Radial sliding bearing with groove-type textured surface and friction testing method of radial sliding bearing

Abstract

The invention provides a radial sliding bearing with a groove-type textured surface and a friction testing method thereof.The radial sliding bearing comprises a bearing, a journal, lubricating oil and surface textures, the lubricating oil is arranged between the inner surface of the bearing and the outer surface of the journal, and the surface textures are in a groove type and are evenly distributed on the inner surface of the bearing; the shaft neck rotates around the geometric center of the shaft neck, so that lubricating oil in a bearing gap generates a fluid dynamic pressure effect to balance an external load; the centerline of the journal is parallel to the centerline of the bearing, and the film thickness of the lubricating oil in the bearing clearance is symmetrically distributed about the centerline of the bearing. According to the radial sliding bearing with the groove type textured surface and the friction testing method of the radial sliding bearing, distribution parameters and shape parameters of the surface texture are optimally designed, so that the bearing with the textured surface can obtain a more remarkable secondary fluid dynamic pressure effect, and the tribological performance of a friction pair interface of the radial sliding bearing is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of radial sliding bearing lubrication, and in particular relates to a radial sliding bearing with a grooved textured surface and a friction testing method thereof. Background Art

[0002] As a classic supporting component, sliding bearings have been widely used in various types of rotating machinery. Compared with rolling bearings, the rotating shaft and supporting components of sliding bearings are separated by a fluid film, which has the advantages of stable operation, low vibration and noise, and high reliability. However, the friction power loss during operation is an issue that cannot be ignored in the design and use of sliding bearing systems. It can be seen that conducting more in-depth research on the friction and lubrication characteristics of sliding bearings and exploring effective friction reduction methods to reduce friction power consumption and improve lubrication performance are of great significance to cost reduction and energy conservation. The essence of friction reduction is to perform tribological intervention on the lubricating medium or friction pair interface through various physical and chemical means, thereby reducing the fluid viscosity or changing the flow field parameters, so as to achieve the purpose of reducing viscous friction resistance. The surface texturing method is to process a specific form of microstructure (micro pits or micro grooves) on the friction pair interface, and use the micro dynamic pressure effect, micro oil storage effect and abrasive capture effect formed by it to influence the flow field, thereby improving the tribological properties of the friction pair interface. Therefore, in order to improve the tribological performance of sliding bearings during operation, it is of great significance to seek a low-cost and effective method that ensures normal lubrication function to ensure the reliable operation and service life of the bearing system. Currently, the authorized and published patents have used surface texturing methods to improve and study the lubrication performance of sliding bearing friction pairs to a certain extent. However, the existing technical solutions for optimizing the distribution parameters and shape parameters of grooved surface textures and tribological testing methods are not clear, and it is particularly important to deeply study the formation conditions of the grooved textured surface friction reduction area, expand this effect to a wider dynamic pressure lubrication area, and achieve the maximum improvement of the friction and lubrication performance of the bearing, so as to provide valuable theoretical guidance for the application and promotion of surface texturing methods in sliding bearing systems. Summary of the invention

[0003] In view of this, the present invention aims to provide a radial sliding bearing with a grooved textured surface to solve the problems of insufficient load-bearing capacity and excessive friction power consumption of sliding bearings in the prior art.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A radial sliding bearing with a grooved textured surface comprises a bearing, a journal, lubricating oil and a surface texture, wherein the lubricating oil is between the inner surface of the bearing and the outer surface of the journal, the surface texture is grooved and evenly distributed on the inner surface of the bearing, and the rotational motion of the journal around its geometric center causes the lubricating oil in the bearing gap to produce a fluid dynamic pressure effect, thereby balancing the external load; the center line of the journal remains parallel to the center line of the bearing, and the film thickness of the lubricating oil in the bearing gap is symmetrically distributed about the center line of the bearing.

[0006] Furthermore, the equation for the oil film thickness h of the lubricating oil is:

[0007]

[0008] Among them, c is the radius clearance, e is the bearing eccentricity, θ is the bearing offset angle, is the circumferential angle of the bearing, h g The film thickness variation caused by the bearing surface texture.

