Monitoring device, monitoring system and monitoring method for motion state of rolling bearing

Abstract

The invention relates to the technical field of sensors, in particular to a monitoring device, a monitoring system and a monitoring method for the motion state of a rolling bearing. The rolling bearing comprises a fixed ferrule, a rotating ferrule and a plurality of rolling bodies arranged between the fixed ferrule and the rotating ferrule, the monitoring device comprises at least one triboelectric sensor, the triboelectric sensor comprises a dielectric film and a stator circuit board, the dielectric film is arranged on the end face of one end of the at least one rolling body in the axial direction of the rolling bodies, and the stator circuit board is arranged on the end face of the other end of the at least one rolling body. The stator circuit board is arranged on the surface, facing the dielectric film, of the fixed ferrule, and an electrode pair is arranged on the stator circuit board; when the rolling body rotates, the dielectric film and the electrode pair generate electrostatic induction so as to generate an electric signal used for monitoring the motion state of the rolling bearing. The monitoring device can more accurately reflect whether the rolling body slips or not and the slipping degree, and the monitoring device can embed the friction electric sensor into the rolling bearing on the premise that the size of the bearing is not increased, so that the real-time monitoring of the rotating speed of the rolling body is realized.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a monitoring device, a monitoring system and a monitoring method for the motion state of a rolling bearing. Background Art

[0002] As a core component of mechanical equipment, rolling bearings are widely used in mechanical systems such as servo motors, high-speed railways, wind turbines and aircraft engines. According to statistics, rolling bearing failures account for about 44% of the total failures of mechanical equipment. Especially under high-speed operation, the dynamic performance of rolling bearings is directly related to the reliability of the equipment.

[0003] During the operation of rolling bearings, rolling element slippage and cage wear may occur. These problems will lead to the accumulation of friction heat, which will cause damage to the rolling bearings such as microcracks and fatigue spalling. Among these fault signs, slippage is one of the important indicators for evaluating the health of bearings. Real-time monitoring of the rolling element speed of the bearing and monitoring whether it slips is essential to ensure the normal operation of mechanical equipment.

[0004] However, existing monitoring technologies, such as eddy current sensing and weak magnetic detection, have problems such as limited installation and insufficient accuracy, which makes it difficult for them to achieve multi-parameter in-situ monitoring. In addition, existing monitoring systems usually monitor the rotation speed of the cage of the rolling bearing because the rotation speed of the cage is relatively easy to measure. However, the rotation speed of the cage does not always accurately reflect the actual rotation speed of the rolling element. If the bearing slips, the actual rotation speed of the rolling element will be different from the rotation speed of the cage. In this case, simply monitoring the rotation speed of the cage may not accurately determine whether the rolling element is slipping and the degree of slippage. Because bearing slippage occurs between the rolling element and the bearing ring, not between the cage and the bearing ring, monitoring the rotation speed of the cage is only an indirect measurement of the slip rate, while monitoring the rotation speed of the rolling element can more accurately reflect whether the bearing is slipping and the degree of slippage. Summary of the invention

[0005] The present application discloses a monitoring device, a monitoring system and a monitoring method for the motion state of a rolling bearing, so as to solve the problems of the existing detection system in that the installation is limited, the accuracy is insufficient or the actual rotation speed of the rolling body cannot be accurately reflected.

[0006] In order to achieve the above objectives, this application provides the following technical solutions: In a first aspect, the present application provides a monitoring device for the motion state of a rolling bearing, wherein the rolling bearing comprises a fixed ring, a rotating ring, and a plurality of rolling bodies arranged between the fixed ring and the rotating ring, and the monitoring device comprises at least one triboelectric sensor, wherein the triboelectric sensor comprises a dielectric film and a stator circuit board, wherein the dielectric film is arranged on an end surface of one end of at least one rolling body along the axial direction of the rolling body, the stator circuit board is arranged on a surface of the fixed ring facing the dielectric film, and an electrode pair is arranged on the stator circuit; wherein, when the rolling body rotates, the dielectric film and the electrode pair generate electrostatic induction to generate an electrical signal for monitoring the motion state of the rolling bearing.

