A bearing accelerated life test method for a rotating system

Abstract

The application relates to the field of testing, in particular to a bearing accelerated life test method of a rotating system, which comprises the following steps: clamping and fixing, clamping a rotating system to be tested on a rotating table of a rotary table; the rotating system comprises a frame and a rotor, the frame is fixed with the rotary table of the rotary table, the rotor is supported on the frame through at least two interval arranged bearings, and the rotating axis of the rotor intersects or interlaces with the extending direction of the rotating axis of the rotary table; load application, driving the rotary table to rotate around the rotating axis thereof, and driving the rotor to rotate around the axis thereof at the same time, so that the rotor generates a gyroscopic moment, the bearing supporting the rotor obtains additional radial load by using the gyroscopic moment, and the equivalent dynamic load of the bearing is improved; test operation and life determination, operating the rotary table and the rotor, and terminating the test when the failure determination index meets the failure determination benchmark, and determining the bearing life according to the cumulative operation revolution number, time or mileage of the bearing during the test.

Description

Technical Field

[0001] This invention relates to a testing field, specifically to a method for accelerated life testing of bearings in rotating systems. Background Technology

[0002] Rotating machinery bearings are core supporting components in various power transmission systems. Their service life directly affects the operational reliability, safety, and maintenance economy of the entire equipment. This is especially true in high-end equipment fields such as aerospace, rail transportation, and wind power generation, where extremely stringent requirements are placed on the long lifespan and high reliability of bearings. However, in the process of bearing R&D verification, product quality testing, and engineering selection, obtaining bearing life data through actual machine natural life tests often takes months or even years. This not only severely lags behind the pace of product development and mass production delivery but also leads to high testing costs due to the long-term occupation of actual machine equipment, site resources, and continuous energy consumption, making it difficult to quickly respond to market demands for bearing product performance verification. The basic rated life method is a quick and easy-to-use method that can be calculated manually with minimal input, such as load and speed. The drawback of this method is that it relies on several simplifying assumptions: the bearing rings are considered rigid, the clearance or preload is considered zero, there are no bending moment loads, there is no misalignment caused by shaft and housing deformation, and the effects of lubricant viscosity and cleanliness are not considered.

[0003] To address these issues, accelerated life testing technology has emerged. Its core logic lies in applying appropriate loads under controlled laboratory conditions to induce bearings to exhibit fatigue failure characteristics consistent with actual service conditions within a short period, thereby rapidly quantifying bearing life based on test data. However, existing accelerated life testing methods have several drawbacks: the increased load not only requires high precision in the load application location, potentially leading to reduced test accuracy, but also makes it unsuitable for applying loads to small rotating devices (such as small impellers and fans).

[0004] Furthermore, the actual service life of a bearing is closely related to the final assembly quality of the bearing. Existing technology cannot accurately measure the bearing life of the finished product (such as a motor or fan) in its actual assembly state. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for accelerated life testing of bearings in rotating systems. This method solves the problems of disconnect between load verification and life targets, poor adaptability to operating conditions, and low testing accuracy in existing technologies. It enables accurate testing of the actual life of bearings in assembled finished products, improves the accuracy and reliability of testing, and provides precise support for the reliability assessment of finished equipment.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for accelerated life testing of bearings in a rotating system, comprising the following steps:

[0007] The rotating system to be tested is clamped onto the rotating platform of the turntable. The rotating system includes a base and a rotor. The base is fixed to the rotating platform of the turntable. The rotor is supported on the base by at least two spaced bearings. The rotation axis of the rotor intersects or crosses the extension direction of the rotation axis of the turntable.

[0008] When a load is applied, the turntable is driven to rotate around its own axis of rotation, and at the same time, the rotor is driven to rotate around its own axis, so that the rotor generates a gyroscopic torque. This gyroscopic torque is used to give the bearings supporting the rotor an additional radial load, thereby increasing the equivalent dynamic load of the bearings.

[0009] The test operation and life determination involve running the turntable and rotor, and terminating the test when the failure determination index meets the failure determination criteria. The bearing life is determined based on the cumulative number of revolutions, time or mileage of the bearing during the test.

[0010] The rotating system obtains electrical energy through an electric slip ring assembly mounted on the turntable; and the structural type of the rotating system is one of the following:

[0011] The rotating system is a fan or a motor, and the rotor of the fan or motor serves as the rotor of the rotating system.

[0012] The rotating system includes a motor for driving the rotor to rotate, the output of which is connected to the rotor drive.