[0009] Furthermore, the area ratio of the surface texture is 45%.

[0010] Furthermore, the characteristic depth of the surface texture is 20 μm.

[0011] Furthermore, the surface texture has six distribution forms, including 0°-360°, 90°-270°, 0°-180°, 180°-360°, 54°-198°, and 162°-306°.

[0012] Furthermore, the surface texture has five shapes including straight grooves, left spiral grooves, right spiral grooves, left herringbone grooves and right herringbone grooves. The mathematical expressions of the five shapes of the surface texture are:

[0013] Straight slot

[0014]

[0015] Left spiral groove

[0016]

[0017] Right spiral groove

[0018]

[0019] Left herringbone groove

[0020]

[0021] Right herringbone groove

[0022]

[0023] Among them, c x , c z and c g are the length, width and depth of the groove texture respectively, and ψ is the deflection angle of the side of the groove texture relative to the z-axis.

[0024] Furthermore, the material of the bearing is tin-based alloy ZChSnSb11-6, and the material of the journal is high-carbon chromium bearing steel Gcr15.

[0025] Compared with the prior art, the radial sliding bearing with grooved textured surface described in the present invention has the following advantages:

[0026] (1) The radial sliding bearing with a grooved textured surface described in the present invention optimizes the distribution parameters and shape parameters of the surface texture so that the textured surface bearing can obtain a more significant secondary fluid dynamic pressure effect, thereby improving the tribological performance of the friction pair interface of the radial sliding bearing.

[0027] (2) The radial sliding bearing with a grooved textured surface described in the present invention arranges a microstructure with certain geometric rules on the surface of the sliding bearing friction pair by a surface texturing method, and optimizes the distribution parameters and shape parameters of the grooved surface texture. It is found that the maximum film pressure of the left herringbone groove textured surface is increased by 18.9% compared with the grooveless surface, and the friction coefficient of the 54°-198° distributed textured surface is reduced by 8.6% compared with the grooveless surface. Therefore, the left herringbone groove shape and the 54°-198° distributed surface texture are optimized to obtain the best tribological performance.

[0028] Another purpose of the invention is to provide a friction testing method for a radial sliding bearing with a grooved textured surface, so as to solve the problems of insufficient load-bearing capacity and excessive friction power consumption of the sliding bearing in the prior art.

[0029] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0030] A friction test method for a radial sliding bearing with a grooved textured surface comprises the following steps:

[0031] S1. Test pretreatment: clean and dry the bearings and journals;

[0032] S2. Install the journal on the lower fixture to ensure that the journal and the lower fixture are well matched and rotate normally and synchronously;

[0033] S3. Install the bearing on the upper fixture so that the inner surface of the bearing faces the outer surface of the journal and remains stationary;

[0034] S4, making the friction arm parallel to the support seat and perpendicular to the support frame;

[0035] S5. Adjust the position of the fixture so that the inner surface of the bearing and the outer surface of the journal are properly matched, and ensure that the inner surface of the bearing and the outer surface of the journal are completely immersed in the lubricating oil;

[0036] S6, test preloading;

[0037] S7, test formal loading;

[0038] S8. After the test, the bearing and journal are restored;

[0039] S9, repeat the operation, replace the new test specimen and lubricating oil, change the test parameters to carry out the next set of test, and repeat the above steps;

[0040] S10. Analyze the data. Based on the above test data, compare and analyze the friction coefficients under different working parameters and texture parameters, and select the best design solution.

