Evaluation method for air cooling convection dissipation influence of rolling bearing bench test

Abstract

The invention discloses a rolling bearing bench test air cooling convection dissipation influence assessment method, which comprises the steps of collecting basic parameters of a rolling bearing bench test, including environmental parameters and cooling air flow field parameters; carrying out a rolling bearing bench test, and collecting temperature data, environment state data and flow data of cooling air of the rolling bearing in the test in real time; based on the basic parameters, the temperature data, the environment state data and the cooling air flow data, thermal physical property parameters of the air and the cooling air in the real-time state and the nominal state are calculated; calculating a convection dissipation coefficient under the comparison of a real-time state and a nominal state in the test based on the parameter; the bearing temperature collected in real time is converted into the equivalent temperature in the nominal state based on the coefficient, and then compliance judgment of the bearing performance is carried out; according to the method, the fairness and comparability of test results are enhanced, and a more scientific and reliable basis is provided for quality evaluation, performance comparison and compliance authentication of bearing products.

Description

Technical Field

[0001] This invention relates to the field of rolling bearing bench testing technology, and in particular to a method for evaluating the effect of air cooling convection dissipation in rolling bearing bench testing. Background Technology

[0002] Regarding the methods for evaluating the reliability of bearing wear and heat generation through bench testing of rolling bearings, in China, especially in the railway industry, the main rolling bearings of locomotives and rolling stock are typically tested using simulated loads, speeds, and other track operating conditions, simulating running air cooling. This method further characterizes the heat generation of the bearing by measuring its temperature, thus identifying the compatibility between the rolling bearing and the locomotive / rolling stock. However, because the simulated running air conditions are relatively simple and lack detailed measurement of the cooling capacity, the bearing temperature rise and heat generation vary under different ambient temperatures. Domestic and international railway industry standards for rolling bearing testing include: TB / T 3017.1—2016 "Roller Rolling Stock Bearing Bench Test Methods Part 1: Axle Box Rolling Bearings", TB / T3017.2—2016 "Roller Rolling Stock Bearing Bench Test Methods Part 2: Traction Motor Rolling Bearings", TB / T 3017.3—2016 "Roller Rolling Stock Bearing Bench Test Methods Part 3: Axle Box Rolling Bearings", and TB / T The test methods for axle box rolling bearings specified in domestic standards are consistent with international standards. These standards include BS EN 12082:2017+A1:2021 "Railway applications - Axleboxes - Performance testing", UIC 515-5:94 "Powered and trailing stock-Bogies-Running_gear-Tests for axle-boxes", NF F18-201:1989 "Test methods for axle box housings of rolling bearings in railway locomotives and rolling stock - thermal testing on an axle box testing machine", and NF F18-202:1989 "Test methods for rolling bearings in axle box housings of railway locomotives and rolling stock - durability testing on an axle box testing machine". The above standards all provide calculation methods for the standard effective temperature when the measured bearing temperature is equivalent to an ambient temperature of 20 degrees Celsius under different ambient temperatures. The correction methods for the influence of simulated running wind under different ambient temperatures are different. In the new version, BS EN12082:2017+A1:2021 proposes an influence coefficient of 0.6, but does not provide an in-depth explanation of the source of 0.6, only using heat dissipation, convection dissipation and test bench experience as explanations.

[0003] In practical engineering applications, the heat transfer capacity of air decreases at lower ambient temperatures. However, at the same wind speed, the volume of air flowing through is the same, but due to the increase in air density and mass, and the proportion of mass increase is relatively large, the cooling capacity of low-temperature air increases, thus enhancing the convective dissipation of heat generated by the test bearing. At higher ambient temperatures, the heat transfer capacity of air increases, but at the same wind speed, the volume of air flowing through is the same, but due to the decrease in air density and mass, and the proportion of mass decrease is relatively large, the cooling capacity of high-temperature air decreases, thus weakening the convective dissipation of heat generated by the test bearing. The standard-specified test method for axle box rolling bearings sets a uniform value for convective dissipation. However, in reality, the convective dissipation capacity and value of air at different ambient temperatures are inconsistent with the actual values. The calculated effective temperature based on the existing influence coefficient and standard differs significantly from the actual standard effective temperature result, leading to a larger deviation in the test results obtained in the bearing test, reduced repeatability of the test verification, and inability to obtain more accurate rolling bearing bench test results. Summary of the Invention