[0013] The rotation axis of the rotor is perpendicular to and intersects the rotation center line of the turntable; or, a flywheel is fixedly connected to the rotor.

[0014] The failure criteria include at least one of the following: mechanical performance criteria, thermal performance criteria, oil performance criteria, and acoustic performance criteria; when any one of the criteria meets the failure criteria, the test is terminated.

[0015] Among them, mechanical performance indicators include at least one of vibration signal parameters, rotational resistance torque, bearing fatigue characteristic frequency, bearing clearance, and axial movement.

[0016] Thermal performance indicators include at least one of the following: temperature difference between the inner and outer rings of the bearing, bearing temperature, and rate of temperature rise;

[0017] The performance indicators of lubricating oil include at least one of the following: metal element content in lubricating oil, lubricating oil viscosity, lubricating oil acid value, and fatigue spalling particles;

[0018] Acoustic performance indicators include at least one of the following: sound pressure level, noise spectrum, and abnormal noise.

[0019] Vibration sensors are fixed on the rotating system to collect the original vibration signals during the accelerated test. The collected original signals are then converted into velocity time-domain signals. Finally, the root mean square (RMS) calculation is performed on the velocity time-domain signals to obtain the final vibration velocity root mean square (VRMS) parameters. The vibration velocity root mean square (VRMS) parameters serve as failure criteria. The failure criteria are determined based on the bearing's factory technical parameters, national standards, industry standards, or the initial stable state of the test.

[0020] Before initiating accelerated life testing, a matching process involving speed matching and maximum load verification is also included, specifically:

[0021] Constraint relationship determination: Based on the known maximum equivalent dynamic load of the bearing, the maximum radial load is calculated backward, and then the maximum allowable gyro torque is derived from the maximum radial load. Finally, the constraint relationship that the turntable speed and rotor speed must satisfy is determined, and the turntable speed does not exceed the turntable limit speed, and the rotor speed does not exceed the rotor limit speed. The gyro torque is calculated based on the vector cross product relationship between the rotor moment of inertia, the turntable speed, and the rotor speed.

[0022] Equivalent dynamic load calculation: Based on the speed constraint relationship determined in the steps, select at least one combination of turntable speed and rotor speed to be verified, and calculate the equivalent dynamic load of the bearing under the combination.

[0023] (3) Verification judgment: The calculated equivalent dynamic load is compared with the preset verification benchmark value, which is determined by the maximum bearing withstand load or the preset maximum equivalent dynamic load. If the equivalent dynamic load does not exceed the verification benchmark value, the verification is deemed to be passed and the accelerated life test can be started. If the equivalent dynamic load exceeds the verification benchmark value, the speed constraint is readjusted or a new speed combination is selected, and the process is repeated until the verification is passed.

[0024] The process of calculating the equivalent dynamic load in the steps includes:

[0025] Parameter acquisition: Extracting the rotor moment of inertia J z The following parameters are considered: the bearing spacing L at both ends of the rotating machinery; the angle θ between the rotor axis and the turntable rotation axis; the turntable speed ω to be verified; and the rotor speed Ω. Simultaneously, the initial radial load F of the bearings is obtained. r0 and axial load F a ;

[0026] Gyroscopic torque calculation: Based on the principle of rigid body rotational dynamics, using the formula M0=J z · Calculate the gyro torque M0 using (ω×Ω), where ω and Ω are vector cross products, and θ is the angle between the two axes;

[0027] Derivation of additional radial load: Based on the principle of lever arm balance, using the formula ΔF r=M0÷L Calculate the additional radial load ΔF r And ΔF needs to be verified. r ≥0;

[0028] Total radial load calculation: using formula F r =F r0 +ΔF r Calculate the total radial load F of the bearing r ;

[0029] Load factor determination: Consult the standard coefficient table for rolling bearings according to bearing type, based on F a With F r The ratio F a / F r Determine the radial load factor X and the axial load factor Y; if F a / F r The ratio did not precisely match the standard coefficient table, so linear interpolation was used for calculation.

[0030] Equivalent dynamic load solution: using the formula P=X×F r +Y×F a The equivalent dynamic load P of the bearing to be verified is calculated.

[0031] The turntable includes a frame, a servo motor, a reducer, a rotation mechanism, and a rotary table;

[0032] The frame is used to mount the servo motor, reducer, and rotary mechanism;

[0033] The servo motor is connected to the reducer for transmission. The pinion fixed at the output end of the reducer meshes with the gear ring of the rotary mechanism. The rotary table is fixedly connected to the rotary mechanism. The rotary table surface is provided with a clamping slot for clamping the rotary system.

