Roller bearing rolling element slip monitoring device and monitoring method

Abstract

The application discloses a kind of roller bearing rolling body slip monitoring device and monitoring method, it is related to bearing test technical field, the device includes: support seat;Measured bearing is set on the support seat by bearing seat upper;The relative position of certain rolling body of the measured bearing is embedded radial magnetization magnet, for producing varying magnetic field;Two annular coils, symmetric coaxial setting on the two sides of the measured bearing, for generating induced voltage according to varying magnetic field;Load component, for applying different direction load to measured bearing;Driving assembly, for driving measured bearing rotation.The application adopts non-contact measurement to rolling body state, uses induced electromotive force in annular coil, analyzes the magnetic field difference of the two sides of rolling body, calculates the skew angle of rolling body, can measure the instantaneous speed of the two ends of rolling body respectively, obtains the instantaneous local slip condition of rolling body.

Description

Technical Field

[0001] This invention relates to the field of bearing testing technology, and in particular to a device and method for monitoring slippage of rolling elements in roller bearings. Background Technology

[0002] Slippage refers to the phenomenon where, during the operation of a rolling bearing, there are no pure rolling points between the rolling elements and the contact surfaces, resulting in macroscopic sliding.

[0003] Slippage of rolling elements in rolling bearings is a major cause of premature bearing failure. When slippage occurs, the frictional heat between the rolling elements and the inner and outer raceways increases dramatically, wear between the contact surfaces intensifies, and the lubricating oil temperature rises. This leads to deformation of the inner and outer raceways and changes in internal clearance, potentially causing bearing scratches, high-temperature burns, and white corrosion cracks, significantly reducing the bearing's service life. Bearing slippage occurs in various industries where bearings are used, causing substantial economic losses to companies.

[0004] Existing methods for measuring bearing slippage mostly involve measuring the average speed of the cage and calculating the average slip rate to describe the severity of the slippage. Cage slippage is an average state, reflecting the macroscopic slippage phenomenon of the bearing. However, in actual operation, the rotational angular velocity of the rolling elements fluctuates more significantly, resulting in localized slippage in the bearing. Therefore, it is impossible to accurately predict the localized slippage state of the bearing based solely on cage slippage. Furthermore, during the rotation of a roller bearing, the rolling elements and the inner and outer raceways are in line contact. Uneven contact can lead to inconsistent rotational speeds at the two ends of the rolling elements or rolling element misalignment, resulting in localized slippage along the rolling element axis. Summary of the Invention

[0005] This invention provides a device and method for monitoring the slippage of rolling elements in roller bearings, which solves the problem that existing traditional methods cannot accurately reflect the local slippage of rolling elements.

[0006] This invention provides a rolling element slippage monitoring device for roller bearings, comprising:

[0007] Support base;

[0008] The bearing under test is mounted above the support via a bearing housing; a radially magnetized magnet perpendicular to the magnetization direction is embedded in the relative position of one of the rolling elements of the bearing under test to generate a changing magnetic field.

[0009] Two ring coils are symmetrically and coaxially arranged on both sides of the bearing under test, and are used to generate induced voltage according to the changing magnetic field;

[0010] Loading assembly, used to apply loads in different directions to the bearing under test;

[0011] Drive assembly, used to drive the bearing under test to rotate.

[0012] Preferably, the diameter of the annular coil is equal to the pitch circle diameter of the bearing being tested, and the radial magnet is coaxially arranged with the rolling element.

[0013] Preferably, the load assembly includes:

[0014] A radially loaded bearing, disposed outside one of the annular coils, is used to apply a radial load to the bearing under test;

[0015] An axially loaded bearing, disposed outside another of the aforementioned annular coil, is used to apply an axial load to the bearing under test;

[0016] Two loading devices are fixedly connected at their output ends to the outer rings of the radial loading bearing and the axial loading bearing, respectively.

[0017] Preferably, the drive assembly includes a motor and a spindle. The motor is located on one side of the support base, and its output end is connected to the spindle via a coupling. The spindle is fixedly connected to the inner rings of the bearing under test, the radial load bearing, and the axial load bearing.

[0018] Preferably, the bearing cage under test is provided with a marker, which is a proximity switch marker or a reflective point of a laser velocimeter.

[0019] Preferred options also include:

[0020] Support bearing, the inner ring of which is fixedly connected to the main shaft;

[0021] The outer casing is fitted over the outside of the bearing under test, the two annular coils, the radial load bearing, the axial load bearing, and the support bearing.

