A magnetic fluid sliding bearing with cooperative lubrication of pressure mapping and non-planar texture

Abstract

The present invention relates to the field of mechanical engineering lubrication technology, and specifically to a magnetic fluid sliding bearing that synergistically lubricates pressure mapping and non-planar textures, comprising a bushing, a journal, a permanent magnet, and a bearing seat, wherein the bushing is arranged on the bearing seat, and a mounting cavity is provided on the bearing seat corresponding to the center of the bushing bottom, a permanent magnet is provided in the mounting cavity, the journal is rotatably arranged in the bushing, a magnetic fluid is provided between the bushing and the journal, and the inner surface of the bushing is provided with a cylindrical surface texture composed of a plurality of inclined planes as the bottom surface. The present invention forms a synergistic lubrication effect by superimposing the micro-dynamic pressure effect generated by the surface texture and the wedge-shaped dynamic pressure effect generated by the inclined plane, thereby greatly optimizing the lubrication state of the magnetic fluid bearing; at the same time, the position of the surface texture is arranged based on the bearing oil film pressure distribution characteristics, and the diameter and depth of each surface texture are mapped in a positive correlation with the oil film pressure, effectively ensuring that each surface texture can maximize the lubrication performance and reliability of the bearing.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical engineering lubrication, and in particular to a design method for a magnetic fluid sliding bearing lubricated by cooperative lubrication of pressure mapping and non-planar texture and non-planar texture. Background Art

[0002] Sliding bearings support external loads with oil film pressure and have advantages that rolling bearings cannot match, such as a low friction coefficient, high load-bearing capacity, and long service life. They are widely used in aerospace, automotive metallurgy, and machine tool manufacturing. The use of magnetic fluid lubrication on sliding bearings can further improve their lubrication performance by taking advantage of the magnetic fluid's adjustable viscosity and position under the action of an external magnetic field. However, under heavy-load conditions such as high-end CNC presses, the eccentricity of the sliding bearing increases significantly, causing the bearing to partially contact the journal, and the bearing's lubrication performance decreases rapidly, seriously restricting the development and application of sliding bearings in high-end equipment. Creating a surface texture of a certain shape, size, and distribution on the surface of the bearing is an effective method to improve the lubrication state. Therefore, how to develop and design a surface texture to improve the lubrication performance of magnetic fluid sliding bearings under heavy-load conditions has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0003] In response to the shortcomings of the above-mentioned existing technologies, the present invention provides a design method for a magnetorheological sliding bearing and a non-planar texture that synergistically lubricates the bearing using pressure mapping and non-planar texture, so as to solve the problem of a rapid decrease in bearing lubrication performance due to a significant increase in the eccentricity of the sliding bearing under heavy load conditions.

[0004] First, in view of the complex and changeable pressure distribution characteristics in the bearing area of ​​the magnetohydrodynamic sliding bearing, the present invention sets a surface texture on the bearing area of ​​the inner surface of the bearing. At the same time, through in-depth analysis and precise mapping of the specific requirements of different pressure areas for surface texture, the size parameters of the surface texture and its spatial layout strategy are cleverly adjusted. This not only effectively ensures that the bearing can continue to maintain an efficient and stable dynamic lubrication state during long-term operation and wear, but also significantly improves the overall load-bearing capacity and lubrication performance of the magnetohydrodynamic bearing, providing solid technical support for the stable operation of the bearing under complex working conditions. Secondly, by combining simulation and single-factor experiments to determine the value ranges of various design parameters of the non-planar texture, the interference of other design parameters is eliminated, and the influence of various design parameters of the non-planar texture on the bearing lubrication performance under different working conditions is more accurately revealed, which helps to obtain the optimal value ranges of various design parameters of the non-planar texture. Finally, based on the response surface methodology, a response relationship model between the various design parameters and performance indicators of the non-planar texture was established. By optimizing the key parameters of the non-planar texture, such as diameter, depth, diameter gradient, and depth gradient, suggestions and technical support were provided for further improving the load-bearing capacity and lubrication stability of pressure mapping and non-planar texture sliding bearings.

[0005] The present invention provides a magnetic fluid sliding bearing with cooperative lubrication using pressure mapping and non-planar texture, comprising a bearing shell, a magnetic fluid, a journal, a surface texture, a permanent magnet, and a bearing seat. The bearing shell is disposed on the bearing seat, and a mounting cavity is provided on the bearing seat corresponding to the center of the bottom of the bearing shell. A permanent magnet is disposed in the mounting cavity. The journal is rotatably disposed in the bearing shell, and a magnetic fluid is disposed between the bearing shell and the journal. The inner surface of the bearing shell is provided with a plurality of cylindrical surface textures having inclined plane bottom surfaces, and the center lines of the plurality of surface textures intersect at the center of the bearing shell.

[0006] The center line of each surface texture intersects with the perpendicular plane of its center line to obtain an intersection point, and the distance from the intersection point to the top of the surface texture is the depth of the surface texture; the bottom inclined surface of each surface texture is obtained by rotating the perpendicular plane of the center line of the surface texture with the intersection point as the center in the direction of the journal rotation, and the rotation angle of the perpendicular plane of the center line of the surface texture is the bottom inclined angle of the surface texture, and the intersection point is located at the center point of the bottom inclined surface of the surface texture;

[0007] There is a central surface texture among several surface textures, and the bottom surface inclination angles of several surface textures are the same as the bottom surface inclination angle of the central surface texture; the center line of the central surface texture coincides with the line formed by the center of the journal and the center of the bearing, and the vertical plane of the center line of the central surface texture coincides with the vertical line of the line formed by the center of the journal and the center of the bearing, and the bottom surface inclination angle of the central surface texture is the acute angle formed by the vertical line of the line formed by the center of the journal and the center of the bearing and the bottom inclination plane of the central surface texture, wherein the journal center is obtained after rotating the journal based on a determined rotation direction.

[0008] Preferably, from a circumferential perspective, several surface textures are located on the inner surface of the bearing within an area mapped at 180° to 270° in the direction of shaft rotation; from an axial perspective, several surface textures are located on the inner surface of the bearing between 15% and 85% of the axial length of the bearing.

[0009] Preferably, within the region mapped at 180° to 270° in the journal rotation direction on the inner surface of the bearing shell, the surface texture located in the bearing oil film pressure region is mapped based on the bearing oil film pressure distribution, and the diameter and depth of each surface texture are positively correlated with the oil film pressure, that is, the diameter and depth of each surface texture gradually decrease from the central region to the surrounding areas, wherein the central surface texture is arranged in the most central region of the bearing oil film pressure distribution; the surface texture in the region outside the outermost oil film pressure isobaric line has the same diameter and depth as the surface texture on the outermost oil film pressure isobaric line;

[0010] In addition, the bottom surface inclination angle θ of the central surface texture is greater than 0° and less than the minimum inverse tangent value of the depth and radius of each surface texture, as shown below:

[0011]

[0012] Where H represents the depth of the center surface texture, D represents the diameter of the center surface texture, and H i represents the depth of the surface texture on the i-th oil film pressure isobar, D i Represents the diameter of the surface texture on the i-th oil film pressure isobar.