[0007] Among them, when the rolling bearing is working, the rolling body will roll on the raceway between the fixed ring and the rotating ring, generating rolling friction. In the above process, each time the rotating ring rotates, the dielectric film and the electrode pair on the stator circuit board will generate at least one electrostatic induction and generate an electrical signal. Because the dielectric film is arranged on the end face of the rolling body, the above electrical signal can be directly processed to obtain the rotation speed of the rolling body, and the slip rate of the rolling bearing can be obtained based on the above rotation speed. Compared with the existing method of obtaining the slip rate of the rolling bearing by monitoring the rotation speed of the retaining frame, the monitoring device in the present application can more accurately reflect whether the rolling body is slipping and the degree of slipping. In addition, the monitoring device has a compact structure, and the triboelectric sensor can be embedded in the interior of the rolling bearing without increasing the size of the bearing, so as to realize the real-time monitoring of the rolling body rotation speed and slip state of the rolling bearing.

[0008] Furthermore, the dielectric film is made of at least one material selected from perfluoroethylene propylene, polytetrafluoroethylene, and polyvinyl chloride.

[0009] Furthermore, the rolling bearing also includes a retaining frame of an annular structure, and the retaining frame is provided with a plurality of mounting grooves along the circumference of the retaining frame, and the mounting grooves are used to install the rolling elements; the dielectric film has a hollow area, and the hollow area at least partially overlaps with the projection of the retaining frame along the axial direction of the rolling elements.

[0010] Furthermore, the multiple rolling bodies include a first type of rolling body and a second type of rolling body, and the monitoring device includes a first sensor and a second sensor; wherein the first sensor includes a first dielectric film, which is arranged on the axial end surface of the first type of rolling body, so that the first sensor monitors the motion state of the first type of rolling body; the second sensor includes a second dielectric film, which is arranged on the axial end surface of the second type of rolling body, so that the second sensor monitors the motion state of the second type of rolling body.

[0011] Furthermore, along the circumferential direction of the rolling bearing, a second type rolling element is provided between any two adjacent first type rolling elements.

[0012] Further, the edge of the first dielectric film has a first notch, and the edge of the second dielectric film has a second notch.

[0013] Furthermore, the stator circuit board is an annular plate, and along the axial direction of the rolling bearing, the annular plate includes a first surface and a second surface arranged opposite to each other, the first surface is provided with an electrode pair, the electrode pair includes a first electrode and a second electrode; the second surface is provided with a first welding pad and a second welding pad for connecting the wire, the first electrode and the first welding pad are electrically connected, and the second electrode and the second welding pad are electrically connected.

[0014] Furthermore, along the axial direction of the rolling bearing, an annular rib is provided at the end of the fixed ring, a surface of the annular rib facing the dielectric film is provided with a groove, and the stator circuit board is installed in the groove; and / or, along the circumference of the annular plate, adjacent first electrodes and second electrodes are spaced apart.

[0015] In a second aspect, the present application provides a system for monitoring the motion state of a rolling bearing, the monitoring system comprising the monitoring device of the first aspect, and a signal acquisition device and a signal processing device, the signal acquisition device being connected to the triboelectric sensor signal for collecting electrical signals; the signal processing device being connected to the signal acquisition device signal for acquiring the electrical signals collected by it and determining the frequency of the electrical signals; and the slip rate of the rolling bearing being determined according to the frequency.

