Bearing testing method

Abstract

The invention relates to the technical field of bearing performance testing, and particularly discloses a bearing testing method which is used for testing at least one to-be-tested bearing on a speed reducer. The predicted service life of a to-be-tested bearing is set, and the to-be-tested bearing is driven to operate according to a set rotating speed; the test tool applies an external load to the speed reducer and transmits the external load to the to-be-tested bearing; adjusting the magnitude and the application angle of the external load to enable the radial load of the to-be-tested bearing to be equal to the rated dynamic load; and when the failure duration of the to-be-tested bearing is greater than or equal to the predicted service life, or the to-be-tested bearing does not fail within the predicted service life duration, judging that the to-be-tested bearing is qualified. According to the invention, the radial load of the to-be-tested bearing is equal to the rated dynamic load by adjusting the external load, so that the fatigue life of the bearing is directly and quantitatively assessed, the stress state of the bearing under the actual working condition can be accurately simulated, and the problem of insufficient verification of the bearing in the prior art is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of bearing performance testing technology, and more specifically to bearing testing methods. Background Technology

[0002] Travel reducers are mainly used in tracked construction machinery. As a core supporting component of the reducer, the main bearing's performance directly determines the overall operational stability and service life of the reducer. The actual operating conditions of construction machinery are complex and varied, placing extremely high demands on the fatigue life and overload impact resistance of the reducer bearings. Therefore, it is necessary to simulate actual operating conditions through corresponding testing methods to verify whether the bearing performance meets design and usage requirements. Bearing performance verification has become a crucial step in the bearing selection and design process.

[0003] Currently, most performance tests on bearings of travel reducers rely on tests of the entire reducer. However, due to limitations in test conditions, equipment, and simulated operating conditions, the tests cannot fully match the weight of the entire machine and the actual load distribution, resulting in insufficient verification of the bearing's performance and inaccurate test results reflecting the bearing's actual performance.

[0004] Meanwhile, using general testing methods cannot accurately simulate the actual installation structure and load state of the main bearing of the travel reducer in the whole machine. The test results deviate significantly from the performance of the bearing under actual operating conditions, and cannot specifically meet the performance verification requirements of the main bearing of the travel reducer. Summary of the Invention

[0005] In view of this, the present invention provides a bearing testing method to solve the problem of "inability to specifically meet the performance verification of the main bearing of the travel reducer".

[0006] In a first aspect, the present invention provides a bearing testing method for testing at least one bearing to be tested on a speed reducer. The speed reducer is mounted on a test fixture. The bearing testing method includes the following steps: setting the expected life of the bearing to be tested; driving the bearing to be tested to rotate at a set speed using the test fixture; applying an external load to the speed reducer and transmitting it to the bearing to be tested using the test fixture; adjusting the magnitude and application angle of the external load so that the radial load of the bearing to be tested is equal to the rated dynamic load; and determining that the bearing to be tested is qualified if the failure time of the bearing to be tested is greater than or equal to the expected life, or if it does not fail within the expected life.

[0007] In one alternative implementation, the step “setting the expected life of the bearing under test;” includes determining the expected life of the bearing under test based on the rotational speed, rated dynamic load, and radial load; the expected life decreases at least as the rotational speed increases, as the rated dynamic load increases, and as the radial load increases.

[0008] In one optional implementation, the formula for calculating the expected life of the bearing under test is: ; Where L10 is the expected life, N is the rotational speed, Cr is the rated dynamic load, and P is the radial load.

[0009] In one alternative implementation, the step “the test fixture applies an external load to the reducer and transmits it to the bearing under test;” includes: the test fixture applies an external load to the reducer in progressively increasing steps, and the radial load of the bearing under test is lower than the rated dynamic load.

[0010] In one alternative embodiment, the reducer has a center of rotation, and the magnitude of the external load increases at least with the increase of the rated dynamic load and with the increase of the angle between itself and the perpendicular line of the center of rotation.