[0013] Preferably, within the bearing oil film pressure region, except for the central point of the central surface texture coinciding with the most central point of the bearing oil film pressure distribution, the central points of the remaining surface textures are all located on the oil film pressure isobars, and the surface textures on each oil film pressure isobar are evenly spaced, and the diameters and depths of the surface textures on each oil film pressure isobar are the same; at the same time, the surface textures in the outer region of the outermost oil film pressure isobar are also evenly spaced.

[0014] In addition, the distance between two adjacent oil film pressure isobars is greater than the sum of the radii of the surface textures on these two isobars.

[0015] Preferably, the mounting cavity is arranged on a bearing seat corresponding to the circumferential length of a 120° arc at the center of the bottom of the bearing shell, and both the mounting cavity and the permanent magnet are in the shape of a shell.

[0016] Preferably, the structural parameters of the non-planar texture include diameter, depth, diameter gradient, and depth gradient, wherein the depth is the distance between the center point of the bottom inclined surface of the surface texture and the top of the surface texture; meanwhile, the diameter and depth are the diameter and depth of the surface texture on the outermost oil film pressure isobaric line, and the diameter and depth of the surface texture on the remaining oil film pressure isobaric lines are obtained by adding the diameter and depth of the surface texture on the previous oil film pressure isobaric line to the diameter gradient and depth gradient;

[0017] In addition, the value ranges of various structural parameters of the non-planar texture are: 1.25mm≤diameter≤1.75mm, 25μm≤depth≤75μm, 0.2mm≤diameter gradient≤0.4mm, 25m≤depth gradient≤75μm.

[0018] Preferably, the optimal values ​​of the structural parameters of the non-planar texture are: diameter of 1.331 mm, depth of 26.509 μm, diameter gradient of 0.240 mm, and depth gradient of 29.115 μm.

[0019] The present invention also provides a design method for a non-planar texture of a magnetic fluid sliding bearing that is lubricated in a cooperative manner by pressure mapping and non-planar texture, which is applied to a magnetic fluid sliding bearing that is lubricated in a cooperative manner by pressure mapping and non-planar texture. The specific steps are as follows:

[0020] S1. Determining an optimization objective and design variables for a non-planar texture, wherein the optimization objective is bearing capacity, and the design variables include diameter, depth, diameter gradient, and depth gradient, where the depth is the distance between the center point of the bottom inclined surface of the surface texture and the top of the surface texture;

[0021] S2. Construct a parametric model of a magnetic fluid sliding bearing with synergistic lubrication using pressure mapping and non-planar textures. Based on single-factor experiments, study the influence of each design variable on the optimization objective to determine the value range of each design variable. The basic performance parameters used to construct the parametric model of a magnetic fluid sliding bearing with synergistic lubrication using pressure mapping and non-planar textures include: oil film inner diameter, oil film outer diameter, oil film width, eccentricity, eccentricity, oil inlet diameter, oil inlet length, inlet pressure, and rated speed.

[0022] S3. Using the optimization target as the response value, the Box-Behnken principle in the Design-Expert software is used to conduct a response surface experiment based on the single-factor experiment in step S2. The performance values ​​of the optimization target are fitted to establish a multiple regression model equation for the optimization target, as shown below:

[0023]

[0024] In the formula, Y represents the response value, X i 、X j are the i-th and j-th design variables respectively, k represents the number of design variables, b0, b i 、b ii 、b ij is the coefficient to be solved;

[0025] S4. Use Design Expert software to draw and analyze the relationship between design variables and response values ​​according to the multivariate regression model, obtain the response surface diagram of the regression equation, and then obtain the optimal design parameters of the non-planar texture.

[0026] Preferably, the design variables determined in step S1, namely, the diameter and depth, are the diameter and depth of the surface texture on the outermost oil film pressure isobaric line, and the diameter and depth of the surface texture on the remaining oil film pressure isobaric lines are obtained by adding the diameter and depth of the surface texture on the previous oil film pressure isobaric line to the diameter gradient and the depth gradient; in addition, the diameter of the central surface texture is obtained by adding the diameter gradient to the diameter of the surface texture on the innermost oil film pressure isobaric line, and the depth of the central surface texture is obtained by adding the depth gradient to the depth of the surface texture on the innermost oil film pressure isobaric line;

[0027] When the value ranges of the design variables are: 1.25 mm ≤ diameter ≤ 1.75 mm, 25 μm ≤ depth ≤ 75 μm, 0.2 mm ≤ diameter gradient ≤ 0.4 mm, 25 m ≤ depth gradient ≤ 75 μm, the regression model equation of the bearing capacity F obtained by simulation in step S3 is as follows:

[0028]

[0029] Where F is the bearing capacity in N; X1 is the diameter, X2 is the depth, X3 is the diameter gradient, and X4 is the depth gradient.

[0030] Preferably, the optimal design parameters of the non-planar texture obtained by using the Design Expert software in step S4 are: diameter of 1.331 mm, depth of 26.509 μm, diameter gradient of 0.240 mm, and depth gradient of 29.115 μm.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention provides surface textures in the oil film bearing area on the inner surface of the magnetic fluid bearing bushing, making the surface textures equivalent to many miniature hydrodynamic bearings, directly providing additional support force to the shaft neck, and significantly enhancing the lubrication efficiency and load-bearing capacity of the magnetic fluid sliding bearing. At the same time, by setting the bottom surface of the surface texture as an inclined plane, the interaction between the surface texture and the wedge-shaped hydrodynamic effect generated when the shaft neck rotates is cleverly enhanced. The two hydrodynamic effects are superimposed on each other to form a synergistic lubrication effect, which greatly optimizes the lubrication state of the magnetic fluid bearing, especially the lubrication state of the magnetic fluid bearing under heavy load conditions.

[0033] 2. The present invention arranges the position of the surface texture based on the pressure distribution characteristics of the bearing oil film. At the same time, by mapping the diameter and depth of each surface texture to the oil film pressure in a positive correlation, the diameter and depth of each surface texture gradually decrease from the central area to the surrounding area, effectively ensuring that each surface texture can maximize the lubrication performance and reliability of the bearing.

[0034] 3. The present invention simulates the working state and oil film pressure distribution of the bearing under different working conditions through simulation without manufacturing actual samples, thereby reducing the number and cost of experiments and effectively shortening the period of finding the value range of various design parameters; at the same time, the value range of various design parameters of the non-planar texture is determined in combination with single-factor experiments on the basis of simulation, which not only eliminates the interference of other design parameters, but also more accurately reveals the influence of various design parameters of the non-planar texture on the lubrication performance of the bearing under different working conditions, and also helps to obtain the optimal value range of various design parameters of the non-planar texture, thereby ensuring that the subsequent optimization experiments are carried out within a reasonable parameter range, effectively avoiding unnecessary waste of resources.