[0016] In a third aspect, the present application provides a method for monitoring the motion state of a rolling bearing, the monitoring method comprising the following steps: acquiring an electrical signal generated by the monitoring device of the first aspect; Perform fast Fourier transform on the electrical signal to obtain the frequency of the electrical signal, and determine the rotation speed of the rolling element according to the frequency; The slip rate of the rolling bearing is determined based on the rotational speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a monitoring device installed on a rolling bearing according to an embodiment of the present application; Figure 2 An exploded view of a rolling bearing provided with a monitoring device according to an embodiment of the present application; Figure 3 This is a schematic diagram of the structure of a monitoring device according to an embodiment of the present application; Figure 4 This is a schematic diagram of the structure in which a rolling element is installed on a retaining frame according to an embodiment of the present application; Figure 5 This is a schematic diagram of the structure in which a rolling element is installed on a retaining frame according to an embodiment of the present application; Figure 6 This is a schematic structural diagram of a stator circuit board according to an embodiment of the present application; Figure 7 This is a schematic structural diagram of a stator circuit board according to an embodiment of the present application; Figure 8This is a cross-sectional view of a monitoring device according to an embodiment of the present application installed on a rolling bearing; Fig. 9 for Figure 8 A local enlarged view of point A shown in FIG. Fig.10 A schematic diagram of a monitoring system according to an embodiment of the present application; Fig.11 This is a flowchart of the steps of a monitoring method according to an embodiment of the present application.

[0018] Figure numbers: 100-rolling bearing; 110-fixed ring; 111-annular rib; 120-rotating ring; 130-rolling element; 131-end face; 140-cage; 200-triboelectric sensor; 210-dielectric film; 220-stator circuit board; 221-first surface; 222-second surface; 223-first electrode; 224-second electrode; 225-first pad; 226-second pad; 230-wire; 300-signal acquisition device; 400-signal processing device; 01-Mounting slot. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0020] The application scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. It is known to those skilled in the art that with the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0021] Figure 1 This is a schematic diagram of a structure in which a monitoring device according to an embodiment of the present application is installed on a rolling bearing. Figure 2 This is an exploded view of a rolling bearing provided with a monitoring device according to an embodiment of the present application. Figure 3 This is a schematic diagram of the structure of a monitoring device according to an embodiment of the present application. Please refer to Figures 1 to 3In an embodiment of the present application, a monitoring device for the motion state of a rolling bearing 100 is provided. The rolling bearing 100 includes a fixed ring 110, a rotating ring 120, and a plurality of rolling bodies 130 disposed between the fixed ring 110 and the rotating ring 120. The rotating ring 120 mentioned above can be an inner ring or an outer ring. Among them, if the inner ring is a rotating ring 120, the outer ring can be called a fixed ring 110, and vice versa. For example, when a rotating shaft is sleeved in the inner ring, the rotation of the rotating shaft will drive the inner ring to rotate. At this time, the inner ring is a rotating ring 120, and the outer ring is a fixed ring 110. On the contrary, when a fixed shaft is sleeved in the inner ring and a rotating component is sleeved on the ring, the rotation of the rotating component will drive the outer ring to rotate. At this time, the outer ring is a rotating ring 120, and the inner ring is a fixed ring 110.

[0022] If there is no special explanation, in the rolling bearing 100 of each embodiment of the present application, the fixed ring 110 refers to the outer ring, and the rotating ring 120 refers to the inner ring.

[0023] Among them, the monitoring device in the present application is suitable for rolling bearings 100 of the types of cylindrical roller bearings, deep groove ball bearings, tapered roller bearings, etc.

[0024] The monitoring device in the embodiment of the present application includes at least one triboelectric sensor 200, which includes a dielectric film 210 and a stator circuit board 220. The dielectric film 210 is provided on the end surface 131 of one end of at least one rolling body 130 along the axial direction of the rolling body 130, and the stator circuit board 220 is provided on the surface of the fixed ring 110 facing the dielectric film 210, and an electrode pair is provided on the stator circuit board 220. When the rolling bearing 100 rotates, the rolling body 130 rotates in the circumferential direction, and relative motion is generated between the dielectric film 210 and the electrode pair. Due to the principle of friction electrification or electrostatic induction, transfer charges are generated between the dielectric film 210 and the electrode pair, and then a corresponding AC signal is generated in the external circuit. The AC signal can be used to monitor the motion state of the rolling bearing 100.