[0011] In one alternative embodiment, the bearing to be tested includes a first sub-bearing and a second sub-bearing, which are spaced apart along the rotation center.

[0012] In one optional implementation, the radial load calculation formula for the first sub-bearing and the second sub-bearing is as follows: ; Wherein, P1 is the first radial load of the first sub-bearing; P2 is the second radial load of the second sub-bearing; L1 is the axial distance between the intersection of the second radial load and the rotation center line and the intersection of the first radial load and the rotation center line; L2 is the axial distance between the intersection of the first radial load and the rotation center line and the intersection of the external load and the rotation center; θ is the angle between the external load and the perpendicular line of the rotation center; X is the radial load coefficient of the first sub-bearing; Y is the axial load coefficient of the first sub-bearing.

[0013] In one alternative implementation, the formula for calculating the external load is: ; Where W is the external load; P2 is the second radial load; L1 is the axial distance between the intersection of the second radial load and the rotation center line and the intersection of the first radial load and the rotation center line; L2 is the axial distance between the intersection of the first radial load and the rotation center line and the intersection of the external load and the rotation center; and θ is the angle between the external load and the perpendicular line to the rotation center.

[0014] Secondly, the present invention also provides a bearing testing method for testing at least one bearing to be tested on a speed reducer. The speed reducer is mounted on a test fixture. The bearing testing method includes the following steps: the test fixture drives the bearing to be tested to rotate at a set speed; the test fixture applies an external load to the speed reducer and transmits it to the bearing to be tested; the magnitude and application angle of the external load are adjusted so that the magnitude of the external load is at least twice the rated dynamic load of the bearing to be tested; the external load is applied cyclically for a preset number of times; if the bearing to be tested is still intact after the preset number of times, the bearing to be tested is deemed qualified.

[0015] In one optional implementation, the step "apply external load cyclically a preset number of times" includes: applying external load and continuing for a first preset time; repeating the previous step according to a second preset time interval.

[0016] The technical solution proposed in this application has at least the following technical effects: The first aspect of the bearing testing method involves adjusting the magnitude and angle of the external load to ensure that the radial load on the bearing under test is equal to its rated dynamic load during the test, thus achieving a direct and quantitative assessment of bearing performance. Compared to existing technologies that indirectly verify bearing performance through gearbox assembly testing, this method accurately simulates the bearing's stress state under actual operating conditions, eliminating verification deviations caused by complex load transmission paths and overall weight distribution in whole-machine testing. By correlating the external load with the bearing's rated dynamic load, radial load, and expected life, the test results accurately reflect the bearing's actual life and reliability, providing an accurate and reliable basis for bearing selection verification and design optimization. Furthermore, by setting the expected life and using failure duration as the criterion, this method makes the test results intuitive and clear, with good operability and repeatability, effectively screening out qualified bearings that meet design requirements.

[0017] The second aspect of the bearing testing method involves adjusting the magnitude and angle of the external load to ensure that the radial load on the bearing under test exceeds its rated dynamic load during the test. This external load is applied cyclically for a preset number of times, enabling a direct and quantitative assessment of the bearing's resistance to overload impact. This method fills the gap in related technologies regarding the lack of targeted overload verification methods for simulating reducer operating conditions. It can accurately simulate the instantaneous overload stress state experienced by bearings in engineering machinery under harsh operating conditions (such as sudden impacts, hard ground travel, obstacle crossing, etc.). By using "the bearing remaining intact after reaching a preset number of cycles" as the criterion, a clear and intuitive quantitative indicator is provided for the bearing's impact resistance, ensuring that the test results truly reflect the bearing's reliability under extreme operating conditions. Compared with traditional whole-machine testing, this method can independently and controllably verify the bearing's own overload tolerance, effectively avoiding interference from other components in whole-machine testing, and providing reliable technical support for bearing limit performance evaluation and selection optimization. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific 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 from these drawings without creative effort.

