Rolling bearing, state monitoring device, and method for detecting revolution slip of rolling bearing

Abstract

To provide a rolling bearing capable of accurately detecting the revolution slip of a rolling element without disassembling a mechanical device, a state monitoring device, and a revolution slip detection method of the rolling bearing.SOLUTION: The method includes a measuring step of measuring a signal including a rolling element passing vibration when the rolling element 40 passes through the vibration generating parts 11 and 12, a calculating step of performing frequency analysis on the signal to calculate spectrum data, and a detecting step of comparing a frequency at which a peak appears due to the rolling element passing vibration with a theoretical revolution frequency due to revolution of the rolling element 40 when the rolling element 40 does not slip on the outer ring raceway surface 21 or the inner ring raceway surface 31 to detect presence or absence of revolution slip of the rolling element 40.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rolling bearing, a condition monitoring device, and a method for detecting orbital slippage of a rolling bearing, and in particular to a rolling bearing, a condition monitoring device, and a method for detecting orbital slippage of a rolling bearing that are capable of accurately detecting orbital slippage of a rolling element without disassembling a mechanical device in which the rolling bearing is incorporated. [Background technology]

[0002] When rolling bearings are used under light loads, high speeds, or excessive lubrication, the rolling elements may not be able to rotate normally and may slip on the raceway, a phenomenon known as orbital slippage. When orbital slippage occurs, each rolling element will advance or lag behind in terms of the number of revolutions, and excessive loads will be applied from the rolling elements to the cage, which in extreme cases may even be damaged.

[0003] Patent Document 1 discloses a rolling bearing that uses an AE sensor embedded in the fixed ring to enable accurate and early detection of abnormalities such as minute damage to the fixed ring. Patent Document 2 also discloses a bearing condition monitoring device that includes a sensor that detects signals based on vibrations and sound generated by the bearing or strain values ​​of the inner ring, outer ring, shaft, and housing, a waveform processing unit that performs frequency analysis on the signals and calculates spectrum data, and a calculation unit that compares the frequency at which peaks in the spectrum data appear with theoretical frequencies due to the rotation and revolution of the rolling elements when there is no slip between the inner and outer rings of the bearing and the rolling elements, and determines fluctuations in the rotation speed and revolution speed of the rolling elements of the bearing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-78203 [Patent Document 2] WO2019-221251 publication Summary of the Invention [Problem to be solved by the invention]

[0005] However, the rolling bearing described in Patent Document 1 is intended to detect damage to the fixed ring and is unable to detect orbital slippage of the rolling elements. Also, the bearing condition monitoring device described in Patent Document 2 is capable of monitoring fluctuations in the rotation and revolution speeds of the rolling elements, but there is a demand for more accurate detection of orbital slippage from vibrations generated by the bearing, and further improvements have been desired.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a rolling bearing that is suitable for accurately detecting vibrations of the rolling bearing, a condition monitoring device that can detect orbital slippage of the rolling bearing, and a method for detecting orbital slippage of the rolling bearing. [Means for solving the problem]

[0007] Therefore, the above object of the present invention is achieved by the following rolling bearing configuration [1]. [1] A rolling bearing comprising an outer ring having an outer ring raceway surface on its inner peripheral surface, an inner ring having an inner ring raceway surface on its outer peripheral surface, and a plurality of rolling elements arranged to roll freely between the outer ring raceway surface and the inner ring raceway surface, A rolling bearing, wherein at least one of the outer ring raceway surface and the inner ring raceway surface is provided with a concave or convex vibration generating portion that generates vibration in the rolling bearing when the rolling element passes over it.

[0008] The above object of the present invention is also achieved by the following configuration [2] relating to the status monitoring device. [2] A condition monitoring device for detecting revolutionary slip of the rolling bearing according to [1], a vibration sensor that detects a signal based on vibration generated from the rolling bearing, including rolling element passing vibration when the rolling element passes through the vibration generating portion; a rotation sensor for detecting a rotation speed of the rolling bearing; a waveform processing unit that performs frequency analysis on the signal detected by the vibration sensor and calculates spectrum data; a calculation unit that detects the presence or absence of orbital slip of the rolling element by comparing a frequency at which a peak appears due to the rolling element passing vibration in the spectrum data with a theoretical revolution frequency due to the revolution of the rolling element when there is no slip of the rolling element; A condition monitoring device comprising:

[0009] The above object of the present invention is also achieved by the following configuration [3] relating to a method for detecting revolutionary slippage of a rolling bearing. [3] A method for detecting revolutionary slip of a rolling bearing using the rolling bearing according to [1], a measuring step of measuring a signal based on vibration generated from the rolling bearing, the signal including rolling element passing vibration when the rolling element passes through the vibration generating section; a calculation step of performing frequency analysis on the signal to calculate spectral data; a detection step of detecting the presence or absence of orbital slip of the rolling element by comparing a frequency at which a peak appears due to the rolling element passing vibration in the spectrum data with a theoretical revolution frequency due to the revolution of the rolling element when there is no slip of the rolling element; A method for detecting revolutionary slippage in a rolling bearing, comprising: [Effects of the Invention]

[0010] According to the rolling bearing and condition monitoring device, and method for detecting orbital slippage of a rolling bearing of the present invention, vibrations are generated when the rolling element passes through a vibration generating section provided on the raceway surface, and by measuring this vibration, orbital slippage of the rolling element, which is the cause of malfunctions in the rolling bearing, can be detected with greater accuracy. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a condition monitoring device that detects whether or not there is orbital slippage in a rolling bearing. [Figure 2] 1 is a schematic diagram of a rolling bearing in which a concave vibration generating portion is formed on an outer ring raceway surface. [Figure 3] FIG. 3(a) is a perspective view of an outer ring of a deep groove ball bearing in which a concave vibration generating portion is formed on the outer ring raceway surface, and FIG. 3(b) is an enlarged view of a main portion. [Figure 4] 1 is a schematic diagram of a rolling bearing in which a concave vibration generating portion is formed on an inner ring raceway surface. [Figure 5] FIG. 5(a) is a perspective view of an inner ring of a deep groove ball bearing in which a concave vibration generating portion is formed on the inner ring raceway surface, and FIG. 5(b) is an enlarged view of a main portion. [Figure 6] FIG. 6(a) is a front view showing a concave vibration generating portion formed on a part of the raceway surface in the axial direction, and FIG. 6(b) is a side view showing the concave vibration generating portion of (a). [Figure 7] FIG. 2 is a front view showing a concave vibration generating portion inclined with respect to the center axis of the bearing ring. [Figure 8] FIG. 10 is a side view showing another concave vibration generating portion. [Figure 9] FIG. 9(a) is a front view showing a concave vibration generating portion formed across the entire width of the raceway surface, and FIG. 9(b) is a side view showing the concave vibration generating portion of (a). [Figure 10] FIG. 2 is a front view showing a concave vibration generating portion inclined with respect to the center axis of the bearing ring. [Figure 11] 11(a) to 11(j) are cross-sectional views showing the shape of the concave vibration generating part. [Figure 12] FIG. 12(a) is a front view showing a concave vibration generating portion formed by an indentation, and FIG. 12(b) is a cross-sectional view showing the concave vibration generating portion of (a). [Figure 13] FIG. 13(a) is a front view of another concave vibration generating portion formed by indentation, and FIG. 13(b) is a cross-sectional view showing the concave vibration generating portion of (a). [Figure 14] FIG. 14(a) is a perspective view of an outer ring of a cylindrical roller bearing in which a concave vibration generating portion is formed on the outer ring raceway surface, and FIG. 14(b) is an enlarged view of a main portion. [Figure 15] FIG. 15(a) is a perspective view of an inner ring of a cylindrical roller bearing in which a concave vibration generating portion is formed on the inner ring raceway surface, and FIG. 15(b) is an enlarged view of a main portion. [Figure 16]FIG. 16(a) is a front view showing a concave vibration generating portion formed on a part of the raceway surface in the axial direction, and FIG. 16(b) is a side view showing the concave vibration generating portion of (a). [Figure 17] 17(a) to 17(c) are side views showing other concave vibration generating portions formed in part of the axial direction of the raceway surface of a cylindrical roller bearing. [Figure 18] FIG. 2 is a front view showing a concave vibration generating portion inclined with respect to the center axis of the bearing ring. [Figure 19] FIG. 19(a) is a front view showing a concave vibration generating portion formed across the entire width of the raceway surface, and FIG. 19(b) is a side view showing the concave vibration generating portion of (a). [Figure 20] Figure 20(a) is a side view showing another concave vibration generating portion formed across the entire width of the raceway surface of a cylindrical roller bearing, and Figure 20(b) is a side view showing yet another concave vibration generating portion. [Figure 21] FIG. 2 is a front view showing a concave vibration generating portion inclined with respect to the center axis of the bearing ring. [Figure 22] 1 is a schematic diagram of a rolling bearing in which a convex vibration generating portion is formed on an outer ring raceway surface. [Figure 23] FIG. 23(a) is a perspective view of an outer ring of a deep groove ball bearing in which a convex vibration generating portion is formed on the outer ring raceway surface, and FIG. 23(b) is an enlarged view of a main portion. [Figure 24] 1 is a schematic diagram of a rolling bearing in which a convex vibration generating portion is formed on an inner ring raceway surface. [Figure 25] FIG. 25(a) is a perspective view of an inner ring of a deep groove ball bearing in which a convex vibration generating portion is formed on the inner ring raceway surface, and FIG. 25(b) is an enlarged view of a main portion. [Figure 26] FIG. 26(a) is a front view showing a convex vibration generating portion formed on a part of the raceway surface in the axial direction, and FIG. 26(b) is a side view showing the convex vibration generating portion of (a). [Figure 27] FIG. 4 is a front view showing a vibration generating portion having a convex shape tilted relative to the center axis of the bearing ring. [Figure 28] FIG. 28(a) is a front view showing a convex vibration generating portion formed across the entire width of the raceway surface, and FIG. 28(b) is a side view showing the convex vibration generating portion of (a). [Figure 29] 29(a) to 29(h) are cross-sectional views showing the shape of the convex vibration generating part. [Figure 30] FIG. 30(a) is a front view showing a convex vibration generating portion formed by indentation, and FIG. 30(b) is a cross-sectional view showing the convex vibration generating portion of (a). [Figure 31] FIG. 31(a) is a front view showing another convex vibration generating part formed by indentation, and FIG. 31(b) is a cross-sectional view showing the convex vibration generating part of (a). [Figure 32] 10A to 10C are cross-sectional views showing an example of a method for forming a convex vibration generating portion. [Figure 33] 10A and 10B are cross-sectional views showing an example of another method for forming a convex vibration generating portion. [Figure 34] FIG. 34(a) is a perspective view of an outer ring of a cylindrical roller bearing in which a convex vibration generating portion is formed on the outer ring raceway surface, and FIG. 34(b) is an enlarged view of a main portion. [Figure 35] FIG. 35(a) is a perspective view of an inner ring of a cylindrical roller bearing in which a convex vibration generating portion is formed on the inner ring raceway surface, and FIG. 35(b) is an enlarged view of a main portion. [Figure 36] FIG. 36(a) is a front view showing a convex vibration generating portion formed on a part of the raceway surface in the axial direction, and FIG. 36(b) is a side view showing the convex vibration generating portion of (a). [Figure 37] FIG. 10 is a front view showing a convex vibration generating portion tilted relative to the center axis of the bearing ring. [Figure 38] FIG. 38(a) is a front view showing a convex vibration generating portion formed across the entire width of the raceway surface, and FIG. 38(b) is a side view showing the convex vibration generating portion of (a). [Figure 39] FIG. 4 is a front view showing a vibration generating portion having a convex shape tilted relative to the center axis of the bearing ring. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a rolling bearing and a revolutionary slip detection method according to the present invention, as well as a condition monitoring device for carrying out the revolutionary slip detection method, will be described. The revolutionary slip of the rolling elements in the rolling bearing can be detected by measuring and analyzing the vibration of the rolling bearing, and in this embodiment, the revolutionary slip is detected using a condition monitoring device 50 described below.

