JPH03120460A - Method and device for locating ae generation position of thrust ball bearing - Google Patents

Abstract

PURPOSE:To accurately locate the Acoustic Emission (AE) generation position of the thrust ball bearing and to diagnose abnormality by narrowing down an AE generation position range by AE generation position range locating based on an AE arrival time difference. CONSTITUTION:The arrival time points t1 and t2 of one AE are detected at two positions A1 and A2. Ball positions B1 - B3 at one of them, e.g. arrival time t1 of A1 are detected. Further, the difference DELTAt between t1 and t2 is calcu lated and a distance (d) by which the AE travels in the time DELTAt is found as the product of DELTAt and the traveling speed of the AE. Then the difference (d) is the difference between the distances from one of unknown AE generation positions B1 - B3 to the points A1 and A2. Further, when a measurement error DELTAd is considered as to the distance (d), the AE generation position is in the hatched zone 22 encircled with two hyperbolic curves 18 and 21 whose differences from the two points A1 and A2 are d+ or -DELTAd. Therefore, the AE genera tion point is one of B1 - B3 in the zone 22 and when B1 - B3 are in the zone, B1 is located.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for determining the amount of rolling fatigue, etc., generated in the outer ring of a thrust ball bearing in a used state. It can be used for diagnosis and research to elucidate the progression process of fatigue cracks in rolling fatigue phenomena.

[Prior Art] A thrust ball bearing supports a rotating shaft in the direction of its axis, and as in the thrust ball bearing 101 shown in FIG. It is equipped with a retainer 103, an outer ring 104, and a plurality of balls 105 held within the retainer 103, and supports the rotating shaft 1 to be supported.
The inner ring 102 rotates according to the rotation of the inner ring 102, and the inner ring 102 rotates accordingly, and the outer ring 1105 revolves on a track 1108 on the outer ring 104 while rotating, and the outer ring 104 is kept in a fixed position.

[Problems to be Solved by the Invention] Not only thrust ball bearings, but also rolling bearings develop fatigue cracks due to rolling fatigue as they are used, which progresses and leads to fatigue peeling failure, that is, the end of its service life, but if it breaks during use, it is extremely dangerous. Therefore, it needs to be replaced before it gets damaged.

However, since the rolling fatigue of bearings cannot be seen from the outside,
In order to ensure the reliability of bearings, sufficient consideration is given at the design stage, and during the use stage they are often replaced at a time shorter than their service life.

However, it is uneconomical to replace even healthy bearings, and even if you do so, the lifespan of individual bearings will vary depending on the product itself and the usage conditions, and if bad conditions happen to occur,
If this happens, the lifespan may be shortened to the 14i end, so it is not possible to completely ensure reliability by simply replacing the battery after a certain period of time.

Therefore, methods of diagnosing bearings in use are becoming popular in order to use each bearing until its end of life, eliminate the uneconomical cost of uniform replacement, and improve the reliability of the bearings.

One of such methods is the occurrence and progression of fatigue cracks, which are a sign of bearing failure.
There is a method that focuses on ``c Emission''.

AE is an ultrasonic wave generated from rolling fatigue points during operation of a ball bearing, and its frequency is about several hundred KH2.

In a normal bearing, AE does not occur, and even if AE occurs, the bearing will not be damaged immediately. However, if fatigue cracks develop in this area over time, it will eventually lead to bearing failure, so detecting the location where AE occurs greatly contributes to diagnosis and research of bearings in use. It is.

The inventor of the present application first developed a technique for locating the AE occurrence position.
Patent application No. 56-196642 was proposed.

This is an AE occurrence position locating device 11 as shown in FIG.
1, the position indicating member 116 is configured as a tooth-shaped unevenness on the outer periphery of the retainer 102 of the thrust I/ball bearing 101.
and a position detection sensor 115 fixed outside the position indicating unit $1116, and an AE detection device 110 including an AE converter 113 that converts AE into an electrical signal, The action is to locate the position of the ball 105 when the ball 105 passes through a portion of the outer ring 104 that is subject to rolling fatigue as the shaft 101 rotates and an AE occurs as a candidate position for the occurrence of AE.