[0025] In this application, along the axial direction of the rolling element 130 , the dielectric film 210 is not limited at which end of the rolling element 130 it is located, as long as the dielectric film 210 and the stator circuit board 220 are located on the same side of the rolling bearing 100 .

[0026] In some embodiments of the present application, the dielectric film 210 can be adhered to the end surface 131 of the rolling body 130 by gluing to ensure that it can rotate synchronously with the rolling body 130. In order to improve the reliability of the bonding between the dielectric film 210 and the rolling body 130, the end surface 131 of the rolling body 130 can be subjected to different surface treatments.

[0027] It is understandable that, among the multiple rolling elements 130 of the rolling bearing 100 , only the end surface 131 of one rolling element 130 may be provided with the dielectric film 210 , or the end surfaces 131 of two or more rolling elements 130 may be provided with the dielectric film 210 .

[0028] In some embodiments of the present application, the dielectric film 210 may be a polymer film having a triboelectric effect. Specifically, the material of the dielectric film 210 may be selected from at least one of perfluoroethylene propylene, polytetrafluoroethylene, and polyvinyl chloride.

[0029] The present application does not limit the shape of the dielectric film 210, as long as the dielectric film 210 and the electrode pair can generate electrostatic induction when the rolling body 130 rotates. For example, the shape of the dielectric film 210 can be circular, annular, square, triangular or other shapes.

[0030] The electrodes of the electrode pair may be metal electrodes such as copper electrodes, aluminum electrodes, etc. The back of the stator circuit board 220 may be insulated to ensure that the electrical signal is not affected during transmission, thereby improving its anti-interference capability.

[0031] It can be understood that the greater the difference in the triboelectric properties between the electrodes of the electrode pair and the dielectric layer, the better the output performance of the triboelectric sensor 200.

[0032] Figure 4 This is a schematic diagram of a rolling element installed on a cage according to an embodiment of the present application. Figure 5 This is a schematic diagram of a rolling element installed in a cage according to an embodiment of the present application. Please refer to Figures 1 to 5 The rolling bearing 100 further includes a retainer 140 of an annular structure. The retainer 140 is provided with a plurality of mounting grooves 01 along the circumference of the retainer 140. The mounting grooves 01 are used to mount the rolling elements 130. The retainer 140 can ensure that the plurality of rolling elements 130 are evenly distributed along the circumference of the rolling bearing 100, and at the same time ensure that adjacent rolling elements 130 do not contact each other. When the rolling bearing 100 is normally installed, the rolling elements 130 are located in the mounting grooves 01 of the retainer 140, and there is a spacing between any two adjacent rolling elements 130 along the circumferential direction.

[0033] The material of the retainer 140 may be copper alloy, non-metal composite material, etc. The retainer 140 may be a cage-type retainer 140 , or a crown-type or wave-type retainer 140 .

[0034] In some embodiments of the present application, the dielectric film 210 has a hollow area, and the hollow area at least partially overlaps with the projection of the retainer 140 along the axial direction of the rolling body 130, so as to reduce the friction between the dielectric film 210 and the retainer 140 and extend the service life of the monitoring device. The shape and area of ​​the hollow area can be set according to the shape and area of ​​the overlapping area of ​​the end face 131 of the rolling body 130 and the projection of the retainer 140 along the axial direction of the rolling body 130, that is, the hollow area and the projection of the retainer 140 along the axial direction of the rolling body 130 can partially overlap or completely overlap.

[0035] Figure 6 This is a schematic diagram of the structure of a stator circuit board according to an embodiment of the present application. Figure 7 This is a schematic diagram of the structure of a stator circuit board of an embodiment of the present application, referring to Figure 6 and Figure 7 The stator circuit board 220 is an annular plate. Along the axial direction of the rolling bearing 100 , the annular plate includes a first surface 221 and a second surface 222 that are oppositely arranged. The first surface 221 is provided with an electrode pair, and the electrode pair includes a first electrode 223 and a second electrode 224 .