[0013] (Condition monitoring device) 1, the condition monitoring device 50 comprises a vibration sensor 51 that detects vibrations of the rolling bearing 10, a rotation sensor 52 that detects the rotational speed of the rolling bearing 10, an A / D conversion unit 53 that A / D converts the vibration data detected by the vibration sensor 51, a waveform processing unit 54 that performs frequency analysis on the A / D converted vibration data and calculates spectrum data, and a calculation unit 55 that compares the frequency of the spectrum data with the theoretical revolution frequency of the rolling element 40 to detect the presence or absence of revolutionary slippage. The A / D conversion unit 53, waveform processing unit 54 and calculation unit 55 are mainly configured using an information processing device 60 such as a personal computer.

[0014] (Method for detecting revolutionary slippage in rolling bearings) In the method of detecting revolutionary slippage using such a condition monitoring device 50, first, the condition monitoring device 50 is set on the rolling bearing 10 incorporated in a mechanical device, and the rotary shaft 61 of the mechanical device is rotated.

[0015] The vibration sensor 51 detects vibrations, including rolling element passing vibrations, generated by the rolling bearing 10 as electrical signals, and the detected electrical signals are amplified by an amplifier 56 and input to an A / D conversion unit 53. The rotation sensor 52 detects the rotation of the rotating shaft 61, and determines the rotation speed with a tachometer 57, which is input to a calculation unit 55. In FIG. 1, the vibration sensor 51 is attached to a housing (not shown) onto which the outer ring 20 is fitted.

