A bearing spalling test method

Abstract

The bearing peeling test method comprises the following steps: calculating the actual working load and rotating speed of the bearing; obtaining two sets of bearing test samples and manufacturing artificial damage points on the outer ring raceway; installing the bearing test samples with artificial damage points in a bearing peeling tester respectively and performing preliminary test and peeling expansion test to obtain bearing peeling test data; and obtaining the bearing test sample result according to the bearing peeling test data. The bearing peeling test method can simulate the working condition of the bearing after peeling, and the peeling expansion process and the mileage of the bearing after peeling can be obtained according to the measured temperature, the measurement of the peeling range during the test and the mileage, and the durability of the bearing after peeling expansion is evaluated, so that the quality problem of the bearing can be controlled before the bearing is installed and used, and the safety of the train is ensured.

Description

Technical Field

[0001] This invention relates to the field of bearing testing technology, and in particular to a bearing peeling test method. Background Technology

[0002] When a bearing rotates under load, the raceway surface or rolling element surface of the inner and outer rings may exhibit a fish-scale-like peeling phenomenon due to rolling fatigue, caused by excessive load, improper installation, foreign object intrusion, water ingress, poor lubrication, unsuitable lubricant, inappropriate bearing clearance, poor bearing housing precision, uneven bearing housing rigidity, large shaft deflection, rust, corrosion points, scratches and indentations (surface deformation phenomena).

[0003] To better verify the durability performance of bearings after peeling, a practical peeling expansion test scheme was summarized based on years of application and operating conditions of high-speed rail bearings. A large number of tests were conducted to verify the scheme, providing a strong quality guarantee for the safe use of bearings in trains.

[0004] During the verification process of high-speed railway axle box bearings, the only basis for unit-level tests of axle box bearings is the type test standard. For research tests such as peeling expansion tests that affect bearing performance, there are no test methods and standards, making it impossible to fully verify the bearing performance. Summary of the Invention

[0005] This invention provides a bearing peeling test method to overcome the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A bearing peel test method includes the following steps:

[0008] Step 1: Calculate the actual operating load and speed of the bearing; the actual operating load of the bearing includes the actual axial load and the actual radial load of the bearing.

[0009] Step 2: Obtain two sets of bearing test specimens;

[0010] Step 3: Create artificial damage points on the outer ring raceway of the obtained bearing test specimen;

[0011] Step 4: Install the bearing test specimens with artificially created damage points into the two test shaft boxes of the bearing peel test machine;

[0012] Step 5: Set the test load and test speed of the bearing testing machine according to the calculated actual operating load and speed of the bearing;

[0013] Step 6: Conduct a preliminary test on the bearing test specimen with artificial damage points according to the set test load and rotation speed;

[0014] Step 7: Perform a peeling propagation test on the bearing test specimens with artificial damage points to obtain bearing peeling test data;

[0015] Step 8: Obtain the bearing test sample results based on the bearing peel test data.

[0016] Furthermore, the artificial damage points created on the outer ring raceway of the obtained bearing test specimens are specifically as follows:

[0017] Artificial damage points are created on the outer raceway at a distance greater than 10mm from both ends of the bearing;

[0018] The artificial damage points were created by using a Rockwell hardness tester with an indentation load of 1.471 kN, and forming a row of defect areas by machining an indentation at intervals of 0.75 mm along the raceway generatrix.

[0019] Furthermore, the bearing test samples are obtained by randomly selecting from the finished bearing boxes of the same code and production batch that have passed inspection at a sampling ratio of 1:15.

[0020] Furthermore, the test loads set include test axial loads and test radial loads;

[0021] The test radial load was set to be equal to the calculated radial load under the actual bearing operating conditions;

[0022] The test axial loads were set to be 25%, 50%, 75%, and 100% of the calculated bearing load under actual operating conditions, respectively.

[0023] The test speeds were set to 25%, 50%, 75%, and 100% of the calculated actual bearing operating speed, respectively.

[0024] Furthermore, the preliminary test includes four test cycles, each consisting of two unidirectional strokes. The test speeds are 25%, 50%, 75%, and 100% of the calculated actual bearing operating speed, respectively. The corresponding axial loads are 25%, 50%, 75%, and 100% of the calculated actual bearing axial load, respectively. The radial load is equal to the calculated actual bearing radial load. Each unidirectional stroke consists of starting speed, constant speed, deceleration, and stopping.