[0004] This invention provides a method for evaluating the influence of air cooling convection dissipation in rolling bearing bench tests, in order to overcome the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A method for evaluating the impact of air cooling convection dissipation in rolling bearing bench tests includes: S1: Collect basic parameters of rolling bearing bench tests, including environmental parameters and cooling airflow field parameters; S2: Conduct rolling bearing bench tests and collect real-time data on rolling bearing temperature, environmental conditions, and cooling airflow during the test. S3: Based on the basic parameters collected in S1, the temperature data, environmental state data, and cooling air flow data collected in S2, calculate the thermophysical property parameters of air and cooling air under real-time and nominal conditions. S4: Calculate the convection dissipation coefficient between the real-time state and the nominal state in the experiment based on the aforementioned thermophysical property parameters; S5: Based on the convection dissipation coefficient, the real-time collected bearing temperature is converted into the equivalent temperature under nominal conditions, and the compliance of bearing performance is determined based on the equivalent temperature.

[0006] Furthermore, the environmental parameters include the gas constant of air, the average molar mass coefficient of air, and the standard atmospheric pressure; the cooling airflow field parameters include the equivalent area of ​​the local test bench cooling airflow through the bearing housing and the equivalent area of ​​the standard-specified test bench cooling airflow through the bearing housing.

[0007] Furthermore, rolling bearing bench tests were conducted, and the temperature at each measuring point of the bearing, the ambient temperature, the atmospheric pressure of the test site, the average speed of the cooling airflow through the bearing housing, and the average speed of the cooling airflow through the bearing housing as specified in the standard were collected in real time.

[0008] Furthermore, based on the basic parameters collected by S1, the temperature data collected by S2, the environmental state data, and the cooling airflow data, the thermophysical properties of the air and cooling air under real-time and nominal conditions are calculated, including: S31. Based on the ambient temperature collected at each moment, calculate the air thermal conductivity at each moment. Calculate the nominal air thermal conductivity based on the nominal ambient temperature, as shown in formulas (1) and (2). (1) (2) in, The value represents the thermal conductivity of air at the ambient temperature at each test moment. The nominal thermal conductivity of air at the nominal ambient temperature. This is the zero-point coefficient of the thermal conductivity of air, with units of W / m·K. The slope of the air thermal conductivity as a function of ambient temperature, expressed in W / m·K. 2 ; The ambient temperature at each moment; The ambient temperature is the nominal temperature, and the unit is °C. S32. Calculate the aerodynamic viscosity at each moment based on the ambient temperature collected at each moment, and calculate the nominal aerodynamic viscosity based on the nominal ambient temperature, as shown in formulas (3) and (4). (3) (4) in, The aerodynamic viscosity at ambient temperature at each test time, The nominal aerodynamic viscosity is the nominal viscosity at the nominal ambient temperature. This is the zero-point coefficient of aerodynamic viscosity, with units of kg / m·s. The slope of the aerodynamic viscosity as a function of ambient temperature is expressed in kg / m·s·k. S33. Calculate the equivalent diameter of the cooling air passing through the bearing housing based on the equivalent area of ​​the cooling airflow through the bearing housing on the local test bench, as shown in formula (5). (5) in, The equivalent diameter of the cooling air passing through the bearing housing, expressed in meters (m); This is the equivalent area of ​​the cooling airflow through the bearing housing on the local test bench, in m². 2 ; S34. Calculate the cooling air density at each moment during the test based on the atmospheric pressure of the test site, the gas constant of air, the average molar mass coefficient of air, and the ambient temperature at each moment. Calculate the cooling air density at the nominal ambient temperature based on the standard atmospheric pressure, the average molar mass coefficient of air, the gas constant of air, and the nominal ambient temperature, as shown in formulas (6) and (7). (6) (7) in, The cooling air density at each moment during the experiment. Cooling air density at nominal ambient temperature, all in kg / m³ 3 ; This represents the atmospheric pressure at the test site at each test moment. Standard atmospheric pressure, all units are N / m 2 ; is the average molar mass coefficient of air, expressed in g / mol; is the gas constant of air, expressed in J / mol·K; S35. Based on the gas constant of air, the cooling air density at each moment, the average velocity of the cooling air flowing through the bearing housing at each moment, the equivalent diameter of the cooling air through the bearing housing, and the aerodynamic viscosity at each moment, the Reynolds coefficient of the cooling air at each moment during the test is calculated as shown in formula (8). (8) in, Let be the Reynolds coefficient of the cooling wind at each test moment, which is dimensionless; The average velocity of the cooling airflow through the bearing housing at each moment is expressed in m / s. Determining the Reynolds Index Based on the Cooling Wind Reynolds Coefficient To solve for the convection dissipation coefficient; S36. Calculate the mass flow rate of cooling air through the bearing housing at each moment during the test based on the cooling air density at each time point, the average velocity of the cooling air flowing through the bearing housing at each moment, and the equivalent area of ​​the cooling air flowing through the bearing housing at the local test platform. Calculate the mass flow rate of cooling air through the bearing housing at the nominal ambient temperature based on the cooling air density at the nominal ambient temperature, the average velocity of the cooling air flowing through the bearing housing at the standard specified in the test platform, and the equivalent area of ​​the cooling air flowing through the bearing housing at the standard specified in the test platform, as shown in formulas (9) and (10). (9) (10) in, This represents the mass flow rate of the cooling air passing through the bearing housing at various points during the test. The mass flow rate of cooling air passing through the bearing housing at the nominal ambient temperature, as specified by the standard, is expressed in kg / s. The average velocity of the cooling airflow through the bearing housing on the test bench, as specified in the standard, is expressed in m / s. The equivalent area of ​​the cooling airflow over the bearing housing as specified in the standard, expressed in m². 2 .

