JP2006214904A - Rolling element support load estimation device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling element support load estimation method allowing estimation of a rolling element support load even when there is no boundary between the bearing outer ring and bearing housing. <P>SOLUTION: The rolling element support load estimation method comprises a step of radiating transverse ultrasonic wave or high-frequency longitudinal ultrasonic wave from an ultrasound probe 1 toward a contact section between the bearing outer ring 20 and a ball 22; a step of detecting the intensity of the reflected wave from the contact section; and a step of calculating the size of the rolling element support load based on calibration curve data where the relation between the intensity of the reflected wave and the rolling element support load is previously determined. The ultrasound probe 1 has a region for transmitting and receiving ultrasonic wave in the circumferential direction of the outer ring 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling element support load estimation device and a rolling element support that estimate a rolling element support load by irradiating a measurement target area with ultrasonic waves from an ultrasonic probe and measuring a reflected wave from the measurement target area. The present invention relates to a load estimation method.

  A bearing is well known as a mechanical element that supports a rotating shaft. As a general configuration of the bearing, an inner ring, an outer ring, a ball (corresponding to a rolling element) that is sandwiched between the inner ring and the outer ring and rolls are provided. The outer diameter portion of the outer ring is inserted into a fitting hole formed in the bearing housing, and the rotary shaft is fitted to the inner diameter portion of the inner ring.

  As a method for knowing the life of such a bearing, a method for measuring a load acting on the bearing is known. In general, the machine is often accompanied by vibration and shock during operation, and it is difficult to know the degree of fitting with the shaft in the assembled state and operating environment, so the actual load applied to the rolling element (Or the load acting on the bearing) cannot be grasped. If the load acting on the bearing can be known, it is considered that the life (remaining life) of the bearing can be correctly estimated.

  Therefore, a measurement technique using an ultrasonic probe is known as a method for measuring the bearing load acting on the bearing in a non-contact manner (for example, Patent Document 1 below). The ultrasonic probe irradiates itself with ultrasonic waves and receives reflected waves (echoes) reflected and bounced off the object to be investigated. Specifically, the ultrasonic probe is attached to the bearing housing, emits ultrasonic waves toward the bearing outer ring, and receives a reflected wave from the boundary between the bearing housing and the bearing outer ring. When the contact area between the bearing housing and the bearing outer ring occupies a large proportion in the ultrasonic irradiation region, the emitted ultrasonic waves are transmitted from the boundary, and the transmittance is proportional to the contact area.

Here, when the bearing load is large, the contact area is increased, so that the transmittance of ultrasonic waves is increased. When the transmittance increases, the magnitude of the reflected wave decreases. Conversely, when the bearing load is small, the magnitude of the reflected wave is large. Therefore, the magnitude of the bearing load can be estimated by measuring the intensity of the reflected wave.
JP 2002-257796 A

  In recent years, a bearing structure in which a bearing outer ring and a bearing housing are integrated is known for weight reduction and space saving. That is, a bearing structure is used in which the race surface is processed with the housing as the outer ring and the shaft as the inner ring, and unitized. In the case of such a bearing, since there is no boundary between the bearing outer ring and the bearing housing, the bearing load cannot be estimated based on the reflected wave from the boundary.

  The present invention has been made in view of the above circumstances, and the problem thereof is a rolling element support load estimation device capable of estimating the rolling element support load even when there is no boundary between the bearing outer ring and the bearing housing, An estimation method and a calibration curve acquisition method are provided. If the rolling element support load can be known, the bearing load can be estimated.

In order to solve the above problems, a bearing load estimation device according to the present invention is:
An ultrasonic probe that emits a transverse wave or high-frequency longitudinal wave toward the contact portion between the bearing outer ring and the rolling element;
Reflected wave detection means for detecting the intensity of the reflected wave from the contact portion;
Calibration curve data storage means for storing calibration curve data obtained in advance for the relationship between the intensity of the reflected wave and the rolling element support load;
Rolling element support load calculating means for calculating the size of the rolling element support load based on the calibration curve data,
The ultrasonic probe has a region for emitting and receiving ultrasonic waves along the circumferential direction of the outer ring.

