and therefore have substantially the same value between the raceway surface 2a and the end surfaces 2b and 2c.

  The “depth where the material is uniform”, the “processing influence amount”, and the “processing influence depth” obtained by the above pre-processing are used when obtaining the fatigue degree of the inner ring 2 after use.

[Fatigue degree acquisition processing]
FIG. 9 is a flowchart illustrating the procedure of the fatigue level acquisition process.
In step S21 in FIG. 9, the X-ray diffraction apparatus 11 measures the internal half width at one of the end surfaces 2b and 2c of the used inner ring 2 from which the fatigue degree is to be obtained. At this time, the depth at which the internal half width is measured is within the “materially homogeneous range H1 (see FIG. 6)” obtained in the pre-processing, and the processing influence depth d2 of the end faces 2b and 2c. The depth is set to be deeper than d3. Thereby, the variation in hardness due to the surface hardening heat treatment is small, and it is possible to measure the internal half width at a portion where the surface processing is not affected.

The inner half widths of the end faces 2b and 2c obtained at this time can be considered to be equivalent to the inner half width on the raceway surface 2a of the inner ring 2 after use, and the raceway surface of the inner ring 2 after use. Since the internal half width at 2a is not affected by rolling fatigue, it can be considered that the internal half width at the raceway surface 2a of the inner race 2 before use is also equal.
The measured internal half width is stored in the storage unit 32 of the processing device 12.

  Next, in step S22, the processing device 12 "estimates" the initial value (half-width before use) of the half-width of the inner raceway surface 2a of the inner race 2 for which the degree of fatigue is to be obtained. Specifically, the processing influence amount of the raceway surface 2a measured in step S15 of the pre-processing is subtracted from the internal half width of the end surfaces 2b and 2c measured in step S21. Since the inner half widths of the end faces 2b and 2c are considered to be equal to the inner half width of the inner raceway surface 2a before use, by subtracting the processing influence amount from the inner half width, the inner raceway surface is obtained. The “half width before use”, which is the initial value of the half width of 2a, can be estimated.

  Through the above processing, the processing device 12 in this embodiment functions as an estimating unit that estimates the initial value of the half-value width of the inner ring raceway surface 2a, and the fatigue degree acquiring device 10 sets the half-value width of the inner ring raceway surface 2a. It functions as an estimating device for estimating an initial value.

Next, in step S23, the X-ray diffractometer 11 measures the half-value width (used half-value width) of the used inner ring 2 on the raceway surface 2a. Then, in step S24, the processing device 12 obtains the degree of decrease in half width by using the above equation (1) by the calculation unit 33.
Then, in step S25, the fatigue level on the inner raceway surface 2a of the inner race 2 after use is acquired using the fatigue level database DB (see FIG. 3) stored in the storage unit 32 of the processing device 12. The acquired degree of fatigue is used to predict the remaining life of the inner ring 2 and to specify the time to replace the inner ring 2.

As described above, the fatigue degree acquisition device 10 according to the present embodiment sets the initial value of the half-value width of the raceway surface 2a that is fatigued by use in the inner ring 2 subjected to the surface processing to the following steps (a) to (d). Estimated by (e).
(A) using the inner ring 2 before surface processing to obtain a range of depth at which the material becomes uniform;
(B) using the unused inner ring 2 after the surface processing to obtain a depth at which the half-value width of the axial end faces 2b and 2c not fatigued by use is affected by the surface processing;
(C) a step of using the unused inner ring 2 after the surface processing to obtain a variation amount (processing amount) of the half-value width of the raceway surface 2a due to the influence of the surface processing;
(D) On the axial end faces 2b and 2c of the inner ring 2 after use, the internal half width of the area within the range obtained in step (a) and deeper than the depth obtained in step (b) is measured. Steps, and
(E) estimating the initial value of the half-width of the inner ring raceway surface 2a by reflecting the variation obtained in step (c) on the half-width measured in step (d).

  According to the above estimation method, the inner half width of the axial end faces 2b and 2c can be measured in a region where hardness variation is small with respect to the inner ring 2 subjected to surface hardening heat treatment such as carburizing and quenching. Further, the initial value of the half width of the inner raceway surface 2a can be estimated using the internal half width in consideration of the influence of the surface processing. Therefore, the initial value of the half width can be accurately estimated, and the initial value can be used for obtaining a highly accurate degree of fatigue.

  In step (d), the inner half width of the end surfaces 2b and 2c may be measured using the unused inner ring 2 equivalent to the inner ring 2 instead of the used inner ring 2. In this case, the same operation and effect can be obtained.

In addition, the fatigue degree acquisition device 10 according to the present embodiment determines the fatigue degree of the inner raceway surface 2a that is fatigued by the use after the use of the inner ring 2 on which the surface processing has been performed by the following steps (f) to (h). get.
(F) measuring the half width of the raceway surface 2a of the inner ring 2 after use;
(G) estimating the initial value of the half width of the track surface 2a by the steps (a) to (e), and
(H) obtaining the degree of fatigue of the raceway surface 2a of the inner race 2 based on the half width measured in step (f) and the initial value of the half width estimated in step (g). Including.

  According to the above acquisition method, it is possible to acquire a highly accurate degree of fatigue using the accurately estimated initial value of the half width.