[0019] Figure 1 This is a structural diagram of a bearing testing method according to an embodiment of the present invention; Figure 2 This is a flowchart of a bearing testing method according to a first aspect of the present invention; Figure 3 This is a flowchart of a bearing testing method according to a second aspect of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Bearing to be tested; 101. First sub-bearing; 102. Second sub-bearing; 2. Reducer; 3. Test fixture; 4. Center of rotation; W. External load; P1. First radial load; P2. Second radial load; L1. First lever arm; L2. Second lever arm. Detailed Implementation

[0021] 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.

[0022] It should be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to impose strict limitations on the technical solutions unless the context clearly indicates otherwise. For example, the use of "a," "an," and "the" to modify a feature does not preclude the possibility that the feature may be plural in other embodiments.

[0023] It should be understood that the terms "comprising," "including," and "having" are open-ended, indicating the presence of the stated features but not excluding the possibility of other features in the embodiment. Similarly, the use of terms such as "first," "second," etc., to describe multiple features only indicates the distinction between one feature and another, and such terms do not imply order or sequence unless explicitly stated in the context.

[0024] It should be understood that, unless the context clearly indicates otherwise, the terms "setup," "connection," and "installation" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrated connection; they can refer to a direct connection or an indirect connection via a medium. Those skilled in the art will understand the specific meaning of these terms in this document based on the specific circumstances.

[0025] In addition, for ease of description, the text will use terms of spatial relative relationship to describe the position of one feature relative to another feature, such as "inner", "outer", "end", "side", "upper", "middle", "lower", "high", "low", "axial", "circumferential", "radial", "horizontal", "vertical", "first direction", "second direction", etc. It can be understood that the spatial relative relationship between two features should include other specific situations besides those shown in the accompanying drawings of the specification.

[0026] A speed reducer (also known as a gearbox) is an independent transmission component consisting of gear drives, worm gear drives, or gear-worm gear drives enclosed in a rigid housing. Its core function is to convert the high-speed input torque of a prime mover (such as an electric motor or hydraulic motor) into a low-speed, high-torque output torque, thereby reducing speed and increasing torque for actuators (such as drive wheels and working devices). In the field of construction machinery, the travel speed reducer is typically directly integrated with the drive wheels of tracked equipment to transmit power and withstand complex loads from the ground. Its internal main bearing, as a key support component, has a significant impact on the overall transmission efficiency and reliability of the machine.

[0027] The bearings in reducer 2 are its core supporting components, playing a crucial role in transmitting loads, ensuring rotational accuracy, and maintaining structural stability. In the travel reducer 2, the main bearings typically employ double-row angular contact ball bearings or double-row tapered roller bearings. These types of bearings are widely used in the drive systems of large and medium-sized tracked engineering machinery because they can simultaneously withstand large radial loads and bidirectional axial loads, and possess high rigidity. The main bearings are generally installed on the cover plate side and motor side of reducer 2, supporting the input and output ends of reducer 2 respectively. During equipment operation, the bearings not only bear the meshing force from the transmission gears but also directly bear the weight of the entire machine, ground reaction forces, and impact loads during travel. Due to the complex and varied operating conditions of engineering machinery, the bearings of reducer 2 are subjected to harsh environments such as heavy loads, variable loads, impacts, and vibrations for extended periods. Their fatigue life and overload resistance directly determine the overall reliability of reducer 2.

[0028] Therefore, conducting thorough performance verification of the main bearing of reducer 2 to ensure that it can reach its design life and have sufficient impact resistance margin under actual working conditions is a key aspect of reducer 2 design selection and quality control.

[0029] The embodiments of this application are described below with reference to the accompanying drawings. It can be understood that the technical features involved in the different embodiments described below can be combined with each other as long as they do not conflict with each other.

[0030] The following is combined Figures 1 to 3 The following describes embodiments of the present invention.

