Bearing and slip monitoring method thereof, and holder stability monitoring and evaluating method

Abstract

The invention discloses a bearing, a slip monitoring method thereof and a holder stability monitoring and evaluating method, and relates to the technical field of intelligent bearings, the bearing comprises a bearing inner ring, a bearing outer ring and a holder, and the bearing outer ring is rotatably arranged on the periphery of the bearing inner ring in a sleeving mode; the retainer is rotatably sleeved between the bearing inner ring and the bearing outer ring, a plurality of rolling bodies are arranged on the retainer along the circumferential direction at intervals, any rolling body is in running fit with the retainer, the inner ring of the retainer is provided with a guide surface which is in rolling fit with the bearing inner ring, the guide surface is provided with a micro texture, the micro texture is provided with a pit, and the pit is provided with a plurality of concave holes. The sliding of the bearing is reduced, and the operation stability of the retainer is improved. By means of the bearing slip monitoring method and the holder stability monitoring and evaluating method, the current motion state of the bearing can be obtained, whether the bearing needs to be maintained or not is judged, and monitoring of the holder stability is more visual and convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent bearings, and particularly to a bearing, a method for monitoring slip thereof, and a method for monitoring and evaluating the stability of a cage. Background Art

[0002] As a core component for supporting the efficient operation of high-performance devices, high-speed rolling bearings are widely used in modern industrial equipment such as new energy vehicles and aerospace. The operating state of high-speed rolling bearings directly affects the working performance, reliability, and service life of the devices equipped with such high-speed rolling bearings. Slip and unstable operation of the cage are the most common and main failure forms of high-speed rolling bearings, which can cause scratches on rolling elements and inner and outer raceways, wear and fracture of the cage, resulting in a decrease in the rotational accuracy of the bearing, and seriously affecting the working performance and service life of the bearing. Summary of the Invention

[0003] The purpose of the present invention is to provide a bearing, a method for monitoring slip thereof, and a method for monitoring and evaluating the stability of a cage, so as to solve the problems existing in the above-mentioned prior art, reduce the slip of the bearing, improve the operating stability of the cage, improve the working performance of the bearing, and extend the service life of the bearing.

[0004] To achieve the above purpose, the present invention provides the following solutions:

[0005] The present invention provides a bearing, comprising: an inner bearing ring, an outer bearing ring, and a cage. The outer bearing ring is rotatably sleeved on the outer periphery of the inner bearing ring; the cage is rotatably sleeved between the inner bearing ring and the outer bearing ring. A plurality of rolling elements are arranged at intervals along the circumferential direction of the cage. Any one of the rolling elements is rotatably engaged with the cage. The inner ring of the cage is provided with a guiding surface that is in rolling engagement with the inner bearing ring, and micro-textures are provided on the guiding surface. The micro-textures have pits.

[0006] In some embodiments, the micro-textures are pits evenly distributed on the guiding surface; or, the micro-textures are stepped grooves that are distributed in a gradient along the axial direction of the guiding surface.

[0007] In some embodiments, the bearing further includes a conductive layer disposed on the non-guiding side of the inner sidewall of the outer ring of the bearing. The conductive layer includes a plurality of first electrodes and a plurality of second electrodes. The plurality of first electrodes and the plurality of second electrodes are distributed at intervals and crosswise in the circumferential direction of the outer ring of the bearing. All the first electrodes are connected in parallel to a first circuit, and all the second electrodes are connected in parallel to a second circuit. The conductive layer is used for external connection to a circuit or device. A protrusion capable of rolling contact and cooperation with the conductive layer is provided on the outer ring of the cage along the circumferential direction of the cage. The protrusion can alternately contact the first electrode and the second electrode during rotation to generate an electric current.

[0008] In some embodiments, a plurality of the protrusions are provided on the outer ring of the cage, and the plurality of protrusions are evenly distributed in the circumferential direction of the outer ring of the cage. The total number of the first electrodes and the second electrodes is an integer multiple of the number of the protrusions.

[0009] In some embodiments, the width of the conductive layer in the axial direction of the bearing is the same as the width of the protrusion in the axial direction of the bearing, and both sides in the width direction of the conductive layer are aligned with both sides in the width direction of the protrusion respectively.

[0010] In some embodiments, the material of the cage is a dielectric material.

[0011] In some embodiments, any one of the first electrodes or any one of the second electrodes is a flexible printed electrode. The flexible printed electrode includes a flexible circuit board and an electrode layer printed on the flexible circuit board. The flexible circuit board is fixedly connected to the inner sidewall of the outer ring of the bearing.

[0012] In some embodiments, an insulating layer is provided between the conductive layer and the inner sidewall of the outer ring of the bearing.

[0013] The present invention also provides a method for monitoring slip of the above-mentioned bearing, including:

[0014] Under the rotating condition of the bearing, receiving and recording the alternating current signal generated by the conductive layer in the bearing, and filtering out high-frequency clutter in the alternating current signal to obtain a triboelectric signal;

[0015] Performing Fourier transform on the triboelectric signal, extracting the characteristic frequency, and calculating the actual rotational speed of the cage based on the characteristic frequency;

[0016] Calculating the theoretical rotational speed of the cage;

[0017] Calculating the slip rate of the cage according to the actual rotational speed of the cage and the theoretical rotational speed of the cage.