[0025] Furthermore, the peeling and expansion test data includes real-time acquisition of temperature and vibration data of the bearing test specimen during the test process, as well as whether the bearing test specimen has through cracks after the test process. If the temperature and vibration data of the bearing test specimen during the test process are less than the set values, and the bearing test specimen has no through cracks after the test process, the bearing test specimen is judged to be qualified; otherwise, the bearing test specimen is judged to be unqualified.

[0026] Furthermore, the preliminary test also includes real-time measurement of the temperature of the bearing test specimen. When the temperature change does not exceed a set value within a set time, the preliminary test ends.

[0027] Furthermore, a peel occurrence test is included prior to the peel expansion test, the peel occurrence test specifically including:

[0028] After the preliminary test is completed, a peeling test is conducted. The peeling test requires no axial load, a radial test load of 163.8 kN, and continuous rotation in a single direction at 1740 r / min, every 5 × 10... 4 After km, the parts were disassembled and inspected to check for peeling. Once peeling was confirmed, a peeling expansion test was conducted.

[0029] Furthermore, during the peeling and expansion test, the test axial load, test radial load, and test speed are the same as the working condition axial load, working condition radial load, and working condition speed in sequence, and the test axial load is an alternating load; and the test is cyclically performed according to a set time.

[0030] Furthermore, it also includes setting up a ventilation device to provide cooling air to the bearing peeling test machine, so that the wind speed measured at the test shaft box is 8m / s to 10m / s; and setting the bearing peeling ambient temperature.

[0031] Beneficial effects: The bearing peeling test method of the present invention can simulate the operating conditions of a bearing after peeling. Based on the measured temperature, the measurement of the peeling range during the test, and the mileage, the process of bearing peeling expansion and the mileage at which the bearing can continue to operate normally after peeling can be obtained. In this way, the durability performance of the bearing after peeling expansion can be evaluated, thereby controlling the quality problems of axle box bearings before installation and use, and providing a guarantee for driving safety. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the bearing peeling test method disclosed in this invention;

[0034] Figure 2 This is a structural diagram of an embodiment of a bearing used in the bearing peeling test method disclosed in this invention;

[0035] Figure 3 A schematic diagram showing the artificial damage points set on a bearing test specimen;

[0036] Figure 4 A timeline diagram for the peeling and expansion experiment. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figure 1 The bearing peeling test method disclosed in this invention includes the following steps:

[0039] Step 1: Calculate the actual operating load and speed of the bearing; the actual operating load of the bearing includes the actual axial load and the actual radial load of the bearing.

[0040] Specifically, the operating speed is calculated using formula (1):

[0041]

[0042] Among them, v max D represents the maximum operating speed of the vehicle; D represents the fully worn wheel diameter.

[0043] The radial load under the working condition is calculated using formula (2):

[0044] F r =0.6×g×(m-m0)……………………(2)

[0045] Where g is the acceleration due to gravity; m is the weight of the shaft; and m0 is the unsprung weight.

[0046] The radial load under the working condition is calculated using formula (3):

[0047] F an =0.255×(10 4 +mg / 3)……………………(3);

[0048] Step 2: Obtain two sets of bearing test specimens;

[0049] Specifically, two sets of samples are randomly selected from the finished bearings of the same code and production batch that have passed inspection. Preferably, the bearing test samples are randomly selected from the finished bearings of the same code and production batch that have passed inspection at a ratio of 1:15.

[0050] Step 3: Create artificial damage points on the outer ring raceway of the obtained bearing test specimen;

[0051] Specifically, the artificial damage points created on the outer ring raceway of the obtained bearing test specimen are as follows:

[0052] like Figure 2 As shown, first determine the location of the defect: according to Figure 2 The requirement is to use a marker and a steel ruler to draw the defect area on the outer ring raceway of the bearing, and measure and confirm the length. The length of the defect area is the middle area on the raceway excluding the two ends 10mm, that is, to create an artificial damage point on the outer ring raceway at a distance greater than 10mm from the two ends of the bearing.

[0053] like Figure 3 As shown, the artificial damage point is formed by using a Rockwell hardness tester with an indentation load of 1.471 kN, creating a row of defect areas by machining an indentation at intervals of 0.75 mm along the raceway generatrix.

[0054] Step 4: Install the bearing test specimens with artificially created damage points into the two test shaft boxes of the bearing peel test machine;

[0055] Step 5: Set the test load and test speed of the bearing testing machine according to the calculated actual operating load and speed of the bearing;

[0056] Specifically, the corresponding loads and rotational speeds are set according to different test processes; the set test loads include test axial loads and test radial loads;

[0057] The test radial load was set to be equal to the calculated radial load under the actual bearing operating conditions;

[0058] The test axial loads were set to be 25%, 50%, 75%, and 100% of the calculated bearing load under actual operating conditions, respectively.