[0034] It also includes: a status acquisition module, which includes a vibration sensor, the vibration sensor being connected to the base of the rotating system for acquiring vibration signals of the rotating system;

[0035] The data processing module, connected to the state acquisition module, is used to receive the vibration signal, process it, and output the state assessment result or control parameters.

[0036] A control module, connected to the data processing module, is used to generate control commands based on the state evaluation results or control parameters to adjust the operating state of the rotating system.

[0037] The control module includes a PLC and a servo driver. The PLC is signal-connected to the servo driver, and the servo driver is electrically connected to the servo motor.

[0038] The rotating platform is provided with at least two clamping structures evenly distributed in the circumferential direction around its own axis of rotation; the clamping structure includes a base plate, on which a connecting bolt passes, the head of the connecting bolt being adapted to fit the T-slot of the rotating platform surface, and a nut being screwed into the connecting bolt to press and fix the base plate on the rotating platform; the base plate is provided with a mounting wall protruding from the upper surface of the base plate, and a through hole is provided in the mounting wall, through which a fastening bolt for connecting with the machine base passes.

[0039] The above scheme has the following beneficial effects: When the rotor rotates around its own axis and rotates with the turntable around the turntable's rotation axis, the rotor will generate a gyroscopic torque M0 that opposes the change in its rotational direction. The magnitude of this gyroscopic torque is determined by the rotor's moment of inertia J. z The rotational speed Ω, the revolution speed ω, and the angle θ between the two rotational axes determine the rotation speed, and the formula is M0=J z • (ω×Ω), where ω and Ω are vector cross products. Since the rotor is supported on the base 110 by bearings, the gyroscopic torque acts on the bearings as a couple. Based on the lever arm balance principle, the additional radial load on the bearings can be derived. This mechanism eliminates the need for additional loading structures such as weights or resistance ropes, avoiding the drawbacks of traditional load application methods such as weight suspension and resistance rope traction, which generally suffer from stringent installation accuracy requirements, poor adaptability, and low load control accuracy. For example, it requires extremely high precision in the load application position; a positional deviation exceeding 0.5mm will directly lead to uneven load distribution. At the same time, due to physical structural limitations, this method cannot be applied to small rotating devices where the rotor is enclosed by a shell (such as fans with mesh covers or micro motors). This invention provides a novel load application mode, fundamentally breaking through the limitations of traditional methods. This invention allows for precise control of the applied radial load by adjusting rotational speed parameters, achieving stepless load adjustment and precise application. It simplifies the test device structure and enhances adaptability to rotating systems of different sizes and types. This invention is applicable to the testing of assembled finished products, with the entire rotating device serving as the test object. It is particularly suitable for devices where the rotor is in a relatively enclosed space, such as when the rotor is located in a closed cavity, or when the end of a fan has a mesh cover, making direct and convenient load application difficult. This invention can not only test the lifespan of rotating systems in their assembled state but also separately determine the accelerated life of bearings, with the rotor and frame serving as test accessories and the bearing as the test piece. This invention improves the accuracy and reliability of testing, providing precise support for the reliability assessment of bearings and finished equipment with bearings.

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of the transfer station in this invention;

[0042] Figure 2 This is a schematic diagram of the actual clamping state of the fan.

[0043] Figure 3 This is a schematic diagram of the clamping structure;

[0044] Figure 4 The wear condition of the bearing raceway of the faulty fan;

[0045] Figure 5 A schematic diagram showing the application of radial load to the bearing.

[0046] In the attached diagram, 100 represents the rotating system; 110 represents the base; 111 represents the rotor; 112 represents the bearing; 200 represents the turntable; 210 represents the rotary table; 220 represents the frame; 221 represents the servo motor; 222 represents the reducer; 223 represents the slewing mechanism; 300 represents the clamping structure; 310 represents the base plate; 320 represents the connecting bolt; 330 represents the nut; and 340 represents the mounting wall. Detailed Implementation

[0047] Referring to the accompanying drawings, specific embodiments of the present invention will be described in detail.

[0048] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] In the description of this application, it should be understood that the terms center, upper, lower, front, back, left, right, vertical, horizontal, top, bottom, inner, and outer, indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this application, the terms first and second are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined as first and second can be used to explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, multiple means two or more. It should be noted that in practical applications, due to limitations in equipment accuracy or installation errors, absolute parallelism or perpendicularity is difficult to achieve. The descriptions of vertical, parallel, or unidirectional in this application are not absolute limitations, but rather indicate that vertical or parallel structural settings can be achieved within a certain error range, and the corresponding effects can be achieved. In this way, the technical effects of the defined features can be maximized, and the corresponding technical solutions can be easily implemented, thus having high feasibility.

