A single-electrode mode sliding bearing motion state monitoring test device and method

Abstract

This invention provides a single-electrode sliding bearing motion state monitoring test device and method, belonging to the field of bearing monitoring technology. The device includes a support platform, a speed-regulating drive assembly, a rotary transmission assembly, and a bearing state signal acquisition unit. A circumferentially arrayed electrode layer is attached to the outer surface of the test bearing, and a friction layer is prepared on the outer surface of the rotating shaft or the inner surface of the bearing, forming a single-electrode triboelectric nanogenerator sensing structure. Through triboelectric induction, an electrical signal is output to achieve in-situ online monitoring of multiple parameters such as bearing speed, wear, and contact state. An oil hole is provided in the first bearing housing to allow injection of different lubricating media to adapt to various operating conditions. The friction layer is prepared using standardized methods such as spraying, spin coating, or patch application, ensuring uniformity and controllability. This invention possesses advantages such as self-powered operation, no need for external power supply, high sensitivity, accurate fault location, continuous online monitoring, and compatibility with multiple lubrication conditions. It is suitable for sliding bearing performance testing and fault diagnosis, demonstrating significant engineering application value.

Description

Technical Field

[0001] This invention relates to the field of online bearing fault monitoring devices, and in particular to a test device and implementation method for synchronous monitoring of multi-dimensional signals of sliding bearing motion state based on a single-electrode triboelectric nanogenerator. Background Technology

[0002] Bearings, as key components in mechanical systems, play a crucial role in supporting rotation and reducing friction. They are widely used in almost all equipment with moving shafts, and their operational stability, reliability, and service life directly affect the stability and reliability of the equipment. Because bearings operate under conditions of high temperature and high speed for extended periods, they are highly susceptible to wear, fatigue, or fracture, making them one of the most prone to failure components in mechanical equipment. Therefore, monitoring bearing condition, analyzing performance, and analyzing failure mechanisms using bearing condition monitoring and testing devices is of significant practical importance for bearing maintenance and ensuring equipment safety.

[0003] Existing conventional bearing testing equipment generally suffers from the following technical shortcomings: First, most existing methods can only determine whether the bearing is operating normally, but it is difficult to accurately locate the fault location, distinguish the fault type, and assess the severity of the fault; it cannot decouple and identify multiple coupled faults. Second, to monitor the bearing condition, it is generally necessary to rely on external sensors, such as vibration sensors, thermal sensors, and acoustic emission sensors, all of which require an external power supply to achieve sensing capabilities. Third, existing fault detection technologies, such as oil analysis and ultrasonic monitoring, can only diagnose faults in offline or semi-online states, making it difficult to achieve continuous online monitoring. Finally, in many practical scenarios, it is impossible to install enough sensors in ideal locations near the bearing, resulting in the failure to detect signals generated by bearing faults.

[0004] Therefore, in view of the many problems of the existing technology, designing a bearing condition monitoring test device that can accurately identify the fault type, locate the fault location, be self-powered, and achieve continuous online monitoring has become an urgent technical problem to be solved. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of the prior art and provide a single-electrode mode sliding bearing motion state monitoring test device and method. By integrating the friction layer on the shaft segment in contact with the test bearing, when the bearing state changes, the corresponding electrical signal is generated by the coupling effect of triboelectric charging and electrostatic induction. By comparing and analyzing the electrical signal generated by the bearing state under normal working conditions, the bearing working condition can be accurately identified, continuously monitored in real time, and self-powered sensing can be achieved.

[0006] To achieve the above-mentioned technical features, the objective of this invention is as follows: The first aspect of the present invention provides a single-electrode mode sliding bearing motion state monitoring test device, including a support platform, a speed regulation drive assembly, a rotary transmission assembly, and a bearing motion state signal acquisition unit; The support platform is an optical platform used to support the overall testing device; The speed control drive assembly includes a speed control motor and a first bracket, with the speed control motor fixed to the optical platform via the first bracket. The rotary transmission assembly includes a rotary shaft, a first bearing housing, a second bearing housing, and a coupling. A speed-regulating motor is connected to the rotary shaft via the coupling. The first bearing housing and the second bearing housing are respectively located in the middle section and the end of the rotary shaft, and are mounted on the optical platform via height-adjustable first and second pads. The bearing motion state signal acquisition unit is based on a single-electrode triboelectric nanogenerator and includes a test bearing, an electrode layer, a friction layer, and wires.