[0059] The test speeds were set to 25%, 50%, 75%, and 100% of the calculated actual bearing operating speed, respectively.

[0060] Step 6: Conduct a preliminary test on the bearing test specimen with artificial damage points according to the set test load and rotation speed;

[0061] Specifically, the preliminary test includes four test cycles, each consisting of two unidirectional strokes. The test speeds are 25%, 50%, 75%, and 100% of the calculated actual bearing operating speed, respectively. The corresponding axial loads are 25%, 50%, 75%, and 100% of the calculated actual bearing axial load, respectively. The radial load is equal to the calculated actual bearing radial load. Each unidirectional stroke consists of starting speed, constant speed, deceleration, and stopping.

[0062] Step 7: Perform a peeling propagation test on the bearing test specimens with artificial damage points to obtain bearing peeling test data;

[0063] Specifically, during the peeling propagation test, the test axial load, test radial load, and test speed are sequentially the same as the operating condition axial load, operating condition radial load, and operating condition speed, respectively. The test axial load is an alternating load. The test is cyclically performed according to a set time to obtain bearing peeling test data. The peeling propagation test data includes real-time temperature and vibration data of the bearing test specimen during the test, as well as whether the bearing test specimen has through-cracks after the test. In this embodiment, the set time is... Figure 4 The test is performed cyclically over a set time, and the test is completed when the bearing reaches the set mileage. The preferred bearing test mileage is 60 × 10. 4 km;

[0064] Step 8: Obtain the bearing test sample results based on the bearing peel test data;

[0065] Specifically, if the temperature and vibration data of the bearing test specimen during the test process are less than the set values, and there are no through cracks in the bearing test specimen after the test process, the bearing test specimen is judged to be qualified; otherwise, the bearing test specimen is judged to be unqualified.

[0066] In a specific embodiment, the set temperature data is 100°C and the set vibration data is 3g. That is, if the temperature of the bearing test specimen is not abnormal (not exceeding 100°C) during the test, the bearing vibration is less than 3g, and no through cracks are found when the bearing test specimen is inspected after the test, the bearing test specimen is judged to be qualified; otherwise, the bearing test specimen is judged to be unqualified.

[0067] The bearing peeling test method disclosed in this invention can effectively simulate the operating conditions of a bearing after peeling. Based on the measured temperature, the measurement of the peeling range during the test, and the mileage, the process of bearing peeling expansion and the mileage at which the bearing can continue to operate normally after peeling can be obtained. In this way, the durability performance of the bearing after peeling expansion can be evaluated, thereby controlling the quality problems of axle box bearings before installation and use, and providing a guarantee for driving safety.

[0068] Furthermore, the preparatory test also includes real-time measurement of the temperature of the bearing test specimen. When the temperature change does not exceed a set value within a set time, the preparatory test ends.

[0069] Specifically, in this embodiment, in the preliminary test, the distance of each cycle is not ended prematurely, but until the temperature stabilizes (the temperature change does not exceed 5°C within at least two hours), at which point the cycle ends. This allows for effective judgment of the preliminary test to proceed to the next bearing expansion peeling test.

[0070] Furthermore, a peel occurrence test is included prior to the peel expansion test, the peel occurrence test specifically including:

[0071] After the preliminary test is completed, a peeling test is conducted. The peeling test requires no axial load, a radial test load of 163.8 kN, and continuous rotation in a single direction at 1740 r / min, every 5 × 10... 4 After km, the bearing is disassembled and inspected to check the peeling situation. Once peeling is confirmed, a peeling expansion test can be performed. This application sets a peeling occurrence test, that is, sets a test condition that is more likely to cause the bearing to peel during the test process, thereby accelerating the effective generation of peeling on the bearing test specimen, and thus effectively carrying out the bearing expansion peeling test.

[0072] Furthermore, it also includes setting up a ventilation device to provide cooling air to the bearing peeling test machine, so that the wind speed measured at the test shaft box is 8m / s to 10m / s; and setting the bearing peeling ambient temperature, which can make the test process close to the actual working environment, so that the test results are more accurate.