[0022] Preferably, the bearing being tested is a cylindrical roller bearing or a tapered roller bearing.

[0023] Preferably, the radially loaded bearing is a double-row cylindrical roller bearing, and the loading device is a motor or hydraulic system.

[0024] A monitoring method for a rolling element monitoring device for roller bearings based on electromagnetic induction, characterized by comprising the following steps:

[0025] The motor drives the rolling elements of the bearing under test to rotate;

[0026] Two radially magnetized magnets rotate, generating a changing magnetic field;

[0027] Two changing magnetic fields generate two induced voltages in two loop coils, respectively;

[0028] Measure the induced voltage of the two loop coils respectively, and calculate the amplitude difference between the two induced voltages;

[0029] The radial skew angle of the rolling element is calculated by the difference in amplitude between the two induced voltages;

[0030] The instantaneous frequency and instantaneous phase angle of the two induced voltages are obtained by time-frequency signal analysis.

[0031] Calculate the instantaneous angular velocities at both ends of the rolling element based on the instantaneous frequencies of the two induced voltages, and calculate the difference between their angular velocities;

[0032] Calculate the instantaneous rotation phase angles at both ends of the rolling element based on the instantaneous phase angles of the two induced voltages, and calculate the rotation phase difference between them;

[0033] Calculate the axial skew angle of the rolling element based on the difference in angular velocity and the phase difference of the rolling element's rotation.

[0034] The local slippage of the rolling elements is monitored based on the radial and axial skew angles of the rolling elements.

[0035] Preferred options also include:

[0036] Measure the induced voltage generated in a certain loop coil;

[0037] The average rotational speed of the cage is obtained by detecting the rotational speed of the marker.

[0038] The instantaneous frequency of the induced voltage is obtained by time-frequency signal analysis.

[0039] Calculate the instantaneous rotational angular velocity of the rolling element based on the instantaneous frequency of the induced voltage;

[0040] The phase angle of the rolling elements is calculated by interpolating the average rotational speed of the cage using the difference method.

[0041] The instantaneous slip rate of the rolling element is calculated based on the instantaneous rotational angular velocity and phase angle of the rolling element, and the cage slip rate is calculated based on the average rotational speed of the cage.

[0042] The slippage of rolling elements is monitored by the instantaneous slippage rate of rolling elements and the slippage rate of cage.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] This invention employs a non-contact measurement method to assess the condition of rolling elements, minimizing the impact on bearing load and operating status. By utilizing the induced electromotive force within the ring coil, the difference in magnetic fields on both sides of the rolling element is analyzed, the skewness of the rolling element is measured, and the skew angle is calculated. This allows for the measurement of the instantaneous velocities at both ends of the rolling element, revealing the instantaneous local slippage of the rolling element. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A schematic diagram illustrating the principle of calculating the slip ratio of rolling elements using existing methods;

[0047] Figure 2 This is a schematic diagram showing how the rotational speed of a rolling element changes with its circumferential position.

[0048] Figure 3 This is a cross-sectional structural schematic diagram of a roller bearing rolling element slippage monitoring device according to the present invention;

[0049] Figure 4 This is a top view schematic diagram of a roller bearing rolling element slippage monitoring device according to the present invention;

[0050] Figure 5 This is a schematic diagram illustrating the principle of measuring the rotational speed of the rolling element according to the present invention.

[0051] Figure 6 A flowchart of a monitoring method for a roller bearing rolling element slippage monitoring device according to the present invention;

[0052] Figure 7 (a) is a schematic diagram of a bearing according to an embodiment of the present invention;

[0053] Figure 7 (b) is a schematic diagram of the axial tilt of the rolling element in an embodiment of the present invention;

[0054] Figure 7 (c) is a schematic diagram of the radial skew of the rolling element in an embodiment of the present invention.

[0055] In the diagram: 1-Motor, 2-Main shaft, 3-Coupling, 4-Support bearing, 5-Radial loading bearing, 6-Annular coil, 7-Radial magnetized magnet, 8-Bearing under test, 9-Axial loading bearing, 10-Support base, 11-Loading device. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Reference Figure 1 Slippage, or macroscopic sliding, occurs when the rolling elements of a rolling bearing slide relative to the inner and outer rings without pure rolling points, and can lead to premature bearing failure. To study the slippage characteristics and underlying causes of bearings, it is necessary to evaluate and measure the severity of the slippage. Currently, the degree of slippage is usually described using the slip ratio, defined as follows: Cage slip ratio S... c The expression is:

[0058]

[0059]

[0060] γ=D / d m

[0061] Where, n c To determine the theoretical rotational speed of the cage without slippage, n′ c To represent the actual rotational speed of the cage, ni is the rotational speed of the inner ring of the bearing, D is the diameter of the rolling element, and dm is the pitch circle diameter of the bearing.