[0035] 4. Based on the response surface methodology, the present invention establishes a response relationship model between various design parameters and performance indicators of non-planar textures. By optimizing key parameters such as the diameter, depth, diameter gradient, and depth gradient of the non-planar texture, it not only reduces the complexity of the optimization process but also effectively ensures the optimization accuracy, providing suggestions and technical support for further improving the load-bearing capacity and lubrication stability of pressure mapping and non-planar texture sliding bearings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic diagram of the structure of a two-dimensional model of a magnetic fluid sliding bearing with cooperative lubrication of pressure mapping and non-planar texture provided by the present invention;

[0038] Figure 2 The present invention provides Figure 1 A partial enlarged view of

[0039] Figure 3 A schematic diagram of the three-dimensional model structure of the surface texture in the oil film pressure area of ​​the bearing provided by the present invention;

[0040] Figure 4 This invention Figure 3 The schematic diagram of the overall distribution of the surface texture of the bearing shell after it is expanded along the circumferential direction is shown;

[0041] Figure 5 This invention Figure 4 The B-direction view of the overall distribution of the surface texture of the bearing shell after it is expanded along the circumferential direction is shown;

[0042] Figure 6 This invention Figure 4 The A-direction view of the overall distribution of the surface texture of the bearing shell after it is expanded along the circumferential direction is shown;

[0043] Figure 7 is a full texture model diagram provided by an embodiment of the present invention;

[0044] Figure 8 This is a pressure mapping I texture model diagram provided by an embodiment of the present invention;

[0045] Figure 9 This is a pressure mapping II texture model diagram provided by an embodiment of the present invention;

[0046] Figure 10This is a pressure mapping III texture model diagram provided by an embodiment of the present invention;

[0047] Figure 11 This is a comparison chart of the lubrication performance of models with different texture mapping modes provided by an embodiment of the present invention;

[0048] Figure 12 is a trend diagram showing the bearing lubrication performance changing with the texture diameter provided by an embodiment of the present invention;

[0049] Figure 13 is a trend diagram showing the bearing lubrication performance changing with texture depth according to an embodiment of the present invention;

[0050] Figure 14 is a trend diagram showing the bearing lubrication performance changing with the texture diameter gradient provided by an embodiment of the present invention;

[0051] Figure 15 is a trend diagram showing the bearing lubrication performance changing with the texture depth gradient provided by an embodiment of the present invention;

[0052] Figure 16 This is a trend diagram showing how the bearing lubrication performance varies with the inclination angle of the texture bottom surface, provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0054] like Figure 1-6 As shown, the present invention provides a magnetic fluid sliding bearing with cooperative lubrication of pressure mapping and non-planar texture, comprising a bearing bush 1, a magnetic fluid 2, a journal 3, a surface texture 4, a permanent magnet 5 and a bearing seat 6, wherein the bearing bush 1 is arranged on the bearing seat 6, and a mounting cavity is provided on the bearing seat 6 corresponding to the bottom center of the bearing bush 1, and a permanent magnet 5 is provided in the mounting cavity, the journal 3 is rotatably arranged in the bearing bush 1, and a magnetic fluid 2 is provided between the bearing bush 1 and the journal 3, and the inner surface of the bearing bush 1 is provided with a plurality of cylindrical surface textures 4 with inclined plane bottom surfaces, and the center lines of the plurality of surface textures 4 intersect at the center of the bearing bush, wherein:

[0055] The center line of each surface texture 4 intersects with the perpendicular plane ① to its center line to obtain an intersection point P, and the distance from the intersection point P to the top of the surface texture 4 is the depth of the surface texture 4; the bottom inclined surface ② of each surface texture 4 is obtained by rotating the perpendicular plane ① to the center line of the surface texture 4 in the direction of rotation of the journal 3 with the intersection point P as the center. The rotation angle of the perpendicular plane ① to the center line of the surface texture 4 is the bottom surface inclination angle of the surface texture 4, and the intersection point P is located at the center point of the bottom inclined surface ② of the surface texture 4;

[0056] There is a central surface texture 41 among the several surface textures 4, and the bottom surface inclination angles of the several surface textures 4 are the same as the bottom surface inclination angle of the central surface texture 41; the center line of the central surface texture 41 coincides with the line formed by the center of the journal 3 and the center of the bearing 1, and the vertical plane of the center line of the central surface texture 41 coincides with the vertical line of the line formed by the center of the journal 3 and the center of the bearing 1, and the bottom surface inclination angle of the central surface texture 41 is the acute angle θ formed by the vertical line of the line formed by the center of the journal 3 and the center of the bearing 1 and the bottom inclination plane of the central surface texture 41, wherein the center of the journal 3 is obtained after rotating the journal 3 based on a determined rotation direction.

[0057] In the embodiment of the present application, during the rotation of the journal 3 around the bearing 1, the cylindrical surface textures 4 with inclined planes on the bottom surface play multiple key roles. First, the cylindrical surface textures 4 with inclined planes on the bottom surface are equivalent to many micro-dynamic pressure bearings. These specially designed surface textures 4 can produce a micro-dynamic pressure effect in the magnetic fluid sliding bearing, directly providing additional support for the journal 3, significantly enhancing the lubrication efficiency and load-bearing capacity of the magnetic fluid sliding bearing. Secondly, the inclined plane design of the surface texture 4 cleverly enhances the wedge-shaped dynamic pressure effect generated when it rotates with the journal 3. The two dynamic pressure effects - the micro-dynamic pressure effect and the wedge-shaped dynamic pressure effect - are superimposed on each other, forming a synergistic lubrication effect, greatly optimizing the lubrication state of the magnetic fluid bearing. Furthermore, the presence of the surface texture 4 enables it to store part of the magnetic fluid 2, thereby continuously replenishing the bearing gap with magnetic fluid 2 during the operation of the bearing, effectively preventing the shortage of lubricating medium, and further improving the oil film load-bearing capacity and overall lubrication performance of the magnetic fluid sliding bearing. Therefore, the design of the surface texture 4 in the present application significantly improves the comprehensive performance of the magnetic fluid sliding bearing.

[0058] Preferably, from a circumferential perspective, the plurality of surface textures 4 are located on the inner surface of the bearing bush 1 within a region mapped at 180° to 270° in the rotation direction of the journal 3, such as Figure 1 From an axial perspective, a plurality of surface textures 4 are located on the inner surface of the bearing bush 1 at an axial length of between 15% and 85%.

[0059] like Figure 1 、 2As shown, in the initial state, the center of the journal 3 is located at point O; when the journal 3 rotates counterclockwise, that is, when it runs counterclockwise from the positive half axis of the x-axis, the positive half axis of the x-axis is 0° and the positive half axis of the y-axis is 90°. Figure 1 The center of the journal 3 shown is moved from O to a new position O1, and the bearing area is now located at Figure 1 The lower left corner shown is the area on the inner surface of the bearing shell 1 that is mapped at 180° to 270° in the rotation direction of the journal 3.

[0060] It should be noted that during actual operation, the journal 3 can also rotate clockwise, from the negative half of the x-axis to the positive half of the y-axis, where the negative half of the x-axis is 0° and the positive half of the y-axis is 90°. Regardless of whether the journal 3 rotates left or right, the bearing's load-bearing area is located within the region mapped between 180° and 270° in the direction of the journal 3's rotation. Therefore, from a circumferential perspective, the plurality of surface textures 4 on the inner surface of the bearing shell 1 are located within the region mapped between 180° and 270° in the direction of the journal 3's rotation.

[0061] In the present application, within the mapping area of ​​180° to 270° in the rotation direction of the journal 3 on the inner surface of the bearing shell 1, the surface texture 4 located in the bearing oil film pressure area is based on the bearing oil film pressure distribution, and the diameter and depth of each surface texture 4 are positively correlated with the oil film pressure, that is, the diameter and depth of each surface texture 4 gradually decrease from the central area to the surrounding areas, wherein the central surface texture 41 is arranged in the most central area of ​​the bearing oil film pressure distribution; the surface texture 4 in the outer area of ​​the outermost oil film pressure isobaric line has the same diameter and depth as the surface texture 4 on the outermost oil film pressure isobaric line.