[0050] In the description of this specification, references to the terms "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0051] Reference Figure 1-5 This invention discloses an accelerated life test method for bearing 112 of a rotating system 100. The test device includes a turntable 200, which is used to carry the test object and perform rotational motion. Specifically, in this embodiment, the turntable 200 includes a frame 220, a servo motor 221, a reducer 222, a rotation mechanism 223, and a rotating table 210.

[0052] The frame 220 serves as the installation reference and load-bearing foundation, used to fix the servo motor 221, reducer 222, and rotary mechanism 223. The servo motor 221 is the power output source, providing the original power required for the movement of the turntable 200. The reducer 222 is connected to the servo motor 221 to reduce the speed and increase the torque, meeting the torque and speed requirements of the turntable 200 in actual operation. The rotary mechanism 223 is the core transmission and support component. The pinion fixed at the output end of the reducer 222 meshes with the gear ring of the rotary mechanism 223. The gear ring and pinion meshing structure of the rotary mechanism meshes with the pinion fixed at the output end of the reducer 222 to realize the direction and transmission of power. The rotary table 210 and the rotary mechanism 223 are rigidly fixedly connected by bolts. The rotary table 210 drives the rotary system 100 to move synchronously through its own rotary motion. The turntable 200 is also equipped with an electric slip ring assembly for transmitting electrical energy to the rotary system 100.

[0053] The rotary table 210 is provided with at least two clamping structures 300 evenly distributed circumferentially around its own axis of rotation. Each clamping structure 300 includes a base plate 310, on which a connecting bolt 320 passes. The head of the connecting bolt 320 is fitted into a T-slot on the surface of the rotary table 210. A nut 330 is screwed onto the connecting bolt 320, pressing and fixing the base plate 310 onto the rotary table 210. The base plate 310 has a mounting wall 340 protruding from its upper surface, with a through hole through which a fastening bolt for connection to the base 110 passes. This allows for the fixing of the base 110 of a rotating system 100, such as a fan. A transparent tempered glass protective cover can be installed on the rotary table 210, and a metal protective cover can be installed on the outside of the gear ring of the rotary mechanism 223 to prevent the operator's limbs from contacting the gears and foreign objects from entering the meshing surface of the gear ring, thus avoiding damage to the gears; an overload protection module can also be set up so that when the load of the servo motor 221 exceeds the set value, the servo driver automatically cuts off the power supply and the servo motor 221 stops running, thus achieving dual protection for the mechanism and the motor.

[0054] It also includes a status acquisition module, which includes a vibration sensor. The status acquisition module may include a vibration sensor, an infrared temperature sensor, and an acoustic sensor, etc. In this embodiment, the vibration sensor can be connected to the base 110 of the rotating system 100 to acquire the vibration signal of the rotating system 100. Its parameters are as follows: sensitivity: 100mV / g; sensitivity accuracy: ±15% at 24°C; acceleration range: 50g (peak); amplitude linearity: ±1%; frequency range (±3dB): 0.5~10,000Hz (30~600,000CPM); resonant frequency (nominal after installation): 22kHz; lateral sensitivity: ≤7%.

[0055] Alternatively, an infrared temperature sensor can be installed on the end face of the corresponding bearing 112 to collect temperature-related parameters of the bearing 112. In some implementation schemes, the sound signal can be manually listened to by the test personnel. When a significant change in sound pressure level occurs, such as an increase of more than 5 decibels during the test, the rotating system 100 can be judged to have failed. Since the bearing 112 will be accelerated to deteriorate under failure conditions, the noise will further increase in a short period of time, which can be more easily identified by humans. Its life error is relatively small. Of course, a higher precision acoustic sensor can also be installed near the rotating system 100 to collect sound pressure level and sound power spectrum.

[0056] It also includes a data processing module, which is connected to the status acquisition module. It can connect to the information via wireless signal connection or signal slip ring, and is used to receive the vibration signal and process it to output status assessment results or control parameters.

[0057] The control module, connected to the data processing module, is used to generate control commands based on the state evaluation results or control parameters to adjust the operating state of the rotating system 100.