[0031] According to an embodiment of the present invention, in one aspect, referring to Figure 1 and Figure 2A bearing testing method is provided for testing at least one bearing 1 under test on a speed reducer 2. The speed reducer 2 is mounted on a test fixture 3. The bearing testing method includes the following steps: setting the expected life of the bearing 1 under test; driving the bearing 1 under test to rotate at a set speed according to the test fixture 3; applying an external load W to the speed reducer 2 and transmitting it to the bearing 1 under test; adjusting the magnitude and application angle of the external load W so that the radial load of the bearing 1 under test is equal to the rated dynamic load; when the failure time of the bearing 1 under test is greater than or equal to the expected life, or when it does not fail within the expected life, the bearing 1 under test is deemed qualified.

[0032] In this embodiment, before the test, the reducer 2 to be tested is first installed on the test fixture 3, which can simulate the installation and operation of the reducer 2 in the actual equipment.

[0033] Optionally, the bearing to be tested 1 can be a double-row angular contact ball bearing or a double-row tapered roller bearing, wherein the double-row angular contact ball bearing or the double-row tapered roller bearing has two sub-bearings.

[0034] Furthermore, the expected life of the bearing under test is set according to the specific design parameters of the bearing under test 1. By comparing the failure time of the test results with the expected life, it is determined whether the bearing under test 1 is qualified.

[0035] After the test is started, the test fixture 3 drives the bearing 1 under test to rotate at the set speed N. The speed N can be determined according to the actual operating speed range of the reducer 2, such as the rated speed or the typical operating speed. At the same time, the rotation direction can be set to counterclockwise or clockwise according to the actual operating conditions.

[0036] During bearing operation, the test fixture 3 applies an external load W to the reducer 2. This external load W is transmitted to the bearing 1 under test through the reducer 2's housing, transmission components, and other structures. The external load W can be applied using hydraulic loading, mechanical loading, or other controllable loading methods to simulate the load experienced by the reducer 2 during actual operation.

[0037] Optionally, the specific design parameters of the bearing 1 to be tested include at least the rated dynamic load, speed and external load W; wherein, the rated dynamic load Cr is 47500N; the speed N is 50rpm; and the value of the external load W is determined according to the rated dynamic load Cr of the bearing.

[0038] It should be noted that the value of the rated dynamic load Cr is related to the performance of the bearing under test. The value of the rated dynamic load Cr will vary for different bearings under test. The speed N is determined according to the specific performance parameters of the reducer.

[0039] In this embodiment, the external load W is 13562N.

[0040] In one embodiment, the step "Setting the expected life of the bearing 1 under test;" includes determining the expected life of the bearing 1 under test based on the rotational speed, rated dynamic load, and radial load; the expected life decreases at least as the rotational speed increases, as the rated dynamic load increases, and as the radial load increases.

[0041] In one embodiment, the formula for calculating the expected life of the bearing 1 under test is: ; Where L10 is the expected life, N is the rotational speed, Cr is the rated dynamic load, and P is the radial load.

[0042] In this embodiment, the step "setting the expected life of the bearing 1 under test" specifically includes: determining the expected life of the bearing 1 under test based on the set rotational speed N, rated dynamic load Cr, and radial load P experienced during the test.

[0043] Specifically, the expected life is determined by the formula, where L10 represents the expected life. This formula shows that the expected life L10 is inversely proportional to the set speed N, meaning the higher the speed N, the lower the expected life L10; the expected life L10 is directly proportional to the cube of the rated dynamic load Cr, meaning the higher the rated dynamic load Cr, the higher the expected life L10; and the expected life L10 is inversely proportional to the cube of the radial load P, meaning the higher the radial load P, the lower the expected life L10. Using this method, the theoretical life of the bearing under test 1 can be accurately calculated based on actual operating parameters, providing a clear quantitative standard for subsequent qualification judgment.

[0044] Furthermore, the first expected life of the first bearing is calculated using the formula: ; L10-1 is the first projected lifetime; Furthermore, the second expected life of the second bearing is calculated using the formula: ; L10-2 is the second projected lifetime; In this embodiment, the value range of L10-1 is 300h≤L10-1≤400h; the value range of L10-1 is 300h≤L10-2≤400h.