  The operation and effect of the rolling element support load estimation device having such a configuration will be described. The ultrasonic waves from the ultrasonic probe are emitted toward the contact portion between the bearing outer ring and the rolling element. The contact state between the bearing outer ring and the rolling element varies according to the magnitude of the rolling element support load (bearing load). That is, if the rolling element support load is large, the contact area accompanying the elastic deformation becomes large, and if the rolling element support load is small, the contact area also becomes small. Therefore, since the intensity of the reflected wave changes according to the size of this area in the ultrasonic irradiation region, it is possible to estimate the rolling element support load even if there is no boundary between the bearing outer ring and the bearing housing. Become.

  The contact area according to the present invention refers to an area (referred to as Hertz contact area) where an elastohydrodynamic lubricating film as described later is formed, and the area of direct contact between solids is referred to as a solid contact area. However, in the mixed lubrication region (the region in which the rolling element support load is shared and supported by both the elastic fluid lubricating film and the solid contact), the contact area includes the solid contact area.

  By detecting the intensity of the reflected wave, the magnitude of the rolling element support load can be known based on calibration curve data obtained in advance. This calibration curve data is obtained by measuring in advance the intensity of the reflected wave and the magnitude of the rolling element support load. In addition, as a physical quantity in the case of measuring the intensity | strength of a reflected wave, the echo height ratio currently disclosed by patent document 1 can be used, for example. The echo height ratio H is defined by the following equation.

H = (1-h / h ₀ ) × 100
h is the echo height when an external bearing load is acting, and h ₀ is a value corresponding to the echo height when no external bearing load is acting (no load). Note that the magnification of 100 is to display% and is not always necessary. As the bearing load is larger, h is smaller (the reflected wave is smaller), and the echo height ratio (H) is larger. Therefore, since the rolling element support load can be estimated from the echo height ratio, the relational expression and function between the echo height ratio and the rolling element support load are obtained in advance as calibration curve data, so that the rolling element support load is obtained. The load can be measured.

  Further, since the relationship between the bearing load and the rolling element support load acting on each rolling element can be obtained in advance, the bearing load can be estimated if the rolling element support load is obtained. For example, the bearing load can be estimated from the echo height measured using two or more ultrasonic probes.

  Further, the ultrasonic probe emits a transverse wave ultrasonic wave or a high-frequency longitudinal wave ultrasonic wave, and can thereby receive a reflected wave according to the contact state between the bearing outer ring and the rolling element.

  Strictly speaking, the type of ultrasonic wave used varies depending on the following three conditions.

(Condition 1) When the entire rolling bearing is immersed in lubricating oil. That is, a lubricating film having a thickness of at least twice the wavelength of the ultrasonic wave in oil is stably present on the inner surface of the outer ring (the surface on which the rolling element hits) over the entire region irradiated with the ultrasonic wave. Thus, in an environment where the echo height h ₀ in the reference state where the probe exists in the center of the adjacent rolling elements is stable and can maintain a constant value, longitudinal waves can also be used. In the case of a longitudinal wave, it is affected by multiple reflections in the surrounding thin film part other than the EHL part, but there is little disturbance including the above-mentioned reference measurement point, and the measured echo height fluctuation is in the EHL state. It is considered that it is determined by the thickness of the thin film at the contact portion and its peripheral portion, and the contact area. Since both of them change depending on the load, it becomes possible to estimate the support load of the rolling element from the echo height. Of course, it is possible to measure the rolling element support load with a transverse wave without any problem.