[0009] Furthermore, the convective dissipation coefficient is calculated based on the aforementioned thermophysical property parameters, comparing the real-time state with the nominal state during the experiment, including: The convection dissipation coefficient under local test conditions compared with the nominal conditions is calculated as shown in formula (11). (11) in, The real-time convection dissipation coefficient is the result of comparing the local test bench with the nominal condition, and it is dimensionless.

[0010] Furthermore, based on the convection dissipation coefficient, the real-time acquired bearing temperature is converted into the equivalent temperature under nominal conditions, including: The nominal effective temperature at each measurement point during the local test bench test, under the influence of real-time convection dissipation, is calculated as shown in formula (12). (12) in, The temperature at each measuring point of the bearing at each moment. The effective temperature under nominal conditions. For measurement point P i Temperature gradient with the bearing housing surface, all in °C.

[0011] Beneficial Effects: This invention provides an evaluation method for the influence of air cooling on convective heat dissipation in rolling bearing bench tests. It comprehensively considers the coupled effects of ambient temperature, test temperature, and cooling air velocity on convective heat transfer, as well as the thermophysical properties of air and cooling air under real-time and nominal conditions. This method scientifically converts bearing temperatures measured in actual test environments to equivalent temperatures under unified standard conditions, eliminating systematic errors caused by fluctuations in the test environment (such as changes in air pressure and temperature) and differences in test benches (such as different flow channel dimensions). It effectively isolates the influence of the test environment and test bench characteristics on the measured bearing temperature rise, allowing bearing bench test results from different times, locations, and test benches to be uniformly corrected to the same nominal benchmark for comparison and judgment. This overcomes the problem of large temperature deviations caused by the simplified approach of using fixed empirical coefficients (such as 1 or 0.6) for coarse correction in current domestic and international standards, enhancing the fairness and comparability of test results and providing a more scientific and reliable basis for bearing product quality assessment, performance comparison, and compliance certification. Attached Figure Description

[0012] 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.