[0058] The control module includes a PLC and a servo driver. It outputs control signals to the servo driver according to a preset test program. Upon receiving instructions, the servo driver precisely regulates the operation of the servo motor 221. By changing the power supply frequency and current direction, it achieves continuous adjustment of the servo motor 221's speed and switching between forward and reverse directions. This, in turn, drives the turntable 200 to achieve forward and reverse rotation at different speeds via a transmission chain. The system is equipped with an incremental encoder as a speed detection element, which collects the actual speed signal of the turntable 200 in real time and feeds it back to the servo driver, forming a closed-loop speed control. The speed display is connected to the speed detection element and can display the actual speed of the turntable 200 in real time, facilitating intuitive monitoring by the operator.

[0059] Working principle of turntable 200: After the servo motor 221 starts, it drives the input end of the reducer 222 to rotate; the reducer 222 reduces the speed and amplifies the torque through the internal gear set, and then the output pinion transmits the power to the gear ring of the rotary mechanism 223; when the gear ring of the rotary mechanism 223 rotates, it synchronously drives the turntable 210 to perform forward and reverse circular motion; the rotating system 100 under test is detachably fixed to the turntable 210 through T-slots and bolts, and moves synchronously with the turntable 210; the electric slip ring assembly is fixed at the central axis of the turntable 200, its stationary end is connected to the external power supply, and its rotating end is connected to the power supply interface of the rotating system 100, realizing the stable transmission of electrical energy during rotation. If multiple rotating systems 100 are set on the turntable 210 as test objects, they are electrically connected to each rotating system 100 through a power distributor; if a sensor is set on the turntable 210, the sensor can transmit signals to the outside through the set signal slip ring.

[0060] This embodiment uses a certain type of AC fan as the test object, and adds the following specific test steps:

[0061] Preparation before the experiment: Define the experimental parameters and objectives, and obtain the principal rotational inertia J of the fan rotor 111 by means of dynamic testing instruments. z =0.00014kg·m², consult the manufacturer's technical manual to obtain the rated dynamic load C=553N for bearing 112; determine the failure judgment criteria: the vibration parameter in the mechanical performance index shall be implemented in accordance with the provisions of BV-4 category VRMS=2.8mm / S in GB / T41973-2022 "Specification for Balance Quality and Vibration Level of Industrial Fans".

[0062] The acoustic performance indicators include at least one of the following: sound pressure level, noise spectrum, and abnormal noise. Meeting any one of these indicators constitutes a failure of the rotating system (100%). Alternatively, it can be determined by setting limits for offline detection of fatigue spalling area ratio, macroscopic crack detection based on crack length exceeding limits, and bearing (112) wear, among other conditions.

[0063] The AC fan is detachably clamped into the T-slot of the rotary table 210, ensuring that the fan base 110 is rigidly fixed to the rotary table 210. The fan rotor 111 is supported on the base 110 by two spaced bearings 112. The installation position is also calibrated with a dial indicator so that the rotation axis of the rotor 111 is perpendicular to and intersects the rotation center line of the rotary table 210, with an included angle θ=90°, to maximize the gyroscopic torque. Alternatively, a flywheel can be fixedly connected to the output end of the fan rotor 111. The flywheel is made of 45# steel, which further enhances the gyroscopic torque effect and improves the stability of the additional radial load by increasing the rotational inertia of the rotor 111.

[0064] The electric slip ring assembly installed on the turntable 200 transmits electrical energy to the fan, ensuring that the power supply voltage is stable at 220V±5V; the vibration sensor is fixed to the fan base 110 near the bearing 112 by means of bonding or other methods, ensuring that the vibration sensor is tightly attached to the base 110 without any looseness.

[0065] Load application and test operation: The rotary table 210 and the fan are started. Under the closed-loop control of the PLC and servo driver, the rotary table 210 rotates uniformly around its own axis of rotation at a speed of 2 r / s. The fan rotor 111 rotates uniformly around its own axis at a speed of 8000 r / min. The rotor 111 generates a stable gyroscopic torque, which gives the bearing 112 an additional radial load of 73.7 N, thereby accelerating the equivalent dynamic load of the bearing 112. During the test, failure criteria are monitored in real time through the status acquisition module: vibration sensors collect vibration signals in real time, infrared temperature sensors collect the temperature of the bearing 112 in real time, and / or acoustic sensors collect sound pressure level and sound power spectrum in real time. Lubricating oil samples are collected every 24 hours. At the same time, the speed display shows the actual speed of the rotary table 200 in real time, and the PLC monitors the operating current, voltage and other parameters of the servo motor 221 in real time to ensure speed stability. The power of the fan is stably transmitted through the electric slip ring assembly on the rotary table 200 to avoid power interruption caused by cable entanglement.