[0016] The vibration data input from the vibration sensor 51 to the A / D conversion unit 53 is converted into a digital signal by the A / D conversion unit 53, and then envelope processing and frequency analysis are performed by the waveform processing unit 54 to calculate spectrum data.

[0017] The calculation unit 55 further calculates the theoretical revolution frequency of the rolling element 40 when there is no revolutionary slip of the rolling element 40, based on the rotation speed of the rotating shaft 61 detected by the rotation sensor 52, and compares this theoretical revolution frequency with the frequency at which the peak of the spectrum data obtained by the waveform processing unit 54 appears, to detect whether or not there is revolutionary slip of the rolling element 40.

[0018] In this embodiment, in order to more accurately detect the presence or absence of orbital slip of the rolling elements, a vibration generating section is provided on the raceway surface of the bearing ring, and the rolling element passing vibration that is generated when the rolling elements pass through the vibration generating section is promoted. Below, a rolling bearing in which a vibration generating section is provided on the raceway surface of the bearing ring will be described in detail with reference to the drawings.

[0019] (First embodiment) In the rolling bearing 10 of the first embodiment, a concave vibration generating portion is provided on the raceway surface of the raceway ring. Specifically, the rolling bearing 10 is a deep groove ball bearing, and as shown in Figures 2 to 5, comprises an outer ring 20 having an outer ring raceway surface 21 on its inner peripheral surface, an inner ring 30 having an inner ring raceway surface 31 on its outer peripheral surface, a plurality of rolling elements 40 arranged so as to be able to roll between the outer ring raceway surface 21 and the inner ring raceway surface 31, and a cage 45 that rotatably holds the plurality of rolling elements 40.

[0020] In this embodiment, at least one of the outer ring raceway surface 21 of the outer ring 20 and the inner ring raceway surface 31 of the inner ring 30 is provided with a concave vibration generating portion 11 . That is, the concave vibration generating portion 11 may be provided on the outer ring raceway surface 21 of the outer ring 20, as shown in Figures 2 and 3, or may be provided on the inner ring raceway surface 31 of the inner ring 30, as shown in Figures 4 and 5. The concave vibration generating portions 11 may be provided on both the outer ring raceway surface 21 and the inner ring raceway surface 31 at the same time, and moreover, a plurality of the concave vibration generating portions 11 may be provided on each of the outer ring raceway surface 21 and the inner ring raceway surface 31. Such a concave vibration generating portion 11 may be formed by any of electric discharge machining, cutting, grinding, and etching.

[0021] Each of the concave vibration generating portions 11 may be a linear groove formed in the axial direction on the outer ring raceway surface 21 or the inner ring raceway surface 31 (hereinafter also referred to as "raceway surface 21, 31"). The linear groove may be formed over part of the axial length of the raceway surface 21, 31, as shown in Figures 6 to 8, or may be formed over the entire axial length of the raceway surface 21, 31, as shown in Figures 9 and 10. Figures 3 and 5 show the outer ring 20 and inner ring 30 in which the vibration generating portion 11 is formed over the entire axial length of the raceway surface 21, 31. Therefore, the axial length L of the concave vibration generating portion 11, including at least the deepest portion, may be 5% or more of the axial length L1 of the raceway surfaces 21, 31.

[0022] Moreover, it is preferable that the circumferential width W of the vibration generating part 11 is 0.05 mm or more in any case. Furthermore, in deep groove ball bearings, vibration generating portion 11 may be formed in an arc shape along raceway surface 21, 31 so that depth d is constant, as shown in Figures 6 and 9, or it may be a recessed groove with a linear bottom along central axis CL of outer ring 20 or inner ring 30, with depth d varying in the axial direction, as shown in Figures 8 and 10. In either case, depth d of vibration generating portion 11 is preferably 1% or less of raceway thickness D. Note that raceway thickness D refers to the thickness of the raceway at the position of the raceway surface where it is at its thinnest.

[0023] In addition, vibration generating part 11 may be formed parallel to the central axis CL of outer ring 20 or inner ring 30, or may be formed inclined circumferentially relative to the central axis CL of outer ring 20 or inner ring 30, as shown in Figures 7 and 10. In either case, the inclination angle θ of vibration generating part 11 relative to the central axis CL of outer ring 20 or inner ring 30 needs to be 1° or less.