[0018] The present invention also provides a method for monitoring and evaluating the stability of the cage of the above-mentioned bearing, including:

[0019] Mark an experimental point in the circumferential direction of the cage. Under the operating conditions of the bearing rotation, obtain the whirling trajectory of the experimental point with the geometric center of the bearing as the reference point.

[0020] According to the whirling trajectory data of the experimental point, process to obtain a fitted circle of the whirling trajectory. Define the shortest distance between the fitted circle of the whirling trajectory and the cage guiding clearance circle as the CF index. The cage guiding clearance circle is a circle formed by the maximum whirling distance of the experimental point with the geometric center of the bearing as the center.

[0021] Under the operating conditions of the bearing rotation, receive and record the output characteristics of the conductive layer in the bearing. The output characteristics include output voltage and / or current data, and perform a correlation fitting on the output characteristics and the CF index to obtain a correlation fitting curve of the output characteristics and the CF index.

[0022] According to the correlation fitting curve, find the correlation between the CF index and the output characteristics to evaluate the stability of the cage.

[0023] The present invention has achieved the following technical effects compared with the prior art:

[0024] The present invention provides a bearing. By machining a micro-texture with pits on the guiding surface of the cage that cooperates with the inner ring of the bearing, during the relative rotation of the cage and the inner ring of the bearing, the lubricating oil can generate a velocity change between the guiding surface and the micro-texture, enhancing the hydrodynamic effect of the lubricating oil. The lubricating oil forms an oil film with a certain thickness in the micro-texture area, separating the friction surfaces of the cage and the inner ring of the bearing, reducing the friction coefficient, reducing the wear of the cage and the inner ring of the bearing, and at the same time improving the stability of the bearing operation. Furthermore, the working performance of the bearing is improved, and the service life of the bearing is extended.

[0025] In some technical solutions of the present invention, by providing a conductive layer on the non-guiding side of the inner side wall of the outer ring of the bearing, and providing protrusions on the outer ring of the cage along the circumferential direction of the cage that can rollingly contact and cooperate with the conductive layer, the protrusions can contact the conductive layer to generate current when the cage rotates, so that the monitoring of the operating condition of the cage can be realized by monitoring the output current or voltage. There is no need to additionally install equipment such as optical fiber sensors on the bearing, ensuring the integrity and compactness of the bearing and being able to guarantee the service life of the bearing.

[0026] The bearing slip monitoring method provided by the present invention can monitor the bearing slip by monitoring the alternating current signal generated in the conductive layer. There is no need to additionally install devices such as optical fiber sensors on the bearing, which ensures the integrity and compactness of the bearing and can also guarantee the service life of the bearing. At the same time, by monitoring the slip rate of the bearing, the current motion state of the bearing can be known, and further, by the abnormal change of the slip rate, it can be known that the internal parts of the bearing are in an abnormal operating state, which can be used as evidence for judging whether the bearing needs maintenance.

[0027] The cage stability monitoring and evaluation method provided by the present invention can know the degree of cage whirling by monitoring the change of the output voltage or output current of the conductive layer, so as to know whether the cage is in a stable operating state under a certain working condition, making the monitoring of cage stability more intuitive and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0029] Figure 1 It is an exploded view of the bearing structure disclosed in the embodiment of the present invention;

[0030] Figure 2 It is a partial sectional view of the bearing disclosed in the embodiment of the present invention;

[0031] Figure 3 It is a comparison chart of the friction coefficients of the bearing disclosed in the embodiment of the present invention and the bearing with a conventional unprocessed micro-texture;

[0032] Figure 4 For Figure 1 It is a partial enlarged view of part H in

[0033] Figure 5 It is a schematic diagram of the bearing current generation principle disclosed in the embodiment of the present invention;

[0034] Figure 6 It is a schematic diagram of the principle of current change caused by cage whirling disclosed in the embodiment of the present invention;

[0035] Figure 7 It is a graph of the alternating current-time change of the bearing at three different rotational speeds;

[0036] Figure 8 It is a fitting curve of the correlation between the output voltage and the CF index;

[0037] Figure 9The figure shows the whirling trajectory of the bearing within 0.5 s under the condition of a bearing rotation speed of 1000 rpm and a combined load (Fr = 60 N; Fa = 60 N).

[0038] In the figure: 100 - bearing; 1 - inner ring of the bearing; 2 - outer ring of the bearing; 3 - cage; 31 - microtexture; 32 - protrusion; 4 - rolling element; 5 - conductive layer; 51 - first electrode; 52 - second electrode; 53 - first circuit; 54 - second circuit; A - rotation direction of the cage; B - whirling direction of the cage; C - initial position of the non-whirling cage; D - cage guiding clearance circle; E - fitting circle of the whirling trajectory; F - whirling trajectory. Detailed implementation manners

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] The purpose of the present invention is to provide a bearing, a slip monitoring method thereof, and a cage stability monitoring and evaluation method, so as to solve the problems existing in the prior art, reduce the slip of the bearing, improve the running stability of the cage, improve the working performance of the bearing, and extend the service life of the bearing.