[0045] In one embodiment, the step “the test fixture 3 applies an external load W to the reducer 2 and transmits it to the bearing 1 under test;” includes: the test fixture 3 applies an external load W to the reducer 2 in progressively increasing steps, and the radial load of the bearing 1 under test is lower than the rated dynamic load.

[0046] In this embodiment, the step "the test fixture 3 applies an external load W to the reducer 2 and transmits it to the bearing 1 under test" specifically includes: after the test is started, the bearing 1 under test is first made to run unloaded at a set speed N for a preset time t. Then, the external load W is gradually increased according to a preset step, for example, 25% external load W, 50% external load W and 75% external load W are applied in sequence, and each loading stage lasts for a preset time t to complete the preheating and initial break-in.

[0047] Optionally, the preset time t can be 8min≤t≤12min.

[0048] In this embodiment, the preset time t is 10 minutes.

[0049] It should be noted that the bearing 1 under test in this embodiment is a double-row bearing with two sub-bearings, namely the first sub-bearing 101 and the second sub-bearing 102. The first radial load of the first sub-bearing 101 is P1, and the second radial load of the second sub-bearing 102 is P2. The reducer 2 is provided with a rotation center 4, and the first sub-bearing 101 and the second sub-bearing 102 are spaced apart along the axial direction of the rotation center 4.

[0050] Furthermore, by controlling the magnitude and application angle of the external load W, the second radial load P2 of the bearing under test 1 is always kept less than its rated dynamic load Cr, thereby avoiding accidental damage to the bearing due to excessive load before the formal test begins. This progressively increasing loading method can simulate the actual operating condition changes of the bearing from startup to full load, allowing the bearing to gradually adapt to the increase in load, eliminating initial assembly clearances, and ensuring the accuracy and reliability of the test data. After completing the progressively increasing pre-loading, the external load W is adjusted according to the design requirements to make the second radial load P2 equal to the rated dynamic load Cr.

[0051] In one embodiment, the reducer 2 has a rotation center 4, and the magnitude of the external load W increases at least with the increase of the rated dynamic load and with the increase of the angle between itself and the perpendicular line of the rotation center 4.

[0052] In this embodiment, specifically, based on the lever arm balance principle, there is a definite mechanical relationship between the external load W and the second radial load P2 of the bearing 1 under test. When it is necessary to make the second radial load P2 equal to the rated dynamic load Cr, the external load W can be determined by the formula, that is, by the following formula: ; Where L2 is the distance from the intersection of the external load W and the rotation center line 4 to the point of application of the second radial load P2, L1 is the distance from the intersection of the first radial load P1 and the second radial load P2 on the bearing under test 1 with the rotation center line 4, and θ is the angle between the external load W and the perpendicular line of the rotation center line 4. From this formula, it can be seen that when L2 and L1 remain constant, the external load W is directly proportional to the rated dynamic load Cr, that is, the larger the rated dynamic load Cr, the larger the required external load W. Simultaneously, the external load W is inversely proportional to the cosine of the angle θ. Since the cosine decreases as the angle increases within the range of 0° to 90°, the external load W increases as the angle θ increases. Through these relationships, the required external load W can be accurately calculated based on the rated dynamic load of the bearing under test 1 and the preset load application angle, ensuring that the bearing under test 1 can withstand a radial load matching its rated capacity during the test, thereby achieving accurate performance evaluation of the bearing.

[0053] Optionally, the included angle θ can range from 25° to 60°.

[0054] Specifically, the included angle θ can be any one of 25°, 30°, 35°, 40°, 45°, 50°, 55°, or 60°, or fall within the range of any two of these values.

[0055] In one embodiment, the bearing to be tested 1 includes a first sub-bearing 101 and a second sub-bearing 102, which are spaced apart along the rotation center 4.

