A device and method for monitoring the lubrication state of a rolling bearing contact zone

Abstract

The application belongs to the technical field of monitoring equipment, and particularly relates to a rolling bearing contact area lubrication state monitoring device and method. The monitoring device comprises a bearing mounting shaft, an insulation assembly, a conductive assembly, a driving unit and a loading unit. The insulation assembly comprises a shaft sleeve and a base, and the shaft sleeve and the base are made of insulation materials. The shaft sleeve is sleeved on the bearing mounting shaft, the shaft ring of the thrust ball bearing is fixed on the shaft sleeve through a metal bearing washer, and the upper side of the base is fixed with the race of the thrust ball bearing. The conductive assembly comprises a conductive contact and a conductive ball plug, and is used for electrically connecting the thrust ball bearing, the metal bearing washer and an external voltage source to form an electric circuit. The voltage source is used for providing a constant voltage for the thrust ball bearing. The driving unit is used for driving the thrust ball bearing to rotate. The loading unit is used for providing an axial loading force for the thrust ball bearing. The processing unit is used for acquiring the current of the electric circuit in real time, and determining the minimum oil film thickness in the thrust ball bearing through the constant voltage provided by the voltage source, so as to judge the lubrication state of the thrust ball bearing.

Description

Technical Field

[0001] This invention belongs to the field of monitoring equipment technology, specifically relating to a device and method for monitoring the lubrication status of the contact area of ​​a rolling bearing. Background Technology

[0002] The lubrication state of rolling bearings is constantly changing during operation. At present, industrial development takes improving bearing life as an important development means. At the same time, bearing life is also a key and difficult point in current research. Real-time observation of the lubrication state of the bearing contact area is an important means and method to improve bearing life.

[0003] Rolling bearings are primarily thrust ball bearings. A thrust ball bearing includes a shaft ring, a housing ring, and steel balls and a cage positioned between them, with the steel balls and cage being integrally formed. Thrust ball bearings play a crucial role in various mechanical equipment, especially under harsh conditions such as high loads and high speeds. Their lubrication condition is a key factor affecting the performance and service life of thrust ball bearings. If the lubrication condition of the thrust ball bearing can be obtained in a timely manner, then by changing the operating conditions of the thrust ball bearing, such as speed and force, the wear in the bearing contact area can be improved, significantly reducing the equipment failure rate and thus preventing major equipment accidents.

[0004] In analyzing the correlation mechanism between changes in lubrication state and overall electric field of thrust ball bearings caused by component contact in the contact area, and in conducting experimental research on how monitoring changes in bearing lubrication state affects the operating conditions of thrust ball bearings to improve wear conditions, lifespan, and reliability, it was found that changes in the lubrication state of the thrust ball bearing contact area are difficult to capture. Although traditional lubrication monitoring methods, such as optical and acoustic methods, can provide relevant lubrication information to some extent, they often suffer from slow response speeds and low monitoring accuracy, making it difficult to obtain high-precision data. This affects the accurate judgment of whether severe frictional damage has occurred in thrust ball bearings in engineering practice. Therefore, there is an urgent need for a device and method for monitoring the lubrication state of the contact area of ​​rolling bearings. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a device and method for monitoring the lubrication status of the contact area of ​​a rolling bearing, which can accurately obtain the real-time lubrication status of the contact area of ​​a thrust ball bearing, providing an accurate and reliable basis for judging the frictional damage of the thrust ball bearing in engineering practice.

[0006] The technical solution of this invention is:

[0007] A device and method for monitoring the lubrication condition of the contact area of ​​a rolling bearing, used for monitoring the lubrication condition of a thrust ball bearing, the monitoring device comprising:

[0008] Bearing mounting shaft;

[0009] An insulating assembly includes a bushing and a base, both of which are made of insulating material. The bushing is fitted onto the bearing mounting shaft, and the race of the thrust ball bearing is fixed to the bushing by a metal bearing washer. The upper side of the base is fixed to the race of the thrust ball bearing. The bushing and the base are used to provide insulation for the thrust ball bearing.