[0036] In some embodiments of the present application, the number of electrode pairs may be the same as the number of dielectric films 210 .

[0037] Wherein, along the circumference of the annular plate, adjacent first electrodes 223 and second electrodes 224 are arranged at intervals. It is understandable that the shapes of the first electrodes 223 and the second electrodes 224 are not limited in the present application and can be flexibly arranged according to specific needs.

[0038] For example, Figure 6 As shown, the first electrode 223 and the second electrode 224 may both be fan-shaped, a second electrode 224 is disposed between any two adjacent first electrodes 223 , and a gap exists between adjacent first electrodes 223 and second electrodes 224 along the circumference of the annular plate.

[0039] In some embodiments of the present application, the second surface 222 is provided with a first pad 225 and a second pad 226 for connecting the wire 230, the first electrode 223 and the first pad 225 are electrically connected, and the second electrode 224 and the second pad 226 are electrically connected, thereby achieving circuit conduction between the first electrode 223 and the second electrode 224.

[0040] Figure 8 This is a cross-sectional view of a monitoring device according to an embodiment of the present application installed on a rolling bearing. Fig. 9 for Figure 8 The enlarged view of the part at A shown in Figure 8 and Fig. 9Along the axial direction of the rolling bearing 100 , an annular rib 111 is provided at the end of the fixed ring 110 , and the stator circuit board 220 can be bonded to the surface of the annular rib 111 facing the dielectric film 210 .

[0041] Optionally, the axial gap between the dielectric film 210 and the first electrode 223 and the axial gap between the dielectric film 210 and the second electrode 224 are both 0.1-0.3 mm, which are set according to actual needs so that the triboelectric sensor 200 generates a triboelectric signal of appropriate size.

[0042] In some embodiments of the present application, a surface of the annular rib 111 facing the dielectric film 210 is provided with a groove, and the stator circuit board 220 is installed in the groove to adjust the axial gap between the dielectric film 210 and the first electrode 223, and the dielectric film 210 and the second electrode 224. The above-mentioned gap will affect the performance of the triboelectric sensor 200.

[0043] Ideally, the multiple rolling elements 130 in the rolling bearing 100 should rotate at the same speed in order to evenly carry the load and distribute the wear. However, in actual applications, factors such as bearing wear, contamination, and uneven load may cause the rotation speed of the rolling elements 130 to vary. For example, the inner ring, outer ring, and rolling elements 130 of the bearing may wear, which may affect the movement of the rolling elements 130. Alternatively, contaminants such as dust, metal chips, etc. may get stuck between the rolling elements 130, thereby affecting their rotation.

[0044] In view of this, the monitoring device in the embodiment of the present application may include at least two triboelectric sensors 200, each of which corresponds to one or more rolling elements 130, so that the rotation speeds of different rolling elements 130 can be monitored separately. The number and position of the rolling elements 130 corresponding to each triboelectric sensor 200 can be set according to actual needs.

[0045] Exemplarily, the rolling elements 130 of the rolling bearing 100 may be divided into two groups of rolling elements 130 , and the monitoring device may include two triboelectric sensors 200 , each triboelectric sensor 200 corresponding to a group of rolling elements 130 . The monitoring device of the above structure will be described in detail below.

[0046] The plurality of rolling elements 130 of the rolling bearing 100 include a first type of rolling element and a second type of rolling element, and the monitoring device includes a first sensor and a second sensor. The first sensor includes a first dielectric film, which is disposed on an axial end face 131 of the first type of rolling element, so that the first sensor monitors the motion state of the first type of rolling element. The second sensor includes a second dielectric film, which is disposed on an axial end face 131 of the second type of rolling element, so that the second sensor monitors the motion state of the second type of rolling element. It can be understood that by analyzing and comparing the electrical signals generated by the first sensor and the second sensor, it can be determined whether the rotation speeds of the first rolling element and the second rolling element are the same.

