Self-lubricating joint bearing service life test platform and test method

Abstract

The invention discloses a self-lubricating joint bearing service life test platform which comprises an oil cylinder, a test support, a main shaft, a bottom plate and a hollow rotating platform. The self-lubricating joint bearing is placed on the bottom plate, the two spindles are located on the two sides of the self-lubricating joint bearing respectively, one end of each spindle is connected with the self-lubricating joint bearing, the other end of each spindle is coaxially connected with one end of the test support, the other end of the test support is connected with a piston of the oil cylinder, and the hollow rotating platform is located below the bottom plate. The hollow rotating platform can rotate, swing and incline, the self-lubricating joint bearing also rotates, swings and inclines along with the hollow rotating platform, the accuracy of bearing service life prediction can be improved, a scientific basis can be provided for design and application of the bearing, the working condition applicability of the bearing is expanded, and the service life of the bearing is prolonged. And a user unit is helped to optimize maintenance and replacement plans, and the method has remarkable practical value and social and economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of life test of self-lubricating spherical bearings, and more specifically, to a life test platform of self-lubricating spherical bearings. Background Art

[0002] Spherical plain bearings are special spherical sliding bearings composed of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface. This type of bearing is particularly suitable for mechanical parts that perform low-speed rotation or swinging motion. Due to its simple and compact design, lightweight size, excellent load-bearing capacity, high impact and corrosion resistance, low vibration level, and convenient maintenance and disassembly process, spherical plain bearings are widely used in various fields of industrial manufacturing. For example, in the field of hydraulic cylinders, spherical plain bearings can withstand high loads and impact loads in hydraulic cylinders, ensuring the stable operation of the hydraulic system, thereby reducing maintenance and downtime caused by bearing damage.

[0003] The design of self-lubricating spherical plain bearings achieves the goal of reducing friction and extending the service life of bearings by attaching self-lubricating liners to the sliding friction surfaces of the bearings, and using the low friction characteristics of these liners. This type of bearing is particularly suitable for various extreme working environments, including low speed and heavy load, high speed and light load, humid and hot environments with salt spray, and extreme high and low temperature conditions. Under these conditions, bearings are prone to various failures, and wear is the most common type of failure. The design of self-lubricating bearings reduces the friction of hydraulic cylinders during movement, which helps to reduce wear and extend the service life of parts. The wear failure of self-lubricating spherical plain bearings is mainly due to the gradual thinning of the self-lubricating layer during the movement of the cylinder, which leads to a larger gap between the inner and outer rings, and no longer has the self-lubricating effect, which leads to a serious decrease in the reliability of the bearing. Therefore, it is very important to evaluate the remaining life of the spherical plain bearings of hydraulic cylinders.

[0004] At present, there are few life prediction schemes for self-lubricating bearings. Patent CN112067293A provides a self-lubricating spherical bearing wear life prediction model correction method. By changing the temperature, load and swing frequency of the spherical bearing test, the service life of the spherical bearing under different test conditions is obtained. However, its research object mainly focuses on the self-lubricating bearings in aircraft. Whether the life prediction application of self-lubricating spherical bearings in hydraulic cylinders is universal remains to be discussed. Patent CN113486455A provides a self-lubricating spherical bearing accelerated degradation reliability assessment and life prediction method, which is mainly based on the establishment of a self-lubricating spherical bearing accelerated degradation model based on the nonlinear Gamma process. The reliability assessment and life prediction of self-lubricating spherical bearings improves the assessment accuracy, but the process time is too long, and it is difficult to be competent for the assessment tasks that need to be completed in a short period of time. Summary of the invention

[0005] In order to achieve these purposes and other advantages according to the present invention, a preferred embodiment of the present invention provides a self-lubricating spherical bearing life test platform, comprising: an oil cylinder, a test bracket, a main shaft, a base plate, and a hollow rotating platform;

[0006] The self-lubricating spherical bearing is placed on the base plate, and two main shafts are respectively located on both sides of the self-lubricating spherical bearing. One end of the main shaft is connected to the self-lubricating spherical bearing, and the other end is coaxially connected to one end of the test bracket. The other end of the test bracket is connected to the piston of the oil cylinder. The hollow rotating platform is located below the base plate. The hollow rotating platform can rotate, swing, and tilt. As the hollow rotating platform rotates, swings, and tilts, the self-lubricating spherical bearing also rotates, swings, and tilts.