(Condition 2) In high-speed rolling bearings, spray-type lubrication may be performed to reduce friction. Further, as described above, the entire bearing is rarely immersed in the lubricating oil, and often stops at about half the diameter of the bearing, for example. In such a case, an oil film having a sufficient thickness as described above is not formed on the inner surface of the outer ring (the surface on which the rolling element hits), and an oil film with unevenness in the circumferential direction adheres to the outer ring. It sticks to the shape. In such a case, the maximum sound pressure amplitude of the first reflected wave from the contact surface (usually at a time distance of one wavelength or more from the head) is affected by the multiple reflection of the sound wave at such an adhesion film portion. Since it changes, this cannot be taken as the reference echo height h ₀ . Therefore, in order to reduce the influence as much as possible, the echo height determined by the maximum sound pressure amplitude at the first or half wavelength of the first reflected wave is taken as the reference echo height h ₀ (the same echo height is observed), Furthermore, a high-frequency longitudinal wave that reduces the wavelength of the ultrasonic wave in oil is used. It can be considered that the fluctuation of the echo height measured at this time is determined by the contact portion in the EHL state, the thickness of the thin film around the contact portion, and the contact area. Since both of them change depending on the load, it is possible to estimate the support load of the rolling element from the echo height using the high-frequency longitudinal wave ultrasonic wave of 10 MHz or higher, for example, as in the above-mentioned condition 1. Of course, it is possible to measure the rolling element support load with a transverse wave without any problem.

(Condition 3) Particularly in a high-speed bearing or the like, fine bubbles may be generated in the oil due to the stirring of the oil. Moreover, the case where the acoustic property in a place and place changes with mixing of a water | moisture content (water droplet) is also assumed. In such a case, in the longitudinal wave propagating in the oil, there is a possibility that the reference echo height h ₀ may fluctuate greatly, and it is fully considered that the reflection of the sound wave at the thin film around the EHL is also affected. Therefore, under such lubrication conditions, the measurement methods of the above conditions 1 and 2 cannot be used. Therefore, it is usually considered to use a transverse wave that does not propagate in the liquid. Since it is difficult for air bubbles and moisture to enter the EHL portion, it may be considered that a continuous oil film is formed there.

  That is, lubricating oil is present in the contact portion between the bearing outer ring and the rolling element, but the region where the high pressure acts between the outer ring and the rolling element is the elastohydrodynamic lubricating portion (EHL portion). In the case of a transverse wave, there is a property that it does not propagate in the lubricating oil under normal pressure, but there is a property that the EHL part in a high pressure state propagates (transmits). In addition, since the size of the EHL portion varies according to the size of the bearing load, the size of the reflected wave also varies depending on the size of the bearing load. In the case of a low-frequency transverse wave, the ultrasonic wave incident on the film part is almost transmitted regardless of the thickness of the EHL film. The EHL portion is acoustically close to solid contact, and the intensity of the reflected wave is controlled by the size of the contact area in the ultrasonic irradiation region where the EHL film is formed. Therefore, the size of the rolling element support load can be accurately estimated by using the transverse wave ultrasonic wave.

  Further, in terms of the size of the ultrasonic probe, it is preferable to have a region for irradiation and reception along the circumferential direction of the outer ring. The size of the EHL portion described above is a very narrow region. If the size of the ultrasonic probe is small in the circumferential direction, the diffusion angle of the sound wave is large, and a part of the reflected wave is the ultrasonic probe. However, it may be difficult to detect the rolling element support load in a wide range. Therefore, by setting the size of the ultrasonic probe to a predetermined size along the circumferential direction, it is possible to estimate the rolling element support load in a wide range of sizes. As described above, it is possible to provide a rolling element support load estimation device capable of estimating the rolling element support load even when there is no boundary between the bearing outer ring and the bearing housing.

In order to solve the above problems, a rolling element support load estimation method according to the present invention is as follows.
Irradiating the ultrasonic wave of the transverse wave from the ultrasonic probe toward the contact portion between the bearing outer ring and the rolling element;
Detecting the intensity of the reflected wave from the contact portion;
A step of calculating the size of the rolling element support load based on calibration curve data obtained in advance for the relationship between the intensity of the reflected wave and the bearing load,
The ultrasonic probe has a region for emitting and receiving ultrasonic waves along the circumferential direction of the outer ring.

  The operations and effects of this configuration are as described above.

  In the present invention, it is preferable that the irradiation and reception areas are set to be substantially the same as or slightly shorter than the arrangement pitch of the rolling elements.