[0066] Failure determination and lifespan assessment: According to the manufacturer of a certain type of ball bearing 112, its basic rated dynamic load C=553N. Under the equivalent dynamic load P=73.7N as described above, its theoretical accelerated life is: The life index of ball bearing 112 is ε=3, which means... The bearing has been rated as qualified after 881 hours.

[0067] The failure determination criteria are determined based on the bearing 112's factory technical parameters, national standards, industry standards, or the initial stable state during testing. In this embodiment, a vibration sensor is used to collect the raw vibration signal. First, the raw vibration signal is collected, then converted into a velocity time-domain signal, and finally, the root mean square (RMS) calculation is performed on the velocity time-domain signal to obtain the final vibration velocity root mean square (VRMS) parameter. The failure determination criteria are implemented according to the requirement of VRMS=2.8mm / s for category BV-4 in GB / T41973-2022 "Specification for Balance Quality and Vibration Level of Industrial Fans". When the vibration velocity root mean square (VRMS) exceeds 2.8mm / s, it is determined to be a failure.

[0068] After 1020 hours of test operation, the status acquisition module detected that the root mean square velocity (VRMS) of the vibration signal parameters of one of the wind turbines exceeded 2.8 mm / s, triggering a failure warning. The turbine was immediately shut down, and offline testing was performed. Measurements of the bearing clearance (112) using a dial indicator revealed an increase in clearance compared to the initial value, wear on the inner ring, and significant fatigue spalling on both the inner and outer rings of bearing 112. Based on both online monitoring and offline testing results, bearing 112 was determined to have failed.

[0069] The lifespan of bearing 112 can be characterized in three ways: ① Cumulative operating time: 1020 hours; ② Cumulative operating revolutions: 8000 r / min × 1020 h × 60 min / h = 489,600,000 revolutions; ③ Cumulative operating mileage: L = π·dm·N, where dm is the pitch circle diameter of bearing 112 and N is the cumulative operating revolutions. All three methods accurately reflect the fatigue life of bearing 112. Cumulative operating revolutions are the most accurate, cumulative operating time is the most intuitive, and cumulative operating mileage closely reflects the actual engineering application scenarios of wind turbines. Other wind turbines continued operating for 1350 hours without reaching the failure judgment criteria, at which point the test was stopped, consistent with the expected lifespan estimate of this type of bearing 112.

[0070] In some implementations, speed matching and maximum load verification are also included: This step is a preliminary process to ensure that the applied load meets the acceleration requirements without damaging bearing 112. The specific process is as follows:

[0071] Consulting the literature, it was determined that the rated dynamic load C of the bearing 112 of a certain type of fan is 553N, and the distance between the two bearings 112 is L=0.02m. Since the ratio of the axial load Fa to the total radial load Fr in this embodiment is relatively small, referring to the standard coefficient table for rolling bearing 112 and the ISO281 international standard for rolling bearing 112, the radial load coefficient X=1 and the axial load coefficient Y=0 were obtained. Based on this, the maximum radial load Fr_max was calculated; then, the maximum permissible gyroscopic torque was derived from the maximum radial load.

[0072] Based on the moment of inertia of the rotor 111 of the fan, Jz = 0.00014 kg·m², the angle between the rotor axis and the rotation axis of the turntable, θ = 90°, and sinθ = 1, the constraint relationship between the turntable speed ω and the rotor speed Ω is derived from the gyro torque formula M0 = Jz·(ω × Ω): ω × Ω ≤ M0_max / Jz. Simultaneously, considering the turntable's limit speed and the rotor's limit speed, two speed constraint ranges are finally determined.

[0073] In actual testing, the turntable's maximum speed was set according to the actual operating conditions. The rotor test speed was selected as the operating speed of 8000 rpm to approximate the failure scenario of bearing 112 under the actual operating conditions of the rotating system 100. In this case, only the turntable speed constraint range needs to be determined. The calculated theoretical speed of the turntable can reach 15.1 r / s. This upper limit ensures that the equivalent dynamic load of bearing 112 does not exceed the rated value, and the turntable's own maximum speed is 5 r / s.

[0074] The rotor test speed was selected as 8000 rpm, which is close to the failure scenario of bearing 112 under the actual working state of the rotating system 100. Combined with the upper limit of the turntable's own speed, 2 r / s was finally selected as the test speed.