[0073] During the experiment, the test speed, ambient temperature, test bearing temperature, bearing housing vibration, and test bench support bearing temperature were monitored in real time. All test data were automatically and continuously recorded by computer, with each parameter value recorded and saved at 1-minute intervals until the end of the test. Simultaneously, during the 5×10 test... 4 After 10 km, inspect the damage propagation and record the width and length of the defect, taking photographs as evidence. During every 10×10 km run of the test... 4 The extent of the peeling was investigated, the dimensions of the peeling locations were measured, and photographs were taken. Real-time vibration data was also recorded for each axle box to facilitate subsequent analysis of the test data.

[0074] During the process of artificially creating damage to the outer raceway, the appearance of the damaged location is recorded by photographs taken by the testing personnel. Before the test, the testing unit re-measures the external dimensions and axial clearance of the test product, and the measurement results are attached to the test report.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bearing peeling test method, characterized in that: Includes the following steps: Step 1: Calculate the actual operating load and speed of the bearing; the actual operating load of the bearing includes the actual axial load and the actual radial load of the bearing. Step 2: Obtain two sets of bearing test specimens; Step 3: Create artificial damage points on the outer ring raceway of the obtained bearing test specimen; Step 4: Install the bearing test specimens with artificially created damage points into the two test shaft boxes of the bearing peel test machine; Step 5: Set the test load and test speed of the bearing testing machine according to the calculated actual operating load and speed of the bearing; Step 6: Conduct a preliminary test on the bearing test specimen with artificial damage points according to the set test load and rotation speed; Step 7: Perform a peeling propagation test on the bearing test specimens with artificial damage points to obtain bearing peeling propagation test data; Step 8: Obtain the bearing test specimen results based on the bearing peeling propagation test data; The bearing peeling propagation test data includes real-time acquisition of temperature and vibration data of the bearing test specimen during the test process, as well as whether the bearing test specimen has through cracks after the test process. If the temperature and vibration data of the bearing test specimen during the test process are less than the set value, and the bearing test specimen has no through cracks after the test process, the bearing test specimen is judged to be qualified; otherwise, the bearing test specimen is judged to be unqualified. A peeling occurrence test is included before the peeling expansion test, and the peeling occurrence test specifically includes: After the preliminary test is completed, a peeling test is conducted. The peeling test requires no axial load, a radial test load of 163.8 kN, and continuous rotation in a single direction at 1740 r / min, every 5 × 10 4 After km, disassemble and inspect the peeling situation. Once peeling is confirmed, conduct a peeling expansion test. During the peeling and expansion test, the test axial load, test radial load, and test speed are the same as the working condition axial load, working condition radial load, and working condition speed in sequence. The test axial load is an alternating load. The test is cyclically performed according to a set time.

2. The bearing peeling test method according to claim 1, characterized in that: The artificial damage points created on the outer ring raceway of the obtained bearing test specimens are specifically as follows: Artificial damage points are created on the outer raceway at a distance greater than 10mm from both ends of the bearing; The artificial damage points were created by using a Rockwell hardness tester with an indentation load of 1.471 kN, and forming a row of defect areas by machining an indentation at intervals of 0.75 mm along the raceway generatrix.

3. The bearing peeling test method according to claim 1, characterized in that: The bearing test samples were obtained by randomly selecting from the finished bearing boxes of the same code and production batch that had passed inspection at a ratio of 1:

15.

4. The bearing peeling test method according to claim 1, characterized in that: The test loads set include the test axial load and the test radial load; The test radial load was set to be equal to the calculated radial load under the actual bearing operating conditions; The test axial loads were set to 25%, 50%, 75%, and 100% of the calculated actual bearing load under bearing operating conditions, respectively. The test speeds were set to 25%, 50%, 75%, and 100% of the calculated actual bearing operating speed, respectively.

5. The bearing peeling test method according to claim 4, characterized in that: The preliminary test includes four test cycles, each consisting of two unidirectional strokes. The test speeds are 25%, 50%, 75%, and 100% of the calculated actual bearing operating speed, respectively. The corresponding axial loads are 25%, 50%, 75%, and 100% of the calculated actual bearing axial load, respectively. The radial load is equal to the calculated actual bearing radial load. Each unidirectional stroke consists of starting speed, constant speed, deceleration, and stopping.

6. The bearing peeling test method according to claim 5, characterized in that: The preliminary test also includes real-time measurement of the temperature of the bearing test specimen. The preliminary test ends when the temperature change does not exceed the set value within a set time.

7. The bearing peeling test method according to claim 1, characterized in that: It also includes setting up a ventilation device to provide cooling air to the bearing peel test machine, so that the wind speed measured at the test shaft box is 8m / s to 10m / s; and setting the bearing peel ambient temperature.

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