Knuckle bearing and knuckle bearing state monitoring method based on friction electric signals

Abstract

The invention discloses a knuckle bearing and a knuckle bearing state monitoring method based on friction electric signals. The knuckle bearing comprises an inner ring and an outer ring which are connected, the inner ring is rotatably arranged in the outer ring, the inner ring is provided with a first spherical surface, the outer ring is provided with a second spherical surface, and the first spherical surface is attached to the second spherical surface; the bearing further comprises a first friction layer, a second friction layer and a wire, the first friction layer is arranged on the first spherical surface, the second friction layer is arranged on the second spherical surface, the first friction layer makes contact with the second friction layer, and friction electric signals are generated between the first friction layer and the second friction layer along with relative rotation of the inner ring and the outer ring. The wire is connected with the outer ring and used for outputting friction electric signals. Friction electric signals generated between the first friction layer and the second friction layer can be utilized to directly reflect the running state of the bearing, and running state monitoring and fault diagnosis of the knuckle bearing can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of bearings, and in particular relates to a spherical bearing and a spherical bearing state monitoring method based on friction electric signals. Background Art

[0002] Spherical bearings are small, impact-resistant, corrosion-resistant, maintenance-free, and have a long lifespan. They are usually used in aerospace, automotive, water conservancy facilities, and military machinery. Spherical bearings may fail during operation due to a variety of factors, including wear, fatigue cracks, and fatigue fractures. When they fail, they may cause great damage to important mechanical equipment or facilities in operation. Therefore, it is of great significance to monitor the operating status of spherical bearings in real time and perform fault diagnosis. Summary of the invention

[0003] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0004] The inventors have realized that since the failure of spherical bearings is ultimately manifested as a sharp increase in friction temperature and an increase in friction torque, the related art often uses friction torque (friction coefficient) and friction temperature to detect the state and diagnose faults of spherical bearings. However, there are many factors that affect the friction torque, and it is necessary to extract the failure characteristics of the collected friction torque signal, which is a relatively complicated process. The temperature change of the bearing takes a certain amount of time, resulting in a certain lag in the state monitoring of spherical bearings using friction temperature.

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0006] To this end, an embodiment of the present invention provides a spherical plain bearing that can realize operating status monitoring and fault diagnosis.

[0007] The embodiment of the present invention also provides a method for monitoring the state of a spherical bearing based on triboelectric signals.

[0008] The spherical bearing of the embodiment of the present invention comprises an inner ring and an outer ring connected to each other, wherein the inner ring is rotatably arranged in the outer ring, the inner ring has a first spherical surface, the outer ring has a second spherical surface, and the first spherical surface and the second spherical surface are in contact with each other;

[0009] Also includes:

[0010] a first friction layer and a second friction layer, wherein the first friction layer is arranged on the first spherical surface, and the second friction layer is arranged on the second spherical surface, the first friction layer and the second friction layer are in contact with each other, and a friction electric signal is generated between the first friction layer and the second friction layer as the inner ring and the outer ring rotate relative to each other;

[0011] A wire is connected to the outer ring and is used to output the friction electric signal.

[0012] The spherical plain bearing of the embodiment of the present invention can directly reflect the operating state of the bearing by utilizing the friction electric signal generated between the first friction layer and the second friction layer, and can realize the operating state monitoring and fault diagnosis of the spherical plain bearing.

[0013] In some embodiments, the first friction layer is a friction layer of positive electrode material, and the second friction layer is a friction layer of negative electrode material.

[0014] In some embodiments, a partial section of the first spherical surface is covered with the first friction layer, and an entire section of the second spherical surface is covered with the second friction layer.

[0015] In some embodiments, the width of the first friction layer covering the first spherical surface in the axial direction of the spherical bearing is greater than or equal to the width of the second friction layer covering the second spherical surface in the axial direction of the spherical bearing.

[0016] In some embodiments, a load-bearing area is provided between the inner ring and the outer ring, and the first friction layer is disposed in the load-bearing area.

[0017] In some embodiments, the second friction layer is a self-lubricating friction layer.

[0018] In some embodiments, the first friction layer is a wear-resistant coating, the first friction layer is a DLC coating, MoS 2 Coating or NiCr coating;

[0019] And / or, the second friction layer is a liner woven from Nomex aramid and PTFE, or a liner woven from Kevlar aramid and PTFE.

[0020] In some embodiments, the first friction layer is coated on the first spherical surface by a vapor deposition method, and the second friction layer is adhered to the second spherical surface.

[0021] In some embodiments, the spherical bearing further comprises a first circuit connected to the lead.