[0047] The first type of rolling element may include one, two or more rolling elements 130, which are specifically configured according to actual needs. Similarly, the second type of rolling element may include one, two or more rolling elements 130, which are specifically configured according to actual needs.

[0048] In some embodiments of the present application, along the circumference of the rolling bearing 100 , a second type rolling element is provided between any two adjacent first type rolling elements.

[0049] In some embodiments of the present application, the edge of the first dielectric film has a first notch, and the edge of the second dielectric film has a second notch. Wherein, when the edge of the first dielectric film has a notch, when the first type of rolling body rotates, the overlapping area of ​​the first dielectric film and the projection of the first electrode 223 along the axial direction of the rolling body 130, and the overlapping area of ​​the first dielectric film and the projection of the second electrode 224 along the axial direction of the rolling body 130 will change, so that the electrical signal will appear inconsistent with the first half of the cycle time and the second half of the cycle time in one cycle. Similarly, when the edge of the second dielectric film has a notch, when the second type of rolling body rotates, the overlapping area of ​​the second dielectric film and the projection of the first electrode 223 along the axial direction of the rolling body 130, and the overlapping area of ​​the second dielectric film and the projection of the second electrode 224 along the axial direction of the rolling body 130 will change, so that the electrical signal will appear inconsistent with the first half of the cycle time and the second half of the cycle time in one cycle.

[0050] Therefore, when the rotation speed of the first type rolling element and the second type rolling element differ, the relative position of the first notch and the second notch along the circumference of the rolling element will change, which will cause the change of the electrical signal. Therefore, by monitoring the electrical signals of the two triboelectric sensors, the rotation speed difference between the first type rolling element and the second type rolling element can be reflected.

[0051] It is to be understood that the shapes of the first notch and the second notch are not limited in the present application. Exemplarily, both the first notch and the second notch can be sector-shaped. The areas of the first notch and the second notch can be the same or different. For example, the first notch is a sector-shaped with a central angle of 60 degrees, and the second notch is a sector-shaped with a central angle of 120 degrees.

[0052] In some embodiments of the present application, the installation process of the monitoring device includes the following steps: Paste the dielectric film 210 on the end surface 131 of the rolling body 130 respectively, and ensure the cleanliness and flatness; The surface of the retaining edge of the fixed ring 110 facing the dielectric film 210 is cleaned, the back side of the stator circuit board 220 is insulated, the back sides of the first electrode 223 and the second electrode 224 are adhered to the surface of the retaining edge, and a wire 230 is led out through the first soldering pad 225 and the second soldering pad 226 respectively to achieve connectivity with the external circuit.

[0053] The structure and installation process of the monitoring device are described in detail above. The working process and principle of the monitoring device will be introduced below.

[0054] In the initial state, the projections of the dielectric film 210 and the first electrode 223 along the axial direction of the rolling body 130 overlap, and due to the difference in electronegativity between the dielectric film 210 and the first electrode 223, the dielectric film 210 accumulates negative charges on the surface. According to the law of conservation of charge, the surface of the first electrode 223 accumulates an equal amount of positive charges. At this time, the positive and negative charges cancel each other out and are in an electrostatic equilibrium state. At this time, since the dielectric film 210 and the first electrode 223 are in a non-contact mode, the amount of transferred charges between the dielectric film 210 and the first electrode 223 is small.

[0055] When the dielectric film 210 rotates under the drive of the retainer 140, the dielectric film 210 begins to rotate relative to the first electrode 223, and the dielectric film 210 gradually overlaps with the projection of the second electrode 224 along the axial direction of the rolling body 130, which generates a potential difference between the two electrodes, causing positive charges to flow from the first electrode 223 to the second electrode 224 along the rotation direction. When the rotor completely overlaps with the projection of the second electrode 224 along the axial direction of the rolling body 130, all positive charges are transferred to the second electrode 224, returning to an electrostatic equilibrium state.