[0007] According to a preferred embodiment of the present invention, it further comprises a test platform, wherein the oil cylinder, the test bracket, the main shaft, the bottom plate, and the hollow rotating platform are all arranged on the test platform;

[0008] The test shaft is used to install the oil cylinder on the test platform; the outer sleeve of the test shaft is provided with a bearing baffle.

[0009] According to a preferred embodiment of the present invention, it also includes:

[0010] A temperature sensor is installed on the self-lubricating spherical plain bearing to monitor the temperature change of the self-lubricating spherical plain bearing during operation in real time;

[0011] A vibration sensor is installed on the self-lubricating spherical plain bearing to detect the vibration generated by the self-lubricating spherical plain bearing during operation in real time;

[0012] A noise sensor is installed on the self-lubricating spherical plain bearing to record the noise generated by the self-lubricating spherical plain bearing in real time during operation;

[0013] The displacement sensor is installed on the self-lubricating spherical bearing to measure the telescopic displacement of the cylinder in real time;

[0014] The flexible piezoelectric sensor is installed on the self-lubricating spherical plain bearing to measure the dynamic pressure on the self-lubricating spherical plain bearing in real time.

[0015] On the other hand, a technical solution of the present invention further provides a testing method for a self-lubricating spherical plain bearing life testing platform, comprising the following steps:

[0016] S1. Test sample selection

[0017] Select 10 qualified self-lubricating spherical plain bearings of the same batch and model as test objects; randomly select 4 of the 10 self-lubricating spherical plain bearings as test samples and divide them into two groups for testing, with 2 self-lubricating spherical plain bearings in each group;

[0018] S2. Test platform installation

[0019] Install the self-lubricating spherical plain bearing on the base plate and apply a radial load of 98kN to ensure that the nominal contact stress reaches 166.4Mpa;

[0020] S3. Initial wear measurement

[0021] After applying a radial load of 98 kN for 15 minutes, the wear value of the test sample was measured using an electron microscope and returned to zero;

[0022] S4, swing frequency setting

[0023] The swing frequency of the inner ring of the self-lubricating spherical plain bearing is set to 90 times / min, and the swing angle is from 0° to +30°, then back to 0°, then to -30°, and finally back to 0°, forming a complete swing cycle;

[0024] S5. Data monitoring

[0025] Regularly observe and record the wear of the inner ring metal surface and liner of the self-lubricating spherical plain bearing. When the outer ring surface temperature of the self-lubricating spherical plain bearing reaches or exceeds 150℃, the test shall be stopped immediately.

[0026] The temperature sensor, vibration sensor, noise sensor, flexible piezoelectric sensor and displacement sensor are used to monitor the temperature, vibration, noise, dynamic pressure of the self-lubricating spherical bearing and the telescopic displacement of the oil cylinder in real time;

[0027] S6. Abnormal situation handling

[0028] Use a stethoscope to listen to the changes in the noise of the self-lubricating spherical plain bearing to determine the operating conditions of the self-lubricating spherical plain bearing. Once an abnormality is found, the machine should be stopped immediately and inspected;

[0029] S7. Life Calculation

[0030] The running time from the start of the test to the end of the test is defined as the wear life of the self-lubricating spherical plain bearing, and the life of each self-lubricating spherical plain bearing is calculated;

[0031] S8. Lifespan prediction

[0032] Life prediction of self-lubricating spherical plain bearings.