[0062] It should be noted that this application Figures 1-6 Only the surface textures 4 and the central surface texture 41 are provided in the bearing oil film pressure region, so as to more clearly distinguish the surface textures 4 in the bearing oil film pressure region from the surface textures 4 in the region outside the outermost oil film pressure isobars. In addition, the surface textures 4 are provided in the bearing oil film pressure region and the region outside the outermost oil film pressure isobars. Figure 10 .

[0063] It should be emphasized that the isobars of the bearing oil film pressure are usually distributed in an elliptical shape, and the oil film pressure gradually decreases from the central area to the surrounding areas. Figure 4As shown, in the embodiment of the present application, each surface texture 4 within the bearing oil pressure area is also distributed in an elliptical shape, and the diameter and depth of each surface texture 4 are also mapped to this pressure change by gradually decreasing from the center area to the surrounding areas. Specifically, the surface texture 4 in the center area is designed to have a relatively large diameter and depth to cope with the higher oil film pressure and ensure sufficient lubricating oil storage and flow; as it moves toward the edge area, the diameter and depth of the surface texture 4 gradually decrease to match the gradually decreasing oil film pressure, thereby reducing unnecessary lubricating oil consumption and loss while maintaining effective lubrication. This design strategy of gradually decreasing from the center to the edge not only achieves a positive correlation mapping between the geometric size of the surface texture 4 and the oil film pressure distribution, but also optimizes the lubrication performance and overall efficiency of the bearing.

[0064] like Figure 5-6 As shown, the diameters of the surface textures 4 from the center to the periphery are D, D1, D2, D3, and D4, respectively, and their depths are H, H1, H2, H3, and H4, respectively. Since the diameter and depth of each surface texture 4 located on the isobar at the exact center are the largest, and the diameter and depth of each surface texture 4 located on the outermost isobar are the smallest, D>D1>D2>D3>D4, and H>H1>H2>H3>H4.

[0065] In the present application, the bottom surface inclination angle θ of the central surface texture 41 is greater than 0° and less than the minimum inverse tangent value of the depth and radius of each surface texture 4, as shown below:

[0066]

[0067] Where H represents the depth of the center surface texture, D represents the diameter of the center surface texture, and H i represents the depth of the surface texture on the i-th oil film pressure isobar, D i Represents the diameter of the surface texture on the i-th oil film pressure isobar.

[0068] It should be noted that, in the embodiment of the present application, a parameterized model of a magnetic fluid sliding bearing with cooperative lubrication of pressure mapping and non-planar texture is constructed, and the influence of different bottom surface inclination angles on the bearing lubrication performance is studied based on a single factor experiment. Figure 16 As the bottom surface inclination angle gradually increases, the load-bearing capacity and maximum oil film pressure gradually increase, while the friction coefficient gradually decreases. The decrease becomes more gradual between 5° and 10°, confirming the superiority of the bottom surface inclination angle in improving bearing lubrication performance. Therefore, precisely controlling the bottom surface inclination angle θ of surface texture 4 to ensure it is within the optimal working range can create a stronger wedge effect between the bottom inclined surface ② of surface texture 4 and the journal 3, better coordinating the micro-dynamic pressure effect of surface texture 4, and thus optimizing the overall performance of surface texture 4.

[0069] However, the bottom surface inclination angle θ must be within a certain range. Take the bottom surface inclination angle θ of the center surface texture 41 as an example to explain: when the bottom surface inclination angle θ is 0°, the vertical plane ① of the center line of the center surface texture 41, that is, the vertical line of the line connecting the center of the journal 3 and the center of the bearing 1, coincides with the bottom inclination plane ② of the center surface texture 41. At this time, the center surface texture 41 is a plane texture; when the bottom surface inclination angle θ is the largest, such as Figure 6 The vertical plane ①' of the center line of the center surface texture 41 shown in the figure, that is, the bottom surface inclination angle θ formed by the vertical line of the line connecting the center of the journal 3 and the center of the bearing 1 and the bottom inclined surface ②' of the center surface texture 41, if the bottom surface inclination angle θ of the center surface texture 41 continues to increase, it is impossible to form a cylindrical surface texture with an inclined plane as the bottom surface. In addition, since the radius and depth of each surface texture on different oil film pressure isobars are different. Therefore, in this application, the maximum value of the bottom surface inclination angle θ of the center surface texture 41 is limited by the minimum inverse tangent value of the depth and radius of the surface texture 4. In addition, in the initial no-load state, the center O1 of the journal 3 and the center O of the bearing 1 coincide with each other. Therefore, it is necessary to first rotate the journal 3 based on the determined rotation direction, find the center of the journal 3 when it rotates, and then determine the line connecting the center of the journal 3 and the center of the bearing 1, and then determine the vertical line connecting the center of the journal 3 and the center of the bearing 1.

[0070] Preferably, in the bearing oil film pressure area, except for the center point of the central surface texture 41 which coincides with the center point of the bearing oil film pressure distribution, the center points of the remaining surface textures 4 are all located on the oil film pressure isobars, and the several surface textures 4 on each oil film pressure isobar are evenly arranged at equal intervals, and the diameters and depths of the several surface textures 4 on each oil film pressure isobar are the same; at the same time, the several surface textures 4 in the outer area of ​​the outermost oil film pressure isobar are also evenly arranged at equal intervals.

[0071] Since the center line of the center surface texture 41 coincides with the line formed by the center of the journal 3 and the center of the bearing shell 1, the center point of the center surface texture 41 coincides with the centermost point of the bearing oil film pressure distribution. Therefore, in this application, the position where the line formed by the center of the journal 3 and the center of the bearing shell 1 passes through the bearing oil film pressure area on the inner surface of the bearing shell 1 coincides with the centermost point of the bearing oil film pressure distribution.

[0072] In this application, by setting several surface textures 4 with the same diameter and depth on each isobar where the bearing oil film pressure is equal, not only is the processing process simplified, making the processing of surface textures 4 on the same isobar more uniform and efficient, but it also ensures that the micro-dynamic pressure effect generated by each surface texture 4 and its surrounding microstructures on the magnetic fluid 2 remains consistent, further improving the stable operating performance of the bearing, while also extending its service life.

[0073] In the present application, the distance between two adjacent oil film pressure isobars is greater than the sum of the radii of the surface textures 4 on the two isobars.

[0074] It should be noted that the number of oil film pressure isobars can be set according to specific circumstances. Generally, the more oil film pressure isobars there are, the better the lubrication effect. However, the more oil film pressure isobars there are, the more surface textures 4 need to be processed, which will greatly increase the manufacturing cost; at the same time, the more oil film pressure isobars there are, the smaller the geometric dimensions of the surface texture 4 will be, further increasing the difficulty of processing. Therefore, considering that the number of oil film pressure isobars is affected by the geometric dimensions of the bearing, the diameter of the surface texture 4, and the diameter gradient, it is set in this application that the distance between two adjacent oil film pressure isobars is greater than the sum of the radii of the surface textures 4 on these two isobars, so as to ensure that there is no interference between the surface textures 4.

[0075] In addition, to ensure the strength of the spaced portions between the surface textures 4, the present embodiment sets the distance between two adjacent oil film pressure isobars to be the sum of twice the radius of the surface texture 4 on the two isobars. In the present embodiment, the number of oil film pressure isobars is 4.