[0041] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following combines the attached Figures 1 to 9 drawings and specific implementation manners to further describe the present invention in detail.

[0042] Embodiment 1

[0043] This embodiment provides a bearing 100, refer to Figures 1 to 2, including: an inner bearing ring 1, an outer bearing ring 2, and a cage 3. The outer bearing ring 2 is rotatably sleeved on the outer circumference of the inner bearing ring 1; the cage 3 is rotatably sleeved between the inner bearing ring 1 and the outer bearing ring 2. A plurality of rolling elements 4 are arranged at intervals along the circumferential direction of the cage 3. Any one of the rolling elements 4 is rotatably engaged with the cage 3. The inner ring of the cage 3 is provided with a guiding surface that is in rolling engagement with the inner bearing ring 1, and a micro-texture 31 is provided on the guiding surface. The micro-texture 31 has pits. For the bearing 100 provided in this embodiment, by machining the micro-texture 31 on the guiding surface of the cage 3, during the relative rotation of the cage 3 and the inner bearing ring 1, the lubricating oil generates a velocity change between the guiding surface and the micro-texture 31, enhancing the hydrodynamic pressure effect of the lubricating oil. The lubricating oil forms an oil film with a certain thickness in the area where the micro-texture 31 is located, separating the friction surfaces of the cage 3 and the inner bearing ring 1, reducing the friction coefficient, reducing the wear between the cage 3 and the inner bearing ring 1, improving the running stability of the bearing 100, further enhancing the working performance of the bearing 100, and extending the service life of the bearing 100. Figure 3 This is a comparison chart of the friction coefficients of the bearing 100 with the micro-texture 31 machined on the inner-ring guiding surface of the cage 3 provided in this embodiment and a conventional bearing without the machined micro-texture 31. The vertical axis represents the friction coefficient, and the horizontal axis represents the sliding distance. It can be seen that the bearing 100 with the micro-texture 31 machined on the inner-ring guiding surface of the cage 3 provided in this embodiment has a lower friction coefficient and runs more smoothly. The pits can be separate concave structures, or the pits can be continuously distributed in the circumferential or axial direction of the cage 3 to form grooves. Taking the circular pits as an example, when the diameter range of the circular pits of the micro-texture 31 is between 0.1 μm and 100 μm, that is, between 1×10 -4 mm and 0.1 mm, the micro-texture 31 on the inner-ring guiding surface of the cage 3 has an obvious effect of enhancing the hydrodynamic pressure effect of the lubricating oil. In some other embodiments, the size of the micro-texture 31 can be adaptively changed according to the specific shape of the pits.

[0044] In some embodiments, referring to Figure 4, the micro-texture 31 is pits evenly distributed on the guiding surface. For the bearing 100 provided in this embodiment, the micro-texture 31 is circular pits evenly distributed along the axial direction of the bearing 100 and along the circumferential direction of the inner ring of the cage 3. When the bearing 100 is working, these circular pits can continuously supply lubricating oil to the friction surface between the guiding surface of the cage 3 and the inner ring of the bearing, and accommodate the tiny particles and foreign matters falling off from the friction surface, protecting the bearing 100 from abrasive wear. At the same time, the lubricating oil moves between the guiding surface and the circular pits and generates a speed change, enhancing the hydrodynamic pressure effect of the lubricating oil, thereby achieving the effect of increasing stability. The hydrodynamic pressure effect is a physical phenomenon in which a high-pressure oil film is automatically formed in the wedge-shaped gap between relatively moving surfaces through the viscous action and moving speed of the lubricating oil, so as to completely separate the friction surfaces and achieve non-contact lubrication. In this embodiment, the wedge-shaped gap is the gap formed between the outer side wall of the inner ring 1 of the bearing and the circular pits. The hydrodynamic pressure effect enables the lubricating fluid to form an oil film or gas film with a certain thickness in the micro-texture 31 area. In this embodiment, lubricating oil is used. During the rotation of the cage 3, the oil film separates the friction surfaces of the cage 3 and the inner ring 1 of the bearing, reducing the friction coefficient, reducing the wear of the cage 3 and the inner ring 1 of the bearing, and at the same time improving the operating stability of the bearing 100. In this embodiment, the specific dimensions of the circular pits are a diameter of 0.08 mm and a depth of about 0.024 mm. The spacing between the circular pits along the axial direction of the bearing 100 and along the circumferential direction of the guiding surface of the inner ring of the cage 3 is 0.24 mm. The surface density of the comprehensive textured surface is about 10%, that is, the ratio of the micro-texture area per unit area is 10%. In some other embodiments, the micro-texture 31 can also be pits of other shapes such as rhombus and square, and other dimensions and the surface density of the comprehensive textured surface can also be selected according to actual needs.