[0007] Preferably, the first bearing housing is a split sliding bearing housing, and the test bearing is installed inside the first bearing housing; the electrode layer is attached to the outer surface of the test bearing, and the friction layer is prepared on the inner surface of the test bearing or the outer surface of the rotating shaft, the two forming a triboelectric dipole pair.

[0008] Preferably, the electrode layers are arranged in a circumferential array along the circumference of the test bearing, and are composed of several conductive films of the same size. Each electrode layer is connected to a multi-channel signal acquisition device through an independent wire.

[0009] Preferably, the friction layer is a non-conductive polymer layer, and the material includes one or more of polytetrafluoroethylene, polyetheretherketone, and hydrogel; the number and distribution of the friction layer are consistent with those of the electrode layer.

[0010] Preferably, the outer surface of the test bearing is covered with an insulating liner to achieve electrical insulation between the electrode layer and the external environment.

[0011] Preferably, the first bearing housing has an oil hole for injecting water-based lubricant, lubricating oil, or ionic solution to adapt to different lubrication conditions.

[0012] Preferably, another aspect of the present invention provides a method for monitoring the motion state of a sliding bearing in a single-electrode mode, characterized in that it is implemented based on the aforementioned test apparatus and includes the following steps: S1. Device assembly: Install the test bearing into the first bearing seat, attach the electrode layer to the outer circumference of the test bearing, and prepare the friction layer on the surface of the rotating shaft to complete the overall device installation and coaxiality adjustment. S2. Lubrication pretreatment: Inject the preset lubricating medium through the oil hole of the first bearing housing, and run at low speed to fully wet the friction pair; S3. Signal Acquisition: Start the speed-regulating motor to drive the rotating shaft to rotate. The friction layer and the test bearing periodically contact and separate to generate triboelectric signals, which are transmitted to the multi-channel signal acquisition unit through the electrode layer and wires to record voltage, current and waveform characteristics in real time. S4. Status Judgment: The acquired signal is compared with the health status reference signal to extract amplitude, frequency and fluctuation characteristic parameters, so as to realize the identification and judgment of bearing motion status and fault type.

[0013] Preferably, the test also includes an off-center load test step: adjusting the height of the first bearing housing and the first and second pads below the second bearing housing to form a preset height difference to construct an off-center load condition, and collecting and analyzing the triboelectric signals under different off-center load degrees.

[0014] Preferably, the friction layer is prepared by spraying, specifically: S10. Apply adhesive tape to the non-sprayed area of ​​the rotating shaft and prepare a polymer friction layer solution. S20, control the spraying rate to 10 mL / min 60 mL / min, rotating shaft speed 1 rad / s 5rad / s, uniform spraying; S30. After curing at room temperature, remove the tape to obtain a friction layer of uniform thickness.

[0015] Preferably, the friction layer is prepared by spin coating or patch coating. Spin coating involves uniformly coating and curing the material by driving a rotating shaft with a motor. Patch coating involves cutting the pre-made friction layer and attaching it to the surface of the rotating shaft.

[0016] The present invention has the following beneficial effects: 1. This invention adopts a single-electrode triboelectric nanogenerator structure to achieve self-powered sensing, eliminating the need for an external power source and simplifying the system structure.

[0017] 2. This invention can continuously monitor the motion state of sliding bearings online in situ, which facilitates early fault identification and life prediction.

[0018] 3. The circular array arrangement of the electrode layer and multi-channel acquisition in this invention enable precise fault location and distinguish the fault type and severity.

[0019] 4. The bearing housing of this invention is equipped with an oil hole, which can adapt to a variety of lubrication conditions, covering a wide range of conditions and having a broad application scope.

[0020] 5. The friction layer of the present invention can be prepared in a standardized manner by spraying, spin coating, and patching, with uniform thickness, good consistency, and high sensing stability.

[0021] 6. The device of the present invention has a simple structure, is easy to install, does not modify the original structure of the bearing, and has strong versatility and engineering applicability.

[0022] 7. This invention is sensitive to wear, contact condition, rotational speed and lubrication condition, and can achieve simultaneous monitoring of multiple parameters. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is an overall structural diagram of the bearing condition monitoring device according to Embodiment 1 of the present invention.

[0025] Figure 2 for Figure 1 A magnified view of the bearing monitoring signal acquisition unit.

[0026] Figure 3 This is a cross-sectional view of the distributed electrodes on the outer surface of the bearing tested in Embodiment 1 of the present invention.

[0027] Figure 4 These are the test data collected by the signal acquisition unit in Embodiment 1 of the present invention.