[0033] According to a preferred embodiment of the present invention, step S8 specifically comprises the following steps:

[0034] S81. Draw a curve of the number of cycles and damage level of the spherical plain bearing;

[0035] S82. Calculate the peak stress level of the test sample during the test and the number of cycles required for the test sample to fail;

[0036] S83. Determine the expected number of cycles to failure by comparing the peak stress levels in actual use;

[0037] S84. Calculate the remaining useful life of the test sample based on the test data and theoretical analysis.

[0038] According to a preferred embodiment of the present invention, step S81 specifically includes the following steps:

[0039] S811. Obtain the metal scratches on the inner ring of the spherical plain bearing by electron microscope analysis, including the width and number of scratches, the degree of adhesion of the inner ring lubricant, the size and shape of the inner ring, the fiber integrity of the outer ring liner, and the size and state information of the transfer film;

[0040] S812, obtaining wear size information of the spherical bearing liner through morphology analysis and size measurement;

[0041] S813. The damage of the spherical bearing is classified into 10 levels d0-d9 from no damage to severe damage based on the metal scratches on the inner ring of the spherical bearing and the wear size information of the spherical bearing liner. At the same time, the subsequent trend is predicted based on the experimental data, and finally a complete cycle number-damage level curve is obtained.

[0042] The present invention has at least the following beneficial effects: the present invention can not only improve the accuracy of bearing life prediction, but also provide a scientific basis for the design and application of bearings, expand their applicability under working conditions, and help users optimize maintenance and replacement plans, and has significant practical value and socio-economic benefits.

[0043] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the structure of the self-lubricating spherical plain bearing life test platform in the present invention.

[0045] Figure 2 It is a schematic diagram of the method for testing the life of a self-lubricating spherical plain bearing in the present invention. DETAILED DESCRIPTION

[0046] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0047] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0048] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0049] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0050] like Figure 1-2 As shown, a preferred embodiment of the present invention provides a self-lubricating spherical bearing life test platform, comprising: an oil cylinder 1, a test bracket 2, a main shaft 3, a base plate 8, and a hollow rotating platform 7;

[0051] The self-lubricating spherical bearing is placed on the base plate 8, and the two main shafts 3 are respectively located on both sides of the self-lubricating spherical bearing. One end of the main shaft 3 is connected to the self-lubricating spherical bearing, and the other end is coaxially connected to one end of the test bracket 2. The other end of the test bracket 2 is connected to the piston of the oil cylinder 1. The hollow rotating platform 7 is located below the base plate 8. The hollow rotating platform 7 can rotate, swing, and tilt. As the hollow rotating platform 7 rotates, swings, and tilts, the self-lubricating spherical bearing also rotates, swings, and tilts.

[0052] In the above technical scheme, there are two oil cylinders 1, and the two oil cylinders are used to realize bidirectional top-to-bottom and extension. The two oil cylinders are loads to each other when they are extended and retracted, and when reciprocating motion is realized, the hydraulic energy is converted into mechanical energy, which serves as an actuator to realize the swing of the bearing. The oil cylinder can be exempted from the reduction device, and there is no transmission gap, and the movement is smooth. There is one main shaft 3, and the function of the main shaft is to connect the test bracket 2 and the oil cylinder 1, to provide support for the oil cylinder and ensure that the extension and retraction movement of the oil cylinder can proceed smoothly. The main shaft 3 transmits power by bearing loads and resisting torsional forces, while maintaining the relative positioning of other components. There is one hollow rotating platform 7, and the function of the hollow rotating platform is to realize multi-axial motions such as rotation, swinging, and tilting through a precise drive and control system to meet various complex motion requirements.

[0053] Another technical solution also includes a test platform, on which the oil cylinder 1, the test bracket 2, the main shaft 3, the base plate 8, and the hollow rotating platform 7 are all arranged; the test shaft 5 is used to install the oil cylinder 1 on the test platform; the outer sleeve of the test shaft 5 is provided with a bearing baffle 4.