[0024] In this way, by specifying the size of the vibration generating section 11, the rolling element passing vibration generated when the rolling element 40 passes through the vibration generating section 11 becomes a vibration of a magnitude that can be reliably measured, and damage to the rolling element 40 can be prevented during normal bearing operation.

[0025] When detecting vibrations of the stationary ring, the vibration generating unit 11 is installed in the load zone phase. The vibration sensor 51 is also installed corresponding to the phase of the vibration generating unit 11, and is preferably installed in the housing of the stationary ring radially opposite the vibration generating unit 11. Furthermore, when detecting vibrations of the rotating wheel, the vibration sensor 51 is preferably installed when the rolling bearing 11 is assembled, and is preferably installed on the rotating shaft 61 that is radially opposite the vibration generating part 11 of the rotating wheel. Furthermore, if the vibration sensor 51 cannot be installed on a housing or rotating shaft 61 that is radially opposite the vibration generating part 11 of the stationary ring or rotating ring, it is preferable to install it on a housing or rotating shaft 61 that is axially opposite the vibration generating part 11 of the stationary ring or rotating ring when the rolling bearing 11 is assembled.

[0026] As described above, according to the rolling bearing 10 and the method for detecting orbital slippage of a rolling bearing of this embodiment, vibrations are generated that are enhanced by the rolling element passing through the vibration generating section 11 provided on the raceway surface, and by measuring these vibrations, orbital slippage of the rolling element 40 can be detected with high accuracy without disassembling the mechanical device in which the rolling bearing 10 is incorporated. Furthermore, by feeding back the detected revolutionary slip state to the machine operation control, it is possible to control the load, rotation speed, and amount of lubricant to maintain the normal operating state of the rolling bearing 10. Specifically, when revolutionary slip occurs, the load can be increased, the rotation speed can be decreased, and the amount of lubricant can be reduced.

[0027] The cross-sectional shape of the vibration generating part 11 can take various shapes as shown in Figures 11(a) to 11(j).Specific examples include the U-shaped groove shown in Figure 11(a), the trapezoidal groove with rounded corners between the vibration generating part 11 and the raceway surfaces 21, 31 shown in Figure 11(b), the U-shaped groove shown in Figure 11(c), the approximately V-shaped groove shown in Figure 11(d), the semicircular groove shown in Figure 11(e), the rectangular U-shaped groove shown in Figure 11(f), the trapezoidal groove shown in Figures 11(g) and (h), the U-shaped groove inclined with respect to the raceway surfaces 21, 31 shown in Figure 11(i), and the dovetail groove shown in Figure 11(j). In particular, by making the corners between the vibration generating part 11 and the raceway surfaces 21, 31 curved as shown in FIG. 11(b), it is possible to prevent the vibration generating part 11 from peeling off when the rolling elements pass over it.

[0028] Furthermore, instead of the linear grooves described in Figures 6 to 11, the concave vibration generating section 11 may be formed by an indentation made by pressing a jig made of a hard material (not shown) against the raceway surfaces 21, 31, as shown in Figures 12 and 13. The shape of the indentation can be any shape by changing the shape of the jig. Figure 12 shows a vibration generating section 11 with a circular indentation made using a jig with a hemispherical tip, while Figure 13 shows a vibration generating section 11 with a roughly diamond-shaped indentation made using a jig with a quadrangular pyramidal tip. In this case as well, the depth d of the vibration generating part 11 is preferably 1% of the bearing ring thickness D or less.

[0029] (Modification of the first embodiment) 14 to 21 show modified examples in which the concave vibration generating portion 11 is applied to a cylindrical roller bearing (NU type). In the modified example, it is also sufficient that a concave vibration generating portion 11 is provided on at least one of the outer ring raceway surface 21 of the outer ring 20 and the inner ring raceway surface 31 of the inner ring 30. Fig. 14 shows a case where a concave vibration generating portion 11 is provided on the outer ring raceway surface 21 of the outer ring 20 which has ribs on both axial ends of the outer ring 20, and Fig. 15 shows a case where a concave vibration generating portion 11 is provided on the inner ring raceway surface 31 of the inner ring 30 which has no ribs. Any of the concave vibration generating portions 11 may be linear grooves formed along the axial direction on the outer ring raceway surface 21 or the inner ring raceway surface 31. The concave vibration generating portions 11 may be formed over part of the axial length of the raceway surfaces 21, 31, as shown in Figures 16 to 18, or may be formed over the entire axial length of the raceway surfaces 21, 31, as shown in Figures 19 to 21.