  In the case where the ultrasonic probe is elongated along the circumferential direction, it is necessary to keep the ultrasonic probe unaffected by the adjacent rolling elements. Accordingly, by making the pitch approximately the same as or slightly shorter than the arrangement pitch of the rolling elements, it becomes possible to measure the rolling element support load in the widest possible range.

  In the present invention, the irradiation and receiving surfaces of the ultrasonic probe are preferably cylindrical surfaces concentric with the revolution center of the rolling element.

  That is, if the mounting surface of the ultrasonic probe with respect to the bearing outer ring is a cylindrical surface concentric with the revolution center of the rolling element, it is possible to suppress the diffusion of sound waves in the radial direction of the outer ring. The reflected wave from the contact portion when passing through the lower part of the probe can be easily captured.

  A preferred embodiment of a rolling element support load estimation device (estimation method) according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a rolling element support load estimation device.

<Configuration of rolling element support load estimation device>
The bearing 2 to be measured in the present invention includes an outer ring 20, an inner ring 21, and a large number of balls 22 (rolling elements) sandwiched between the outer ring 20 and the inner ring 21. The rotating shaft 3 is fixed to the inner diameter portion of the inner ring 21 by an appropriate method such as press fitting. The outer peripheral portion 20a of the outer ring 20 is also formed in a cylindrical shape, and the ultrasonic probe 1 is attached by an appropriate method such as adhesion. The outer ring 20 of the bearing 2 is usually fitted to a member called a bearing housing. However, in the present invention, a rolling element support load estimating device suitable for a structure in which the outer ring 20 and the bearing housing are integrated is provided. provide. In a mechanical device aiming at miniaturization and cost reduction, a bearing, a housing, and a shaft may be supplied as a unitized part.

  The ultrasonic probe 1 generates a transverse wave ultrasonic wave in a direction perpendicular to the mounting surface. In the example of FIG. 1, the generated ultrasonic wave travels toward the rotation center of the rotation shaft 3. This ultrasonic wave is reflected by the inner peripheral portion 20 b of the outer ring 20, or when the ball 22 is on the sound axis, it is reflected or transmitted by the contact portion between the ball 22 and the outer ring 20. The ultrasonic probe 1 also has a function of receiving a reflected wave reflected by the inner peripheral portion 20b. Note that the sound axis is an axis along which the ultrasonic wave travels, but in the present embodiment, it is set as a straight line L connecting the center of the ultrasonic probe 1 and the center of the rotary shaft 3.

  The ultrasonic probe 1 is connected to an ultrasonic flaw detector 4 (corresponding to reflected wave detection means). The ultrasonic flaw detector 4 incorporates a drive circuit for driving the ultrasonic probe 1 and a reception circuit for receiving reflected waves. Further, the ultrasonic flaw detector 4 is connected to a personal computer 5 (computer), and a signal received by the ultrasonic probe 1 is A / D converted and transmitted to the personal computer 5. The personal computer 5 incorporates a computer program for estimating the ball support load and the bearing load from the received reflected wave signal.

<Description of principle>
Next, the principle of the method for estimating the ball support load using the ultrasonic probe 1 will be described with reference to FIG. FIG. 2A shows a state where the ball 22 is positioned directly below the ultrasonic probe 1 (on the sound axis), and FIG. 2B shows a state where the ball 22 is positioned directly below the ultrasonic probe 1. It is in a position. The ultrasonic wave emitted from the ultrasonic probe 1 is directed to the boundary between the outer ring 20 and the ball 22 (the inner peripheral portion 20b of the outer ring 20), a part of which is transmitted from the boundary, and the rest is reflected at the boundary. This reflected wave is received by the ultrasonic probe 1.

  When the contact area between the outer ring 20 and the ball 22 is large, the emitted ultrasonic wave is easily transmitted from the boundary, and the transmittance is substantially proportional to the contact area. As shown in FIG. 2A, when the ball 22 is positioned directly below the ultrasonic probe 1, the contact area within the ultrasonic irradiation region increases and the magnitude of the reflected wave decreases. On the other hand, in the state as shown in (b), since the ball 22 does not exist, the ultrasonic wave becomes difficult to transmit and the magnitude of the reflected wave increases. The contact area increases as the bearing load (ball support load) increases.