[0076] like Figure 7-10As shown, in order to verify the superiority of the surface texture 4 proposed in the present invention in the bearing lubrication performance, especially the superiority in load-bearing capacity, friction coefficient and maximum oil film pressure, a texture-free model, a full-texture model, a pressure mapping I texture model, a pressure mapping II texture model and a pressure mapping III texture model are constructed in this application. By finely controlling the arrangement and characteristics of the surface texture 4, such as diameter and depth, in different models, the influence of changes in the arrangement and characteristics of the texture on the bearing lubrication performance is explored.Among them, the texture-free model is a benchmark model, which is used to understand the bearing lubrication performance without texture; the full-texture model is a radial sliding bearing, starting from the load position, on the inner surface of the bearing shell 1, in the area of ​​180° to 270° mapping in the rotation direction of the journal 3, there are several surface textures 4 with inclined planes evenly spaced, which are used to evaluate the effect of setting the surface texture 4 between 180° and 270° on the bearing lubrication performance; the pressure mapping I texture model is based on the full-texture model, according to the pressure gradient of the pressure cloud map simulated by the texture-free model, a number of similar textures are evenly spaced on different isobars in the bearing oil film pressure area. The surface texture 4 with the same diameter and depth and inclined planes, and the outer area of ​​the outermost oil film pressure isobaric line also uniformly arranges a number of surface textures 4 with inclined planes at equal intervals, wherein the surface texture 4 in the outer area of ​​the outermost oil film pressure isobaric line and the surface texture 4 on the outermost oil film pressure isobaric line have the same diameter and depth, which is used to evaluate the influence of using the surface texture 4 with the same diameter and depth on the bearing performance on all isobars of the bearing oil film pressure in the area of ​​180° to 270°; the pressure mapping II texture model is based on the full texture model, and according to the pressure gradient of the pressure cloud map simulated by the no-texture model, the pressure of the bearing oil film pressure is obtained. Several surface textures 4 with different diameters but the same depth and inclined planes are evenly arranged at equal intervals on different isobars in the pressure region. Several surface textures 4 with inclined planes are also evenly arranged at equal intervals in the outer region of the outermost oil film pressure isobar. The surface texture 4 in the outer region of the outermost oil film pressure isobar is the same as the surface texture 4 on the outermost oil film pressure isobar. The purpose is to evaluate the effect of using surface textures 4 with different diameters but the same depth on different isobars of the bearing oil film pressure in the region of 180° to 270° on the bearing performance. The pressure mapping III texture model is based on the full texture model. The pressure gradient of the pressure cloud map simulated by the texture-free model, in which several surface textures 4 with different diameters, different depths and inclined planes are evenly arranged at equal intervals on different isobars in the bearing oil film pressure area, and several surface textures 4 with inclined planes are also evenly arranged at equal intervals in the outer area of ​​the outermost oil film pressure isobar. The surface texture 4 in the outer area of ​​the outermost oil film pressure isobar has the same diameter and depth as the surface texture 4 on the outermost oil film pressure isobar, which is used to evaluate the impact of using surface textures 4 with different diameters and depths on different isobars of the bearing oil film pressure in the area of ​​180° to 270° on the bearing performance.

[0077] It should be noted that the bearing load area in this application is located in the area mapped from 180° to 270° in the rotation direction of the journal 3. This is because the simulation model takes the negative half axis of the y-axis as 0° and the negative half axis of the x-axis as 90°. Figure 7-10The pressure cloud is between 0° and 90°, not between 180° and 270° as described in this application. This difference should be ignored when viewing the diagram. Figure 7 The full texture model shown does not have the center surface texture 41, for a fair comparison. Figures 8-10 The pressure mapping I texture model, the pressure mapping II texture model, and the pressure mapping III texture model shown in the figure do not include the central surface texture 41, but the bottom surface inclination angle of each surface texture 4 is still obtained based on the bottom surface inclination angle of the central surface texture 41.

[0078] from Figure 11 The lubrication performance comparison chart for different types of texture models clearly shows that the full texture model, pressure mapping I texture model, pressure mapping II texture model, and pressure mapping III texture model all outperform the untextured model in terms of load capacity, friction coefficient, and maximum oil film pressure. Specifically, the pressure mapping III texture model achieves the best performance in terms of load capacity, friction coefficient, and maximum oil film pressure compared to the untextured, full texture model, pressure mapping I texture model, and pressure mapping II texture model. This indicates that rationally arranging and adjusting the surface texture 4 based on the bearing oil film pressure within the region mapped from 180° to 270° relative to the rotational direction of the journal 3 on the inner surface of the bearing shell 1 can maintain a good lubrication state, thereby improving the bearing's load capacity and maximum oil film pressure, and reducing the friction coefficient.

[0079] Preferably, the mounting cavity is provided on the bearing seat 6 corresponding to the circumferential length of the arc of 120° at the bottom center of the bearing bush 1, and both the mounting cavity and the permanent magnet 5 are in the shape of a bush.

[0080] In the embodiment of the present application, by disposing the permanent magnet 5 , the viscosity of the magnetic fluid 2 is significantly increased under the action of the magnetic field of the tile-shaped permanent magnet 5 , thereby effectively improving its performance as a lubricant.

[0081] In summary, the present invention innovatively integrates the complex and changeable pressure distribution characteristics in the load-bearing area of ​​the magnetohydrodynamic sliding bearing and the optimization principle of the surface texture 4 design, and especially proposes a refined solution for the non-uniform stress conditions that the bearing 1 is subjected to in the actual working environment; at the same time, through in-depth analysis and precise mapping of the specific requirements of different pressure areas for the surface texture 4, the dimensional parameters of the surface texture 4 and its spatial layout strategy are cleverly adjusted, which not only effectively ensures that the bearing 1 can continue to maintain an efficient and stable dynamic lubrication state during long-term operation and wear, but also significantly improves the overall load-bearing capacity and lubrication performance of the magnetohydrodynamic bearing, providing solid technical support for the stable operation of the bearing 1 under complex working conditions, especially under heavy-load conditions.

[0082] It should be noted that, for the sake of convenience of description, in this application, “pressure mapping and non-planar texture cooperatively lubricated magnetic fluid sliding bearing” is briefly described as “pressure mapping and non-planar texture sliding bearing”.

[0083] The present invention also provides a method for designing a non-planar texture of a magnetic fluid sliding bearing that is lubricated in a coordinated manner using pressure mapping and non-planar texture. The specific steps are as follows:

[0084] S1. Determine the optimization objectives and design variables of non-planar textures.

[0085] In this application, the optimization target includes bearing capacity, and the design variables include diameter, depth, diameter gradient and depth gradient, wherein the depth is the distance between the center point of the bottom inclined surface of the surface texture 4 and the top of the surface texture 4 .

[0086] It should be noted that the optimization target is not limited to load-bearing capacity. In practical applications, the optimization target may also include friction coefficient and / or maximum oil film pressure. In addition, the bottom surface inclination angle of each surface texture 4 may also be used as a design variable.

[0087] It should be emphasized that the design variables determined in step S1 - diameter and depth - are the diameter and depth of the surface texture 4 on the outermost oil film pressure isobar, and the diameter and depth of the surface texture 4 on the remaining oil film pressure isobars are obtained by adding the diameter and depth of the surface texture 4 on the previous oil film pressure isobar to the diameter gradient and depth gradient.