[0056] As the holder 140 continues to rotate, the positive charge on the second electrode 224 flows in the opposite direction again, toward the first electrode 223, forming a reverse current in the external circuit. Due to the electrostatic induction between the dielectric film 210 and the electrode pair, the charge on the dielectric film 210 gradually begins to accumulate, and the above charge transfer process is repeated periodically, and the charge on the dielectric film 210 also continues to increase until saturation, thereby achieving stable output.

[0057] Based on the same technical concept, the present application also provides a system for monitoring the motion state of a rolling bearing. Fig.10 This is a schematic diagram of a monitoring system according to an embodiment of the present application, referring to Fig.10 The monitoring system includes a signal acquisition device 300, a signal processing device 400 and a monitoring device in various possible embodiments of the present application. The signal acquisition device 300 is signal-connected to the triboelectric sensor 200 for collecting electrical signals; the signal processing device 400 is signal-connected to the signal acquisition device 300 to obtain the electrical signals collected by it and determine the frequency of the electrical signals; the slip rate of the rolling bearing 100 is determined according to the frequency.

[0058] The signal acquisition device 300 may be a data acquisition card, which is used to collect data from the triboelectric sensor 200, convert the data into a form that can be processed by a computer, and then transmit the data to the signal processing device 400 for processing.

[0059] In some embodiments of the present application, the signal acquisition device 300 can establish a signal connection with the triboelectric sensor 200 through wireless means such as infrared rays.

[0060] The signal processing device 400 includes a digital signal processor, which can be used to perform complex mathematical operations, such as Fast Fourier Transform (FFT), signal compression, etc.

[0061] In some embodiments of the present application, the monitoring system may include a display device, the display device includes a display screen, and the display screen may be used to display the rotation speed and slip rate of the rolling body 130 in real time.

[0062] In addition, according to the actual working conditions, the staff can set a threshold value for the slip rate of the rolling bearing 100 and input it into the display device. When the slip rate of the rolling bearing 100 exceeds the above threshold value, an alarm reminder can be issued through the display.

[0063] The working process of the monitoring system in the embodiment of the present application is as follows: The signal acquisition device 300 collects the time domain signal of the triboelectric speed sensor and transmits it to the signal processing device 400. The signal processing device 400 extracts the frequency of the signal by performing FFT. The above frequency can reflect the rotation speed of the rolling body 130. The real-time monitoring of the slip rate of the rolling body 130 can be achieved through calculation by a formula.

[0064] Based on the same technical concept, the embodiment of the present application also provides a method for monitoring the motion state of a rolling bearing 100. Fig.11 This is a flowchart of the steps of the monitoring method of the monitoring system of an embodiment of the present application, referring to Fig.11, the monitoring method comprises the following steps: Acquire an electrical signal generated by a monitoring device in various possible embodiments of the present application; Performing a fast Fourier transform on the electrical signal to obtain the frequency of the electrical signal, and determining the rotation speed of the rolling element 130 according to the frequency; The slip rate of the rolling bearing 100 is determined based on the rotational speed, based on which the movement state of the rolling bearing 100 can be evaluated.

[0065] In summary, the monitoring device, monitoring system and monitoring method in the embodiments of the present application have the following beneficial effects: 1) It can be used for in-situ monitoring of the rotation speed and slip state of the rolling element 130 of the rolling bearing 100, and can analyze the slip state of a single rolling element 130 from a more microscopic level; 2) The triboelectric sensor 200 has a compact structure, which improves the integration of the monitoring device. The triboelectric sensor 200 can be embedded in the bearing without increasing the size of the bearing, which has less impact on the dynamic characteristics of the bearing, high reliability, and a wide range of applications; 3) The monitoring system can realize real-time monitoring of the rotation speed of the bearing rolling element 130 and slip warning through signal processing and threshold setting.