[0062] Rolling element slip rate S R The expression is:

[0063]

[0064]

[0065] Where, n r Let n′ be the theoretical rotational speed of the rolling element under the condition that no slippage occurs. r This represents the actual rotational speed of the rolling element.

[0066] According to the definition of slip ratio, the measurement of bearing slip ratio is transformed into the measurement of the rotational speed of the bearing rolling elements or the cage speed. c To determine the theoretical rotational speed of the cage, n r v is the theoretical rotational speed of the rolling element. i and v o These are the relative sliding speeds between the rolling element and the inner and outer raceways, respectively, and D is the diameter of the rolling element.

[0067] Existing methods for measuring bearing slippage primarily focus on characterizing bearing slippage by measuring the average cage rotational speed and calculating the cage slippage rate. (Refer to...) Figure 2 The slip rate of rolling elements varies significantly across different phases of the circumference. As the load increases upon entering the load-bearing zone, the rotational speed of the rolling element increases, and the relative sliding speed between it and the inner and outer raceways decreases accordingly. Conversely, as it leaves the load-bearing zone, the load decreases, the rotational speed decreases, and the relative sliding speed increases. Therefore, measuring only the cage slip rate cannot accurately reflect the bearing's slippage condition. Furthermore, because the rotational speed of the rolling elements varies over a large range and at a rapid rate, it is necessary to measure the instantaneous rotational speed of the rolling elements to predict their instantaneous slip rate.

[0068] Therefore, refer to Figure 3 and Figure 4 This invention provides a roller bearing rolling element slippage monitoring device, including a support base 10. A bearing 8 to be tested is mounted above the support base 10 via a bearing housing. Radial magnets 7 are embedded in both end faces of the rolling elements of the bearing 8 to generate a changing magnetic field. Markers are provided on the cage of the bearing 8 to measure the average rotational speed of the cage, i.e., the average revolution speed of the rolling elements. Circular coils 6 are symmetrically and coaxially arranged on both sides of the bearing 8. The diameter of the circular coils 6 is approximately equal to the pitch circle diameter of the bearing 8, used to generate an induced voltage. A radial loading bearing 5 is located outside one of the circular coils 6 to apply a radial load to the bearing 8. An axial loading bearing 9 is located outside the other circular coil 6 to apply a radial load to the bearing 8. A drive assembly, a motor 1, is located on one side of the support base 10. Its output end is connected to a main shaft 2 via a coupling 3. The main shaft 2 is fixedly connected to the inner rings of the bearing 8, the radial loading bearing 5, and the axial loading bearing 9. Two loading devices 11 are also provided above the support base 10, and their output ends are fixedly connected to the outer rings of the radial loading bearing 5 and the axial loading bearing 9, respectively.

[0069] In this embodiment, the monitoring device also includes a support bearing 4, the inner ring of which is fixedly connected to the main shaft 2. The tested bearing 8, two annular coils 6, radial loading bearing 5, axial loading bearing 9, and support bearing 4 are all fitted with outer casings.

[0070] In this embodiment, the spindle 2 is a high-rigidity spindle, the bearing under test 8 is a cylindrical roller bearing or a tapered roller bearing, the marker is a proximity switch marker or a reflective point of a laser velocimeter, and the radial loading bearing 5 is a double-row cylindrical roller bearing. The loading device is a motor or hydraulic system.

[0071] By embedding radial magnets on both ends of the rolling elements of a roller bearing, a magnetic field that changes with the rotation of the rolling elements is formed on both sides of the rolling elements. Using a method of symmetrically and coaxially arranging annular coils on both sides of the bearing, the principle of electromagnetic induction is utilized. The instantaneous rotational angular velocity of the rolling elements is indirectly measured by measuring the induced voltage in the induction coils generated by the changing magnetic field produced by the rotation of the rolling elements. Furthermore, the real-time phase and average revolution speed of the rolling elements are measured using cage markings.