[0088] For example, in the present application, the number of oil film pressure isobars is set to 4, which are the first, second, third and fourth from the outside to the inside. The diameter of the upper surface texture 4 on the second oil film pressure isobar is obtained by adding the diameter gradient and the diameter of the upper surface texture 4 on the first oil film pressure isobar, and the depth of the upper surface texture 4 on the second oil film pressure isobar is obtained by adding the depth gradient and the depth of the upper surface texture 4 on the first oil film pressure isobar; the diameter of the upper surface texture 4 on the third oil film pressure isobar is obtained by adding the diameter gradient and the diameter of the upper surface texture 4 on the second oil film pressure isobar, and the depth of the upper surface texture 4 on the third oil film pressure isobar is obtained by adding the depth gradient and the depth of the upper surface texture 4 on the second oil film pressure isobar, and the diameter and depth of the upper surface texture 4 on each oil film pressure isobar are calculated by analogy.

[0089] In addition, if Figure 4-6 As shown, the central surface texture 41 is arranged in the centralmost area of ​​the bearing oil film pressure distribution, wherein the diameter of the central surface texture 41 is obtained by adding the diameter gradient and the diameter of the surface texture 4 on the innermost oil film pressure isobar, and the depth of the central surface texture 41 is obtained by adding the depth gradient and the depth of the surface texture 4 on the innermost oil film pressure isobar.

[0090] S2. Construct a parametric model of a magnetohydrodynamic sliding bearing with synergistic lubrication of pressure mapping and non-planar texture, and study the influence of each design variable on the optimization objective based on single-factor experiments to determine the value range of each design variable.

[0091] In an embodiment of the present application, the basic performance parameters used to construct a parametric model of a magnetohydrodynamic sliding bearing with cooperative lubrication of pressure mapping and non-planar texture include: oil film inner diameter, oil film outer diameter, oil film width, eccentricity, eccentricity, oil inlet diameter, oil inlet length, inlet pressure, and rated speed.

[0092] In the embodiment of this application, the basic performance parameters are shown in Table 1 below:

[0093] Table 1. Basic performance parameters

[0094]

[0095] like Figure 12 As shown in the figure, first, the diameter of the surface texture 4 is selected to be in the range of 1.0mm to 2.0mm based on conventional design experience; second, in the parameterized model of the magnetic fluid sliding bearing with synergistic lubrication of pressure mapping and non-planar texture, the depth, diameter gradient, and depth gradient remain unchanged. By systematically changing the diameter of the surface texture 4, the effect of different diameters of the surface texture 4 on the bearing lubrication performance is studied, that is, the effect of the diameter in the range of 1.0mm to 2.0mm on the bearing lubrication performance, thereby determining the range of the diameter. Figure 12 It can be seen that as the diameter gradually increases, the bearing capacity and maximum film pressure first increase and then decrease, and the friction coefficient first decreases and then increases. When the diameter is 1.5 mm, the bearing capacity and maximum oil film pressure are the largest, and the friction coefficient is the smallest. At this time, the bearing lubrication effect is the best. Therefore, the diameter value range in this application is 1.25 mm to 1.75 mm.

[0096] like Figure 13 As shown in the figure, first, the depth range of surface texture 4 is selected as 25μm to 125μm based on conventional design experience; second, in the parameterized model of a magnetic fluid sliding bearing lubricated by pressure mapping and non-planar texture, the diameter, diameter gradient, and depth gradient remain unchanged. By systematically changing the depth of surface texture 4, the influence of different depths of surface texture 4 on the lubrication performance of the bearing is studied, that is, the influence of the depth in the range of 25μm to 125μm on the lubrication performance of the bearing, thereby determining the range of depth. Figure 13 It can be seen that as the depth gradually increases, the bearing capacity and maximum film pressure first increase and then decrease, and the friction coefficient first decreases and then increases. When the depth is 50μm, the bearing capacity and maximum oil film pressure are the largest, and the friction coefficient is the smallest. At this time, the bearing lubrication effect is the best. Therefore, the depth value range in this application is 25μm to 75μm.

[0097] like Figure 14 As shown in the figure, first, the diameter gradient value range of surface texture 4 is selected as 0mm to 0.5mm based on conventional design experience; second, in the parameterized model of the magnetohydrodynamic sliding bearing with synergistic lubrication of pressure mapping and non-planar texture, the diameter, depth and depth gradient remain unchanged. By systematically changing the diameter gradient of surface texture 4, the influence of different diameter gradients of surface texture 4 on the lubrication performance of the bearing is studied, that is, the influence of the diameter gradient in the range of 0mm to 0.5mm on the lubrication performance of the bearing is studied, thereby determining the value range of the diameter gradient. Figure 14 It can be seen that as the diameter gradient gradually increases, the bearing capacity and maximum film pressure first increase and then decrease, and the friction coefficient first decreases and then increases. When the diameter gradient is 0.3 mm, the bearing capacity and maximum oil film pressure are the largest, and the friction coefficient is the smallest. At this time, the bearing lubrication effect is the best. Therefore, the value range of the diameter gradient in this application is 0.2 mm to 0.4 mm.

[0098] like Figure 15 As shown in the figure, first, based on conventional design experience, the depth gradient of surface texture 4 is selected to have a value range of 0m to 100μm; second, in the parameterized model of a magnetic fluid sliding bearing lubricated by pressure mapping and non-planar texture, the diameter, depth, and diameter gradient remain unchanged. By systematically changing the depth gradient of surface texture 4, the influence of different depth gradients of surface texture 4 on the lubrication performance of the bearing is studied, that is, the influence of the depth gradient in the range of 0m to 100μm on the lubrication performance of the bearing, thereby determining the value range of the depth gradient. Figure 15 It can be seen that as the depth gradient gradually increases, the bearing capacity and maximum film pressure first increase and then decrease, and the friction coefficient first decreases and then increases. Among them, when the depth gradient is 50μm, the bearing capacity and maximum oil film pressure are the largest, and the friction coefficient is the smallest. At this time, the bearing lubrication effect is the best. Therefore, the value range of the depth gradient in this application is 25m~75μm.

[0099] In summary, in this application, the diameter ranges from 1.25 mm to 1.75 mm, the depth ranges from 25 μm to 75 μm, the diameter gradient ranges from 0.2 mm to 0.4 mm, and the depth gradient ranges from 25 μm to 75 μm.

[0100] S3. Using the optimization target as the response value, the Box-Behnken principle in the Design-Expert software is used to conduct a response surface experiment based on the single-factor experiment in step S2. The performance values ​​of the optimization target are fitted to establish a multiple regression model equation for the optimization target, as shown below:

[0101]

[0102] In the formula, Y represents the response value, X i 、Xj are the i-th and j-th design variables respectively, k represents the number of design variables, b0, b i 、b ii 、b ij is the coefficient to be solved.

[0103] In this example, based on the range of design variables determined by single-factor experiments, and with bearing capacity as the response value, a four-factor, three-level response surface experiment was designed. Four factors (diameter, depth, diameter gradient, and depth gradient) were selected according to the Box-Behnken principle. This yielded 29 experimental schemes, which were then simulated using Fluent flow field simulation to obtain the response values. The selected factor levels and codes are shown in Table 2, and the experimental factor combination schemes and results are shown in Table 3.