[0010] The conductive component includes a conductive contact and a conductive ball plug, which are used to electrically connect with the thrust ball bearing, the metal bearing washer and an external voltage source to form an energized circuit, wherein the voltage source is used to provide a constant voltage to the thrust ball bearing;

[0011] A drive unit, the output of which is connected to the bearing mounting shaft, is used to drive the thrust ball bearing to rotate;

[0012] The loading unit, whose output end is connected to the base, is used to provide axial loading force to the thrust ball bearing;

[0013] The processing unit includes a data acquisition module and a processing module. The data acquisition module is used to acquire the current of the energized circuit in real time. The processing module is used to determine the minimum oil film thickness inside the thrust ball bearing by using a constant voltage provided by a voltage source and the real-time acquired current, thereby judging the lubrication status of the thrust ball bearing.

[0014] Preferably, an oil injection unit for providing different lubrication states to the thrust ball bearing is also provided on one side of the thrust ball bearing. The oil injection unit includes an oil reservoir, an oil pump, an oil supply pipe, and oil nozzles. The oil inlet of the oil pump is connected to the oil reservoir, and the oil outlet is connected to one end of the oil supply pipe. Multiple oil nozzles are arranged in a circumferential array on the periphery of the thrust ball bearing. The other end of the oil supply pipe is connected to the multiple oil nozzles through a distributor.

[0015] Preferably, the driving unit includes:

[0016] A drive spindle is coaxial with the bearing mounting shaft, and the drive spindle and the bearing mounting shaft are connected by a stabilizing component;

[0017] A drive motor, the output shaft of which is fixed coaxially with the drive spindle;

[0018] The bearing mounting shaft has its upper end connected to the drive spindle via a stabilizing component, and its lower end fitted and fixed inside the bushing.

[0019] The stabilizing component includes a housing, a spindle, and a single-row angular contact ball bearing. The housing is used to fix it to the frame. The spindle is coaxially arranged with the drive spindle and is inserted through the housing. The upper end of the spindle is fixedly connected to the drive spindle, and the lower end is fixedly connected to the bearing mounting shaft. The upper end of the spindle is connected to the inner wall of the housing through one single-row angular contact ball bearing, and the lower end is connected to the inner wall of the housing through two single-row angular contact ball bearings.

[0020] Preferably, a torque sensor is connected to the drive spindle, and the detection end of the torque sensor is connected to the drive spindle to monitor the magnitude of the torque generated during the operation of the thrust ball bearing.

[0021] Preferably, the loading unit includes:

[0022] A support shaft is parallel to the bearing mounting shaft, and its upper end is fixed to the base.

[0023] A loading spring is fixed at its upper end to the support shaft;

[0024] The lifting plate is fixed to the lower end of the loading spring;

[0025] The lifting assembly, whose output end is connected to the lifting plate, is used to drive the lifting plate to move up and down in the vertical direction to compress the loading spring, so as to apply axial force to the thrust ball bearing.

[0026] Preferably, a weighing sensor is installed between the loading spring and the support shaft to monitor the magnitude of the axial force applied by the loading spring to the thrust ball bearing.

[0027] Preferably, the lifting assembly includes:

[0028] Rotary drive;

[0029] A lead screw is vertically installed, with its upper end inserted through the lifting plate. A lead screw nut is fitted on the lead screw and fixed to the lifting plate. A loading spring is fitted on the upper end of the lead screw and its lower end is fixedly connected to the output shaft of the rotary drive.

[0030] Two optical rods are arranged parallel to and symmetrically on both sides of the lead screw. Support plates are fixedly connected to the upper and lower ends of the optical rods, and the lower support plate is fixedly connected to the housing of the rotary driver. Lifting plates are respectively fitted on the two optical rods, and the lifting plates are slidably connected to the optical rods.