[0072] The induced voltage is measured by a signal acquisition card. Based on the measured induced voltage curve, filtering is performed. The instantaneous frequency of the induced voltage is obtained by time-frequency analysis methods such as Hilbert and wavelet transform. Based on the correspondence between the induced voltage frequency and the angular velocity of the rolling element, the instantaneous angular velocity of the rolling element can be calculated.

[0073] By using sensors to measure the passage time of the cage markers and using interpolation to obtain the phase angles corresponding to different rotational speeds of the rolling elements, the slippage rate of the rolling elements at different circumferential positions can be calculated.

[0074] Based on the measured induced voltage curves on both sides, the instantaneous frequency of the induced voltage in the two coils is obtained through time-frequency analysis methods such as Hilbert or wavelet transform. According to the correspondence between the induced voltage frequency and the rotation speed of the rolling element, the instantaneous speed of the rolling element at both ends can be calculated. By comparing the difference in the instantaneous frequency and amplitude of the induced voltage in the two coils at the same moment, it can be determined that the rolling element is tilted, and the tilt angle of the rolling element can be calculated.

[0075] During actual bearing operation, the rolling elements experience varying loads at different phases of the circumference, causing their rotational speed to constantly change, which in turn leads to continuous changes in their slippage. This invention achieves real-time prediction of the slippage rate of the rolling elements in roller bearings by measuring their rotational speed in real time.

[0076] Reference Figures 5-7 This invention provides a monitoring method for a roller bearing rolling element slippage monitoring device, comprising the following steps:

[0077] S1: The rolling elements of the bearing 8 under test are driven to rotate by the motor 1, and the two radially magnetized magnets 7 rotate to generate a changing magnetic field. The two changing magnetic fields generate two induced voltages in the two annular coils 6 respectively.

[0078] S2: Measure the induced voltage of the two loop coils 6 respectively, and calculate the amplitude difference between the two induced voltages.

[0079] S3: Calculate the radial skew angle of the rolling element by the amplitude difference between the two induced voltages.

[0080] S4: Obtain the instantaneous frequency and instantaneous phase of the two induced voltages through time-frequency signal analysis.

[0081] S5: Calculate the instantaneous angular velocities at both ends of the rolling element based on the instantaneous frequencies of the two induced voltages, and calculate the difference between their angular velocities.

[0082] S6: Calculate the instantaneous rotation phase angle at both ends of the rolling element based on the instantaneous phase of the two induced voltages, and calculate the rotation phase difference between them;

[0083] S7: Calculate the axial skew angle of the rolling element based on the difference in angular velocity and the phase difference of the rolling element's rotation.

[0084] S8: Monitor the local slippage of the rolling elements based on the radial and axial skew angles of the rolling elements.

[0085] S9: Measure the induced voltage generated in a certain loop coil 6 and the average rotational speed of the cage;

[0086] S10: Obtain the instantaneous frequency of the induced voltage through time-frequency signal analysis;

[0087] S11: Calculate the instantaneous self-rotation angular velocity of the rolling element based on the instantaneous frequency of the induced voltage;

[0088] S12: The phase angle of the rolling elements is calculated by interpolating the average rotational speed of the cage using the difference method;

[0089] S13: Calculate the instantaneous slip rate of the rolling element based on the instantaneous rotational angular velocity and phase angle of the rolling element, and calculate the cage slip rate based on the average rotational speed of the cage;

[0090] S14: The slippage of the rolling elements is monitored by the instantaneous slippage rate of the rolling elements and the slippage rate of the cage.

[0091] Non-contact measurement of rolling element condition minimizes the impact on bearing load and operating status. Real-time measurement of the rolling element's rotational angular velocity and phase angle reflects information such as the instantaneous rotational angular velocity at different positions within the circumference during operation, providing a more accurate indication of bearing slippage. Instantaneous velocities at both ends of the rolling element can be measured separately to obtain instantaneous local slippage information. The induced electromotive force within the toroidal coil can be used to analyze the magnetic field difference on both sides of the rolling element, measuring the skewness and calculating the skew angle. Real-time prediction of rolling element slippage in roller bearings enables simultaneous measurement of the instantaneous slippage rate of the rolling elements and the average slippage rate of the cage.