[0104] Table 2. Box-Behnken experimental factor levels and coding table

[0105]

[0106] It should be noted that a four-factor three-level response surface experiment was designed based on four design variables in this application. In actual use, the number of levels can be set according to needs.

[0107] Table 3. Experimental factor combination scheme

[0108]

[0109] This application performs regression difference analysis on the data in Table 3 and obtains the bearing capacity F regression model equation through regression analysis using response surface testing software, wherein the bearing capacity F regression model equation is as follows:

[0110]

[0111] Where F is the bearing capacity in N; X1 is the diameter, X2 is the depth, X3 is the diameter gradient, and X4 is the depth gradient.

[0112] In addition, the embodiment of the present application also conducted variance analysis, significance analysis and error analysis on the load-bearing capacity F regression model equation. Table 4 is the variance analysis table of the simplified quadratic model, and Table 5 is the model equation error analysis table. 2 , Adjusted R 2 ,Predicted R 2 and Adeq Precision to measure the adequacy of the model.

[0113] Table 4. ANOVA table of simplified quadratic model

[0114]

[0115] Table 5. Error analysis

[0116]

[0117] Table 4 shows that the model F-value is 91.64 and the p-value is <0.0001, indicating that the model as a whole is highly significant. The model's significance means that it is effective in capturing the relationships between factors. In addition, the p-values ​​for the four factors (diameter, depth, diameter gradient, and depth gradient) are all <0.0001, indicating that they have a significant impact on the response variable (carrying capacity).

[0118] Correlation coefficient R 2 The closer it is to 1, the better the quadratic regression model fits. As shown in Table 5, the R 2 The Predicted R 2 is 0.9378, Adjusted R 2 is 0.9784, so we can see that Predicted R 2 With Adjusted R 2 The difference is within 0.05, indicating that the model's predictive and fitting abilities for new data are relatively consistent and within a reasonable range. Overall, the model can well describe the true relationship between each factor and the response value, and its regression simulation equation can be used to determine the optimal design parameters for non-planar textures.

[0119] S4. Use Design Expert software to draw and analyze the relationship between design variables and response values ​​according to the multivariate regression model, obtain the response surface diagram of the regression equation, and then obtain the optimal design parameters of the non-planar texture.

[0120] In the embodiment of the present application, the optimal design parameters of the non-planar texture obtained by the Design Expert software are: when the diameter is 1.331 mm, the depth is 26.509 μm, the diameter gradient is 0.240 mm, and the depth gradient is 29.115 μm, the maximum bearing capacity can be 362.796 N.

[0121] This application calculates the optimal diameter and depth of each surface texture 4 by simulating pressure mapping and the working state and oil film pressure distribution of non-planar textured sliding bearings under different working conditions. It can not only reveal the influence of the diameter and depth of each surface texture 4 on the oil film pressure distribution, thereby finding the optimal parameters to maximize the bearing load capacity under specific working conditions, ensuring that each surface texture 4 can maximize the lubrication performance and reliability of the bearing, but also adjust the design parameters of each surface texture 4 according to different working conditions, so that the bearing has stronger adaptability and flexibility; in addition, through simulation, the performance of the bearing can be predicted without manufacturing actual samples, thereby effectively reducing the number and cost of tests.

[0122] To verify the accuracy of the optimization results, numerical simulations were performed using the established finite element model and optimized conditions. For ease of processing, the diameter was set to 1.33 mm, the depth was set to 27 μm, the diameter gradient was set to 0.24 mm, and the depth gradient was set to 29 μm. Table 6 shows a comparison of the simulation results with the predicted results.

[0123] Table 6. Comparison of simulation results and prediction results

[0124]

[0125] Table 6 shows a comparison between the finite element simulation results and the response surface model prediction results. As can be seen from Table 6, the numerical results are basically consistent with the prediction results, indicating that the optimization results are effective. Therefore, this application once again demonstrates the appropriateness and accuracy of the regression model through the comparison between the finite element simulation results and the response surface model prediction results.

[0126] In addition, this application also compares the load-bearing capacity of the optimized pressure mapping and non-planar textured sliding bearing with the load-bearing capacity of the pressure mapping and non-planar textured sliding bearing before optimization. The comparison results are shown in Table 7, where the design variables of the pressure mapping and non-planar textured sliding bearing before optimization are based on conventional experience settings, specifically: diameter 1.5 mm, depth 150 μm, diameter gradient 0.5 mm, depth gradient 50 μm.

[0127] Table 7. Improvement effect after optimization

[0128]

[0129] It can be seen from Table 7 that the load-bearing capacity of the optimized pressure mapping and non-planar texture sliding bearing is increased by 4.089% compared with the load-bearing capacity of the pressure mapping and non-planar texture sliding bearing before optimization, which further proves the correctness of the design method of the non-planar texture of the pressure mapping and non-planar texture collaborative lubrication magnetohydrodynamic sliding bearing designed in this application.

[0130] In summary, the present invention simulates the working state and oil film pressure distribution of the bearing under different working conditions through simulation without manufacturing actual samples, thereby reducing the number and cost of experiments and effectively shortening the period of finding the value range of various design parameters; at the same time, it also determines the value range of various design parameters of the non-planar texture based on the simulation combined with the single-factor experiment, which not only eliminates the interference of other design parameters, but also more accurately reveals the influence of various design parameters of the non-planar texture on the lubrication performance of the bearing under different working conditions, and also helps to obtain the optimal value range of various design parameters of the non-planar texture, thereby ensuring that the subsequent optimization experiments are carried out within a reasonable parameter range, effectively avoiding unnecessary waste of resources.

[0131] In addition, the present invention establishes a response relationship model between various design parameters and performance indicators of non-planar textures based on the response surface methodology. By optimizing key parameters such as the diameter, depth, diameter gradient, and depth gradient of the non-planar texture, it not only reduces the complexity of the optimization process but also effectively ensures the optimization accuracy, providing suggestions and technical support for further improving the load-bearing capacity and lubrication stability of pressure mapping and non-planar texture sliding bearings.

[0132] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A magnetic fluid sliding bearing with cooperative lubrication of pressure mapping and non-planar texture, characterized in that: The invention comprises a bearing shell, a magnetic fluid, a journal, a surface texture, a permanent magnet and a bearing seat. The bearing shell is arranged on the bearing seat. A mounting cavity is provided on the bearing seat corresponding to the center of the bottom of the bearing shell. A permanent magnet is provided in the mounting cavity. The journal is rotatably arranged in the bearing shell. A magnetic fluid is provided between the bearing shell and the journal. The inner surface of the bearing shell is provided with a plurality of cylindrical surface textures with inclined plane bottom surfaces. The center lines of the plurality of surface textures intersect at the center of the bearing shell. The center line of each surface texture intersects with the perpendicular plane of its center line to obtain an intersection point, and the distance from the intersection point to the top of the surface texture is the depth of the surface texture; the bottom inclined surface of each surface texture is obtained by rotating the perpendicular plane of the center line of the surface texture with the intersection point as the center in the direction of the journal rotation, and the rotation angle of the perpendicular plane of the center line of the surface texture is the bottom inclined angle of the surface texture, and the intersection point is located at the center point of the bottom inclined surface of the surface texture; There is a central surface texture among several surface textures, and the bottom surface inclination angles of several surface textures are the same as the bottom surface inclination angle of the central surface texture; the center line of the central surface texture coincides with the line formed by the center of the journal and the center of the bearing, and the vertical plane of the center line of the central surface texture coincides with the vertical line of the line formed by the center of the journal and the center of the bearing, and the bottom surface inclination angle of the central surface texture is the acute angle formed by the vertical line of the line formed by the center of the journal and the center of the bearing and the bottom inclination plane of the central surface texture, wherein the journal center is obtained after rotating the journal based on a determined rotation direction.