[0075] (2) Select the combination of speeds to be verified

[0076] A turntable with a rotational speed of 200 rpm and a corresponding angular velocity ω = 4π rad / s is selected; the rotor speed Ω = 8000 rpm and the corresponding angular velocity Ω = 8000 × 2π / 60 rad / s. This combination satisfies the speed constraint relationship derived above. The following is a detailed calculation of the equivalent dynamic load under this combination:

[0077] Parameter Acquisition

[0078] The rotor moment of inertia is extracted as Jz = 0.00014 kg·m², the bearing spacing L = 20 mm = 0.02 m, the angle between the rotor axis and the turntable rotation axis is θ = 90°, the turntable angular velocity is ω = 4π rad / s, and the rotor angular velocity is Ω = 8000 × 2π / 60 rad / s. At the same time, the axial load Fa = 8 N, the initial radial load Fr0 = 0.16 N, and the rated dynamic load Cr = 553 N are obtained.

[0079] Gyroscope torque calculation

[0080] Based on the principles of rigid body rotational dynamics, the gyroscopic torque is calculated using the formula M0 = Jz·(ω×Ω). Since θ = 90° and sinθ = 1, the magnitude of the vector cross product is |ω||Ω|sinθ, which is the scalar product of the two angular velocities. Substituting the updated parameters, we get: M0 = 0.00014 × 4π × (8000 × 2π / 60) = 1.474 N·m. This gyroscopic torque is the core power source for the additional radial load generated by bearing 112.

[0081] Derivation of Additional Radial Load

[0082] Based on the principle of lever arm balance, the additional radial load is calculated using the formula ΔFr=M0÷L.

[0083] Substituting the parameters M0 = 1.474 N·m and L = 0.02 m, we get: ΔFr = 1.474 ÷ 0.02 = 73.7 N. Verifying ΔFr ≥ 0, it conforms to mechanical logic, indicating no load deviation.

[0084] Total radial load calculation

[0085] The total radial load actually borne by bearing 112 is calculated using the formula Fr = Fr0 + ΔFr. ΔFr = 73.7 N, which is much larger than the initial radial load Fr0 = 0.16 N. Therefore, the influence of Fr0 can be ignored, meaning the total radial load Fr ≈ ΔFr = 73.7 N.

[0086] Load factor determination

[0087] According to the ISO 281 international standard for rolling bearings 112 and the corresponding load factor value-taking rules for deep groove ball bearings 112, the determination coefficient e = 0.19 (general standard value) of this type of bearing 112 is determined. Calculate the relative axial load Fa / Fr = 8 / 73.7 ≈ 0.108, and it is determined that Fa / Fr < e. According to the ISO 281 standard rules, when the relative axial load is less than the determination coefficient e, the influence of the axial load on the life of the bearing 112 can be ignored. Take the radial load coefficient X = 1 and the axial load coefficient Y = 0.

[0088] Equivalent dynamic load solution

[0089] Calculate according to the equivalent dynamic load formula P = X×Fr + Y×Fa of rolling bearings 112 specified in the ISO 281 standard. Substitute the updated load coefficients and the total radial load to get: P = 1×73.7 + 0×8 = 73.7 N. This value is the equivalent dynamic load of the bearing 112 to be verified. Since ΔFr is significantly greater than Fr0, the calculation can be simplified and the influence of Fr0 on the result can be ignored. ΔFr is the equivalent dynamic load.

[0090] Verification determination

[0091] Compare the calculated equivalent dynamic load P = 73.7 N with the rated dynamic load Cr = 553 N of the bearing 112 to verify the reference value. Without correction, the rated dynamic load is directly used for comparison. Since 73.7 N < 553 N, the equivalent dynamic load does not exceed the verification reference value, and it is determined that the verification passes, and the accelerated life test can be started. If the equivalent dynamic load exceeds the reference value due to subsequent parameter adjustment, return to readjust the speed constraint or select a new speed combination, and loop until the verification passes.

[0092] In some embodiments, the influence of factors such as the environment can be further considered. During the verification process, the corresponding correction factors need to be incorporated into the calculation and the verification reference value is adjusted synchronously.