[0092] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0093] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A monitoring method of a roller bearing roller slip monitoring device, characterized by, The monitoring device comprises: a support seat (10); a measured bearing (8) arranged above the support seat (10) through a bearing seat; the relative position of a certain rolling element of the measured bearing (8) is embedded with a radial magnetization magnet (7) for generating a changing magnetic field; two annular coils (6) symmetrically and coaxially arranged on both sides of the measured bearing (8) for generating induced voltages according to the changing magnetic field; a load assembly for applying loads in different directions to the measured bearing (8); a driving assembly for driving the measured bearing (8) to rotate; the driving assembly comprises a motor (1) and a main shaft (2); The monitoring method comprises the following steps: the motor (1) drives the rolling element of the measured bearing (8) to rotate; the two radial magnetization magnets (7) rotate to generate changing magnetic fields; the two changing magnetic fields generate two induced voltages in the two annular coils (6) respectively; the induced voltages of the two annular coils (6) are measured respectively, and the amplitude difference of the two induced voltages is calculated; the radial skew angle of the rolling element is calculated through the amplitude difference of the two induced voltages; the instantaneous frequency and the instantaneous phase angle of the two induced voltages are obtained through a time-frequency signal analysis method; the instantaneous angular velocities at both ends of the rolling element are calculated according to the instantaneous frequencies of the two induced voltages, and the angular velocity difference is calculated; the instantaneous rotation phase angles at both ends of the rolling element are calculated according to the instantaneous phase angles of the two induced voltages, and the rotation phase difference is calculated; the axial skew angle of the rolling element is calculated according to the angular velocity difference and the rotation phase difference of the rolling element; the local slip of the rolling element is monitored according to the radial skew angle and the axial skew angle of the rolling element.

2. A method of monitoring a roller bearing rolling element slip monitoring device as claimed in claim 1, characterised in that, The diameter of the annular coil (6) is equal to the pitch circle diameter of the measured bearing (8), and the radial magnetization magnet (7) is coaxially arranged with the rolling element.

3. A method of monitoring a roller bearing roller slip monitoring device as set forth in claim 1, characterized in that, The load assembly comprises: a radial loading bearing (5) arranged outside one of the annular coils (6) for applying a radial load to the measured bearing (8); an axial loading bearing (9) arranged outside the other annular coil (6) for applying an axial load to the measured bearing (8); two loading devices (11), the output ends of which are fixedly connected with the outer rings of the radial loading bearing (5) and the axial loading bearing (9) respectively.

4. A method of monitoring a roller bearing rolling element slip monitoring device as claimed in claim 3, characterised in that, The motor (1) is arranged on one side of the support seat (10), and the output end thereof is connected with the main shaft (2) through a shaft coupling (3), and the main shaft (2) is fixedly connected with the inner rings of the measured bearing (8), the radial loading bearing (5) and the axial loading bearing (9).

5. A method of monitoring a roller bearing rolling element slip monitoring device as set forth in claim 1, characterized in that, A marker is arranged on the cage of the measured bearing (8), and the marker is a marker of a proximity switch or a reflective point of a laser speed measuring instrument.

6. A method of monitoring a roller bearing rolling element slip monitoring device as set forth in claim 4, characterized in that, Further comprising: a support bearing (4) with the inner ring fixedly connected with the main shaft (2); an outer shell arranged outside the measured bearing (8), the two annular coils (6), the radial loading bearing (5), the axial loading bearing (9) and the support bearing (4).

7. A method of monitoring a roller bearing roller slip monitoring device as set forth in claim 1, characterized in that, The measured bearing (8) is a cylindrical roller bearing or a tapered roller bearing.

8. A method of monitoring a roller bearing rolling element slip monitoring device as set forth in claim 4, characterized in that, The radial loading bearing (5) is a double-row cylindrical roller bearing, and the loading device (11) is a motor or a hydraulic device.

9. A method of monitoring a roller bearing rolling element slip monitoring device as set forth in claim 5, characterized in that, Further comprising: Measuring the induced voltage generated in a certain annular coil (6); Obtaining the average rotating speed of the retainer through rotating speed detection of the marker; Obtaining the instantaneous frequency of the induced voltage through time-frequency signal analysis method; Calculating the instantaneous self-rotating angular speed of the rolling body according to the instantaneous frequency of the induced voltage; Calculating the phase angle of the rolling body through interpolation of the average rotating speed of the retainer by difference method; Calculating the instantaneous slip rate of the rolling body according to the instantaneous self-rotating angular speed of the rolling body and the phase angle of the rolling body, and calculating the slip rate of the retainer according to the average rotating speed of the retainer; Monitoring the slip condition of the rolling body through the instantaneous slip rate of the rolling body and the slip rate of the retainer.

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