2. The pressure mapping and non-planar texture cooperative lubrication magnetic fluid sliding bearing according to claim 1, characterized in that: From a circumferential perspective, several surface textures are located on the inner surface of the bearing within the area mapped at 180° to 270° in the direction of journal rotation; from an axial perspective, several surface textures are located on the inner surface of the bearing between 15% and 85% of the axial length of the bearing.

3. The pressure mapping and non-planar texture cooperative lubrication magnetic fluid sliding bearing according to claim 2, characterized in that: In the area mapped at 180° to 270° in the journal rotation direction on the inner surface of the bearing shell, the surface texture located in the bearing oil film pressure area is mapped based on the bearing oil film pressure distribution, and the diameter and depth of each surface texture are positively correlated with the oil film pressure, that is, the diameter and depth of each surface texture gradually decrease from the central area to the surrounding areas, among which the central surface texture is set in the most central area of ​​the bearing oil film pressure distribution; the surface texture in the area outside the outermost oil film pressure isobar isobar has the same diameter and depth as the surface texture on the outermost oil film pressure isobar. In addition, the bottom surface inclination angle θ of the central surface texture is greater than 0° and less than the minimum inverse tangent value of the depth and radius of each surface texture, as shown below: Where H represents the depth of the center surface texture, D represents the diameter of the center surface texture, and H i represents the depth of the surface texture on the i-th oil film pressure isobar, D i Represents the diameter of the surface texture on the i-th oil film pressure isobar.

4. The pressure mapping and non-planar texture cooperative lubrication magnetic fluid sliding bearing according to claim 3, characterized in that: Within the bearing oil film pressure region, except for the central point of the central surface texture coinciding with the central point of the bearing oil film pressure distribution, the central points of the remaining surface textures are all located on the oil film pressure isobars, and the surface textures on each oil film pressure isobar are evenly spaced, and the diameters and depths of the surface textures on each oil film pressure isobar are the same; at the same time, the surface textures in the outer region of the outermost oil film pressure isobar are also evenly spaced. In addition, the distance between two adjacent oil film pressure isobars is greater than the sum of the radii of the surface textures on these two isobars.

5. The pressure mapping and non-planar texture cooperative lubrication magnetic fluid sliding bearing according to claim 1, characterized in that: The mounting cavity is arranged on a bearing seat corresponding to the circumferential length of a 120° arc at the center of the bottom of the bearing bush, and both the mounting cavity and the permanent magnet are in the shape of a bush.

6. The pressure mapping and non-planar texture cooperative lubrication magnetic fluid sliding bearing according to claim 4, characterized in that: The structural parameters of the non-planar texture include diameter, depth, diameter gradient, and depth gradient. The depth is the distance between the center point of the bottom inclined surface of the surface texture and the top of the surface texture. Meanwhile, the diameter and depth are the diameter and depth of the surface texture on the outermost oil film pressure isobar. The diameter and depth of the surface texture on the remaining oil film pressure isobars are obtained by adding the diameter and depth of the surface texture on the previous oil film pressure isobar to the diameter gradient and depth gradient. In addition, the value ranges of various structural parameters of the non-planar texture are: 1.25mm≤diameter≤1.75mm, 25μm≤depth≤75μm, 0.2mm≤diameter gradient≤0.4mm, 25m≤depth gradient≤75μm.

7. The pressure mapping and non-planar texture cooperatively lubricated magnetic fluid sliding bearing according to claim 6, characterized in that: The optimal values ​​of the structural parameters of the non-planar texture are: diameter of 1.331 mm, depth of 26.509 μm, diameter gradient of 0.240 mm, and depth gradient of 29.115 μm.

8. A method for designing a non-planar texture of a magnetic fluid sliding bearing with cooperative lubrication of pressure mapping and non-planar texture, applied to a magnetic fluid sliding bearing with cooperative lubrication of pressure mapping and non-planar texture according to any one of claims 1 to 7, characterized in that: The specific steps are as follows: S1. Determining an optimization objective and design variables for a non-planar texture, wherein the optimization objective is bearing capacity, and the design variables include diameter, depth, diameter gradient, and depth gradient, where the depth is the distance between the center point of the bottom inclined surface of the surface texture and the top of the surface texture; S2. Construct a parametric model of a magnetic fluid sliding bearing with synergistic lubrication using pressure mapping and non-planar textures. Based on single-factor experiments, study the influence of each design variable on the optimization objective to determine the value range of each design variable. The basic performance parameters used to construct the parametric model of a magnetic fluid sliding bearing with synergistic lubrication using pressure mapping and non-planar textures include: oil film inner diameter, oil film outer diameter, oil film width, eccentricity, eccentricity, oil inlet diameter, oil inlet length, inlet pressure, and rated speed. S3. Using the optimization target as the response value, the Box-Behnken principle in the Design-Expert software is used to conduct a response surface experiment based on the single-factor experiment in step S2. The performance values ​​of the optimization target are fitted to establish a multiple regression model equation for the optimization target, as shown below: In the formula, Y represents the response value, X i 、X j are the i-th and j-th design variables respectively, k represents the number of design variables, b0, b i 、b ii 、b ij is the coefficient to be solved; S4. Use Design Expert software to draw and analyze the relationship between design variables and response values ​​according to the multivariate regression model, obtain the response surface diagram of the regression equation, and then obtain the optimal design parameters of the non-planar texture.

9. The method for designing a non-planar texture of a magnetic fluid sliding bearing for cooperative lubrication of pressure mapping and non-planar texture according to claim 8, characterized in that: The design variables determined in step S1, namely, diameter and depth, are the diameter and depth of the surface texture on the outermost oil film pressure isobar. The diameter and depth of the surface texture on the remaining oil film pressure isobars are obtained by adding the diameter and depth of the surface texture on the previous oil film pressure isobar to the diameter gradient and depth gradient. In addition, the diameter of the central surface texture is obtained by adding the diameter gradient to the diameter of the surface texture on the innermost oil film pressure isobar, and the depth of the central surface texture is obtained by adding the depth gradient to the depth of the surface texture on the innermost oil film pressure isobar. When the value ranges of the design variables are: 1.25 mm ≤ diameter ≤ 1.75 mm, 25 μm ≤ depth ≤ 75 μm, 0.2 mm ≤ diameter gradient ≤ 0.4 mm, 25 m ≤ depth gradient ≤ 75 μm, the regression model equation of the bearing capacity F obtained by simulation in step S3 is as follows: Where F is the bearing capacity in N; X1 is the diameter, X2 is the depth, X3 is the diameter gradient, and X4 is the depth gradient.

10. The method for designing a non-planar texture of a magnetic fluid sliding bearing for cooperative lubrication of pressure mapping and non-planar texture according to claim 9, characterized in that: The optimal design parameters of the non-planar texture obtained using the Design Expert software in step S4 are: diameter of 1.331 mm, depth of 26.509 μm, diameter gradient of 0.240 mm, and depth gradient of 29.115 μm.

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