  In the present invention, a physical quantity called an echo height ratio is used to quantitatively represent the magnitude of the reflected wave. The echo height ratio (H) is defined by the following equation.

H = (1-h / h ₀ ) × 100
h is the echo height when an external bearing load (indicated by W in FIG. 1) is acting. h ₀ is the echo height when an external bearing load is not applied (no load), and actually uses the echo height when the probe is located at the center of the adjacent rolling elements. Note that the magnification of 100 is to display%, and is not necessarily required. As the bearing load increases, the contact area between the outer ring 20 and the ball 22 increases and h decreases (the magnitude of the reflected wave decreases), so the echo height ratio (H) increases.

<Ultrasonic probe>
Next, the size of the ultrasonic probe 1 will be described. FIG. 3 is a diagram showing the relationship between the size of the ultrasonic probe 1 and the sound pressure distribution. The ultrasonic probe 1 is disposed along the circumferential direction of the outer ring 20 and has a predetermined width dimension A in the circumferential direction. The size of the dimension A is preferably the same as or slightly shorter than the arrangement pitch γ of the balls 22.

  When the dimension A of the ultrasonic probe 1 is short, as shown in FIG. 4, the range in which the ultrasonic wave is irradiated by the ultrasonic probe 1 becomes very narrow, and the region where the load can be estimated becomes narrow. . Therefore, by increasing the length of the ultrasonic probe 1, a long sound pressure distribution in the circumferential direction as shown in FIG. 3 can be obtained, and the range in which the load can be estimated can be expanded. However, in order not to be affected by the adjacent ball 22, the dimension A (the dimension measured by the angle) is preferably slightly shorter than the arrangement pitch (angle γ) of the balls 22. The mounting surface of the probe has a shape along the circumferential surface (cylindrical surface) of the outer ring 20.

  FIG. 3 representatively shows the ultrasonic probe 1 with the delay member 15. If the outer ring 20 is thin and the distance between the ultrasonic probe 1 and the EHL portion is within the short-distance sound field limit distance, the sound pressure in the irradiation region changes in a complicated manner. And the contact area cannot be matched. The delay material 15 made of a polymer having a slower sound speed than steel so that measurement can be performed in a region where the sound pressure gradually changes in the radial direction from the sound axis (for example, the sound pressure distribution shown in FIG. 3). Is attached to the tip of the probe, and the EHL portion is placed in the far field.

<Shear wave ultrasound>
Next, it will be described that it is preferable to use a transverse wave as the ultrasonic wave to be used. Up to now, it has been explained that when the contact area between the outer ring 20 and the ball 22 increases, the magnitude of the reflected wave decreases. However, in actuality, there is lubricating oil in the contact portion between the outer ring 20 and the ball 22. To do. In particular, a region sandwiched between the outer ring 20 and the ball 22 has a high pressure, and a region called an EHL (elastic fluid lubrication) portion is formed. The periphery of the EHL portion is a region where the lubricating oil exists although it is not in a high pressure state. The EHL portion is a region indicated by a contact area A in FIG.

  In particular, in the case of condition 3 described above, when longitudinal ultrasonic waves are used, the ultrasonic waves are transmitted not only to the EHL portion but also to the region where the surrounding lubricating oil exists. Therefore, the ultrasonic wave is generally transmitted, which is not preferable for estimating the bearing load.

  On the other hand, when a shear wave is used, the shear wave does not propagate in the lubricating oil under normal pressure. However, the EHL portion is a region where the lubricating oil is compressed at a high pressure, and an ultrasonic wave can propagate unlike a region where the lubricating oil simply exists. The size (Hertz contact area) of the EHL portion has a property of fluctuating depending on the bearing load, and the Hertz contact area increases as the bearing load increases. Accordingly, the magnitude of the reflected wave also changes depending on the size of the Hertz contact area in the ultrasonic irradiation region.