This is an effective method for locating the AE generation candidate position on the outer ring 104, but since a plurality of balls 105 (for example, three) are used, even if the true AE generation position is one, the AE A plurality of locations were identified as potential AE locations (FIG. 9), and there was the inconvenience that the true location of AE occurrence could not be determined.

This invention has been made in view of the above circumstances, and it is possible to accurately locate the position where AE occurs in thrust ball bearings, and thereby, it is possible to accurately locate the occurrence position of AE in thrust ball bearings. AE of thrust ball bearings can be effectively used to elucidate the progression process of rolling fatigue, which is a serious damage, and can contribute to a method for diagnosing abnormalities in thrust ball bearings during use.
The object of the present invention is to provide a method and device for locating the location of occurrence.

[Means for Solving Problem 1] Corresponding to this purpose, the AE of the thrust ball bearing of the present invention
The occurrence position locating method detects the arrival time of each AE generated in an operating thrust ball bearing at multiple different points.
A difference d in the distance from the AE occurrence position to the plurality of points is determined from the difference in the detected arrival times, and a position where the difference in distance to the plurality of points corresponds to d is directly located as an AE generation candidate. AE generation candidate position n based on the ball position d at the time of AE occurrence, which locates the AE generation candidate position based on the AE arrival time difference, detects the ball position at one of the arrival times, and sets these as the AE generation candidate position. The above A
Orientation of AE generation candidate position correction based on E arrival time difference and the above AE
The AE occurrence position locating device for a thrust ball bearing of the present invention is characterized in that the AE occurrence candidate position that is common to the result of locating the AE occurrence candidate position based on the ball position at the time of occurrence is used as the AE occurrence position head, and the AE occurrence position locating device for a thrust ball bearing of the present invention Multiple A that can detect the arrival time of
E detection device, a ball position detection device that detects the orbital position of the ball at the detected time, and a difference between the arrival times of the AE detected by the plurality of AE detection devices from the plurality of AE detection devices d. Difference in distance d to the position where the AE occurs
and calculate the difference n in distance to the plurality of AE detection devices for each of the detected ball positions, compare it with the d, and detect a ball position that matches the d within a predetermined error range. The invention is characterized by comprising a device for doing so.

[Operation 1] In the method for locating the AE occurrence position of a thrust ball bearing according to the present invention, the arrival times of the generated AE at a plurality of different points are detected.

The arrival times are generally distributed within a certain time difference range. The ball position at one of these is regarded as the ball position at the time of AE occurrence, and is set as the AE occurrence candidate position.

Although the arrival time is not the AE generation time, the propagation speed of the AE, which is an ultrasonic wave, is much faster than the movement speed of the ball, so the time required for the ball to travel from the AE generation position to the detection position is This is because the amount of movement can be considered zero.

In order to identify the true AE occurrence location among these AE occurrence candidate locations, the difference in the arrival time of the AE to the different points is measured, and it is converted into a distance from these points. The difference d between the distances to the AE occurrence position is determined. Since a point where the difference in distance from two points is a constant 1 fid is on a certain hyperbola, the AE occurrence position is on this hyperbola.

Among the AE generation candidate positions, those located on the hyperbola are determined as AE generation positions. However, in actual orientation, d
Considering the measurement error of , the hyperbola is considered as a zone with a certain width, and anything that falls within this zone is determined as the AE occurrence position.

When the above-mentioned "multiple points" is "two points", the hyperbola is one set, and although it is very rare, there are cases where two AE occurrence candidate positions are included on this hyperbola and it is not possible to identify one. The problem is that it is possible. In this case, "3 points"
That will solve this problem. - If there are many balls and the error in d is large, you can also choose [4 points] to ensure accuracy.