[0045] Different forms of the micro-texture 31 have different effects on the motion characteristics of the bearing 100. In some other embodiments, the micro-texture 31 can also be stepped grooves with a gradient distribution along the axial direction of the guiding surface of the cage 3, where a single groove is an annular groove arranged along the circumferential direction of the guiding surface of the inner ring of the cage 3. While reducing the wear between the cage 3 and the inner ring 1 of the bearing, it also improves the operating stability of the bearing 100. By setting the structure of the stepped grooves, the depth of the grooves gradually becomes deeper from one end of the bearing 100 towards the direction of the rolling elements 4 along the axial direction of the bearing 100. Due to the directional diffusion effect of the stepped grooves with a gradient distribution on the lubricating oil, the lubricating oil can diffusely flow back spontaneously from one end of the bearing 100 towards the direction of the rolling elements 4 during the rotation of the bearing 100, enabling the cage 3 to have the function effect of one-way self-driving of droplets and improving the lubrication effect between the guiding surface of the cage 3 and the inner ring 1 of the bearing.

[0046] In some embodiments, referring to Figure 2 and Figure 5, the bearing 100 further includes a conductive layer 5. The conductive layer 5 is disposed on the non-guiding side of the inner sidewall of the bearing outer ring 2. The conductive layer 5 includes a plurality of first electrodes 51 and a plurality of second electrodes 52. The plurality of first electrodes 51 and the plurality of second electrodes 52 are distributed at intervals and crosswise along the circumferential direction of the bearing outer ring 2. All the first electrodes 51 are connected in parallel to the first circuit 53, and all the second electrodes 52 are connected in parallel to the second circuit 54. The conductive layer 5 is used to connect to an external circuit or other related devices. When specifically connected, it is connected in series with the external device or circuit through the first circuit 53 and the second circuit 54 to form a complete circuit. A protrusion 32 capable of rolling contact and cooperation with the conductive layer 5 is provided along the circumferential direction of the outer ring of the cage 3. The protrusion 32 can alternately contact the first electrode 51 and the second electrode 52 during rotation and generate an electric current. The non-guiding side of the inner sidewall of the aforementioned bearing outer ring 2 is specifically the shoulder of the bearing outer ring 2. When the bearing 100 rotates, the cage 3 will generate a planar whirling while rotating around the axis of the bearing 100, causing the protrusion 32 to rub against the conductive layer 5. Through the frictional action between the protrusion 32 and the conductive layer 5, charges are generated by triboelectrification on the surfaces of the protrusion 32, the first electrode 51, and the second electrode 52. After triboelectrification between the protrusion 32 and the first electrode 51 and the second electrode 52, they approach each other again, and an induced current is generated in the first circuit 53 and the second circuit 54 connected in series. Reference Figure 5 , after the initial charge is generated, there is electrostatic induction between the charges on the protrusion 32 and the charges in the conductive layer 5. As the cage 3 rotates, a current is generated between the first electrode 51 and the second electrode 52 through the first circuit 53 and the second circuit 54. When the protrusion 32 rotates from the position corresponding to the first electrode 51 to the position of the adjacent next second electrode 52, the current direction is from the second circuit 54 to the first circuit 53. When the protrusion 32 rotates from the position corresponding to the second electrode 52 to the position of the adjacent next first electrode 51, the current direction is from the first circuit 53 to the second circuit 54. Therefore, an alternating current signal is generated. Reference Figure 6 , A is the rotation direction of the cage, B is the whirling direction of the cage, and the dotted line C is the initial position of the cage without whirling. When the cage 3 whirls, the friction between the protrusion 32 and the conductive layer 5 causes an increase in the amount of charge generated, and the output current and output voltage increase accordingly. Thus, by monitoring the output current or voltage, the operating condition of the cage 3 can be monitored. There is no need to additionally install equipment such as fiber optic sensors on the bearing 100, and the integrity and compactness of the bearing 100 are ensured, which can ensure the service life of the bearing 100. And by connecting the first circuit 53 and the second circuit 54 in series with an existing electrostatic acquisition device externally, it is convenient to monitor the working state of the bearing 100.

[0047] Further, in this embodiment, the conductive layer 5 is an interdigital electrode with a thickness of 0.1 mm. The first electrode 51 and the second electrode 52 are the comb teeth arranged alternately in the interdigital electrode. The electrostatic acquisition device can be the Keithley 6517B produced by Keithley Instruments in the United States, or other devices capable of measuring and recording current.