  When the pressure is higher than 0.1 GPa, even if the transverse wave does not propagate in the liquid at normal pressure, the viscosity of the liquid is extremely high and the shear rigidity becomes extremely large, so that a phenomenon occurs in which the liquid is transmitted and multiple reflection occurs in the EHL part . FIG. 5 is a graph showing the relationship between the height of the reflected echo and the film thickness / wavelength (or 1 / shear rigidity). If low-frequency (for example, 2 MHz or less) ultrasonic waves are used, in the region where the film thickness is small, that is, in the EHL part, most of the ultrasonic waves are transmitted from the EHL film part regardless of the film thickness. (The echo height is almost zero). For this reason, this EHL film | membrane part will be in the state close | similar to the whole surface solid contact acoustically. Therefore, the echo height there is governed by the size of the contact area on which the EHL film is formed, rather than the actual size of the solid contact area. Therefore, even in a rolling bearing operated under mixed lubrication in which partial solid contact has occurred, a relationship similar to EHL lubrication in which the echo height is proportional to the X power of the load is obtained. From this, it becomes possible to measure the rolling element support load by the ultrasonic method over the entire region from EHL lubrication to mixed lubrication.

  The bearing load (ball support load) may be estimated by measuring the influence of the change in the EHL film thickness due to the load fluctuation. In that case, it is preferable to use a high frequency with a large echo height variation depending on the film thickness. In this case, a high-frequency longitudinal wave may be used.

<Longitudinal wave ultrasound>
The case where the transverse wave ultrasonic wave is used has been described above. However, in the case of the above-described conditions 1 and 2, a high-frequency longitudinal wave ultrasonic wave may be used. In the case of condition 2, the echo height determined by the maximum amplitude at the first one wavelength or half wavelength (the portion indicated by S in FIG. 6) of the first reflected wave is measured, so that it adheres to the inner surface of the outer ring on the outer periphery of the EHL portion It is possible to avoid the influence of multiple reflection of ultrasonic waves caused by a relatively thick oil film or oil droplets. The film thickness at the EHL portion and in the vicinity thereof also changes under the influence of the bearing load. Therefore, for example, the rolling element support load can be measured even if longitudinal high-frequency ultrasonic waves of 10 MHz or higher are used.

  However, if the entire bearing is immersed in lubricating oil, as explained in Condition 1 above, normal longitudinal waves may be used instead of high-frequency longitudinal waves in a predetermined environment. A shear wave is also possible.

<PC functions>
Next, functions of a computer program incorporated in the personal computer 5 will be described. As shown in FIG. 7, a bearing load estimation program 10 is installed in the personal computer 5 as software for calculating the bearing load based on the reflected wave signal received by the ultrasonic probe 1.

  The echo height ratio calculating means 10a has a function of calculating the echo height ratio based on the intensity of the received reflected wave. The ball support load calculating means 10b has a function of calculating the ball support load and the bearing load based on the calculated echo height ratio. A relational expression between the echo height ratio and the ball support load is obtained in advance as a calibration curve and stored in the calibration curve data storage unit 11. If the calibration curve data is known, the bearing load (ball support load) can be obtained from the echo height ratio. The calibration curve calculation means 10c has a function of calculating a calibration curve from the echo height ratio and the known ball support load magnitude.

  The display data generation unit 10d has a function of generating display data for displaying the received data, the calculated ball support load, and the like on the monitor 19.

<Calibration curve>
In order to estimate the bearing height by obtaining the echo height ratio, it is necessary to obtain a calibration curve in advance. FIG. 8 is a diagram illustrating an example of a calibration curve. The vertical axis represents the echo height ratio (H), and the horizontal axis represents the ball support load w. If the magnitude of the bearing load acting on the rotating shaft is known, the magnitude of the support load shared and supported by each ball 22 can be obtained by calculation according to the angular position φ of the ball 22. Therefore, when obtaining the calibration curve, several kinds of known bearing loads may be applied to the rotating shaft to obtain the echo height ratio at that time. As the calibration curve, a bearing load acting on the rotating shaft may be used instead of the ball support load.