[0031] Preferably, a monitoring method for a rolling bearing contact area lubrication condition monitoring device includes the following steps:

[0032] An axial force is applied to the thrust ball bearing to drive it to rotate;

[0033] When the thrust ball bearing reaches a stable state, a constant voltage is applied to the energized circuit consisting of the thrust ball bearing, conductive ball plug, metal bearing washer, and thrust ball bearing through a voltage source. At the same time, the real-time current in the energized circuit is collected by the acquisition module and transmitted to the processing module. The processing module obtains the peak value of the current change in the received current, and when the peak value of the current change reaches a set proportion, it determines the minimum oil film thickness in the thrust ball bearing by using the obtained peak current and the constant voltage provided by the voltage source, thereby judging the lubrication state of the thrust ball bearing.

[0034] Preferably, the minimum oil film thickness within the thrust ball bearing is determined according to the following formula:

[0035] ,

[0036] in, ,

[0037] In the formula, h Oil film thickness, in μm; U The measured voltage drop in the contact area is expressed in V. U = IR , R The measured contact resistance of the thrust ball bearing contact area is ; I The measured current in the contact area of ​​the thrust ball bearing is expressed in A. R 0 The reference resistor is used; h 0 The characteristic thickness parameter of the contact area of ​​the thrust ball bearing is in μm; k 1 is a correction factor for the surface roughness of the contact area of ​​the thrust ball bearing; k 2 represents the correction factor for the temperature effect on the contact area of ​​the thrust ball bearing; k 3 represents the load effect correction factor for the contact area of ​​the thrust ball bearing; k 4 is the correction factor for the rotational shear in the contact area of ​​the thrust ball bearing; For the surface roughness of the contact area of ​​the thrust ball bearing, This is an empirical coefficient, with a value between 0.5 and 1.0. T This represents the measured temperature of the contact area of ​​the thrust ball bearing. T 0 is the reference temperature of the contact area of ​​the thrust ball bearing. This is the temperature coefficient, with a value ranging from 0.02 to 0.05. This refers to the axial load in the contact area of ​​the thrust ball bearing. This is the reference load for the contact area of ​​the thrust ball bearing; This is the load factor, with a value between 0.1 and 0.3. n The rotational speed of the thrust ball bearing; n0 represents the reference speed of the thrust ball bearing; This is the speed coefficient, with a value between 0.05 and 0.1.

[0038] Compared with the prior art, the rolling bearing contact area lubrication condition monitoring device and method of the present invention has the following advantages:

[0039] This invention employs a drive unit and a loading unit, enabling the seat ring, steel balls, and shaft ring of a thrust ball bearing to contact and then be subjected to a certain axial force through the rotation of the drive spindle. This simulates the working state of the thrust ball bearing. When the thrust ball bearing reaches a stable state, a constant voltage is applied to the energized circuit consisting of the conductive ball plug, metal bearing washer, and conductive contact via a voltage source. Simultaneously, a data acquisition module collects the real-time current in the energized circuit and transmits it to a processing module. The processing module obtains the peak value of the current change from the received current and calculates the minimum oil film thickness within the thrust ball bearing when the peak value reaches a set proportion. This allows for the determination of the lubrication state of the thrust ball bearing, enabling real-time monitoring of the lubrication state changes in the overall contact area of ​​the bearing under actual operating conditions. It also allows for efficient monitoring of the micro-contact area, facilitating the timely detection and handling of bearing lubrication failures and impact wear. This provides an accurate and reliable basis for judging frictional damage to thrust ball bearings in engineering practice. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the bearing connection unit in an embodiment of the present invention;