[0056] In one embodiment, the radial load calculation formula for the first sub-bearing 101 and the second sub-bearing 102 is as follows: ; Wherein, P1 is the first radial load P1 of the first sub-bearing 101; P2 is the second radial load P2 of the second sub-bearing 102; L1 is the axial distance between the intersection of the radial load of the second sub-bearing 102 and the rotation center line 4, and the intersection of the radial load of the first sub-bearing 101 and the rotation center line 4; L2 is the axial distance between the intersection of the radial load of the first sub-bearing 101 and the rotation center line 4, and the intersection of the external load W and the rotation center line 4; θ is the angle between the external load W and the perpendicular line of the rotation center line 4; X is the radial load coefficient of the first sub-bearing 101; and Y is the axial load coefficient of the first sub-bearing 101.

[0057] In this embodiment, the reducer 2 includes a cover plate side and a motor side. A first sub-bearing 101 can be mounted on the motor side, and a second sub-bearing 102 can be mounted on the cover plate side. The first sub-bearing 101 and the second sub-bearing 102 jointly support the rotating components of the reducer 2. They are arranged at intervals along the rotation center 4 axis of the reducer 2 to withstand the combined loads from the drive end and the working end. Specifically, the first radial load P1 and the second radial load P2 are calculated and determined using the following formulas: The formula for calculating the first radial load P1 is: ; The formula for calculating the second radial load P2 is: ; Wherein, P1 is the first radial load on the first sub-bearing 101, and P2 is the second radial load on the second sub-bearing 102; L1 is the axial distance between the intersection of the second radial load P2 and the rotation center line 4, and the intersection of the first radial load P1 and the rotation center line 4, that is, the distance between the two bearing force application points; L2 is the axial distance between the intersection of the first radial load P1 and the rotation center line 4, and the intersection of the external load W and the rotation center line 4, that is, the distance from the application point of the external load W to the application point of the first radial load P1; θ is the angle between the external load W and the perpendicular line of the rotation center line 4; X is the radial load coefficient of the first sub-bearing 101, and Y is the axial load coefficient of the first sub-bearing 101. The specific values ​​of X and Y can be determined according to the parameters provided by the bearing manufacturer.

[0058] Furthermore, using the above formula, the actual radial loads borne by the first sub-bearing 101 and the second sub-bearing 102 during the test can be calculated based on the set external load W, the load application angle θ, and the first lever arm L1 and the second lever arm L2 of the reducer 2. This provides a precise theoretical basis for adjusting the magnitude and application angle of the external load W, ensuring that the stress state of the two bearings can be accurately controlled and verified during the test.

[0059] In one alternative implementation, the formula for calculating the external load W is: ; Wherein, W is the external load; P2 is the radial load of the second sub-bearing 102; L1 is the axial distance between the intersection of the radial load of the second sub-bearing 102 and the rotation center line 4, and the intersection of the radial load of the first sub-bearing 101 and the rotation center line 4; L2 is the axial distance between the intersection of the radial load of the first sub-bearing 101 and the rotation center line 4, and the intersection of the external load W and the rotation center line 4. The angle between the external load W and the perpendicular line from the center of rotation 4 is given.

[0060] According to an embodiment of the present invention, on the other hand, referring to Figure 1 and Figure 3 Furthermore, a bearing testing method is provided for testing at least one bearing 1 to be tested on a speed reducer 2. The speed reducer 2 is mounted on a test fixture 3. The bearing testing method includes the following steps: the test fixture 3 drives the bearing 1 to be tested to rotate at a set speed; the test fixture 3 applies an external load W to the speed reducer 2 and transmits it to the bearing 1 to be tested; the magnitude and application angle of the external load W are adjusted so that the magnitude of the external load is at least twice the rated dynamic load of the bearing to be tested; the external load W is applied cyclically for a preset number of times; if the bearing 1 to be tested is still intact after the preset number of times, the bearing 1 to be tested is deemed qualified.

[0061] In this embodiment, the method is used to test the overload impact resistance of at least one bearing 1 on the reducer 2. Before testing, the reducer 2 to be tested is first installed on the test fixture 3. The test fixture 3 can simulate the installation state and force boundary conditions of the reducer 2 in actual equipment. The bearing 1 to be tested can be the main bearing in the reducer 2, such as a double-row angular contact ball bearing or a double-row tapered roller bearing. After the test is started, the test fixture 3 drives the bearing 1 to be tested to rotate at a set speed N. The speed N can be determined according to the actual operating speed range of the reducer 2, for example, set to the rated speed. At the same time, the rotation direction can be set to counterclockwise or clockwise according to the actual working conditions.