[0066] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A device for monitoring the motion state of a rolling bearing, wherein the rolling bearing comprises a fixed ring, a rotating ring and a plurality of rolling bodies arranged between the fixed ring and the rotating ring, characterized in that: The monitoring device comprises at least one triboelectric sensor, the triboelectric sensor comprises a dielectric film and a stator circuit board, the dielectric film is arranged on the end surface of one end of at least one of the rolling elements along the axial direction of the rolling element, the stator circuit board is arranged on the surface of the fixed ring facing the dielectric film, and an electrode pair is arranged on the stator circuit board; When the rolling body rotates, the dielectric film and the electrode pair generate electrostatic induction to generate an electrical signal for monitoring the motion state of the rolling bearing.

2. The monitoring device according to claim 1, characterized in that: The dielectric film is made of at least one material selected from perfluoroethylene propylene, polytetrafluoroethylene, and polyvinyl chloride.

3. The monitoring device according to claim 1, characterized in that: The rolling bearing further comprises a retaining frame of an annular structure, wherein the retaining frame is provided with a plurality of mounting grooves along the circumference of the retaining frame, and the mounting grooves are used for mounting the rolling elements; The dielectric film has a hollow area, and the hollow area at least partially overlaps with a projection of the retaining frame along the axial direction of the rolling body.

4. The monitoring device according to any one of claims 1 to 3, characterized in that: The plurality of rolling bodies include a first type of rolling body and a second type of rolling body, and the monitoring device includes a first sensor and a second sensor; Wherein, the first sensor comprises a first dielectric film, and the first dielectric film is arranged on the axial end surface of the first type of rolling body, so that the first sensor monitors the motion state of the first type of rolling body; The second sensor includes a second dielectric film, and the second dielectric film is arranged on the axial end surface of the second type rolling body, so that the second sensor monitors the movement state of the second type rolling body.

5. The monitoring device according to claim 4, characterized in that: Along the circumferential direction of the rolling bearing, the second type of rolling element is arranged between any two adjacent first type of rolling elements.

6. The monitoring device according to claim 4, characterized in that: The first dielectric film has a first notch at its edge, and the second dielectric film has a second notch at its edge.

7. The monitoring device according to any one of claims 1 to 3, characterized in that: The stator circuit board is an annular plate. Along the axial direction of the rolling bearing, the annular plate includes a first surface and a second surface arranged opposite to each other. The first surface is provided with the electrode pair, and the electrode pair includes a first electrode and a second electrode; the second surface is provided with a first welding pad and a second welding pad for connecting wires, the first electrode is electrically connected to the first welding pad, and the second electrode is electrically connected to the second welding pad.

8. The monitoring device according to claim 7, characterized in that: An annular rib is provided at the end of the fixed ring along the axial direction of the rolling bearing, a surface of the annular rib facing the dielectric film is provided with a groove, and the stator circuit board is mounted in the groove; And / or, along the circumference of the annular plate, adjacent first electrodes and second electrodes are arranged with intervals therebetween.

9. A system for monitoring the motion state of a rolling bearing, characterized in that: include: The monitoring device according to any one of claims 1 to 8; A signal acquisition device, connected to the triboelectric sensor signal, for acquiring the electrical signal; A signal processing device, connected to the signal acquisition device to acquire the electrical signal acquired by the signal acquisition device and determine the frequency of the electrical signal; The slip rate of the rolling bearing is determined based on the frequency.

10. A method for monitoring the motion state of a rolling bearing, characterized in that: The steps include: Obtaining an electrical signal generated by a monitoring device according to any one of claims 1 to 8; Performing a fast Fourier transform on the electrical signal to obtain a frequency of the electrical signal, and determining a rotation speed of the rolling element according to the frequency; A slip rate of the rolling bearing is determined based on the rotational speed.

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