[0013] Figure 1 A flowchart of a method for evaluating the effect of air cooling convection dissipation in rolling bearing bench testing provided by the present invention; Figure 2 This is a schematic diagram of the bearing test bench. Figure 3 This is a graph showing the trend of air thermal conductivity as a function of ambient temperature. Figure 4 This is a graph showing the trend of aerodynamic viscosity as a function of ambient temperature. Detailed Implementation

[0014] 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.

[0015] This embodiment provides a method for evaluating the impact of air cooling convection dissipation in rolling bearing bench tests, such as... Figure 1 As shown, it includes: S1: Collect basic parameters of rolling bearing bench tests, including environmental parameters and cooling airflow field parameters; S2: Conduct rolling bearing bench tests and collect real-time data on rolling bearing temperature, environmental conditions, and cooling airflow during the test. S3: Based on the basic parameters collected in S1, the temperature data, environmental state data, and cooling air flow data collected in S2, calculate the thermophysical property parameters of air and cooling air under real-time and nominal conditions. S4: Calculate the convection dissipation coefficient between the real-time state and the nominal state in the experiment based on the aforementioned thermophysical property parameters; S5: Based on the convection dissipation coefficient, the real-time collected bearing temperature is converted into the equivalent temperature under nominal conditions, and the compliance of bearing performance is determined based on the equivalent temperature.

[0016] Specifically, firstly, basic parameters for rolling bearing bench tests are collected, including environmental parameters and cooling airflow parameters. Rolling bearing bench tests are then conducted, and real-time data on the rolling bearing's temperature, environmental conditions, and cooling airflow are collected during the tests. Figure 2 As shown, the atmospheric conditions at different locations vary for a certain bearing test bench. To assess the impact of airflow dissipation during bench testing on the bearing test temperature, the local atmospheric pressure readings of the test bench must be recorded during the test. The ambient temperature of the cooling fan 1 on the test bench The ambient temperature of the cooling fan 2 on the test bench The wind speed of cooling fan 1 on the test bench The wind speed of cooling fan 2 on the test bench and the ventilation area of ​​the cooling fan 1 on the test bench. The ventilation area of ​​the cooling fan 2 on the test bench The diameter of the ventilation surface of the cooling fan 1 on the test bench The diameter of the ventilation surface of the cooling fan 2 on the test bench Temperature measurement points on the test bench It records the parameters of the cooling air during the test on the test bench in detail, and can calculate in detail the convective dissipation effect of the cooling air caused by environmental changes; Secondly, based on the collected basic parameters, environmental condition data, and cooling air flow data, the thermophysical properties of air and cooling air under real-time and nominal conditions are calculated. Taking into account the coupled influence of ambient temperature, test temperature, and cooling air flow velocity on the convective heat transfer effect, the thermophysical properties of air and cooling air under real-time and nominal conditions can scientifically convert the bearing temperature measured in the actual test environment to the equivalent temperature under unified standard conditions. This eliminates the systematic errors caused by fluctuations in the test environment (such as changes in air pressure and temperature) and differences in the test bench (such as different flow channel dimensions), effectively separating the influence of the test environment and test bench characteristics on the bearing temperature rise measurement value. Finally, based on the aforementioned thermophysical property parameters, the convection dissipation coefficient under the real-time condition and nominal condition in the test is calculated. Based on the convection dissipation coefficient, the real-time collected bearing temperature is converted into the equivalent temperature under the nominal condition. Based on this equivalent temperature, the compliance of the bearing performance is judged. The wear temperature rise state during the bearing test is evaluated according to the effective temperature of each measurement point under the nominal condition and the threshold value specified in the standard. This method is more detailed and accurate than the current domestic and international standards that use a single coefficient (1 or 0.6) to correct the effective temperature under the nominal condition.