[0062] Furthermore, during the operation of the bearing, the test fixture 3 applies an external load W to the reducer 2. This external load W is transmitted to the bearing 1 under test through the housing, transmission components and other structures of the reducer 2. The external load W can be applied by hydraulic loading, mechanical loading or other controllable loading methods to simulate the ultimate impact load that the reducer 2 experiences in actual operation.

[0063] Optionally, the range of rotational speed N can be determined based on the actual assembly performance parameters; the magnitude of the external load W is calculated based on the weight of the engineering machinery to which the bearing under test is adapted.

[0064] Furthermore, during the application of the external load W, the magnitude of the external load W and the application angle θ are adjusted according to the force analysis of the bearing 1 under test, so that the parameters of the external load W are greater than or equal to twice the weight of the engineering machinery.

[0065] Furthermore, the formula for calculating the external load W is: ; Where G equals the weight of the engineering machinery to which the bearing under test is adapted.

[0066] In this embodiment, the applied angle θ is 30°; the rotational speed N can be in the range of 45rpm≤N≤55rpm.

[0067] In one embodiment, the step "apply external load W cyclically a preset number of times" includes: applying external load W and continuing for a first preset time; repeating the previous step according to a second preset time interval.

[0068] In this embodiment, the first preset time t1 can be set according to the actual duration of the impact load to simulate the instantaneous overload of engineering machinery under conditions such as obstacle crossing, walking on hard ground, or sudden braking. After one load holding cycle, the external load W is unloaded, allowing the bearing 1 under test to recover in an unloaded or lightly loaded state, and then waiting at intervals according to the second preset time interval t2 to simulate the normal working interval between two impacts, avoiding the interference of cumulative thermal and fatigue effects caused by continuous loading on the test results. The second preset time interval t2 can be set according to the time interval between two impacts in actual working conditions. Subsequently, the above steps of applying the external load W and continuing for the first preset time t1, unloading and waiting at intervals of the second preset time t2 are repeated until the preset number of cycles n is reached.

[0069] Optionally, the first preset time t1 can be in the range of 8s≤t1≤12s; the number of cycles n can be in the range of 4≤n≤8.

[0070] This embodiment limits the range of the first preset time t1. When t1 is too large, the single overload time of the bearing 1 under test is too long. However, in actual engineering conditions, the impact load borne by the travel reducer 2 is usually instantaneous and has a very short duration. For example, the impact generated by engineering machinery when crossing obstacles or walking on hard ground is often completed within the range of milliseconds to several seconds.

[0071] Furthermore, when t1 is too large, the bearing will operate under overload conditions for a much longer period than the actual operating conditions. This will cause continuous stress concentration between the bearing rolling elements and raceways, which may lead to the accumulation of fatigue damage. This will cause the bearing failure mode to change from the expected impact failure to fatigue failure, and will not be able to truly reflect the bearing's overload resistance under short-term impact conditions.

[0072] This embodiment defines a first preset time range t1. When t1 is too short, for example, less than the actual duration of the impact load, the bearing load may be unloaded before reaching its peak, resulting in the test being unable to effectively simulate the real impact condition.

[0073] Furthermore, when t1 is too small, even if the bearing passes the overload test, its impact resistance under real working conditions cannot be guaranteed, and the test results will lose their reference value.

[0074] Furthermore, by using the aforementioned cyclic loading method, it is possible to realistically simulate the multiple, intermittent impact load conditions that the bearing experiences during actual use, thereby accurately assessing the bearing's resistance to overload impact.