[0022] The method for monitoring the state of a spherical bearing based on a triboelectric signal according to an embodiment of the present invention, wherein the spherical bearing is a spherical bearing as described in any one of the above embodiments, and the method for monitoring the state includes:

[0023] Acquiring a triboelectric signal generated between the first friction layer and the second friction layer in the spherical bearing;

[0024] Establishing a time-varying curve graph based on the triboelectric signal;

[0025] Based on the triboelectric signal, the operating state of the spherical bearing is monitored and faults are diagnosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of a spherical bearing according to an embodiment of the present invention.

[0027] Figure 2 Schematic diagram of the structure of the outer ring in the embodiment of the present invention.

[0028] Figure 3 Schematic diagram of the structure of the inner ring in an embodiment of the present invention.

[0029] Figure 4 It is a schematic structural diagram of the joint bearing in the spatial support coordinate system in an embodiment of the present invention.

[0030] Figure 5 It is a schematic structural diagram of the reciprocating swing of the spherical bearing in the XY plane in an embodiment of the present invention.

[0031] Figure 6 It is a schematic structural diagram of the reciprocating swing of the spherical bearing in the YZ plane in an embodiment of the present invention.

[0032] Figure 7 It is a curve diagram of the relationship between the output voltage and time in the spherical bearing in the embodiment of the present invention.

[0033] Reference numerals:

[0034] 100. Spherical plain bearings;

[0035] 1. Inner ring; 11. First spherical surface;

[0036] 2. Outer ring; 21. Second spherical surface;

[0037] 3. The first friction layer;

[0038] 4. Second friction layer;

[0039] 5. Wire. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0041] The following combination Figure 1-Figure 7 The spherical bearing and the spherical bearing state monitoring method based on triboelectric signals in the embodiments of the present invention are described in detail.

[0042] like Figures 1 to 3 As shown, the spherical bearing 100 of the embodiment of the present invention includes an inner ring 1 and an outer ring 2 connected to each other, the inner ring 1 is rotatably arranged in the outer ring 2, the inner ring 1 has a first spherical surface 11, the outer ring 2 has a second spherical surface 21, and the first spherical surface 11 and the second spherical surface 21 are in contact with each other.

[0043] It should be understood that the first spherical surface 11 (convex spherical surface) of the inner ring 1 and the second spherical surface 21 (concave spherical surface) of the outer ring 2 are matched, and the inner ring 1 and the outer ring 2 can rotate relative to each other, and the spherical bearing 100 is mostly a reciprocating swinging motion during normal operation. Figure 4 As shown in FIG. 1 , the inner ring 1 can swing relative to the outer ring 2 in three-dimensional directions of XYZ.

[0044] The spherical bearing 100 of the embodiment of the present invention also includes a first friction layer 3, a second friction layer 4 and a wire 5. The first friction layer 3 is arranged on the first spherical surface 11, and the second friction layer 4 is arranged on the second spherical surface 21. The first friction layer 3 and the second friction layer 4 are in contact with each other. A friction electric signal is generated between the first friction layer 3 and the second friction layer 4 as the inner ring 1 and the outer ring 2 rotate relative to each other. The wire 5 is connected to the outer ring 2, and the wire 5 is used to output the friction electric signal.

[0045] Specifically, the first friction layer 3 is arranged on the first spherical surface 11 of the inner ring 1, and the second friction layer 4 is arranged on the second spherical surface 21 of the outer ring 2. After the inner ring 1 and the outer ring 2 rotate relative to each other, contact friction will occur between the first friction layer 3 and the second friction layer 4 as the inner ring 1 and the outer ring 2 move relative to each other, thereby generating positive charge on one of them and negative charge on the other.

[0046] When the spherical plain bearing 100 operates normally, it is mostly a reciprocating swinging motion. When relative motion occurs between the inner ring 1 and the outer ring 2 of the spherical plain bearing 100, the contact area between the first friction layer 3 and the second friction layer 4 changes, and friction electricity is generated.

[0047] The spherical plain bearing 100 of the embodiment of the present invention can directly reflect the operating state of the bearing by utilizing the friction electric signal generated between the first friction layer 3 and the second friction layer 4, and can realize operating state monitoring and fault diagnosis of the spherical plain bearing 100.

[0048] The inner ring 1 and the outer ring 2 of the spherical plain bearing 100 of the embodiment of the present invention are in sliding contact, and the spherical plain bearing is a sliding bearing.

[0049] Furthermore, in the embodiment of the present invention, the first friction layer 3 is a friction layer of positive electrode material, and the second friction layer 4 is a friction layer of negative electrode material.

[0050] In some embodiments, a partial section of the first spherical surface 11 is covered with the first friction layer 3 , and the entire section of the second spherical surface 21 is covered with the second friction layer 4 .