[0041] Furthermore, the specific method of analyzing the data in S10 is:

[0042] The radial sliding bearing with grooved textured surface is modeled. The lubricating oil is assumed to be a flowing Newtonian fluid. The laminar flow cannot be compressed. The effects of volume force and inertia force are ignored. The governing equation of the oil film pressure p is:

[0043]

[0044] The mass conservation boundary condition is used to determine the full film area and the cavitation area. When the lubricating oil film in the bearing gap breaks, cavitation will occur. At this time, the lubrication area will be divided into the full film area and the cavitation area. In the full film area, the bearing gap is completely filled with the lubricating oil film to form a fluid dynamic pressure. In the cavitation area, the lubricating oil film exists in a strip shape. When the fluid pressure p is greater than the cavitation pressure p cav When the cavitation fraction Θ is between 0 and 1, it is expressed as the full film area, that is, the cavitation fraction Θ is equal to 1, and when the cavitation fraction Θ is between 0 and 1, it is expressed as the cavitation area, that is, the fluid pressure p is equal to the cavitation pressure p cav ;

[0045]

[0046] Among them, ρ is the fluid density, μ is the fluid viscosity, U=ωR is the linear velocity of the journal, ω is the angular velocity of the journal, R is the bearing radius, L is the bearing width, and p cav is the cavitation pressure, Θ is the cavitation fraction, Oxyz is the coordinate system, and in order to simplify the complex terms in the equation, dimensionless parameters are introduced, and the expression is:

[0047]

[0048] The equation for the dimensionless oil film pressure P of a textured surface sliding bearing is:

[0049]

[0050] The mass conservation boundary conditions for automatically determining oil film rupture and reconstruction are:

[0051]

[0052] Where n represents the normal direction of the reconstructed boundary of the fluid film;

[0053] The bearing capacity is expressed as the external load that it can withstand, the bearing capacity W e The horizontal component W x and the vertical component W y Composition, its expression is:

[0054]

[0055] The horizontal component of the bearing capacity W x and the vertical component W y It is obtained by integrating the fluid pressure, and its expression is:

[0056]

[0057] Due to the rotation of the journal, there is a viscous shear stress in the bearing gap. By integrating the shear stress, the friction force F of the fluid on the journal surface is calculated. f , whose expression is:

[0058]

[0059] The friction coefficient f of the bearing is expressed as the friction force F f With bearing capacity W e The ratio of is expressed as:

[0060]

[0061] Furthermore, the specific method for formal loading of the test in S7 is: setting the working condition parameters through the loading device, using the signal acquisition device to measure the dynamic friction coefficient of each group of tests, when the friction coefficient curve reaches a relatively stable state, it is considered to be the friction coefficient of this test; each group of tests is repeated 3 times under the same working conditions, the running time is 20 minutes, and the average friction coefficient of the 3 tests is calculated as the final friction coefficient of this group of tests.

[0062] The friction test method of the radial sliding bearing with a grooved textured surface is the same as the advantages of the radial sliding bearing with a grooved textured surface over the prior art, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0064] Figure 1 A front view showing a schematic diagram of the geometric structure and coordinate system of a textured surface sliding bearing according to an embodiment of the present invention;

[0065] Figure 2 for Figure 1 Enlarged view of part A in the middle;

[0066] Figure 3 A side view of a schematic diagram of the geometric structure and coordinate system of a textured surface sliding bearing according to an embodiment of the present invention;

[0067] Figure 4 It is a schematic diagram of the bearing development of the textured surface sliding bearing according to an embodiment of the present invention;

[0068] Figure 5 Described for the embodiments of the present invention are schematic diagrams of textured surface sliding bearings at texture distributions of 0°-360°, 90°-270°, 0°-180°, 180°-360°, 54°-198° and 162°-306°;

[0069] Figure 6 Schematic diagram of the textured surface profile under the texture shapes of straight groove (a), left spiral groove (b), right spiral groove (c), left herringbone groove (d) and right herringbone groove (e).

[0070] Figure 7 is the film thickness distribution diagram under five texture shapes;

[0071] Figure 8 is the film pressure distribution diagram under five texture shapes;

[0072] Fig. 9 are the distribution diagrams of dimensionless bearing capacity (a) and dimensionless friction coefficient (b) under six texture distributions;

[0073] Fig.10 This is the working principle diagram of the friction and wear testing machine.