[0042] Figure 3 This is a partial structural schematic diagram of the bearing connection unit in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the loading unit in an embodiment of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Drive motor; 2. Drive spindle; 3. Torque sensor; 4. Housing; 5. Bearing mounting shaft; 6. Support shaft; 7. Loading spring; 8. Lifting plate; 9. Guide bar; 10. Support plate; 11. Rotary actuator; 12. Single-row angular contact ball bearing; 13. Bushing; 14. Thrust ball bearing; 15. Base; 16. Conductive contact; 17. Metal bearing washer; 18. Conductive ball plug; 19. Mounting seat; 20. Weighing sensor; 21. Lead screw; 22. Bearing housing; 23. Oil injector; 24. Bearing cavity. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0048] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0049] See Figures 1 to 4 As shown, in order to accurately obtain the real-time lubrication status of the contact area of ​​the thrust ball bearing 14 and provide an accurate and reliable basis for judging the frictional damage of the thrust ball bearing 14 in engineering practice, this embodiment provides a rolling bearing contact area lubrication status monitoring device and method for monitoring the lubrication status of the thrust ball bearing 14. The monitoring device includes a frame, a bearing mounting shaft 5, an insulation component, a conductive component, a drive unit, a loading unit, and a processing unit.

[0050] The thrust ball bearing 14 consists of a shaft ring, a housing ring, steel balls, and a cage for positioning the steel ball assembly. The steel ball assembly and the cage are integrally formed, while the shaft ring and housing ring are located on the upper and lower sides of the steel ball assembly and are designed separately.

[0051] The insulating assembly includes a bushing 13 and a base 15, both made of insulating material. The bushing 13 is fitted onto the bearing mounting shaft 5. The bearing race of the thrust ball bearing 14 is fixed to the bearing mounting shaft 5 via a metal bearing washer 17. During installation, the metal bearing washer 17 is insulated from the bearing mounting shaft 5. The upper side of the base 15 is fixed to the bearing race of the thrust ball bearing 14, and the lower side is fixed to the bearing housing 22. The bearing housing 22 is mounted on the bearing cavity 24, and a mounting seat 19 is provided inside the bearing housing 22, which is fixed to the bearing cavity 24. Thus, the bushing 13 and base 15 achieve insulation isolation of the thrust ball bearing 14, reducing the influence of external conductive metal components on the monitoring data during the monitoring process.

[0052] The conductive component includes a conductive contact 16 and a conductive ball plug 18. The conductive contact 16 is disposed on the outside of the thrust ball bearing 14, and the conductive ball plug 18 is connected to the lower side of the base 15. The conductive contact 16, the conductive ball plug 18, the thrust ball bearing 14, the metal bearing washer 17 are electrically connected to an external voltage source to form a power circuit. The voltage source can provide a constant voltage to the thrust ball bearing 14 during the monitoring process.

[0053] The drive unit is mounted on the frame and mainly includes a drive motor 1, a drive spindle 2, and a stabilizing assembly. The drive motor 1 is fixed to the frame and located at the top of the frame. The output shaft of the drive motor 1 is coaxially fixed to the vertically arranged drive spindle 2, and the lower end of the drive spindle 2 is fixed to the bearing mounting shaft 5 through the stabilizing assembly. The bearing mounting shaft 5 is also coaxially arranged with the drive spindle 2, and its lower end is fitted and fixed inside a bushing 13. The stabilizing assembly consists of a housing 4, a spindle, and single-row angular contact ball bearings 12. Specifically, the housing 4 is fixed to the frame, the spindle is coaxially arranged with the drive spindle 2 and inserted through the housing 4, the upper end of the spindle is fixedly connected to the drive spindle 2, and the lower end is fixedly connected to the bearing mounting shaft 5. The upper end of the spindle is connected to the inner wall of the housing 4 through a single-row angular contact ball bearing 12, and the lower end is connected to the inner wall of the housing 4 through two single-row angular contact ball bearings 12. Thus, the stabilizing assembly can effectively suppress the shaking of the drive spindle 2 and the bearing mounting shaft 5 during transmission. In use, the drive spindle 2 and the bearing mounting shaft 5 are connected by a stabilizing component to form an integrated design. The drive motor 1 provides power to the drive spindle 2 and the bearing mounting shaft 5, enabling the drive spindle 2 and the bearing mounting shaft 5 to rotate as a whole.