[0051] It should be understood that when a partial section of the first spherical surface 11 is covered with the first friction layer 3, and the entire section of the second spherical surface 21 is covered with the second friction layer 4, and the spherical bearing 100 is operating normally, due to the existence of radial force, there is a load-bearing area between the inner ring 1 and the outer ring 2, and the first friction layer 3 and the second friction layer 4 are in contact near the load-bearing area. When the inner ring 1 and the outer ring 2 swing back and forth, a part of the first friction layer 3 will leave the load-bearing area, and this part of the first friction layer 3 will separate from the second friction layer 4. Therefore, when the outer ring 2 and the inner ring 1 of the bearing swing relative to each other, there will be a process in which the contact area between the first friction layer 3 and the second friction layer 4 gradually increases or decreases.

[0052] like Figures 1 to 6 In the spherical bearing 100 shown, the second friction layer 4 is arranged on the second spherical surface 21 of the outer ring 2, the first friction layer 3 is arranged on the first spherical surface 11 of the inner ring 1, the load-bearing area is located in the lower middle part of the inner ring 1 and the outer ring 2, negative charges are generated on the second friction layer 4, and positive charges are generated on the first friction layer 3.

[0053] The following establishes a spatial rectangular coordinate system, such as Figure 4 As shown, according to the triboelectric principle, the basic principle of generating triboelectric signals in the embodiment of the present invention is explained:

[0054] Take the example that the inner ring 1 of the spherical bearing 100 swings only in the XY plane relative to the outer ring 2. Figure 5 As shown, when the inner ring 1 of the spherical bearing 100 swings from the initial position to the extreme position, the contact area between the first friction layer 3 and the second friction layer 4 gradually decreases. According to the law of conservation of charge, the outer ring 2 of the spherical bearing 100 will stimulate induced charge and gradually increase, and electrons flow from the outer ring 2 of the spherical bearing 100 to the ground.

[0055] When the inner ring 1 of the spherical bearing 100 returns to the initial position from the extreme position, the contact area between the second friction layer 4 and the first friction layer 3 will gradually increase, and according to the law of charge conservation, the induced charge stimulated by the outer ring 2 of the spherical bearing 100 will gradually decrease until it reaches zero, and at this time, electrons flow from the ground to the outer ring 2 of the spherical bearing 100. In summary, when the spherical bearing 100 completes a swing cycle, the charging and discharging process of the outer ring 2 of the spherical bearing 100 will be cycled twice.

[0056] When the inner ring 1 of the spherical bearing 100 is relative to the outer ring 2 only in the ZY plane (such as Figure 6 As shown in the figure) or when it swings in the ZX plane, the charging and discharging process is the same as the above principle, so it will not be repeated here.

[0057] Furthermore, during the test, the relationship curve between the output voltage and time of the triboelectric signal generated in the spherical bearing 100 of the embodiment of the present invention is as follows: Figure 7 shown.

[0058] Optionally, the width of the first friction layer covering the first spherical surface in the axial direction of the spherical plain bearing 100 is greater than or equal to the width of the second friction layer covering the second spherical surface in the axial direction of the spherical plain bearing 100. At this time, when the inner ring 1 and the outer ring 2 are relatively displaced in the XY, XZ, or YZ plane, the contact area between the first friction layer 3 and the second friction layer 4 will change, thereby generating a triboelectric signal.

[0059] In some embodiments, the second friction layer 4 is a self-lubricating friction layer. That is, due to its self-lubricating property, the spherical plain bearing 100 can be self-lubricated, thereby improving the stability of the movement of the spherical plain bearing 100.

[0060] Furthermore, the first friction layer 3 is a wear-resistant coating, and the first friction layer 3 is a DLC coating, MoS 2 Coating or NiCr coating. The coating has wear resistance and can be used as the positive electrode material of the friction layer.

[0061] Among them, DLC coating is diamond-like carbon film, MoS 2 The coating is a molybdenum disulfide coating, and the NiCr coating is a nickel-chromium alloy coating.

[0062] Furthermore, the second friction layer 4 is a liner woven from Nomex aramid and PTFE, or a liner woven from Kevlar aramid and PTFE.

[0063] Among them, Nomex aramid is meta-aramid, with good heat resistance, high strength, and good mechanical properties. PTFE is polytetrafluoroethylene material, which is resistant to high temperature and has a low friction coefficient and good lubrication performance. Kevlar aramid is a poly(p-phenylene terephthalamide) aramid composite material, which has good thermal stability and strength, as well as good mechanical properties, and can be used as a negative electrode friction material. The second friction layer 4 of the embodiment of the present invention is a liner made of Nomex aramid and PTFE, or a liner made of Kevlar aramid and PTFE, which can meet the lubrication and mechanical properties of the friction layer.

[0064] The liner of the embodiment of the present invention has the function of continuous lubrication, can improve the lubrication performance between the inner ring 1 and the outer ring 2 in the spherical bearing 100, reduce the heat generated by friction, and increase the service life. At the same time, the liner can serve as the negative electrode material of the friction layer.