[0074] Description of reference numerals:

[0075] 1-bearing, 2-journal, 3-lubricating oil, 4-surface texture, 5-loading device, 6-compression spring, 7-upper clamp, 8-lower clamp, 9-support seat, 10-support frame, 11-friction arm, 12-level meter, 13-signal acquisition device. DETAILED DESCRIPTION

[0076] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0077] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0078] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0079] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0080] Radial plain bearings with grooved textured surfaces, such as Figures 1 to 10 As shown, it includes a bearing 1, a journal 2, a lubricating oil 3, and a surface texture 4. The lubricating oil 3 is between the inner surface of the bearing 1 and the outer surface of the journal 2 and provides a fluid dynamic pressure effect. The surface texture 4 is groove-shaped and evenly distributed on the inner surface of the bearing 1. The material of the bearing 1 is tin-based alloy ZChSnSb11-6, and the material of the journal 2 is high-carbon chromium bearing steel Gcr15. The rotation of the journal 2 around its geometric center causes the lubricating oil 3 in the gap of the bearing 1 to produce a fluid dynamic pressure effect, thereby balancing the external load. The center line of the journal 2 remains parallel to the center line of the bearing 1, and the film thickness of the lubricating oil 3 in the gap of the bearing 1 is symmetrically distributed about the center line of the bearing 1. The equation for the oil film thickness h of the lubricating oil is:

[0081]

[0082] Among them, c is the radius clearance, e is the bearing eccentricity, θ is the bearing offset angle, is the circumferential angle of the bearing, h g The film thickness change caused by the bearing surface texture. In the bearing gap, the fluid flows along the rotation direction of the shaft. When the fluid flows into the texture area, the fluid film pressure in the divergent area decreases. When the fluid film pressure drops to a certain value, cavitation occurs. When the fluid flows out of the texture area, the fluid film pressure in the convergent area increases.

[0083] The distribution parameters and shape parameters of the surface texture 4 may adopt the following embodiments:

[0084] Example 1

[0085] like Figure 4 As shown, the surface texture 4 is a groove type, the shape of the surface texture 4 is a straight groove, the area ratio of the surface texture 4 is 45%, the characteristic depth of the surface texture 4 is 20 μm, and the distribution form of the surface texture 4 is six, including 0°-360°, 90°-270°, 0°-180°, 180°-360°, 54°-198°, and 162°-306°. The mathematical expression of the straight groove shape of the surface texture 4 is:

[0086] Straight slot

[0087]

[0088] Example 2

[0089] like Figure 5 As shown, the surface texture 4 is a groove type, the distribution form of the surface texture 4 is 54°-198°, the area ratio of the surface texture 4 is 45%, the characteristic depth of the surface texture 4 is 20μm, the distribution form of the surface texture 4 is six types including 0°-360°, 90°-270°, 0°-180°, 180°-360°, 54°-198°, 162°-306°, the shape of the surface texture 4 is five types including straight groove, left spiral groove, right spiral groove, left herringbone groove and right herringbone groove, and the mathematical expressions of the five shapes of the surface texture 4 are:

[0090] Left spiral groove

[0091]

[0092] Right spiral groove

[0093]

[0094] Left herringbone groove

[0095]

[0096] Right herringbone groove

[0097]

[0098] Among them, c x , c z and c g are the length, width and depth of the groove texture respectively, and ψ is the deflection angle of the side of the groove texture relative to the z-axis.

[0099] like Figure 1 As shown in the figure, the radial sliding bearing with grooved textured surface is modeled, and the lubricating oil 3 is assumed to be a flowing Newtonian fluid, the laminar flow is incompressible, and the effects of volume force and inertia force are ignored. The governing equation of the oil film pressure p is:

[0100]

[0101] The mass conservation boundary condition is used to determine the full film area and the cavitation area. When the lubricating oil film in the bearing gap breaks, cavitation may occur. At this time, the lubrication area will be divided into the full film area and the cavitation area. In the full film area, the bearing gap is completely filled with the lubricating oil film, forming a fluid dynamic pressure. In the cavitation area, the lubricating oil film exists in a strip shape. When the fluid pressure p is greater than the cavitation pressure p cav When the cavitation fraction Θ is between 0 and 1, it is expressed as the full film area, that is, the cavitation fraction Θ is equal to 1, and when the cavitation fraction Θ is between 0 and 1, it is expressed as the cavitation area, that is, the fluid pressure p is equal to the cavitation pressure p cav .