[0054] In the above technical solution, there is one bearing baffle 4, which is used to limit the axial movement and circumferential rotation of the shaft to prevent the shaft from being separated from the connecting piece and causing accidents and dangers. There is one test shaft 5, which is used to connect the oil cylinder and the test platform, and is mainly used to support the rotating parts and rotate with them to transmit motion, torque or bending moment, so as to realize the telescopic movement of the oil cylinder.

[0055] Another technical solution also includes:

[0056] A temperature sensor is installed on the self-lubricating spherical plain bearing to monitor the temperature change of the self-lubricating spherical plain bearing during operation in real time;

[0057] A vibration sensor is installed on the self-lubricating spherical plain bearing to detect the vibration generated by the self-lubricating spherical plain bearing during operation in real time;

[0058] A noise sensor is installed on the self-lubricating spherical plain bearing to record the noise generated by the self-lubricating spherical plain bearing in real time during operation;

[0059] The displacement sensor is installed on the self-lubricating spherical bearing to measure the telescopic displacement of the cylinder in real time;

[0060] The flexible piezoelectric sensor is installed on the self-lubricating spherical plain bearing to measure the dynamic pressure on the self-lubricating spherical plain bearing in real time.

[0061] In another technical solution, a testing method for a self-lubricating spherical plain bearing life test platform is provided, comprising the following steps:

[0062] S1. Test sample selection

[0063] Select 10 qualified self-lubricating spherical plain bearings of the same batch and model as test objects; randomly select 4 of the 10 self-lubricating spherical plain bearings as test samples and divide them into two groups for testing, with 2 self-lubricating spherical plain bearings in each group;

[0064] S2. Test platform installation

[0065] The self-lubricating spherical bearing is mounted on the base plate 8, and a radial load of 98 kN is applied to ensure that the nominal contact stress reaches 166.4 MPa;

[0066] S3. Initial wear measurement

[0067] After applying a radial load of 98 kN for 15 minutes, the wear value of the test sample was measured using an electron microscope and returned to zero;

[0068] S4, swing frequency setting

[0069] The swing frequency of the inner ring of the self-lubricating spherical plain bearing is set to 90 times / min, and the swing angle is from 0° to +30°, then back to 0°, then to -30°, and finally back to 0°, forming a complete swing cycle;

[0070] S5. Data monitoring

[0071] Regularly observe and record the wear of the inner ring metal surface and liner of the self-lubricating spherical plain bearing. When the outer ring surface temperature of the self-lubricating spherical plain bearing reaches or exceeds 150℃, the test shall be stopped immediately.

[0072] The temperature sensor, vibration sensor, noise sensor, flexible piezoelectric sensor and displacement sensor are used to monitor the temperature, vibration, noise, dynamic pressure of the self-lubricating spherical bearing and the telescopic displacement of the oil cylinder in real time;

[0073] Among them, during load monitoring, when force is applied or bending is applied to the piezoelectric film, an electrical signal is generated between the upper and lower electrodes of the film. The signal is processed by the amplifier and processor to obtain the required monitoring signal.

[0074] S6. Abnormal situation handling

[0075] Use a stethoscope to listen to the changes in the noise of the self-lubricating spherical plain bearing to determine the operating conditions of the self-lubricating spherical plain bearing. Once an abnormality is found, the machine should be stopped immediately and inspected;

[0076] S7. Life Calculation

[0077] The running time from the start of the test to the end of the test is defined as the wear life of the self-lubricating spherical plain bearing, and the life of each self-lubricating spherical plain bearing is calculated;

[0078] S8. Lifespan prediction

[0079] Life prediction of self-lubricating spherical plain bearings.

[0080] S81. Draw the cycle number-damage level curve of the spherical plain bearing; obtain the direction and trend of change through comparison.