[0030] The shape of the bottom of the vibration generating unit 11 may be formed as an arc shape with a constant depth d, as shown in Figure 16(b), or as a straight line along the central axis CL of the outer ring 20 or inner ring 30, as shown in Figure 17(a), or as shown in Figures 17(b) and (c), it may be inclined with respect to the central axis CL of the outer ring 20 or inner ring 30, with the depth d varying in the axial direction.

[0031] The axial length L, circumferential width W, depth d, inclination angle θ of the outer ring 20 or inner ring 30 relative to the center axis CL, and cross-sectional shape of the vibration generating part 11 can be set in the same way as the above-mentioned deep groove ball bearing. Also, in the cylindrical roller bearing, the concave vibration generating portion 11 may be formed by an indentation as shown in the above-mentioned FIGS.

[0032] (Second embodiment) Next, in a rolling bearing 10 of a second embodiment, a convex vibration generating portion is provided on the raceway surface of the raceway ring. Specifically, the rolling bearing 10 is a deep groove ball bearing, and as shown in Figures 22 to 25, comprises an outer ring 20 having an outer ring raceway surface 21 on its inner peripheral surface, an inner ring 30 having an inner ring raceway surface 31 on its outer peripheral surface, a plurality of rolling elements 40 arranged so as to be able to roll between the outer ring raceway surface 21 and the inner ring raceway surface 31, and a cage 45 that rotatably holds the plurality of rolling elements 40.

[0033] In this embodiment, at least one of the outer ring raceway surface 21 of the outer ring 20 and the inner ring raceway surface 31 of the inner ring 30 is provided with a convex vibration generating portion 12 . That is, the convex vibration generating portion 12 may be provided on the outer ring raceway surface 21 of the outer ring 20, as shown in Figures 22 and 23, or may be provided on the inner ring raceway surface 31 of the inner ring 30, as shown in Figures 24 and 25. Furthermore, the convex vibration generating portions 12 may be provided on both the outer ring raceway surface 21 and the inner ring raceway surface 31 at the same time, and moreover, a plurality of the vibration generating portions 12 may be provided on each of the outer ring raceway surface 21 and the inner ring raceway surface 31. Such convex vibration generating parts 12 shown in FIGS. 22 to 25 may be formed by any of electric discharge machining, cutting, grinding, and etching.

[0034] Each of the convex vibration generating portions 12 may be a ridge formed along the axial direction on the outer ring raceway surface 21 or the inner ring raceway surface 31. The ridge may be formed over part of the axial length of the raceway surfaces 21, 31, as shown in Figures 26 and 27, or may be formed over the entire axial length of the raceway surfaces 21, 31, as shown in Figure 28. In this case, too, the axial length L of the convex vibration generating portion 12, including at least the deepest part, needs to be 5% or more of the axial length L1 of the raceway surfaces 21, 31.

[0035] Moreover, it is preferable that the circumferential width W of the vibration generating part 12 is 0.05 mm or more in any case. Furthermore, in a deep groove ball bearing, the vibration generating portion 12 is formed in an arc shape along the raceway surfaces 21, 31 so that the height H is constant, as shown in Figures 26 and 28, and it is preferable that the height H is 1% or less of the raceway thickness D.

[0036] Additionally, vibration generating part 12 may be formed parallel to the central axis CL of outer ring 20 or inner ring 30, or may be formed tilted circumferentially with respect to the central axis CL of outer ring 20 or inner ring 30, as shown in Fig. 27. In either case, the tilt angle θ of vibration generating part 12 with respect to the central axis CL of outer ring 20 or inner ring 30 needs to be 1° or less.

[0037] In this case too, by specifying the size of the vibration generating section 12, the rolling element passing vibration generated when the rolling element 40 passes through the vibration generating section 12 becomes a vibration of a magnitude that can be reliably measured, and damage to the rolling element 40 can be prevented during normal bearing operation.

[0038] The cross-sectional shape of the vibration generating section 12 can take various shapes as shown in Figures 29(a) to 29(h).Specific examples include U-shaped ridges shown in Figure 29(a), circumferentially inclined ridges shown in Figure 29(b), trapezoidal ridges shown in Figure 29(c), semicircular ridges shown in Figure 29(d), inverted U-shaped ridges shown in Figure 29(e), inverted V-shaped ridges with rounded tops shown in Figure 29(f), rectangular ridges with rounded leading edges shown in Figure 29(g), and trapezoidal ridges with rounded leading edges shown in Figure 29(h). In particular, by forming the leading edge of the vibration generating part 12 into a curved surface, it is possible to prevent the vibration generating part 11 from peeling off when the rolling element 40 passes by.