[0102]

[0103] Among them, ρ is the fluid density, μ is the fluid viscosity, U=ωR is the linear velocity of the journal, ω is the angular velocity of the journal, R is the bearing radius, L is the bearing width, and p cav is the cavitation pressure, Θ is the cavitation fraction, and Oxyz is the coordinate system. In order to simplify the complex terms in the equation, dimensionless parameters are introduced, and the expression is:

[0104]

[0105] The equation for the dimensionless oil film pressure P of a textured surface sliding bearing is:

[0106]

[0107] The mass conservation boundary conditions for automatically determining oil film rupture and reconstruction are:

[0108]

[0109] Where n represents the normal direction of the reconstructed boundary of the fluid film.

[0110] The bearing capacity is expressed as the external load that it can withstand, the bearing capacity W e The horizontal component W x and the vertical component W y Composition, its expression is:

[0111]

[0112] The horizontal component of the bearing capacity W x and the vertical component W y It can be obtained by integrating the fluid pressure, and its expression is:

[0113]

[0114] Due to the rotation of the journal, there is a viscous shear stress in the bearing gap. By integrating the shear stress, the friction force F of the fluid on the journal surface can be calculated. f , whose expression is:

[0115]

[0116] The friction coefficient f of the bearing is expressed as the friction force F f With bearing capacity W e The ratio of is expressed as:

[0117]

[0118] Through the above evaluation, it can be concluded that Figure 6 and Figure 7 Distribution diagrams of film thickness and film pressure under straight groove, left spiral groove, right spiral groove, left herringbone groove and right herringbone groove texture shapes, and Figure 8 The dimensionless bearing capacity and dimensionless friction coefficient diagrams under the texture distributions of 0°-360°, 90°-270°, 0°-180°, 180°-360°, 54°-198° and 162°-306° show that the maximum film pressure of the left herringbone groove textured surface is increased by 18.9% compared with the grooveless surface, and the friction coefficient of the 54°-198° distribution textured surface is reduced by 8.6% compared with the grooveless surface. Therefore, the left herringbone groove shape and the surface texture of 54°-198° distribution are optimized to obtain the best tribological properties.

[0119] A friction test method for a radial sliding bearing with a grooved textured surface is used. Fig. 9The friction and wear testing machine shown in the figure includes a loading device 5, a compression spring 6, an upper clamp 7, a lower clamp 8, a support seat 9, a support frame 10, a friction arm 11, a level 12 and a signal acquisition device 13. The support seat 9 and the friction arm 11 are installed in parallel above and below the support frame 10. The level 12 and the loading device 5 are installed above the friction arm 11. The loading device 5 is fixedly connected to the connecting rod through the compression spring 6. The connecting rod passes through the friction arm 11 and is connected to the upper clamp 7. The upper clamp 7 is used to install the bearing 1; the support seat 9 is provided with a groove, and the lower clamp 8 is installed in the groove. The lower clamp 8 is used to install the journal 2. The level 12 and the signal acquisition device 13 are both connected to the controller by signal. The loading device 5, the level 12 and the signal acquisition device 13 can be any existing equipment or electronic components that can realize the corresponding functions, and will not be repeated here.

[0120] The friction testing method of a radial sliding bearing with a grooved textured surface of the present invention is specifically implemented in the following steps:

[0121] S1. Test pretreatment. Wash the bearing 1 and the journal 2 in anhydrous ethanol to remove the remaining impurities and grinding debris. The cleaning time is 20 minutes. After cleaning, dry the bearing 1 and the journal 2. The drying time is 5 minutes.

[0122] S2. Install and fix the journal 2. Install the journal 2 on the lower fixture 8 through the tapered structure on the inner surface, and ensure that the journal 2 and the lower fixture 8 are well matched and rotate normally and synchronously.