[0048] In some embodiments, a plurality of protrusions 32 are provided on the outer ring of the cage 3, and the plurality of protrusions 32 are evenly distributed in the circumferential direction of the outer ring of the cage 3. The total number of the first electrodes 51 and the second electrodes 52 is an integer multiple of the number of the protrusions 32. In some preferred embodiments, as Figure 1 , Figure 5 and Figure 6 it can be seen, the number of the first electrodes 51 and the second electrodes 52 is the same, the total number of the first electrodes 51 and the second electrodes 52 is twice the total number of the protrusions 32. When the first electrodes 51 and the second electrodes 52 are evenly distributed along the circumference, a first electrode 51 is provided between every two adjacent second electrodes 52, and a second electrode 52 is provided between every two adjacent first electrodes 51. The central angle between every two adjacent protrusions 32, the central angle between every two adjacent first electrodes 51, and the central angle between every two adjacent second electrodes 52 are the same. By setting the protrusions 32 to be evenly distributed in the circumferential direction of the outer ring of the cage 3, and setting the total number of the first electrodes 51 and the second electrodes 52 to be an integer multiple of the number of the protrusions 32, in this embodiment, that is, the number of the comb teeth of the interdigital electrode is an integer multiple of the number of the protrusions 32, when the protrusions 32 rub against the comb teeth of the interdigital electrode, since one protrusion 32 contacts one or more comb teeth, one or more comb teeth generate charges, thereby generating current in the first circuit 53 and the second circuit 54. Compared with the current generated when a plurality of protrusions 32 contact one or more comb teeth at the same time, when the number of the comb teeth is an integer multiple of the number of the protrusions 32, the generated current is periodic, which is more conducive to analyzing the regularity of the current, and thus it is easier to monitor the running stability of the bearing 100.

[0049] In some embodiments, the width of the conductive layer 5 in the axial direction of the bearing 100 is the same as the width of the protrusions 32 in the axial direction of the bearing 100, and both sides in the width direction of the conductive layer 5 are aligned with both sides in the width direction of the protrusions 32 respectively. This structural design can ensure that when the first electrodes 51 and the second electrodes 52 rub against the protrusions 32, the surface contact area is larger, charges are more easily generated, and the force is more evenly distributed during the friction, so as to avoid the occurrence of a force concentration point between the first electrodes 51, the second electrodes 52 and the protrusions 32, which may damage the first electrode 51 or the second electrode 52.

[0050] In some embodiments, the material of the cage 3 is a dielectric material. A dielectric material is a material that can be polarized under the action of an electric field but hardly conducts electricity, such as polyethylene, polypropylene and other materials. When a dielectric material rubs against other materials, it is easy to gain or lose electrons, thereby generating charges. The charges generated by friction can accumulate on the surface area of the dielectric material and jointly form an electrostatic field with the charges in the conductive layer 5, so that when the cage 3 approaches the conductive layer 5, a current is generated between the first electrode 51 and the second electrode 52.

[0051] In some embodiments, any one of the first electrodes 51 or any one of the second electrodes 52 is a flexible printed electrode. The flexible printed electrode includes a flexible circuit board and an electrode layer printed on the flexible circuit board. The flexible circuit board is fixedly connected to the inner side wall of the bearing outer ring 2. The first electrode 51 and the second electrode 52 being flexible printed electrodes can make the conductive layer 5 fit completely with the inner side wall of the bearing outer ring 2, and the gaps between the inner side wall of the bearing outer ring 2 and the outer side wall of the cage 3 are uniform everywhere, making the measurement results reliable and the measured current and voltage data reliable, so that the experiment has repeatability. In this embodiment, the flexible circuit board is bonded to the inner side wall of the bearing outer ring 2, which can reduce the replacement cost of the conductive layer 5 and the maintenance cost of the bearing 100. In some other embodiments, the form of the fixed connection between the flexible circuit board and the inner side wall of the bearing outer ring 2 can also be welding or bolt connection and other forms.

[0052] The above-mentioned first electrode 51, second electrode 52 and protrusion 32, in conjunction with the assembly movement relationship between the bearing outer ring 2 and the cage 3, form a triboelectric nanogenerator with a floating free layer. When the bearing 100 rotates, the rotation of the cage 3 causes the protrusion 32 to generate triboelectrification effect and electrostatic induction on the surface of the interdigital electrodes. As the protrusion 32 rotates relative to the interdigital electrodes, the induced charges flow back and forth between the teeth of the two interdigital electrodes to generate an alternating current signal. While the cage 3 rotates around the axis of the bearing 100, it will generate a planar vortex, causing the radial distance between the protrusion 32 and the interdigital electrodes to change, thereby changing the internal gap of the triboelectric nanogenerator, and thus affecting the output characteristics of the triboelectric nanogenerator. The stability of the cage 3 is evaluated according to the correlation between the change in the output characteristics and the degree of vortex of the cage 3, and the self-sensing of the operating stability of the bearing 100 can be realized.

[0053] Moreover, the thickness of the interdigital electrodes determines the gap between the cage 3 and the interdigital electrodes. To ensure the service life of the bearing, when designing the internal gap of the triboelectric nanogenerator, the remaining guiding gap of the cage after the installation of the interdigital electrodes should be fully considered. In this embodiment, the thickness of the interdigital electrodes is 0.1 mm, and the gap between the cage 3 and the interdigital electrodes is set to 0.1 mm.

[0054] In some embodiments, an insulating layer is provided between the conductive layer 5 and the inner sidewall of the outer bearing ring 2. The insulating layer is used to isolate the conductive layer 5 and the outer bearing ring 2, prevent charge from leaking through the outer bearing ring 2, and ensure that the charge generated by friction only flows through the first circuit 53 and the second circuit 54, making the relevant data of the obtained bearing 100 more accurate.