[0028] Figure 5 This is a plan view of the distribution of friction layers on the surface of the rotating shaft in Embodiment 1 of the present invention (2, 4, and 6 friction layers).

[0029] Figure 6 This is a cross-sectional view of the distribution of friction layers on the surface of the rotating shaft in Embodiment 1 of the present invention (2, 4, and 6 friction layers).

[0030] In the figure: 1. Optical platform, 2. Speed-regulating motor, 3. First bracket, 4. First bearing seat, 5. Signal acquisition unit, 6. Rotating shaft, 7. Second bearing seat, 8. First pad, 9. Second pad, 10. Coupling, 11. Test bearing, 12. Friction layer, 13. Electrode layer, 14. Wire. Detailed Implementation

[0031] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This example is implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0032] Example 1 See Figure 1-6This embodiment discloses a single-electrode sliding bearing motion state monitoring test device, the overall structure of which is as follows: the speed-regulating motor 2 is fixedly mounted on the optical platform 1 through the first bracket 3, the main shaft of the speed-regulating motor 2 is kept parallel to the optical platform 1, and the speed-regulating motor 2 is connected to the rotating shaft 6 through the coupling 10; the first bearing seat 4 is installed in the middle section of the rotating shaft 6, and the first bearing seat 4 is a split sliding bearing seat; the second bearing seat 7 is installed at the end of the rotating shaft 6; the first bearing seat 4 and the second bearing seat 7 are adjusted in installation height through the first pad 8 and the second pad 9 respectively to ensure that the bearing seat holes of the two are coaxial, and are fixed on the optical platform 1 by bolts.

[0033] This device also includes a bearing motion status signal acquisition unit 5; see [link / reference] Figure 2 The test bearing 11 is installed inside the first bearing housing 4. Four copper foils of the same size are attached to the outer surface of the test bearing 11 in a circumferential array as electrode layers 13. The cross-sectional structure of the electrode layers 13 is as follows: Figure 3 As shown; the electrode layer 13 is led out from the test bearing 11 through the wire 14, and the wire 14 is connected to the multi-channel signal acquisition device; the outer surface of the test bearing 11 is covered with an insulating liner to achieve electrical insulation between the electrode layer 13 and the external environment; the rotating shaft 6 is installed inside the test bearing 11, and the friction layer 12 is fixed to the surface of the rotating shaft 6 and contacts the inner surface of the test bearing 11.

[0034] After the device is assembled, when the bearing is running normally, the friction layer 12 and the inner surface of the test bearing 11 form periodic contact as the rotating shaft 6 rotates. During separation, stable triboelectric charges are generated due to the difference in electronegativity of the materials. Electrode layer 13 acquires electrical signals through electrostatic induction and transmits them to a multi-channel signal acquisition unit via wire 14. When the bearing experiences abnormalities such as wear or poor lubrication, the triboelectric charges and induced signals change, forming distinguishable characteristics from the signals under normal operating conditions. The circumferential array arrangement of electrode layer 13 allows for the simultaneous acquisition of triboelectric signals from different positions of the bearing, enabling fault location.

[0035] Work process: After the device is assembled, a preset amount of lubricating oil is injected through the oil hole of the first bearing seat 4. The speed-regulating motor 2 is started to drive the rotating shaft 6 to rotate at a constant speed for 1 minute, so that the lubricating oil can fully wet the friction pair and complete the lubrication pretreatment. The output parameters of the speed-regulating motor 2 are adjusted to make the test bearing 11 run stably at the set speed. The friction electrical signal is collected in real time by the signal acquisition unit 5. The rotation of the rotating shaft 6 causes the friction layer 12 to periodically contact and separate from the test bearing 11, generating periodic electrical signals. The voltage, current and waveform characteristics are recorded by the multi-channel signal acquisition device. The test data are as follows. Figure 4As shown, the controlled variable method is used to collect bearing health status signals under various operating conditions and establish a health status database; test bearings 11 with different wear levels and different defect types are replaced, and the corresponding fault signals are repeatedly collected; the fault signals are compared with the health reference signals, and the amplitude, frequency, and fluctuation characteristic parameters are extracted to establish the correspondence between bearing status and triboelectric signals, so as to realize the identification and judgment of wear, defects and abnormal operation.