[0017] In a specific embodiment, the scheme for collecting basic parameters of rolling bearing bench tests, including environmental parameters and cooling airflow field parameters, is as follows: Collect basic parameters for rolling bearing bench tests, including environmental parameters such as the gas constant of air, the average molar mass coefficient of air, and the standard atmospheric pressure; and cooling airflow field parameters such as the equivalent area of ​​the local test bench cooling airflow through the bearing housing and the equivalent area of ​​the standard test bench cooling airflow through the bearing housing. In this scheme, the gas constant of air is taken as 8.314 J / mol·K; the average molar mass coefficient of air is taken as 28.8 g / mol; and the standard atmospheric pressure is taken as 1.013 × 10⁻⁶. 5 N / m 2 The nominal ambient temperature during the test is specified as 20℃; the equivalent area of ​​the cooling airflow through the bearing housing of the local test bench and the equivalent area of ​​the cooling airflow through the bearing housing of the test bench specified in the standard shall be determined according to the actual test bench model, size and international standards.

[0018] In a specific embodiment, the scheme for conducting rolling bearing bench tests and collecting real-time data on the rolling bearing's temperature, environmental conditions, and cooling airflow during the tests is as follows: Rolling bearing bench tests were conducted, and the temperature at each measuring point of the bearing, the ambient temperature, the atmospheric pressure of the test site, the average speed of the cooling airflow through the bearing housing, and the average speed of the cooling airflow through the bearing housing as specified in the standard were collected in real time.

[0019] By recording the parameters of the cooling air during the test on the test bench, the impact of convective dissipation caused by environmental changes can be calculated in detail. This ensures that the convective dissipation coefficient can be adaptively adjusted according to different test benches, overcoming systematic errors caused by fluctuations in the test environment (such as changes in air pressure and temperature) and differences in test benches (such as different flow channel dimensions).