[0054] The loading unit is located at the bottom of the frame, and its output end is fixedly connected to the bearing cavity 24. It is used to drive the bearing cavity 24 to move the base 15 up and down in the vertical direction, so as to realize the contact and separation between the seat ring, shaft ring and steel ball of the thrust ball bearing 14.

[0055] See Figure 1 As shown, a torque sensor 3 is installed between the drive spindle 2 and the frame. The detection end of the torque sensor 3 is connected to the drive spindle 2 and is used to monitor the magnitude of the torque generated during the operation of the thrust ball bearing 14.

[0056] See Figure 1As shown, the oil injection unit includes an oil reservoir, an oil pump, an oil supply pipe, and oil injectors 23. The oil pump inlet is connected to the oil reservoir, and the oil outlet is connected to one end of the oil supply pipe. Multiple oil injectors 23 are arranged in a circumferential array around the thrust ball bearing 14. The other end of the oil supply pipe is connected to the multiple oil injectors 23 via a distributor. The end of the oil supply pipe closest to the oil injectors 23 is fixed to the frame to maintain the stable position of the oil injectors 23. To ensure uniform oil injection, it is advisable to arrange three oil injectors 23 in a circumferential array around the thrust ball bearing 14 to facilitate improvement of lubrication conditions and provide guidance for subsequent production applications.

[0057] See Figure 1 As shown, to better simulate the actual working conditions of the thrust ball bearing 14 and provide reliable reference value for monitoring the lubrication status of the contact area, the loading unit includes a support shaft 6, a loading spring 7, a lifting plate 8, and a lifting assembly. The lifting assembly consists of a rotary actuator 11, a lead screw 21, and two guide rods 9. The support shaft 6 is parallel to the bearing mounting shaft 5, and its upper end is fixed to the bearing cavity 24. The upper end of the loading spring 7 is fixed to the support shaft 6, and its lower end is fixed to the lifting plate 8. The lead screw 21 is vertically arranged, with its upper end inserted through the lifting plate 8 and its lower end fixed to the output shaft of the rotary actuator 11, which is a servo motor. A lead screw 21 nut is fitted onto the lead screw 21, and the lead screw 21 nut is fixed to the lifting plate 8. The loading spring 7 is fitted onto the upper end of the lead screw 21. Two guide rods 9 are arranged parallel and symmetrically on both sides of the lead screw 21. Support plates 10 are fixedly connected to the upper and lower ends of the guide rods 9, and the lower support plate 10 is fixedly connected to the housing and frame of the rotary drive 11. Lifting plates 8 are respectively fitted onto the two guide rods 9, and the lifting plates 8 are slidably connected to the guide rods 9. Thus, during use, the lifting components drive the lifting plates 8 to move up and down in the vertical direction to compress the loading spring 7, thereby achieving contact between the thrust ball bearing 14 seat ring, shaft ring, and steel ball assembly.

[0058] See Figure 1 As shown, a load cell 20, specifically a spoke-type load cell 20, is installed between the loading spring 7 and the support shaft 6. This load cell 20 is used to monitor the magnitude of the axial force applied by the loading spring 7 to the thrust ball bearing 14.

[0059] The method for monitoring the lubrication status of the contact area of ​​a rolling bearing, as described above, includes the following steps:

[0060] First, lubricating oil is supplied to the lubrication zone of the thrust ball bearing 14 through the oil injection unit according to experimental requirements, thereby simulating the initial lubrication state of the thrust ball bearing 14. In practice, the oil injection unit can be used to simulate various lubrication states of the thrust ball bearing 14 according to different experimental requirements.