[0036] Example 2 This embodiment provides a test scheme for off-center load conditions based on the test device described in Embodiment 1. After the device is assembled, the height of the first pad 8 and the second pad 9 is adjusted so that the first bearing seat 4 and the second bearing seat 7 are at the same height and coaxial. The level is calibrated using a level. At this time, the rotating shaft 6 is horizontal, and the test bearing 11 is in a state without off-center load. The speed-regulating motor 2 is started to the preset speed, and the off-center load reference voltage, current and waveform characteristics are recorded by the signal acquisition unit 5.

[0037] The height difference between the first bearing housing 4 and the second bearing housing 7 is set according to the test requirements: when upward bias is required, the first pad 8 is raised or the second pad 9 is lowered; when downward bias is required, the first pad 8 is lowered or the second pad 9 is raised. During the adjustment process, the level is monitored in real time. After the preset height difference is reached, the pads are bolted to the bearing housing to ensure the stability of the biased load state. The speed-regulating motor 2 is started to make the rotating shaft 6 rotate at a uniform speed. The friction electrical signal of the test bearing 11 is collected in real time through the signal acquisition unit 5. Multiple height differences are set to simulate different degrees of bias, and the corresponding data are collected and the correlation between the degree of bias and the signal characteristics is analyzed.

[0038] Example 3 This embodiment utilizes the aforementioned testing apparatus to monitor multiple lubrication conditions. The steps are as follows: Lubricating medium, including water-based lubricant, lubricating oil, or ionic solution, is slowly injected into the bearing cavity through the oil hole at the top of the first bearing housing 4 using an oil injection tool. The injection process controls the flow rate to prevent overflow and contamination of components. After injection, the oil hole is sealed with a sealing plug to prevent leakage and impurities from entering. The speed-regulating motor 2 is started and initially runs at low speed for 1-2 minutes to allow the lubricating medium to fully wet the friction pair, then increased to the rated speed. The signal acquisition unit 5 collects and records the triboelectric signals under different lubricating media, compares and analyzes the influence of lubrication status on signal characteristics, and achieves online determination of bearing lubrication status.

[0039] Example 4 This embodiment provides a method for preparing the friction layer 12 in the signal acquisition unit 5, using polyvinyl alcohol, polytetrafluoroethylene, acetic acid, and glutaraldehyde to prepare the friction layer material.

[0040] Polyvinyl alcohol (PVA) and deionized water were mixed at a mass ratio of 15:85 and heated in a water bath at 95°C with stirring until completely dissolved to obtain an aqueous PVA solution. Polytetrafluoroethylene (PTFE) emulsion was mixed with the PVA aqueous solution at a volume ratio of 20:80 and stirred at 60°C for 15 minutes to obtain polyvinyl alcohol. Polytetrafluoroethylene precursor solution: Add 1 mL of acetic acid and 0.5 mL of glutaraldehyde solution to 100 mL of precursor solution, stir at 60 °C for 10 min to obtain the friction layer spraying solution.

[0041] Friction layer 12 was prepared by spraying: adhesive tape was applied to the non-sprayed area of ​​the rotating shaft 6, exposing only the section to be sprayed; the spraying rate was controlled at 10 mL / min–60 mL / min, and the rotation speed of the rotating shaft 6 was controlled at 1 rad / s–5 rad / s, ensuring uniform spraying; after drying and curing at room temperature, the adhesive tape was removed, resulting in a friction layer 12 with uniform thickness, clear boundaries, and strong adhesion. Figure 5 As shown, the distance between adjacent friction layers is d, the circumference of the rotation axis is D, and the width of the friction layer is L; Figure 6 This is a schematic diagram of the cross-sectional distribution of the friction layer.

[0042] The friction layer 12 can also be prepared by spin coating or patch coating: spin coating is performed by driving the rotating shaft 6 to rotate at a constant speed with the speed-regulating motor 2 to uniformly coat and solidify the friction layer solution; patch coating is performed by spreading the friction layer solution in a petri dish, curing it at room temperature to form a film, cutting it to a preset size, and then tightly attaching it to the surface of the rotating shaft 6.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any modifications, equivalent substitutions, improvements, etc., made based on the technical solutions of the present invention should be included within the protection scope of the present invention.