[0020] In a specific embodiment, the scheme for calculating the thermophysical property parameters of air and cooling air under real-time and nominal conditions based on the basic parameters collected in S1, the temperature data collected in S2, the environmental state data, and the cooling air flow data is as follows: S31. Based on the ambient temperature collected at each moment, calculate the air thermal conductivity at each moment. Calculate the nominal air thermal conductivity and nominal air dynamic viscosity based on the nominal ambient temperature, as shown in formulas (13) and (14). (13) (14) in, The value represents the thermal conductivity of air at the ambient temperature at each test moment. The nominal thermal conductivity of air at the nominal ambient temperature. The zero-point coefficient of air thermal conductivity is taken as 2.453 × 10⁻⁶ in this scheme. -2 All units are W / m·k; The slope of the air thermal conductivity as a function of ambient temperature is taken as 7.32 × 10⁻⁶ in this scheme. -5 The unit is W / m·k 2 ; The ambient temperature at each moment; The ambient temperature is the nominal temperature, and the unit is °C. The trend of air thermal conductivity changing with ambient temperature is as follows: Figure 3 As shown, from Figure 3 As can be seen, the thermal conductivity of air increases with rising ambient temperature. Air thermal conductivity is one of the core thermophysical parameters for calculating convective heat transfer efficiency. The higher the thermal conductivity, the stronger the air's ability to carry away heat as a cooling medium. Considering the air thermal conductivity ensures that the final effective temperature is closer to reality, resulting in more accurate experimental results. S32. Based on the ambient temperature collected at each moment, calculate the aerodynamic viscosity at each moment. Calculate the nominal aerodynamic viscosity based on the nominal ambient temperature, as shown in formulas (15) and (16). (15) (16) in, The aerodynamic viscosity at ambient temperature at each test time, The nominal aerodynamic viscosity is the nominal viscosity at the nominal ambient temperature. The zero-point coefficient of aerodynamic viscosity is taken as 1.706 × 10⁻⁶ in this scheme. -5 All units are kg / m·s; The slope of the aerodynamic viscosity as a function of ambient temperature is taken as 4.529 × 10⁻⁶ in this scheme. -8 The unit is kg / m·s·k; The trend of aerodynamic viscosity with ambient temperature is as follows: Figure 4 As shown in the figure, the aerodynamic viscosity increases continuously with the rise in ambient temperature. Aerodynamic viscosity is an indicator that measures the internal frictional resistance or flowability of air. Its changes directly affect the flow characteristics of cooling air. Calculating the aerodynamic viscosity, and then the Reynolds coefficient, ensures that the Reynolds coefficient changes in real time with the test bench and temperature, guaranteeing the accuracy of the final temperature calculation. S33. Calculate the equivalent diameter of the cooling airflow through the bearing housing based on the equivalent area of ​​the cooling airflow through the bearing housing on the local test bench, as shown in formula (17). (17) in, The equivalent diameter of the cooling air passing through the bearing housing, in meters; This is the equivalent area of ​​the cooling airflow through the bearing housing on the local test bench, in m². 2 ; S34. Calculate the cooling air density at each moment during the test based on the atmospheric pressure of the test site, the gas constant of air, the average molar mass coefficient of air, and the ambient temperature at each moment. Calculate the cooling air density at the nominal ambient temperature based on the standard atmospheric pressure, the average molar mass coefficient of air, the gas constant of air, and the nominal ambient temperature, as shown in formulas (18) and (19). (18) (19) in, The cooling air density at each moment during the experiment. Cooling air density at nominal ambient temperature, all in kg / m³ 3 ; This represents the atmospheric pressure at the test site at each test moment. Standard atmospheric pressure, all units are N / m 2 ; is the average molar mass coefficient of air, expressed in g / mol; is the gas constant of air, expressed in J / mol·K; S35. Based on the gas constant of air, the cooling air density at each moment, the average velocity of the cooling air flowing through the bearing housing at each moment, the equivalent diameter of the cooling air through the bearing housing, and the aerodynamic viscosity at each moment, the Reynolds coefficient of the cooling air at each moment during the test is calculated as shown in formula (20). (20) in, Let be the Reynolds coefficient of the cooling wind at each test moment, which is dimensionless; The average velocity of the cooling airflow through the bearing housing at each moment is expressed in m / s. Determining the Reynolds Index Based on the Cooling Wind Reynolds Coefficient Solving for the convection dissipation coefficient and determining the Reynolds index based on the Reynolds coefficient are conventional techniques used by those skilled in the art. This embodiment does not describe the specific steps. The value of the Reynolds index in this scheme is as follows: When the Reynolds coefficient of the cooling wind is at When the range is , When the Reynolds coefficient of the cooling wind is at a certain value , When the Reynolds coefficient of the cooling wind is at a certain value , During the experiment, the calculated Reynolds coefficient of the cooling wind will not be less than [a certain value]. Therefore, this embodiment does not consider the following situation. Reynolds index at that time; S36. Calculate the mass flow rate of cooling air through the bearing housing at each moment during the test based on the cooling air density at each time point, the average velocity of the cooling air flowing through the bearing housing at each moment, and the equivalent area of ​​the cooling air flowing through the bearing housing at the local test platform. Calculate the mass flow rate of cooling air through the bearing housing at the nominal ambient temperature based on the cooling air density at the nominal ambient temperature, the average velocity of the cooling air flowing through the bearing housing at the standard specified in the test platform, and the equivalent area of ​​the cooling air flowing through the bearing housing at the standard specified in the test platform, as shown in formulas (21) and (22). (twenty one) (twenty two) in, This represents the mass flow rate of the cooling air passing through the bearing housing at various points during the test. The mass flow rate of cooling air passing through the bearing housing at the nominal ambient temperature, as specified by the standard, is expressed in kg / s. The average velocity of the cooling airflow through the bearing housing on the test bench, as specified in the standard, is expressed in m / s. The equivalent area of ​​the cooling airflow over the bearing housing as specified in the standard, expressed in m². 2 .

[0021] This scheme comprehensively considers the coupled effects of ambient temperature, test temperature, and cooling air flow velocity on convective heat transfer. The thermophysical properties of air and cooling air under real-time and nominal conditions can scientifically convert the bearing temperature measured in the actual test environment to the equivalent temperature under unified standard conditions. This eliminates systematic errors caused by fluctuations in the test environment (such as changes in air pressure and temperature) and differences in the test bench (such as different flow channel dimensions), effectively separating the influence of the test environment and test bench characteristics on the bearing temperature rise measurement value.

[0022] In a specific embodiment, the scheme for calculating the convection dissipation coefficient between the real-time state and the nominal state in the experiment based on the thermophysical property parameters is as follows: calculate the convection dissipation coefficient between the local test bench and the nominal state, as shown in formula (23). (twenty three) in, The real-time convection dissipation coefficient is the result of comparing the local test bench with the nominal condition, and it is dimensionless.