[0123] S3. Install and fix the bearing 1. Install the bearing 1 on the upper fixture 7 through the top protrusion, ensuring that the inner surface of the bearing 1 faces the outer surface of the journal 2 and remains stationary.

[0124] S4. Adjust the horizontal position. By observing the scale of the level 12, ensure that the friction arm 11 is parallel to the support seat 9 and vertical to the support frame 10.

[0125] S5. Adjust the position of the clamp. By adjusting the position of the upper clamp 7, the inner surface of the bearing 1 and the outer surface of the journal 2 are properly matched, and the inner surface of the bearing 1 and the outer surface of the journal 2 are ensured to be completely immersed in the lubricating oil 3.

[0126] S6, pre-loading of the test. The loading device 5 loads the bearing 1 in the vertical direction through the compression spring 6. When the external load reaches the preset value, the compression amount of the compression spring 6 will remain unchanged. For the test pre-loading, the external load is initially set to 5N, the rotation speed is initially set to 50rpm, and the running time is initially set to 5min. S7, formal loading of the test. The working condition parameters are set by the loading device 5, and the dynamic friction coefficient of each group of tests is measured by the signal acquisition device 13. When the friction coefficient curve reaches a relatively stable state, it is considered to be the friction coefficient of this test. Each group of tests is repeated 3 times under the same working conditions, with a running time of 20min. The average friction coefficient of the 3 tests is calculated as the final friction coefficient of this group of tests.

[0127] S8, post-test processing. After the test is completed, the bearing 1 and the journal 2 are removed from the upper fixture 7 and the lower fixture 8 respectively, and are cleaned and dried in anhydrous ethanol again.

[0128] S9, repeat the operation. Replace the new test specimen and lubricating oil, reinstall it on the testing machine, and repeat the test operation. Change the test parameters to carry out the next set of test and repeat the above steps.

[0129] S10. Analyze data. Based on the above test data, compare and analyze the friction coefficients under different working parameters and texture parameters, and select the best design scheme according to the improvement degree of the tribological performance of the textured surface bearing.

[0130] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A radial sliding bearing with a grooved textured surface, characterized in that: It includes a bearing, a journal, a lubricating oil and a surface texture. The lubricating oil is between the inner surface of the bearing and the outer surface of the journal. The surface texture is groove-shaped and evenly distributed on the inner surface of the bearing. The rotational motion of the journal around its geometric center causes the lubricating oil in the bearing gap to produce a fluid dynamic pressure effect, thereby balancing the external load. The center line of the journal remains parallel to the center line of the bearing, and the film thickness of the lubricating oil in the bearing gap is symmetrically distributed about the center line of the bearing.

2. The radial sliding bearing with a grooved textured surface according to claim 1, characterized in that: The equation for the film thickness h of the lubricating oil is: Where c is the radial clearance, e is the bearing eccentricity, and θ is the bearing offset angle. is the circumferential angle of the bearing, h g The film thickness variation caused by the bearing surface texture.

3. The radial sliding bearing with a grooved textured surface according to claim 1, characterized in that: The area ratio of the surface texture is 45%.

4. The radial sliding bearing with a grooved textured surface according to claim 1, characterized in that: The characteristic depth of the surface texture is 20 μm.

5. The radial sliding bearing with a grooved textured surface according to claim 1, characterized in that: There are six distribution forms of surface texture, including 0°-360°, 90°-270°, 0°-180°, 180°-360°, 54°-198°, and 162°-306°.

6. The radial sliding bearing with a grooved textured surface according to claim 1, characterized in that: There are five shapes of surface textures, including straight grooves, left spiral grooves, right spiral grooves, left herringbone grooves and right herringbone grooves. The mathematical expressions of the five shapes of surface textures are: Straight slot Left spiral groove Right spiral groove Left herringbone groove Right herringbone groove Among them, c x , c z and c g are the length, width and depth of the groove texture respectively, and ψ is the deflection angle of the side of the groove texture relative to the z-axis.