[0061] Furthermore, the loading unit pushes the bearing cavity 24 to move the base 15 upward in the vertical direction, so that the seat ring, steel ball and shaft ring of the thrust ball bearing 14 come into contact in sequence, and provides axial force loading to the thrust ball bearing 14 under the drive of the drive spindle 2.

[0062] Start the drive unit to rotate the drive spindle 2, which in turn drives the thrust ball bearing 14 to rotate at a certain speed.

[0063] When the thrust ball bearing 14 reaches a stable state, a constant voltage is applied to the energized circuit consisting of the conductive ball plug 18, the metal bearing washer 17, and the conductive contact 16 through a voltage source. At the same time, the real-time current in the energized circuit is collected by the acquisition module and transmitted to the processing module. The processing module obtains the peak value of the current change from the received current, and when the peak value of the current change reaches a set proportion, it calculates the minimum oil film thickness in the thrust ball bearing 14 based on the acquired peak value, thereby determining the lubrication state of the thrust ball bearing 14.

[0064] Specifically, the minimum oil film thickness inside the thrust ball bearing 14 is determined according to the following formula:

[0065] ,

[0066] in R To measure the contact resistance, R 0 is the reference resistance (related to contact material and surface treatment). h The thickness of the oil film is (μm). h 0 represents the characteristic thickness parameter (μm) (related to lubricant viscosity and surface roughness).

[0067] Rearrange the above formula and apply Ohm's law U = IR After replacing the resistor, you can get

[0068]

[0069] in U This represents the measured voltage drop (V) in the contact area. I The measured current (A) in the contact area.

[0070] Since some experimental conditions during the experiment can affect the results, the following correction coefficient is added to the above formula:

[0071]

[0072] Since the microscopic protrusions on the surface can pierce the oil film, leading to an increase in the actual contact area and a decrease in resistance, a surface roughness correction factor is added. k1. Since increased oil temperature leads to decreased lubricating oil viscosity, a thinner oil film, and reduced resistance, a temperature-related correction factor is added. k 2. Since axial loads alter the pressure distribution in the contact area, thus affecting the oil film extrusion thickness, a load effect correction factor is added. k 3. Since increasing the rotational speed enhances the hydrodynamic effect of the lubricating oil, leading to increased oil film thickness and resistance, a rotational speed shear correction factor is added. k 4.

[0073] After introducing a correction factor, the formula for calculating oil film thickness is revised as follows:

[0074]

[0075] In the formula, h Oil film thickness, in μm; U The measured voltage drop in the contact area is expressed in V. U = IR , R The measured contact resistance of the thrust ball bearing contact area is ; I The measured current in the contact area of ​​the thrust ball bearing is expressed in A. R 0 The reference resistor is used; h 0 The characteristic thickness parameter of the contact area of ​​the thrust ball bearing is in μm; k 1 is a correction factor for the surface roughness of the contact area of ​​the thrust ball bearing; k 2 represents the correction factor for the temperature effect on the contact area of ​​the thrust ball bearing; k 3 represents the load effect correction factor for the contact area of ​​the thrust ball bearing; k 4 is the correction factor for the rotational shear in the contact area of ​​the thrust ball bearing; For the surface roughness of the contact area of ​​the thrust ball bearing, This is an empirical coefficient, with a value between 0.5 and 1.0. T This represents the measured temperature of the contact area of ​​the thrust ball bearing. T 0 is the reference temperature of the contact area of ​​the thrust ball bearing. This is the temperature coefficient, with a value ranging from 0.02 to 0.05. This refers to the axial load in the contact area of ​​the thrust ball bearing. This is the reference load for the contact area of ​​the thrust ball bearing; This is the load factor, with a value between 0.1 and 0.3. n The rotational speed of the thrust ball bearing; n 0 represents the reference speed of the thrust ball bearing; This is the speed coefficient, with a value between 0.05 and 0.1.