[0023] In this scheme, the calculated convection dissipation coefficient enables bearing bench test results conducted at different times, locations, and test benches to be uniformly corrected to the same nominal standard for comparison and judgment. This overcomes the problem of large temperature deviations caused by the simplistic approach of using fixed empirical coefficients (such as 1 or 0.6) for coarse correction in current domestic and international standards. It enhances the fairness and comparability of test results and provides a more scientific and reliable basis for the quality assessment, performance comparison, and compliance certification of bearing products.

[0024] In a specific embodiment, the scheme for converting the real-time collected bearing temperature into an equivalent temperature under nominal conditions based on the convection dissipation coefficient, and then determining the compliance of bearing performance based on this equivalent temperature, is as follows: The nominal effective temperature at each measurement point during the local test bench test, under the influence of real-time convection dissipation, is calculated as shown in formula (24). (twenty four) in, The temperature at each measuring point of the bearing at each moment. The effective temperature under nominal conditions. For measurement point P i The temperature gradient with respect to the bearing housing surface is in °C. The measuring points on the bearing housing surface are set to 0, and the measuring points inside the bearing housing are selected according to the temperature gradient characteristics of the bearing housing structure. This is a conventional technique for those skilled in the art, and no specific data limitations are imposed in this embodiment.

[0025] 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 method of evaluating the influence of air cooling convection dissipation on a rolling bearing bench test, characterized in that, The method comprises the following steps: S1: collecting basic parameters of the rolling bearing bench test, the basic parameters comprising environmental parameters and cooling air flow field parameters; S2: performing the rolling bearing bench test and collecting temperature data of the rolling bearing, environmental state data and cooling air flow data in real time during the test; S3: calculating thermal physical property parameters of air and cooling air under real-time state and nominal state based on the basic parameters collected in S1, the temperature data, the environmental state data and the cooling air flow data collected in S2; S4: calculating a convective dissipation coefficient under comparison between the real-time state and the nominal state based on the thermal physical property parameters; S5: converting the bearing temperature collected in real time into equivalent temperature under the nominal state based on the convective dissipation coefficient, and performing compliance judgment of the bearing performance based on the equivalent temperature.

2. A method of evaluating the influence of air cooling convection dissipation in a rolling bearing bench test according to claim 1, characterized in that, The environmental parameters comprise gas constant of air, average molar mass coefficient of air and standard atmospheric pressure; the cooling air flow field parameters comprise equivalent area of the local test bench cooling air flowing through the bearing box and equivalent area of the standard specified test bench cooling air flowing through the bearing box.

3. A method of evaluating the influence of air cooling convection dissipation in a rolling bearing bench test according to claim 2, characterized in that, The rolling bearing bench test is performed, and the temperature of each measuring point of the bearing at each moment, the environmental temperature at each moment, the atmospheric pressure of the test site, the average speed of the test bench cooling air flowing through the bearing box at each moment and the average speed of the standard specified test bench cooling air flowing through the bearing box are collected in real time.