  In FIG. 8, θ = 0 indicates a state where the ball 22 is just on the sound axis, and the θ coordinate is taken with reference to the sound axis L as shown in FIG. Normally, when the center of the ball 22 is on the sound axis, the echo height ratio becomes the largest, and the echo height ratio tends to decrease as θ increases.

  If a sensor 6 for detecting the position of the ball 22 is provided as shown in FIG. 3, a signal when the ball 22 has reached the sensor position can be detected. That is, if the sensor 6 is provided on the sound axis, the echo height ratio when the ball 22 comes to θ = 0 can be obtained. The echo height ratio when θ is not 0 is obtained by obtaining the echo height ratio after a predetermined time from the timing when the ball 22 is detected by the sensor 6 because the speed at which the ball 22 revolves is known in advance. be able to.

  Note that the maximum echo height ratio is not always when θ = 0, and the echo height ratio may be maximum when θ is finite. It is often seen that the echo height ratio is maximized at a position other than θ = 0, particularly under variable load. In consideration of such a case, it is preferable to provide a sensor 6 (see FIG. 3) for detecting the ball, and obtain the correspondence between the position of the ball 22 and the echo height ratio in advance.

<Another embodiment>
In this embodiment, a ball (sphere) has been described as an example of a rolling element. However, the present invention is not limited to this, and the present invention can also be applied when a cylindrical rolling element or the like is used.

  The ultrasonic probe can be attached not only in the first and second quadrants but also in the third and fourth quadrants. In this case, the rotational load can also be measured.

Schematic diagram showing the configuration of the bearing load estimation device Diagram explaining the principle of estimating bearing load using an ultrasonic probe The figure explaining the relationship between an ultrasonic probe, sound pressure distribution, and an EHL part Diagram showing the sound pressure distribution when using an ultrasonic probe with a small ultrasonic irradiation area Graph showing the relationship between echo height and film thickness Diagram showing echo height signal when using longitudinal wave ultrasound Diagram showing functions of bearing load estimation program Diagram showing the relationship between ball support load and echo height ratio

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Bearing 3 Rotating shaft 4 Ultrasonic flaw detector 5 Personal computer 6 Sensor 10 Bearing load estimation program 10a Echo height ratio calculation means 10b Bearing load calculation means 10c Calibration curve calculation means 10d Display data generation means 11 Calibration curve Data storage means 12 Array type probe 19 Monitor 20 Outer ring 20a Outer part 20b Inner part 21 Inner ring 22 Ball H Echo height ratio w Ball support load

Claims (4)

An ultrasonic probe that emits a transverse wave or high-frequency longitudinal wave toward the contact portion between the bearing outer ring and the rolling element;
Reflected wave detection means for detecting the intensity of the reflected wave from the contact portion;
Calibration curve data storage means for storing calibration curve data obtained in advance for the relationship between the intensity of the reflected wave and the rolling element support load;
Rolling element support load calculating means for calculating the size of the rolling element support load based on the calibration curve data,
The rolling element support load estimation device, wherein the ultrasonic probe has a region for irradiating and receiving ultrasonic waves along a circumferential direction of an outer ring. Irradiating a ultrasonic wave of a transverse wave or a high-frequency longitudinal wave from an ultrasonic probe toward a contact portion between a bearing outer ring and a rolling element;
Detecting the intensity of the reflected wave from the contact portion;
Calculating the magnitude of the rolling element support load based on the calibration curve data obtained in advance for the relationship between the intensity of the reflected wave and the rolling element support load,
The rolling element support load estimation method, wherein the ultrasonic probe has a region for irradiating and receiving ultrasonic waves along a circumferential direction of an outer ring.   3. The rolling element support load estimation method according to claim 2, wherein the irradiation and receiving areas are set to be substantially the same as or slightly shorter than the arrangement pitch of the rolling elements. The rolling element support load estimation method according to claim 3, wherein the irradiation and receiving surfaces of the ultrasonic probe are cylindrical surfaces concentric with the revolution center of the rolling element.

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