[0081] S811. Obtain the metal scratches on the inner ring of the spherical plain bearing by electron microscope analysis, including the width and number of scratches, the degree of adhesion of the inner ring lubricant, the size and shape of the inner ring, the fiber integrity of the outer ring liner, and the size and state information of the transfer film;

[0082] S812, obtaining wear size information of the spherical bearing liner through morphology analysis and size measurement;

[0083] S813. The damage of the spherical bearing is classified into 10 levels d0-d9 from no damage to severe damage based on the metal scratches on the inner ring of the spherical bearing and the wear size information of the spherical bearing liner. At the same time, the subsequent trend is predicted based on the experimental data, and finally a complete cycle number-damage level curve is obtained.

[0084] S82. Calculate the peak stress level of the test sample during the test and the number of cycles required for the test sample to fail;

[0085] S83. Determine the expected number of cycles to failure by comparing the peak stress levels in actual use;

[0086] In the test, the spherical plain bearings are often tested with acceleration and reduction. The number of cycles obtained at this time is the life of the test spherical plain bearings. For the spherical plain bearings in actual use, the actual life needs to be predicted in proportion based on the test data. For general reduction bearings, the size and load are reduced in proportion, and the test life is the expected life in actual use.

[0087] S84. Calculate the remaining useful life of the test sample based on the test data and theoretical analysis.

[0088] Specifically, after the test is completed, analyze whether the temperature during operation is greater than 150°C or directly observe whether the liner is worn through. If it is worn through before the end of the test, the current number of cycles is the life of the test sample. If it is not worn through, the damage level-cycle number curve is fitted through the points obtained by multiple electron microscope test results and morphology measurement during the test. Finally, the number of cycles corresponding to complete damage obtained by the fitted curve is the service life.

[0089] The invention can significantly improve the accuracy of wear life prediction of the self-lubricating spherical bearing of the hydraulic oil cylinder. The failure criterion determination test and the tolerance limit load determination test adopted by the invention provide a basis for the design and improvement of the self-lubricating spherical bearing.

[0090] The wear behavior under different working conditions is taken into account in the test of the present invention, so that the life prediction model can be applied to a wider range of environmental and load conditions. This improvement in flexibility and adaptability provides solid technical support for the application of self-lubricating spherical plain bearings in diversified industrial occasions. The present invention can obtain more accurate life prediction data, and the user unit can more effectively plan the maintenance and replacement plan of the self-lubricating spherical plain bearings, avoiding replacement too early or too late, thereby maximizing the operating efficiency of the equipment and reducing operating costs.

[0091] In summary, the present invention can not only improve the accuracy of bearing life prediction, but also provide a scientific basis for the design and application of bearings, expand their applicability in working conditions, and help users optimize maintenance and replacement plans. It has significant practical value and socio-economic benefits.

[0092] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A self-lubricating spherical bearing life test platform, characterized in that: include: Oil cylinder, test bracket, spindle, base plate, hollow rotating platform; The self-lubricating spherical bearing is placed on the base plate, and two main shafts are respectively located on both sides of the self-lubricating spherical bearing. One end of the main shaft is connected to the self-lubricating spherical bearing, and the other end is coaxially connected to one end of the test bracket. The other end of the test bracket is connected to the piston of the oil cylinder. The hollow rotating platform is located below the base plate. The hollow rotating platform can rotate, swing, and tilt. As the hollow rotating platform rotates, swings, and tilts, the self-lubricating spherical bearing also rotates, swings, and tilts.

2. The self-lubricating spherical bearing life test platform according to claim 1 is characterized in that: It also includes a test platform, on which the oil cylinder, the test bracket, the main shaft, the bottom plate, and the hollow rotating platform are all arranged; The test shaft is used to install the oil cylinder on the test platform; a bearing baffle is provided on the outside of the test shaft.