In addition, in the AE occurrence position locating device for a thrust ball bearing of the present invention, a plurality of AE detection devices are arranged at different points outside the thrust ball bearing, and each AE detection device has an AE occurrence position locating device.
The time at which the time has arrived is detected.

The ball position at one of these is detected by a ball position detection device and becomes the AE occurrence candidate position cost.

In order to identify the true AE occurrence position from among these AER raw candidate positions, a computing device calculates the difference in the time when the AE reaches the AE detection device U placed at the different points (i.e., the AE detects the The difference in arrival time required to reach the device is calculated, and this difference in arrival time is converted into distance using the speed of the AE.
The difference d in distance to the E occurrence position is determined. Furthermore, the performance device determines that the difference in distance to the plurality of AE detection devices for each of the detected AE generation candidate positions is determined by the performance device.
The amount that matches d or whose difference from d is within the error range is determined as the AE occurrence rate.

[Example] FIG. 1, FIG. 2, and FIG. 3 show the AE generation position IIA formula for the thrust ball bearing of the present invention.

First, the thrust ball bearing, the orbit 10 of the balls 105 of 101
8 on the plane containing two points A1. An AE converter 113 is placed at each of A2 so that when an AE arrives, each is converted into an electric signal and generated so that the arrival time of the AE can be detected.

Further, the position detection sensor 15 for detecting the upper position is placed in a position that does not interfere with the AE converter, so that the position d of the ball 105 at any time can be detected. Such techniques are known.

First, for one AE, its arrival time t1 at two points A, , A2. t2 is detected (AE arrival time detection). The upper position 81. at the arrival time t1 to one of them, for example, A. B2. B3 (Fig. 1) is detected (upper position detection). B, , B2゜B are the upper positions at the time when AE reaches A1, but as mentioned above, they can be regarded as the upper positions when AE occurs, so these are considered as AE generation candidate positions (when AE occurs, the occurrence candidate location location).

Also 1 4. , -, -1, , is calculated, and the distance ld traveled by the AE in time Δt is determined as the product of Δt and the speed of progress of the AE. Then, d is the unknown AE generation position (B1
．． This is the difference in distance from one of B2 and B3) to point A1°A2. The difference in distance from point A,,A2 is d(
constant) is A1. A, is on a certain hyperbola with 2 as the focal point, for example, in the case of tl x t2, 1 as shown in Figure 1.
It lies on one curve 17 of a pair of hyperbolas. Considering the measurement error Δd for d, the AE occurrence position is indicated by diagonal lines in Figure 1, which is sandwiched between two hyperbolas a18.21 where the difference in distance from the two points A1°A2 is d±Δd. Zu zone 2
2 (range determination of AE position based on AE arrival time difference). Therefore, the AE occurrence positions are al, B2. B3
If the point is within the noura zone 22 and is within the zone 20 of the AE generation position range in FIG. 3, for example, if it is located at 81°82.83 as shown in FIG.
B1 (AE occurrence position location).

Although zone 22.20 is shown as one location in FIGS. 1 and 3, zone 20 is shown as one location in FIGS. ) may be divided into 2-inch zones, as shown in zones 20a and 20b. However, the orbit of B1, 82.83 is 108
The angular coordinate θ1 with the center as the pole. θ2. There is no change in the fact that the θ3 that falls within at least one of these zones is located as the AE occurrence position.

Here, when 01 falls into zone 20, θ2. which does not fall into zone 20 as shown in FIG. It is easy to add the AE occurrence count number of θ3 to B1, and thereby the AE occurrence position can be determined at a glance.

As described above, in the method for locating the AE occurrence position of a thrust ball bearing according to the present invention, the AE occurrence position is first determined by determining the AE occurrence candidate position, and then the AE occurrence position is determined from a finite number of AE occurrence candidate positions (01, θ2, etc. in FIG. 3) on the orbit. It is expressed as θ3.

This is no different from the conventional force test results shown in FIG.