[0055] In some embodiments, the rolling element 4 can be made of ceramic material, which can increase the limiting speed of the bearing 100 and is more suitable for the development prospects of new energy vehicles and the aerospace industry.

[0056] In some embodiments, multiple bearings 100 provided with micro-textures 31, protrusions 32, and conductive layers 5 can also be combined to increase the total output power generated during the rotation of the bearing 100, and also have the potential to solve the power supply problem of wireless sensor network nodes.

[0057] In summary, the present invention aims to improve the stability and service life of the cage 3 of the bearing 100, reduce wear and energy loss, and solve the problems of slipping of the existing bearing 100 and difficulty in directly monitoring the stability of the cage 3, which requires the additional installation of large-sized sensors, in order to meet the requirements of lightweight and intelligent high-performance equipment. A stability self-sensing bearing with micro-textures on the cage guiding surface is proposed. The device first processes micro-textures 31 on the inner guiding surface of the cage 3, forms and maintains a lubricating oil film with a gradient pressure between the inner guiding surface of the cage 3 and the friction surface of the inner bearing ring 1, reduces the friction coefficient, and improves the operating stability of the cage 3. Then, with interdigital electrodes and a dielectric material cage with radial protrusions 32 as the main structure, by installing the interdigital electrodes on the shoulder of the outer bearing ring 2, the frictional mechanical energy generated during the rotation of the dielectric material cage around the axis of the bearing 100 is effectively converted into electrical energy. By analyzing the triboelectric signal, the real-time slip rate and the stability of the cage of the bearing 100 are evaluated, which plays a role in real-time monitoring of the stability enhancement effect of the micro-textures 31. It has the characteristics of simple and compact structure, anti-vibration interference, self-sensing, and high precision. The specific beneficial effects are as follows:

[0058] (1) By processing surface micro-textures 31 on the guiding surface of the dielectric material cage, it can act as a micro-lubricant reservoir and change the flow characteristics of the lubricating oil, greatly improving the service life and stability of the bearing 100.

[0059] (2) By processing periodic equally spaced protrusions 32 on the outer ring of the dielectric material cage, the integration of the basic elements of the triboelectric nanogenerator can be accurately completed without affecting the structural integrity and functional integrity of the bearing 100, thereby endowing the bearing 100 with unique triboelectric properties.

[0060] (3) The bearing 100 provided by the present invention generates an alternating current signal through electrostatic induction between the dielectric material cage that rotates around the axis of the bearing 100 and undergoes planar whirling and the stationary interdigital electrodes. The frequency of this alternating current signal will change synchronously with the rotational speed of the cage 3. Therefore, by collecting the frequency of the alternating current signal generated by friction and performing relevant calculations, the slip rate of the bearing 100 can be calculated. By statistically analyzing the period of the alternating current signal generated by friction, the rotational speed stability of the cage 3 can be evaluated. By statistically analyzing the amplitude of the alternating current signal generated by friction, the whirling stability of the cage 3 can be evaluated;

[0061] During the operation of the bearing 100, the cage 3 will generate planar whirling while rotating around the axis of the bearing 100, causing the radial distance between the protrusions 32 and the interdigital electrodes to change, thereby changing the internal gap of the triboelectric nanogenerator, and further affecting the output characteristics of the triboelectric nanogenerator. According to the correlation between the change in output characteristics and the whirling degree of the cage 3, the stability of the cage 3 is evaluated, realizing the self-sensing of the operation stability of the bearing 100. Since the bearing 100 provided in this embodiment adopts a non-contact mode, that is, there is a gap between the cage 3 and the interdigital electrodes, and micro-textures 31 are processed on the guiding surface of the cage 3, the bearing 100 has an extremely long service life and extremely high stability, can realize real-time condition monitoring of the bearing 100, and has the advantages of self-driven sensing, wide monitoring range, and long service life.

[0062] (4) During use, multiple bearings 100 with micro-textures 31 processed on the guiding surface of the cage 3 can be combined simultaneously, thereby further increasing the output power and having the potential to solve the power supply problem of wireless sensor network nodes.

[0063] (5) The bearing 100 provided by the present invention greatly reduces the manufacturing and replacement costs of friction power generation. Only by fixing the interdigital electrodes on the shoulder of the outer ring 2 of the bearing and processing periodic equally spaced protrusions 32 on the outer ring of the dielectric material cage can the integration of the basic components of the triboelectric nanogenerator be realized, and the installation is convenient.

[0064] (6) When the bearing 100 rotates, a triboelectric effect and electrostatic induction occur on the surfaces of the dielectric material cage and the interdigital electrodes. As the dielectric material cage and the interdigital electrodes rotate relative to each other, the induced charges flow periodically between the teeth of the two interdigital electrodes, generating an alternating current signal. The frequency of this alternating current signal will change synchronously with the rotational speed of the cage 3 of the bearing 100. By collecting the frequency of the generated alternating current signal and performing relevant calculations, the slip rate of the bearing 100 can be calculated. By statistically analyzing the magnitude of the output voltage of the triboelectric nanogenerator, the stability of the cage 3 can be evaluated, and the condition monitoring of the high-speed bearing 100 can be realized.