[0039] 26 to 29, the convex vibration generating portion 12 may be formed by a protrusion (burr) formed on the outer periphery of a ring-shaped indentation or a rectangular frame-shaped indentation formed when a jig made of a hard material (not shown) is pressed against the track surfaces 21, 31, as shown in FIGS. 30 and 31. Furthermore, as shown in Figure 32, for example, a spherical member 13 can be inserted or hammered into the raceway surfaces 21, 31 to form the vibration generating part 12, or as shown in Figure 33, the vibration generating part 12 can be formed by welding, padding or coating.

[0040] (Modification of the second embodiment) 34 to 39 show modified examples in which a convex vibration generating portion 12 is applied to a cylindrical roller bearing (NU type). In this modified example, too, it is sufficient that convex vibration generating parts 12 are provided on at least one of the outer ring raceway surface 21 of the outer ring 20 and the inner ring raceway surface 31 of the inner ring 30. Figure 34 shows a case where convex vibration generating parts 12 are provided on the outer ring raceway surface 21 of the outer ring 20, which has ribs on both axial ends of the outer ring 20, and Figure 35 shows a case where convex vibration generating parts 12 are provided on the inner ring raceway surface 31 of the inner ring 30, which has no ribs. Any of the convex vibration generating portions 12 may be ridges formed along the axial direction on the outer ring raceway surface 21 or the inner ring raceway surface 31. The convex vibration generating portions 12 may be formed over part of the axial length of the raceway surfaces 21, 31, as shown in Figures 36 and 37, or may be formed over the entire axial length of the raceway surfaces 21, 31, as shown in Figures 38 and 39.

[0041] The axial length L, circumferential width W, height H, inclination angle θ of the outer ring 20 or inner ring 30 relative to the center axis CL, and cross-sectional shape of the vibration generating part 12 can be set in the same way as the above-mentioned deep groove ball bearing. Also, in the cylindrical roller bearing, the convex vibration generating portions 12 may be formed by indentations as shown in the above-mentioned FIGS.

[0042] The present invention is not limited to the above-described embodiment, and modifications and improvements are possible as appropriate. For example, while the above explanation has been given of examples in which the vibration generating portion is formed in a deep groove ball bearing and an NU-type cylindrical roller bearing, the present invention is not limited to these and can be similarly applied to angular contact ball bearings, tapered roller bearings, self-aligning roller bearings, needle roller bearings, and cylindrical roller bearings other than the NU type. Examples of cylindrical roller bearings other than the NU type include the NJ type, which has ribs on both axial sides of the outer ring and one axial side of the inner ring, the NUP type, which uses a rib ring on the inner ring and has ribs on both axial sides of the outer and inner rings, the NH type, which uses an L-shaped rib ring on the inner ring and has ribs on both axial sides of the outer and inner rings, the N type, which has no rib on the outer ring but has ribs on both axial sides of the inner ring, and the NF type, which has a rib on one axial side of the outer ring and ribs on both axial sides of the inner ring.

[0043] Furthermore, in the case of a rolling bearing with two rows of raceway surfaces, by providing a vibration generating unit on the outer ring of one row and on the inner ring of the other row, it is possible to separate the vibration frequencies of each row and simultaneously detect the orbital slip state of both rows. Furthermore, because the rolling element passing vibration frequency of the outer ring is higher than that of the inner ring, when measuring the orbital slip of the outer ring and inner ring simultaneously when the orbital slip is significant, it is desirable to provide multiple vibration generating units on the inner ring. This increases the vibration acceleration output, amplifying the acceleration of higher-order components and enabling highly accurate measurements.

[0044] As described above, the present specification discloses the following: (1) A rolling bearing comprising an outer ring having an outer ring raceway surface on its inner peripheral surface, an inner ring having an inner ring raceway surface on its outer peripheral surface, and a plurality of rolling elements disposed so as to roll freely between the outer ring raceway surface and the inner ring raceway surface, A rolling bearing, wherein at least one of the outer ring raceway surface and the inner ring raceway surface is provided with a concave or convex vibration generating portion that generates vibration in the rolling bearing when the rolling element passes over it. With this configuration, the vibration of the rolling bearing when the rolling element passes through the vibration generating section is enhanced, allowing for accurate measurement, and by analyzing the vibration, the orbital slip of the rolling element can be detected more accurately without disassembling the mechanical device in which the rolling bearing is incorporated.

[0045] (2) The vibration generating portion is formed along the axial direction of the outer ring raceway surface or the inner ring raceway surface. (1) The rolling bearing according to (1). According to this configuration, the revolutionary slip of the rolling element can be detected with higher accuracy by using the vibration generating part, which can be easily processed.