Claims

1. A single-electrode mode sliding bearing motion state monitoring test device, characterized in that, This includes a support platform, a speed control drive assembly, a rotary transmission assembly, and a bearing motion status signal acquisition unit; The support platform is an optical platform (1) used to support the overall test device; The speed control drive assembly includes a speed control motor (2) and a first bracket (3), with the speed control motor (2) fixed to the optical platform (1) via the first bracket (3); The rotary transmission assembly includes a rotary shaft (6), a first bearing housing (4), a second bearing housing (7), and a coupling (10). The speed-regulating motor (2) is connected to the rotary shaft (6) via the coupling (10). The first bearing housing (4) and the second bearing housing (7) are respectively located in the middle section and the end of the rotary shaft (6), and are mounted on the optical platform (1) via a height-adjustable first pad (8) and a second pad (9). The bearing motion state signal acquisition unit is based on a single-electrode triboelectric nanogenerator and includes a test bearing (11), an electrode layer (13), a friction layer (12), and a wire (14).

2. A single-pad mode of a sliding bearing motion state monitoring test device according to claim 1, characterized in that, The first bearing housing (4) is a split sliding bearing housing, and the test bearing (11) is installed inside the first bearing housing (4); the electrode layer (13) is attached to the outer surface of the test bearing (11), and the friction layer (12) is prepared on the inner surface of the test bearing (11) or the outer surface of the rotating shaft (6), and the two form a triboelectric dipole pair.

3. A single-pad mode of a sliding bearing motion state monitoring test device according to claim 2, characterized in that, The electrode layer (13) is arranged in a circular array along the circumference of the test bearing (11), and is composed of several conductive films of the same size. Each electrode layer is connected to the multi-channel signal acquisition device through an independent wire (14).

4. A single-pad mode of a sliding bearing motion state monitoring test device according to claim 2, characterized in that, The friction layer (12) is a non-conductive polymer layer, and the material includes one or more of polytetrafluoroethylene, polyetheretherketone, and hydrogel; the number and distribution of the friction layer (12) are consistent with those of the electrode layer (13).

5. A single-electrode mode of a sliding bearing motion state monitoring test device according to claim 1, characterized by The outer surface of the test bearing (11) is covered with an insulating liner to achieve electrical insulation between the electrode layer (13) and the external environment.

6. A single-electrode mode of a sliding bearing motion state monitoring test device according to claim 1, characterized by The first bearing housing (4) has an oil hole for injecting water-based lubricant, lubricating oil or ionic solution to adapt to different lubrication conditions.

7. A method for monitoring the motion state of a sliding bearing using a single-electrode mode, characterized in that, Based on claim 1 6 The test device implementation of any of the preceding claims, comprising the steps of: S1. Device assembly: The test bearing (11) is installed into the first bearing seat (4), the electrode layer (13) is attached to the outer periphery of the test bearing (11), and the friction layer (12) is prepared on the surface of the rotating shaft (6) to complete the overall device installation and coaxiality adjustment. S2, Lubrication pretreatment: Inject the preset lubricating medium through the oil hole of the first bearing housing (4), and run at low speed to fully wet the friction pair; S3, Signal Acquisition: Start the speed-regulating motor (2) to drive the rotating shaft (6) to rotate. The friction layer (12) and the test bearing (11) periodically contact and separate to generate a triboelectric signal, which is transmitted to the multi-channel signal acquisition unit through the electrode layer (13) and the wire (14) to record the voltage, current and waveform characteristics in real time. S4. Status Judgment: The acquired signal is compared with the health status reference signal to extract amplitude, frequency and fluctuation characteristic parameters, so as to realize the identification and judgment of bearing motion status and fault type.

8. The single-electrode mode sliding bearing motion state monitoring method according to claim 7, characterized in that, It also includes the test steps for off-center load conditions: adjusting the height of the first pad (8) and the second pad (9) under the first bearing housing (4) and the second bearing housing (7) to form a preset height difference to construct an off-center load condition, and collecting and analyzing the triboelectric signals under different off-center load degrees.

9. The single-electrode mode sliding bearing motion state monitoring method according to claim 7, characterized in that, The friction layer (12) is prepared by spraying, specifically as follows: S10. Apply adhesive tape to the non-sprayed area of ​​the rotating shaft (6) and prepare a polymer friction layer solution; S20, control the spraying rate to 10 mL / min 60 mL / min, rotating shaft speed 1 rad / s 5rad / s, uniform spraying; S30. After curing at room temperature, remove the tape to obtain a friction layer of uniform thickness (12).

10. The method for monitoring the motion state of a sliding bearing in single-electrode mode according to claim 7, characterized in that, The friction layer (12) is prepared by spin coating or patch coating. Spin coating is carried out by rotating the shaft at a constant speed by a motor to coat and cure the material. Patch coating is used to cut the pre-made friction layer and attach it to the surface of the rotating shaft (6).

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