[0065] The second friction layer 4 can be adhered to the second spherical surface 21 by adhesive, and the liner is completely in contact with the second spherical surface. The first friction layer 3 can be coated on the first spherical surface 11 by physical or chemical vapor deposition.

[0066] Furthermore, the second friction layer 4 covers the entire section of the second spherical surface, and the second friction layer 4 has lubricating properties, which can further improve its lubricating properties.

[0067] The first friction layer 3 and the second friction layer 4 are not limited to the above materials, and may also be made of other materials that can meet the requirements in terms of function and effect.

[0068] In some embodiments, the spherical plain bearing 100 further includes a first circuit, which is connected to the wire 5. The first circuit is an external circuit, which is used to connect to the outer ring 2 of the spherical plain bearing 100 through the wire 5 to obtain a triboelectric signal, without the need to configure other additional sensors or monitoring devices, with a simple structure, fewer parts, easy installation, better practicality, and the ability to obtain triboelectric signals in real time, thus avoiding the problem of state monitoring lag in related technologies.

[0069] Electrical signals with different characteristics will be generated under different lubrication conditions. By collecting the electrical signals generated by friction, the operating status of the spherical bearing can be monitored and its faults can be diagnosed.

[0070] The method for monitoring the state of a spherical bearing based on a triboelectric signal in an embodiment of the present invention, wherein the spherical bearing is a spherical bearing in any one of the above embodiments, and the method for monitoring the state includes:

[0071] S101, obtaining a triboelectric signal generated between a first friction layer and a second friction layer in a spherical bearing.

[0072] S102. Create a curve graph showing changes over time based on the friction electric signal.

[0073] S103. Based on the friction electric signal, monitor the operation status and diagnose the faults of the spherical plain bearing.

[0074] The embodiment of the present invention can obtain the triboelectric signal change curve under normal working conditions, and then judge the abnormal triboelectric signal during the real-time monitoring of the spherical bearing, so as to reflect the operating status of the spherical bearing and perform fault diagnosis.

[0075] The embodiment of the present invention can also collect and process data on friction electric signals under different operating states and faults, and establish a database for different operating conditions and different fault situations, so as to more effectively feedback the operating status of the spherical bearing and diagnose faults.

[0076] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0077] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0078] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0079] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0080] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A spherical bearing, characterized in that: It comprises an inner ring and an outer ring connected to each other, wherein the inner ring is rotatably arranged in the outer ring, the inner ring has a first spherical surface, the outer ring has a second spherical surface, and the first spherical surface and the second spherical surface are in contact with each other; Also includes: a first friction layer and a second friction layer, wherein the first friction layer is arranged on the first spherical surface, and the second friction layer is arranged on the second spherical surface, the first friction layer and the second friction layer are in contact with each other, and a friction electric signal is generated between the first friction layer and the second friction layer as the inner ring and the outer ring rotate relative to each other; A wire is connected to the outer ring and is used to output the friction electric signal.

2. The spherical plain bearing according to claim 1, characterized in that: The first friction layer is a friction layer of positive electrode material, and the second friction layer is a friction layer of negative electrode material.

3. The spherical plain bearing according to claim 1, characterized in that: A partial section of the first spherical surface is covered with the first friction layer, and an entire section of the second spherical surface is covered with the second friction layer.

4. The spherical plain bearing according to claim 3, characterized in that: The width of the first friction layer covering the first spherical surface in the axial direction of the spherical bearing is greater than or equal to the width of the second friction layer covering the second spherical surface in the axial direction of the spherical bearing.

5. The spherical plain bearing according to claim 3, characterized in that: A load-bearing area is provided between the inner ring and the outer ring, and the first friction layer is arranged in the load-bearing area.

6. The spherical plain bearing according to any one of claims 1 to 5, characterized in that: The second friction layer is a self-lubricating friction layer.

7. The spherical plain bearing according to claim 6, characterized in that: The first friction layer is a wear-resistant coating, and the first friction layer is a DLC coating, a MoS2 coating or a NiCr coating; And / or, the second friction layer is a liner woven from Nomex aramid and PTFE, or a liner woven from Kevlar aramid and PTFE.

8. The spherical plain bearing according to claim 7, characterized in that: The first friction layer is coated on the first spherical surface by a vapor deposition method, and the second friction layer is adhered to the second spherical surface.

9. The spherical plain bearing according to claim 1, characterized in that: The spherical bearing further includes a first circuit connected to the lead wire.

10. A method for monitoring the state of a spherical bearing based on triboelectric signals, characterized in that: The spherical plain bearing is a spherical plain bearing according to any one of claims 1 to 9, and the condition monitoring method comprises: Acquiring a triboelectric signal generated between the first friction layer and the second friction layer in the spherical bearing; Establishing a time-varying curve graph based on the triboelectric signal; Based on the triboelectric signal, the operating state of the spherical bearing is monitored and faults are diagnosed.

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