[0046] (3) The vibration generating portion is configured by an indentation or a protrusion formed on the outer periphery of the indentation. (1) The rolling bearing according to (1). According to this configuration, the revolutionary slip of the rolling element can be detected with higher accuracy by using the vibration generating part, which can be easily processed.

[0047] (4) A condition monitoring device for detecting revolutionary slip of the rolling bearing according to any one of (1) to (3), a vibration sensor that detects a signal based on vibration generated from the rolling bearing, including rolling element passing vibration when the rolling element passes through the vibration generating portion; a rotation sensor for detecting a rotation speed of the rolling bearing; a waveform processing unit that performs frequency analysis on the signal detected by the vibration sensor and calculates spectrum data; a calculation unit that detects the presence or absence of orbital slip of the rolling element by comparing a frequency at which a peak appears due to the rolling element passing vibration in the spectrum data with a theoretical revolution frequency due to the revolution of the rolling element when there is no slip of the rolling element; A condition monitoring device comprising: According to this configuration, the revolutionary slip of the rolling elements can be detected with higher accuracy without being affected by the operating state of the rolling bearing.

[0048] (5) A method for detecting revolutionary slip of a rolling bearing using the rolling bearing according to any one of (1) to (3), comprising: a measuring step of measuring a signal based on vibration generated from the rolling bearing, the signal including rolling element passing vibration when the rolling element passes through the vibration generating section; a calculation step of performing frequency analysis on the signal to calculate spectral data; a detection step of detecting the presence or absence of orbital slip of the rolling element by comparing a frequency at which a peak appears due to the rolling element passing vibration in the spectrum data with a theoretical revolution frequency due to the revolution of the rolling element when there is no slip of the rolling element; A method for detecting revolutionary slippage in a rolling bearing, comprising: According to this configuration, the revolutionary slip of the rolling elements can be detected with higher accuracy without being affected by the operating state of the rolling bearing. [Explanation of symbols]

[0049] 10. Rolling bearings 11, 12 Vibration generating unit 20 outer ring 21 Outer ring raceway 30 Inner Circle 31 Inner ring raceway surface 40 rolling elements CL: Center axis of outer or inner ring D Raceway thickness d Depth of vibration generating part H Height of vibration generating part L Axial length of the vibration generating part L1 Axial length of the outer ring raceway and inner ring raceway W Circumferential width of the vibration generating part θ: Inclination angle of the vibration generating part

Claims

1. A rolling bearing comprising an outer ring having an outer ring raceway surface on its inner peripheral surface, an inner ring having an inner ring raceway surface on its outer peripheral surface, and a plurality of rolling elements arranged to roll freely between the outer ring raceway surface and the inner ring raceway surface, A rolling bearing, wherein at least one of the outer ring raceway surface and the inner ring raceway surface is provided with a concave or convex vibration generating portion that generates vibration in the rolling bearing when the rolling element passes over it.

2. the vibration generating portion is formed along the axial direction of the outer ring raceway surface or the inner ring raceway surface, 2. The rolling bearing according to claim 1.

3. The vibration generating portion is configured by an indentation or a protrusion formed on the outer periphery of the indentation.

2. The rolling bearing according to claim 1.

4. A condition monitoring device for detecting revolutionary slip of the rolling bearing according to any one of claims 1 to 3, a vibration sensor that detects a signal based on vibration generated from the rolling bearing, including rolling element passing vibration when the rolling element passes through the vibration generating portion; a rotation sensor for detecting a rotation speed of the rolling bearing; a waveform processing unit that performs frequency analysis on the signal detected by the vibration sensor and calculates spectrum data; a calculation unit that detects the presence or absence of orbital slip of the rolling element by comparing a frequency at which a peak appears due to the rolling element passing vibration in the spectrum data with a theoretical revolution frequency due to the revolution of the rolling element when there is no slip of the rolling element; A condition monitoring device comprising:

5. A method for detecting revolutionary slip of a rolling bearing using the rolling bearing according to any one of claims 1 to 3, comprising: a measuring step of measuring a signal based on vibration generated from the rolling bearing, the signal including rolling element passing vibration when the rolling element passes through the vibration generating section; a calculation step of performing frequency analysis on the signal to calculate spectral data; a detection step of detecting whether or not there is an orbital slip of the rolling element by comparing a frequency at which a peak appears due to the rolling element passing vibration in the spectrum data with a theoretical orbital frequency due to the revolution of the rolling element when there is no slip of the rolling element; A method for detecting revolutionary slippage in a rolling bearing, comprising:

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