[0075] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A bearing testing method for testing at least one bearing (1) to be tested on a speed reducer (2), wherein the speed reducer (2) is mounted on a test fixture (3), characterized in that, The bearing testing method includes the following steps: Set the expected life of the bearing to be tested (1); The test fixture (3) drives the bearing to be tested (1) to rotate at the set speed; The test fixture (3) applies an external load (W) to the reducer (2) and transmits it to the bearing (1) under test; Adjust the magnitude and angle of the external load (W) so that the radial load of the bearing under test (1) is equal to the rated dynamic load; If the failure duration of the bearing under test (1) is greater than or equal to the expected life, or if it does not fail within the expected life, the bearing under test (1) is deemed qualified.

2. The bearing testing method according to claim 1, characterized in that, The step "Set the expected life of the bearing to be tested (1)" includes: determining the expected life of the bearing to be tested (1) based on the rotational speed, rated dynamic load and radial load; the expected life decreases at least as the rotational speed increases, as the rated dynamic load increases and as the radial load increases.

3. The bearing testing method according to claim 2, characterized in that, The formula for calculating the expected life of the bearing (1) under test is as follows: ； Where L10 is the expected life, N is the rotational speed, Cr is the rated dynamic load, and P is the radial load.

4. The bearing testing method according to claim 1, characterized in that, The step "The test fixture (3) applies an external load (W) to the reducer (2) and transmits it to the bearing (1) under test" includes: The test fixture (3) applies an external load (W) to the reducer (2) in progressively increasing steps, and the radial load of the bearing (1) under test is lower than the rated dynamic load.

5. The bearing testing method according to claim 1, characterized in that, The reducer (2) has a rotation center (4), and the magnitude of the external load (W) increases at least with the increase of the rated dynamic load and with the increase of the angle between itself and the perpendicular line of the rotation center (4).

6. The bearing testing method according to claim 5, characterized in that, The bearing to be tested (1) includes a first sub-bearing (101) and a second sub-bearing (102), which are spaced apart along the rotation center (4).

7. The bearing testing method according to claim 6, characterized in that, The formulas for calculating the radial load of the first sub-bearing (101) and the second sub-bearing (102) are as follows: ； Wherein, P1 is the first radial load (P1) of the first sub-bearing (101); P2 is the second radial load (P2) of the second sub-bearing (102); L1 is the first lever arm (L1), the axial distance between the intersection of the second radial load (P2) and the rotation center (4) line and the intersection of the first radial load (P1) and the rotation center (4) line forms the first lever arm (L1); L2 is the second lever arm (L2), the axial distance between the intersection of the first radial load (P1) and the rotation center (4) line and the intersection of the external load (W) and the rotation center (4) line forms the second lever arm (L2); θ is the angle between the external load (W) and the perpendicular line of the rotation center (4); X is the radial load coefficient of the first sub-bearing (101); Y is the axial load coefficient of the first sub-bearing (101).

8. The bearing testing method according to claim 6, characterized in that, The formula for calculating the external load (W) is: ； Wherein, W is the external load (W); P2 is the second radial load (P2); L1 is the first lever arm (L1); L2 is the second lever arm (L2); and θ is the angle between the external load (W) and the perpendicular line of the rotation center (4).

9. A bearing testing method, characterized in that, A bearing testing method for testing at least one bearing (1) on a speed reducer (2), the speed reducer (2) being mounted on a test fixture (3), characterized in that the bearing testing method includes the following steps: The test fixture (3) drives the bearing to be tested (1) to rotate at the set speed; The test fixture (3) applies an external load (W) to the reducer (2) and transmits it to the bearing (1) under test; Adjust the magnitude and application angle of the external load (W) so that the magnitude of the external load (W) is at least twice the rated dynamic load of the bearing (1) under test; The external load (W) is applied cyclically a preset number of times. If the bearing under test (1) is still intact after the preset number of tests, the bearing under test (1) is deemed to be qualified.

10. The bearing testing method according to claim 9, characterized in that, The step "Apply external load (W) cyclically a preset number of times" includes: applying external load (W) and continuing for a first preset time; Repeat the previous step according to the second preset time interval.

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