7. The radial sliding bearing with a grooved textured surface according to claim 1, characterized in that: The material of the bearing is tin-based alloy ZChSnSb11-6, and the material of the journal is high-carbon chromium bearing steel Gcr15.

8. The friction testing method for a radial sliding bearing with a grooved textured surface according to any one of claims 1 to 7, characterized in that: The steps include: S1. Test pretreatment: clean and dry the bearings and journals; S2. Install the journal on the lower fixture to ensure that the journal and the lower fixture are well matched and rotate normally and synchronously; S3. Install the bearing on the upper fixture so that the inner surface of the bearing faces the outer surface of the journal and remains stationary; S4, making the friction arm parallel to the support seat and perpendicular to the support frame; S5. Adjust the position of the fixture so that the inner surface of the bearing and the outer surface of the journal are properly matched, and ensure that the inner surface of the bearing and the outer surface of the journal are completely immersed in the lubricating oil; S6, test preloading; S7, test formal loading; S8. After the test, the bearing and journal are restored; S9, repeat the operation, replace the new test specimen and lubricating oil, change the test parameters to carry out the next set of test, and repeat the above steps; S10. Analyze the data. Based on the above test data, compare and analyze the friction coefficients under different working parameters and texture parameters, and select the best design solution.

9. The friction testing method for a radial sliding bearing with a grooved textured surface according to claim 8, characterized in that: The specific method of analyzing data in S10 is: The radial sliding bearing with grooved textured surface is modeled. The lubricating oil is assumed to be a flowing Newtonian fluid. The laminar flow cannot be compressed. The effects of volume force and inertia force are ignored. The governing equation of the oil film pressure p is: The mass conservation boundary condition is used to determine the full film area and the cavitation area. When the lubricating oil film in the bearing gap breaks, cavitation will occur. At this time, the lubrication area will be divided into the full film area and the cavitation area. In the full film area, the bearing gap is completely filled with the lubricating oil film to form a fluid dynamic pressure. In the cavitation area, the lubricating oil film exists in a strip shape. When the fluid pressure p is greater than the cavitation pressure p cav When the cavitation fraction Θ is between 0 and 1, it is expressed as the full film area, that is, the cavitation fraction Θ is equal to 1, and when the cavitation fraction Θ is between 0 and 1, it is expressed as the cavitation area, that is, the fluid pressure p is equal to the cavitation pressure p cav ; Among them, ρ is the fluid density, μ is the fluid viscosity, U=ωR is the linear velocity of the journal, ω is the angular velocity of the journal, R is the bearing radius, L is the bearing width, and p cav is the cavitation pressure, Θ is the cavitation fraction, Oxyz is the coordinate system, and in order to simplify the complex terms in the equation, dimensionless parameters are introduced, and the expression is: The equation for the dimensionless oil film pressure P of a textured surface sliding bearing is: The mass conservation boundary conditions for automatically determining oil film rupture and reconstruction are: Where n represents the normal direction of the reconstructed boundary of the fluid film; The bearing capacity is expressed as the external load that it can withstand, the bearing capacity W e The horizontal component W x and the vertical component W y Composition, its expression is: The horizontal component of the bearing capacity W x and the vertical component W y It is obtained by integrating the fluid pressure, and its expression is: Due to the rotation of the journal, there is a viscous shear stress in the bearing gap. By integrating the shear stress, the friction force F of the fluid on the journal surface is calculated. f , whose expression is: The friction coefficient f of the bearing is expressed as the friction force F f With bearing capacity W e The ratio of is expressed as:

10. The friction testing method for radial sliding bearing with grooved textured surface according to claim 8, characterized in that: The specific method for the formal loading of the test in S7 is: setting the working condition parameters through the loading device, using the signal acquisition device to measure the dynamic friction coefficient of each group of tests, when the friction coefficient curve reaches a relatively stable state, it is considered to be the friction coefficient of this test; each group of tests is repeated 3 times under the same working conditions, the running time is 20 minutes, and the average friction coefficient of the 3 tests is calculated as the final friction coefficient of this group of tests.

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