[0065] Embodiment 2

[0066] This embodiment provides a method for monitoring the slippage of the bearing 100 in Embodiment 1, including the following steps:

[0067] (1) When the bearing 100 is rotating, an electrostatic collection device is used to receive and record the AC signal generated by the conductive layer 5 in the bearing 100. The frequency range of the high-frequency noise is estimated according to the rotation speed of the bearing 100, the number of protrusions 32, and the cage frequency formula. The high-frequency noise in the AC signal is filtered out by a signal processing module to obtain a triboelectric signal. The signal processing module can use a filter and other equipment. Here, the triboelectric signal refers to the AC signal generated by the friction between the protrusion 32 and the conductive layer 5. Reference Figure 7 This embodiment records the AC current-time variation diagram output by the bearing 100 at three different speeds (3000 rpm, 4500 rpm, 6000 rpm). It can be seen that the amplitude of the AC current generated by the bearing 100 increases with the increase of the speed, and the period of the AC current decreases with the increase of the speed.

[0068] (2) Perform Fourier transform on the triboelectric signal, extract the characteristic frequency, and calculate the actual speed of the cage based on the characteristic frequency. The calculation formula for the actual speed of the cage is:

[0069] n c =f sig ×60 / N e

[0070] where n c is the actual speed of the cage, f sig is the characteristic frequency of the AC signal, N e is the number of teeth of the interdigitated electrode.

[0071] (3) According to the inner ring speed of the bearing 100 and the cage speed calculation formula, the cage theoretical speed calculation formula is calculated as follows:

[0072]

[0073] where n bm is the theoretical speed of the cage, ω i is the speed of the inner ring of the bearing, D is the diameter of the rolling element, d m is the bearing pitch diameter, and α0 is the bearing contact angle.

[0074] (4) Calculate the cage slip rate based on the cage actual speed and the cage theoretical speed. The cage slip rate calculation formula is:

[0075]

[0076] where r sk is the cage slip rate, that is, the overall slip rate of the bearing 100.

[0077] By monitoring the alternating current signal generated in the conductive layer 5, it is possible to monitor the slippage of the cage 3. There is no need to additionally install devices such as fiber optic sensors on the bearing 100, ensuring the integrity and compactness of the bearing 100 and also guaranteeing the service life of the bearing 100. At the same time, by monitoring the slippage rate of the bearing 100, the current motion state of the bearing 100 can be known. Furthermore, by detecting the abnormal change of the slippage rate, it can be known that the internal parts of the bearing 100 are in an abnormal operating state, which can serve as evidence for judging whether the bearing 100 needs maintenance.

[0078] Embodiment 3

[0079] This embodiment provides a method for monitoring and evaluating the stability of the cage 3 of the bearing 100 in Embodiment 1, including the following operating steps:

[0080] (1) Mark an experimental point on the circumferential direction of the cage 3. Under the rotating condition of the bearing 100, use a high-speed camera to obtain the image information of this experimental point. From the image information, obtain the whirling trajectory F of the experimental point with the geometric center of the bearing 100 as the reference point. The whirling of the experimental point is an orbital motion in which the experimental point rotates around the geometric center of the bearing 100 without self-rotation. In this embodiment, the whirling trajectory F is a line graph formed by connecting the actual positions of the experimental points in the image information in chronological order.

[0081] (2) Process the whirling trajectory data to obtain a whirling trajectory fitting circle E. Define the shortest distance between the whirling trajectory fitting circle E and the cage guiding clearance circle D as the CF index. The cage guiding clearance circle D is a circle formed by the maximum whirling distance of the experimental point with the geometric center of the bearing 100 as the reference point. The maximum whirling distance refers to the maximum distance that the experimental point can deviate. Figure 9 For the whirling trajectory diagram of the experimental point within 0.5 s under the condition of the bearing speed of 1000 rpm and the combined load (Fr = 60 N; Fa = 60 N). In the figure, the horizontal axis is the whirling distance in the X direction, that is, the whirling distance of the experimental point along the radial direction of the bearing 100, and the vertical axis is the whirling distance in the Y direction, that is, the whirling distance of the experimental point along the circumferential direction of the bearing 100. The outer dotted line is the cage guiding clearance circle D, the inner dotted line is the whirling trajectory fitting circle E, and the solid line is the whirling trajectory F. The center of the cage guiding clearance circle D is the geometric center of the bearing. It can be seen that under the action of the radial load, the center of the whirling trajectory fitting circle E deviates from the geometric center of the bearing. The whirling direction of the cage 3 is the vector sum of the radial load and the rotating direction of the bearing 100. The smaller the CF index, the greater the planar displacement oscillation of the cage 3 and the worse the stability of the cage 3.