This embodiment discloses an apparatus for estimating an X-ray parameter and a degree of fatigue acquisition of a metal component having the following configuration in addition to the above estimation method and fatigue degree acquisition method.
That is, the X-ray parameter estimating apparatus calculates the initial value of the X-ray parameter (half-value width) of the first surface (the raceway surface 2a) that is fatigued by use in the metal part (the inner ring 2) subjected to the surface processing. An estimating device, a first acquisition unit that acquires a range of depths at which the material becomes uniform using the metal parts before the surface processing, and an unused metal part after the surface processing. A second acquisition unit for acquiring the depth at which the X-ray parameters of the second surfaces (axial end faces 2b, 2c) that do not fatigue due to the surface processing are affected by the surface processing, and an unused metal part after the surface processing. A third obtaining unit configured to obtain a variation amount of an X-ray parameter of the first surface due to the influence of the surface processing; and a first obtaining unit configured to obtain the first surface of the metal part after use or unused. Within the range obtained by the part and the second A measuring unit that measures an X-ray parameter in a region deeper than the depth acquired by the acquiring unit, and by reflecting the variation acquired by the third acquiring unit on the X-ray parameter measured by the measuring unit. And an estimating unit for estimating an initial value of the X-ray parameter of the first surface.

  According to such an estimation device, the X-rays in the second surface of the used or unused metal part within the range of the depth where the material becomes uniform and deeper than the depth affected by the surface processing By measuring the parameter and reflecting the variation of the X-ray parameter due to the influence of surface processing on the X-ray parameter, the initial value of the X-ray parameter of the first surface that is fatigued by use is estimated. The initial value of the line parameter can be accurately estimated, and the initial value can be used to accurately acquire the degree of fatigue.

  Further, the fatigue degree acquisition device is a fatigue degree acquisition device that acquires the fatigue degree of the first surface (the raceway surface 2a) that is fatigued by the use after use of the metal part (the inner ring 2) subjected to the surface processing. A measuring unit for measuring an X-ray parameter (half width) of the first surface of the used metal component, the estimating device, the X-ray parameter measured by the measuring unit, and the estimating device And an acquisition unit for acquiring the degree of fatigue of the first surface based on the initial value of the X-ray parameter estimated in.

  According to such a fatigue level acquisition device, a highly accurate fatigue level can be acquired using the more accurately estimated initial value.

The present invention is not limited to the above embodiment, and can be appropriately modified within the scope of the invention described in the claims.
For example, in the above-described embodiment, a case has been described in which the degree of fatigue of the raceway surface 2a of the inner ring 2 is obtained. However, the present invention can also be applied to a case in which the degree of fatigue of the raceway surface 3a of the outer ring 3 is obtained. When acquiring the degree of fatigue on other surfaces (inner peripheral surface, outer peripheral surface, axial end surface, etc.) of the inner ring 2 or the outer ring 3 or acquiring the degree of fatigue of metal parts other than the inner ring 2 and the outer ring 3 The present invention can also be applied to

  In the above embodiment, obtaining the degree of fatigue of a tapered roller bearing has been described. However, the present invention may be applied to obtain the degree of fatigue of other types of rolling bearings such as a cylindrical roller bearing and a ball bearing. it can. Further, the present invention can be applied to obtain the degree of fatigue of a metal component other than the rolling bearing.

  In the above-described embodiment, an example in which carburizing and quenching is performed on a metal component from which fatigue is to be acquired has been described. However, a surface hardening heat treatment other than carburizing and quenching may be performed on a metal component. Further, the present invention can be applied to a case where a heat treatment other than the surface hardening heat treatment (for example, a normal quenching and tempering treatment) is performed on the metal component.

  In the above embodiment, the half width of the diffracted X-ray is used as the X-ray parameter, but other parameters having a correlation with the degree of fatigue, such as residual stress and residual austenite, may be used.

  2: inner ring (metal part), 2a: raceway surface (first surface), 2b: axial end surface (second surface), 2c: axial end surface (second surface), 10: fatigue degree acquisition device, 11: X-ray diffraction device (measuring unit), 12: processing device, 13: hardness measuring device

Claims (4)

A method for estimating an initial value of an X-ray parameter of a first surface that is fatigued by use in a metal part subjected to surface processing,
(A) obtaining a range of depth at which the material becomes uniform using the metal part before the surface processing;
(B) using an unused metal part after the surface processing to obtain a depth at which an X-ray parameter of the second surface that does not fatigue due to use is affected by the surface processing;
(C) using an unused metal part after the surface processing to obtain a variation amount of an X-ray parameter of the first surface due to the influence of the surface processing;
(D) X-ray parameters of an area within the range obtained in step (a) and deeper than the depth obtained in step (b) on the second surface of the used or unused metal part. Measuring, and
(E) estimating an initial value of the X-ray parameter of the first surface by reflecting the variation obtained in step (c) on the X-ray parameter measured in step (d). And a method for estimating X-ray parameters in a metal part.   The method for estimating X-ray parameters in a metal component according to claim 1, wherein the metal component is subjected to a surface hardening heat treatment.   3. The method according to claim 1, wherein the X-ray parameter is a half-value width of a diffracted X-ray. A method for obtaining a degree of fatigue of a first surface that is fatigued by using the metal part after the surface-treated metal component is used,
(F) measuring an X-ray parameter of the first surface of the metal component after use;
(G) estimating an initial value of an X-ray parameter of the first surface by the estimation method according to any one of claims 1 to 3, and
(H) acquiring the degree of fatigue of the first surface based on the X-ray parameters measured in step (f) and the initial values of the X-ray parameters estimated in step (g); And a method for obtaining the degree of fatigue of a metal part.