[0076] Therefore, the above methods can be used to monitor the changes in the lubrication status of the overall contact area of ​​the bearing in real time under actual working conditions, and can achieve efficient monitoring of the micro-contact area. This is conducive to timely detection and handling of bearing lubrication failure and collision wear, and provides accurate and reliable judgment basis for the friction damage of the thrust ball bearing 14 in engineering practice.

[0077] 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 rolling bearing contact zone lubrication state monitoring device for monitoring the lubrication state of a thrust ball bearing (14), characterized in that The monitoring device includes: Bearing mounting shaft (5); An insulating assembly includes a bushing (13) and a base (15), both of which are made of insulating material. The bushing (13) is fitted onto the bearing mounting shaft (5). The ring of the thrust ball bearing (14) is fixed onto the bushing (13) by a metal bearing washer (17). The upper side of the base (15) is fixed to the seat ring of the thrust ball bearing (14). The bushing (13) and the base (15) are used to achieve insulation and isolation of the thrust ball bearing (14). The conductive component includes a conductive contact (16) and a conductive ball plug (18) for electrically connecting with the thrust ball bearing (14), the metal bearing washer (17) and an external voltage source to form an energized circuit, wherein the voltage source is used to provide a constant voltage to the thrust ball bearing (14); The drive unit, whose output end is connected to the bearing mounting shaft (5), is used to drive the thrust ball bearing (14) to rotate; The loading unit, whose output end is connected to the base (15), is used to provide axial loading force to the thrust ball bearing (14); The processing unit includes a data acquisition module and a processing module. The data acquisition module is used to acquire the current of the energized circuit in real time. The processing module acquires the peak value of the current change in the received current and determines the minimum oil film thickness in the thrust ball bearing (14) by acquiring the peak value of the current change and the constant voltage provided by the voltage source when the peak value of the current change reaches a set ratio, thereby judging the lubrication state of the thrust ball bearing (14). The minimum oil film thickness within the thrust ball bearing (14) is determined according to the following formula: ， in, , In the formula, h Oil film thickness, in μm; U The measured voltage drop in the contact area is expressed in V. U = IR , R This represents the measured contact resistance of the contact area of ​​the thrust ball bearing. ; I The measured current in the contact area of ​​the thrust ball bearing is expressed in A. R 0 As a reference resistor, ; h 0 The characteristic thickness parameter of the contact area of ​​the thrust ball bearing is in μm; k 1 is a correction factor for the surface roughness of the contact area of ​​the thrust ball bearing; k 2 represents the correction factor for the temperature effect on the contact area of ​​the thrust ball bearing; k 3 represents the load effect correction factor for the contact area of ​​the thrust ball bearing; k 4 is the correction factor for the rotational shear in the contact area of ​​the thrust ball bearing; For the surface roughness of the contact area of ​​the thrust ball bearing, This is an empirical coefficient, with a value between 0.5 and 1.

0. T This represents the measured temperature of the contact area of ​​the thrust ball bearing. T 0 is the reference temperature of the contact area of ​​the thrust ball bearing. This is the temperature coefficient, with a value ranging from 0.02 to 0.

05. This refers to the axial load in the contact area of ​​the thrust ball bearing. This is the reference load for the contact area of ​​the thrust ball bearing; This is the load factor, with a value between 0.1 and 0.

3. n The rotational speed of the thrust ball bearing; n 0 represents the reference speed of the thrust ball bearing; This is the speed coefficient, with a value between 0.05 and 0.

1.

2. The rolling bearing contact area lubrication condition monitoring device according to claim 1, characterized in that, The thrust ball bearing (14) is also provided with an oil injection unit for providing different lubrication states to the thrust ball bearing (14). The oil injection unit includes an oil reservoir, an oil pump, an oil supply pipe and an oil nozzle (23). The oil inlet of the oil pump is connected to the oil reservoir, and the oil outlet is connected to one end of the oil supply pipe. There are multiple oil nozzles (23). The multiple oil nozzles (23) are arranged in a circumferential array on the periphery of the thrust ball bearing (14). The other end of the oil supply pipe is connected to the multiple oil nozzles (23) through a distributor.