[0082] (3) Under the rotating condition of the bearing 100, use the electrostatic acquisition device to receive and record the output characteristics of the conductive layer in the bearing 100. The output characteristics include output voltage and / or current data. In this embodiment, the output voltage is used. Perform a correlation fitting on the output voltage and the CF index to obtain Figure 8 The correlation fitting curve of the output voltage and the CF index as shown in

[0083] (4) According to the correlation fitting curve, find the correlation between the CF index and the output characteristics to evaluate the stability of the cage 3. Generally, by monitoring the changes in the output voltage or output current obtained by the electrostatic acquisition device, the magnitude of the whirling degree of the cage 3 can be correspondingly obtained in the correlation fitting curve, so as to be able to know whether the cage 3 is in a stable operating state under a certain working condition, making the monitoring of the stability of the cage 3 more intuitive and convenient. Referring to Figure 8 , it can be known that as the output voltage increases, the CF index gradually decreases, that is, the whirling degree of the cage 3 increases. Therefore, the output voltage has a negative correlation with the whirling of the cage 3.

[0084] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A bearing, characterized in that: Comprising: Inner ring of the bearing; Outer ring of the bearing, the outer ring of the bearing being rotatably sleeved on the outer periphery of the inner ring of the bearing; and Cage, the cage being rotatably sleeved between the inner ring of the bearing and the outer ring of the bearing, a plurality of rolling elements being circumferentially spaced on the cage, any one of the rolling elements being in rotational cooperation with the cage, a guiding surface in rolling cooperation with the inner ring of the bearing being provided on the inner ring of the cage, and a micro-texture being provided on the guiding surface, the micro-texture having pits.

2. The bearing according to claim 1, wherein: The micro-texture is pits uniformly distributed on the guiding surface; Or, the micro-texture is stepped grooves distributed in a gradient along the axial direction of the guiding surface.

3. The bearing according to claim 1, wherein: It further comprises a conductive layer, the conductive layer being provided on the non-guiding side of the inner side wall of the outer ring of the bearing, the conductive layer comprising a plurality of first electrodes and a plurality of second electrodes, the plurality of first electrodes and the plurality of second electrodes being circumferentially spaced and cross-distributed along the outer ring of the bearing, all the first electrodes being connected in parallel to a first circuit, all the second electrodes being connected in parallel to a second circuit, the conductive layer being used for external connection to a circuit or equipment; A protrusion capable of making rolling contact and cooperation with the conductive layer is provided on the outer ring of the cage along the circumferential direction of the cage, and the protrusion can alternately contact the first electrode and the second electrode during rotation to generate an electric current.

4. The bearing according to claim 3, wherein: A plurality of the protrusions are provided on the outer ring of the cage, and the plurality of protrusions are uniformly distributed in the circumferential direction of the outer ring of the cage, and the total number of the first electrodes and the second electrodes is an integer multiple of the number of the protrusions.

5. The bearing according to claim 3, wherein: The width of the conductive layer in the axial direction of the bearing is the same as the width of the protrusion in the axial direction of the bearing, and both sides in the width direction of the conductive layer are aligned with both sides in the width direction of the protrusion respectively.

6. The bearing according to any one of claims 3 to 5, wherein: The material of the cage is a dielectric material.

7. The bearing according to any one of claims 3 to 5, wherein: Any one of the first electrodes or any one of the second electrodes is a flexible printed electrode, the flexible printed electrode comprising a flexible circuit board and an electrode layer printed on the flexible circuit board, and the flexible circuit board is fixedly connected to the inner side wall of the outer ring of the bearing.

8. The bearing according to any one of claims 3 to 5, wherein: An insulating layer is provided between the conductive layer and the inner side wall of the outer ring of the bearing.

9. A method for monitoring slip of the bearing according to any one of claims 3 to 8, characterized in that, Comprising: Under the rotating condition of the bearing, receiving and recording the alternating current signal generated in the conductive layer of the bearing, and filtering out high-frequency clutter in the alternating current signal to obtain a triboelectric signal; Performing Fourier transform on the triboelectric signal, extracting the characteristic frequency, and calculating the actual rotational speed of the cage based on the characteristic frequency; Calculating the theoretical rotational speed of the cage; Calculating the slip rate of the cage according to the actual rotational speed and the theoretical rotational speed of the cage.

10. A method for monitoring and evaluating the stability of the cage of the bearing according to any one of claims 3 to 8, characterized in that, Comprising: Mark an experimental point in the circumferential direction of the cage. Under the operating conditions of the bearing rotation, obtain the whirling trajectory of the experimental point with the geometric center of the bearing as the reference point. Based on the whirling trajectory data of the experimental point, process to obtain a fitted circle of the whirling trajectory. Define the shortest distance between the fitted circle of the whirling trajectory and the cage guiding clearance circle as the CF index. The cage guiding clearance circle is a circle formed by the maximum whirling distance of the experimental point with the geometric center of the bearing as the center. Under the operating conditions of the bearing rotation, receive and record the output characteristics of the conductive layer in the bearing. The output characteristics include output voltage and / or current data, and perform a correlation fitting on the output characteristics and the CF index to obtain a correlation fitting curve of the output characteristics and the CF index. Based on the correlation fitting curve, find the correlation between the CF index and the output characteristics to evaluate the stability of the cage.

Images