3. The self-lubricating spherical bearing life test platform according to claim 1, characterized in that: Also includes: A temperature sensor is installed on the self-lubricating spherical plain bearing to monitor the temperature change of the self-lubricating spherical plain bearing during operation in real time; A vibration sensor is installed on the self-lubricating spherical plain bearing to detect the vibration generated by the self-lubricating spherical plain bearing during operation in real time; A noise sensor is installed on the self-lubricating spherical plain bearing to record the noise generated by the self-lubricating spherical plain bearing in real time during operation; The displacement sensor is installed on the self-lubricating spherical bearing to measure the telescopic displacement of the cylinder in real time; The flexible piezoelectric sensor is installed on the self-lubricating spherical plain bearing to measure the dynamic pressure on the self-lubricating spherical plain bearing in real time.

4. The testing method of the self-lubricating spherical plain bearing life test platform according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Test sample selection Select 10 self-lubricating spherical bearings of the same batch and model that have passed the inspection as test objects; randomly select 4 of the 10 self-lubricating spherical bearings as test samples and divide them into two groups for testing, with 2 self-lubricating spherical bearings in each group; S2. Test platform installation Install the self-lubricating spherical plain bearing on the base plate and apply a radial load of 98kN to ensure that the nominal contact stress reaches 166.4Mpa; S3. Initial wear measurement After applying a radial load of 98 kN for 15 minutes, the wear value of the test sample was measured using an electron microscope and returned to zero; S4, Swing frequency setting The swing frequency of the inner ring of the self-lubricating spherical plain bearing is set to 90 times / min, and the swing angle is from 0° to +30°, then back to 0°, then to -30°, and finally back to 0°, forming a complete swing cycle; S5. Data monitoring Regularly observe and record the wear of the inner ring metal surface and liner of the self-lubricating spherical plain bearing. When the outer ring surface temperature of the self-lubricating spherical plain bearing reaches or exceeds 150℃, the test shall be stopped immediately. Temperature sensors, vibration sensors, noise sensors, flexible piezoelectric sensors, and displacement sensors are used to monitor the temperature, vibration, noise, dynamic pressure of the self-lubricating spherical bearing and the telescopic displacement of the oil cylinder in real time; S6. Abnormal situation handling Monitor the changes in the noise of the self-lubricating spherical plain bearing to determine the operation of the self-lubricating spherical plain bearing. If any abnormality is found, the machine should be stopped immediately and inspected; S7. Life Calculation The running time from the start of the test to the end of the test is defined as the wear life of the self-lubricating spherical plain bearing, and the life of each self-lubricating spherical plain bearing is calculated; S8. Lifespan prediction Life prediction of self-lubricating spherical plain bearings.

5. The self-lubricating spherical bearing life test platform according to claim 4, characterized in that: The step S8 specifically includes the following steps: S81. Draw a curve of the number of cycles and damage level of the spherical plain bearing; S82. Calculate the peak stress level of the test sample during the test and the number of cycles required for the test sample to fail; S83. Determine the expected number of cycles to failure by comparing the peak stress levels in actual use; S84. Calculate the remaining useful life of the test sample based on the test data and theoretical analysis.

6. The self-lubricating spherical bearing life test platform according to claim 5, characterized in that: The step S81 specifically includes the following steps: S811. Obtain the metal scratches on the inner ring of the spherical plain bearing by electron microscope analysis, including the width and number of scratches, the degree of adhesion of the inner ring lubricant, the size and shape of the inner ring, the fiber integrity of the outer ring liner, and the size and state information of the transfer film; S812, obtaining wear size information of the spherical bearing liner through morphology analysis and size measurement; S813. The damage of the spherical bearing is classified into 10 levels d0-d9 from no damage to severe damage based on the metal scratches on the inner ring of the spherical bearing and the wear size information of the spherical bearing liner. At the same time, the subsequent trend is predicted based on the experimental data, and finally a complete cycle number-damage level curve is obtained.

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