3. The rolling bearing contact area lubrication condition monitoring device according to claim 1, characterized in that, The driving unit includes: The drive spindle (2) is coaxial with the bearing mounting shaft (5), and the drive spindle (2) and the bearing mounting shaft (5) are connected by a stabilizing component; The drive motor (1) has its output shaft fixed coaxially with the drive spindle (2); The stabilizing component includes a housing (4), a spindle, and a single-row angular contact ball bearing (12). The housing (4) is used to fix it on the frame. The spindle is coaxially arranged with the drive spindle (2) and inserted through the housing (4). The upper end of the spindle is fixedly connected to the drive spindle (2), and the lower end is fixedly connected to the bearing mounting shaft (5). The upper end of the spindle is connected to the inner wall of the housing (4) through one single-row angular contact ball bearing (12), and the lower end is connected to the inner wall of the housing (4) through two single-row angular contact ball bearings (12).

4. The rolling bearing contact area lubrication condition monitoring device according to claim 3, characterized in that, The drive spindle (2) is connected to a torque sensor (3), the detection end of which is connected to the drive spindle (2) to monitor the magnitude of the torque generated during the operation of the thrust ball bearing (14).

5. The rolling bearing contact area lubrication condition monitoring device according to claim 3, characterized in that, The loading unit includes: The support shaft (6) is parallel to the bearing mounting shaft (5), and its upper end is fixed to the base (15); A loading spring (7) is fixed at its upper end to the support shaft (6); The lifting plate (8) is fixed to the lower end of the loading spring (7); The lifting assembly, whose output end is connected to the lifting plate (8), is used to drive the lifting plate (8) to move up and down in the vertical direction to compress the loading spring (7) so as to apply axial force to the thrust ball bearing (14).

6. The rolling bearing contact area lubrication condition monitoring device according to claim 5, characterized in that, A weighing sensor (20) is installed between the loading spring (7) and the support shaft (6) to monitor the magnitude of the axial force applied by the loading spring (7) to the thrust ball bearing (14).

7. The rolling bearing contact area lubrication condition monitoring device according to claim 5, characterized in that, The lifting assembly includes: Rotary driver (11); The lead screw (21) is vertically set, with its upper end inserted through the lifting plate (8), and a lead screw nut is fitted on the lead screw (21). The lead screw nut is fixed to the lifting plate (8). The loading spring (7) is fitted on the upper end of the lead screw (21), and its lower end is fixedly connected to the output shaft of the rotary driver (11). Two optical rods (9) are arranged parallel and symmetrically on both sides of the lead screw (21). Support plates (10) are fixedly connected to the upper and lower ends of the optical rods (9), and the lower support plate (10) is fixedly connected to the outer shell of the rotary driver (11). The lifting plates (8) are respectively fitted on the two optical rods (9), and the lifting plates (8) are slidably connected to the optical rods (9).

8. A monitoring method for a rolling bearing contact area lubrication condition monitoring device according to any one of claims 1-7, characterized in that, Includes the following steps: An axial force is applied to the thrust ball bearing (14) to drive the thrust ball bearing (14) to rotate; When the thrust ball bearing (14) moves to a stable state, a constant voltage is applied to the energized circuit consisting of the thrust ball bearing (14), conductive contact (16), metal bearing washer (17) and conductive ball plug (18) through a voltage source. At the same time, the real-time current in the energized circuit is collected by the acquisition module and transmitted to the processing module. The processing module obtains the peak value of the current change in the received current, and when the peak value of the current change reaches a set ratio, it determines the minimum oil film thickness in the thrust ball bearing (14) by the obtained peak value of the current and the constant voltage provided by the voltage source, thereby judging the lubrication state of the thrust ball bearing (14).

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