), and further narrowed down the range of the AE occurrence position by locating the range of the AE occurrence position based on the AE arrival time difference (zone 20 shown by the chain line in FIG. 3), and locating the AE occurrence position etr.

The range of the angle θ corresponding to the shaded zone 22 is quite wide, so if there are many man-hours, there may be two upper positions in this zone 22, but if three or four AE converters are used, , θ are narrowly limited to correspond to the intersections of a plurality of zones, which also solves this problem.

In this case, the AE generation position of the thrust ball bearing is H4! The ff determining device may be constructed as shown in FIG.

[Experiment Example 1 Figure 6 shows the rolling fatigue test of a test bearing simulating a thrust ball bearing.AE generation position rj4 of the present invention! : Shows the results of locating the AE occurrence position using the constant force method and η.

The horizontal axis of the figure shows one orbit of the test bearing as 0.0 to 1.0. In the figure, a beak 23 can be seen near 1.0, and rolling fatigue flaking actually occurred at a position on the orbit corresponding to this orientation result.

[Effects of the Invention] As is clear from the above description, according to the present invention, it is possible to accurately detect the position where AE occurs in a thrust ball bearing, and thereby to detect the progress of abnormalities, especially in ball bearings. A method for locating the position of AE occurrence in thrust ball bearings and loading, which can be effectively used to elucidate the progress of rolling fatigue, which is a typical flaw, and can contribute to a method for diagnosing abnormalities in thrust ball bearings during use. can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory plan view showing the standard method for the AE generation chamber of the thrust ball bearing of the present invention, Fig. 2 is a block explanatory diagram showing the standard method of the AE generation chamber for the thrust ball bearing of the present invention, and Fig. 3 is the AE generation candidate position. Figure 4 (a) is a diagram showing the positional relationship between the AE occurrence position range determination based on the AE arrival time difference and the AE arrival time difference.
Figure 4 (b
) Figure 5 is a diagram showing how to create a graph of the experimental example shown in Figure 6, Figure 6 is a diagram showing an example of the experimental results using the orientation method of this invention, and Figure 7 is a diagram showing how to create a graph of the experimental example shown in Figure 6. FIG. 8 is a block diagram showing an AE generation positioning device for a thrust ball bearing; FIG.
and FIG. 9 are diagrams showing the result of locating by the conventional AE occurrence position locating device. 105... ball, 108... orbit, 113...
...AEE switch, 115...Top position detection sensor, B1.82.83...Ball position, θ4. θ2. θ3...AE generation candidate position, 20.22
...AE occurrence position range zone 3 (B) 2 (B2) 3 (B3) 360° orbit 1 position diagram (0) Figure 4 (b) Ryu ℃ weight upper l 1 wealth 5 diagram e3 1 θ2 πS6 Figure 08O 0,5 1,0

Claims (2)

[Claims] (1) Detect the arrival times of AE generated in an operating thrust ball bearing at a plurality of different points, and determine the distance from the AE generation position to the plurality of points based on the difference in the detected arrival times. An AE that calculates a difference d and locates a position where the difference in distance to the plurality of points corresponds to d as an AE occurrence candidate position.
The AE generation candidate position is located based on the arrival time difference, and the ball positions at one of the arrival times are detected and all of these are considered as AE generation candidate positions.The AE generation candidate position is located based on the ball position at the time of AE occurrence. The A common to the results of locating the AE occurrence candidate position based on the AE arrival time difference and AE occurrence candidate position based on the ball position at the time of AE occurrence.
A method for locating the AE occurrence position of a thrust ball bearing characterized by setting the E occurrence candidate position as the AE occurrence position (2) A plurality of AE detection devices that can detect the arrival time of the AE, a ball position detection device that detects the orbital position of the ball at the detected time, and the AE detected by the plurality of AE detection devices. Convert the difference in arrival time of
AE of a thrust ball bearing characterized by comprising: a device that calculates a difference in distance to a detection device, compares it with the d, and detects a ball position that matches the d within a predetermined error range.
Occurrence position locating device