4. A method of evaluating the influence of air cooling convection dissipation in a rolling bearing bench test according to claim 3, characterized in that, Based on the basic parameters collected in S1, the temperature data, the environmental state data and the cooling air flow data collected in S2, the thermal physical property parameters of air and cooling air under real-time state and nominal state are calculated, comprising: S31, calculating the air heat conduction coefficient at each moment based on the collected environmental temperature at each moment, and calculating the nominal air heat conduction coefficient based on the nominal environmental temperature, as shown in formulas (1) and (2), （1） （2） wherein, is the air heat transfer coefficient at the ambient temperature at each test time, is the nominal air heat transfer coefficient at the nominal ambient temperature, is the zero point coefficient of the air heat transfer coefficient, both in W / m-k; is the slope of the air heat transfer coefficient with respect to the ambient temperature, in W / m-k 2 ; is the ambient temperature at each time, is the nominal ambient temperature, both in °C; S32, calculating the air dynamic viscosity at each moment based on the collected environmental temperature at each moment, and calculating the nominal air dynamic viscosity based on the nominal environmental temperature, as shown in formulas (3) and (4), （3） （4） wherein is the air dynamic viscosity at the ambient temperature at the respective test time, is the nominal air dynamic viscosity at the nominal ambient temperature, is the zero point coefficient for the air dynamic viscosity, both in kg / m-s, is the slope of the air dynamic viscosity with respect to the ambient temperature in kg / m-s-k; S33, calculating the equivalent diameter of the cooling air passing through the bearing box based on the equivalent area of the local test bench cooling air flowing through the bearing box, as shown in formula (5), （5） wherein, D is the equivalent diameter of the cooling air passing through the bearing housing, in m; D is the equivalent diameter of the cooling air passing through the bearing housing, in m; 2 ; S34, calculating the cooling air density at each moment during the test based on the atmospheric pressure of the test site, the gas constant of air, the average molar mass coefficient of air and the environmental temperature at each moment, and calculating the cooling air density under the nominal environmental temperature based on the standard atmospheric pressure, the average molar mass coefficient of air, the gas constant of air and the nominal environmental temperature, as shown in formulas (6) and (7), （6） （7） wherein, is the cooling air density at each time instant of the test, is the cooling air density at nominal ambient temperature, both in kg / m 3 ; is the atmospheric pressure at each test instant of the test site, is the standard atmospheric pressure, both in N / m 2 ; is the average molar mass coefficient of air, in g / mol; is the gas constant of air, in J / mol.k; S35, calculating the Reynolds coefficient of the cooling air at each moment during the test based on the gas constant of air, the cooling air density at each moment, the average speed of the test bench cooling air flowing through the bearing box at each moment, the equivalent diameter of the cooling air passing through the bearing box and the air dynamic viscosity at each moment, as shown in formula (8), （8） wherein, Reno is the cooling air Reynolds number at each test time, dimensionless; V is the average velocity of the cooling air flowing through the bearing housing at each test time, in m / s; Determination of reynolds index based on cooling air reynolds number To solve the convective dispersion coefficient; S36、based on the cooling air density at each time, the average speed of the test bench cooling air flowing through the bearing box at each time, and the equivalent area of the test bench cooling air flowing through the bearing box, calculate the mass flow rate of the cooling air through the bearing box at each time during the test, based on the cooling air density at the nominal ambient temperature, the average speed of the standard specified test bench cooling air flowing through the bearing box, and the equivalent area of the standard specified test bench cooling air flowing through the bearing box, calculate the mass flow rate of the cooling air through the bearing box at the nominal ambient temperature, as shown in formulas (9) and (10), （9） （10） wherein, is the mass flow rate of cooling air through the bearing housing at each time instant during the test, is the standard specified mass flow rate of cooling air through the bearing housing at nominal ambient temperature, both in kg / s; is the standard specified average velocity of the test stand cooling air through the bearing housing, in m / s; is the standard specified equivalent area of the test stand cooling air through the bearing housing, in m 2 .

5. A method of evaluating the influence of air cooling convection dissipation in a rolling bearing bench test according to claim 4, characterized in that, based on the thermal physical property parameters, calculate the convective dissipation coefficient under the comparison between the real-time state in the test and the nominal state, including: calculate the convective dissipation coefficient under the comparison between the local test bench during the test and the nominal state, as shown in formula (11), （11） wherein, Kf is the real-time convective heat loss coefficient under the comparison of the nominal state during the local test bench test, dimensionless.

6. A method of evaluating the influence of air cooling convection dissipation in a rolling bearing bench test according to claim 5, characterized in that, based on the convective dissipation coefficient, convert the real-time collected bearing temperature into the equivalent temperature under the nominal state, including: calculate the effective temperature under the nominal state of each measurement point during the test of the local test bench due to the influence of real-time convective dissipation, as shown in formula (12), （12） wherein, is the temperature of each measuring point of the bearing at each time, is the effective temperature in the nominal state, is the measuring point P i and the temperature gradient of the bearing housing surface, both in °C.

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