[0093] The above embodiments, through a complete experimental process, fully verify that the core technical solution of the present invention achieves gyroscopic torque loading through the dual rotation of "rotor 210 and rotor 111", adapting to the accelerated testing requirements of the test shaft system of the rotating system 100. When rotor 111 rotates around its own axis and rotates with turntable 200 around the rotation axis of turntable 200, rotor 111 generates a gyroscopic torque M0 that opposes the change of its rotation direction. The magnitude of this gyroscopic torque is determined by the moment of inertia Jz, rotational speed Ω, revolution speed ω, and the angle θ between the two rotation axes of rotor 111. The core formula is M0 = Jz·(ω×Ω), where ω and Ω are vector cross products. Since rotor 111 is supported on base 110 through bearing 112, the gyroscopic torque acts on bearing 112 in the form of a couple. Based on the lever arm balance principle, the additional radial load on bearing 112 can be derived. This mechanism eliminates the need for additional loading structures such as weights and resistance ropes. It overcomes the technical challenges of traditional load application methods like weight suspension and resistance rope traction, which require high installation precision, have poor adaptability, cannot be adapted to small rotating devices, and suffer from low load control accuracy. By adjusting rotational speed parameters, the additional radial load can be precisely controlled, achieving stepless adjustment and precise application of the load. This simplifies the test device structure and improves adaptability to rotating systems 100 of different sizes and types, such as fans and motors. This invention is applicable to the testing of assembled finished products, with the entire rotating device as the test object. It is particularly useful in situations where the rotor 111 is in a relatively enclosed device, the motor is in a closed cavity, or the fan end has a mesh cover, making direct and convenient load application difficult. This invention can not only test the lifespan of the rotating system 100 in its assembled state but also separately determine the accelerated life of the bearing 112, with the rotor 111 and base 110 as test accessories and the bearing 112 as the test piece. This invention improves the accuracy and reliability of the test, providing precise support for the reliability assessment of the bearing 112 and finished equipment with the bearing 112. The test results show that the operation process of the present invention is standardized, the load application is precise and controllable, and the life determination is accurate and reliable. It can effectively solve the problems of load verification and life target disconnection, low test accuracy, and inability to determine the actual life of finished bearing 112 in the prior art. It has significant technical advantages and engineering application value.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method for accelerated life testing of bearings in a rotating system, characterized in that, Includes the following steps: The rotating system (100) to be tested is clamped onto the rotary table (210) of the turntable (200). The rotating system (100) includes a base (110) and a rotor (111). The base (110) is fixed to the rotary table (210) of the turntable (200). The rotor (111) is supported on the base (110) by at least two spaced bearings. The rotation axis of the rotor (111) intersects or crosses the extension direction of the rotation axis of the turntable (200). When a load is applied, the turntable (200) is driven to rotate around its own axis of rotation, and at the same time the rotor (111) is driven to rotate around its own axis, so that the rotor (111) generates a gyroscopic torque. The gyroscopic torque is used to give the bearing supporting the rotor (111) an additional radial load, so as to increase the equivalent dynamic load of the bearing. Test operation and life determination: run the turntable (200) and rotor (111), and terminate the test when the failure determination index meets the failure determination criteria. Determine the bearing life based on the cumulative number of revolutions, time or mileage of the bearing during the test. Before initiating accelerated life testing, a speed matching process is also included, specifically: Based on the known maximum equivalent dynamic load of the bearing, the maximum radial load is deduced, and then the maximum permissible gyro torque is derived through the maximum radial load. Finally, the constraint relationship that the rotation speed of the turntable (200) and the rotation speed of the rotor (111) must satisfy is determined, and the rotation speed of the turntable (200) does not exceed the limit speed of the turntable (200), and the rotation speed of the rotor (111) does not exceed the limit speed of the rotor (111). The gyro torque is calculated based on the moment of inertia of the rotor (111), the vector cross product relationship between the rotation speed of the turntable (200) and the rotation speed of the rotor (111), and is less than or equal to the maximum permissible gyro torque.

2. The accelerated life test method for bearings in a rotating system according to claim 1, characterized in that, The rotating system (100) obtains electrical energy through an electric slip ring assembly provided on the turntable (200); and the structural type of the rotating system (100) is one of the following: (1) The rotating system (100) is a fan or a motor, and the rotor of the fan or motor is the rotor of the rotating system; (2) The rotating system (100) includes a motor for driving the rotor to rotate, the output of which is connected to the rotor drive.

3. The accelerated life test method for bearings in a rotating system according to claim 1, characterized in that, The rotation axis of the rotor (111) is perpendicular to and intersects the rotation center line of the turntable (200) and the rotating table (210); or, a flywheel is fixedly connected to the rotor (111).

4. The accelerated life test method for bearings in a rotating system according to claim 1, characterized in that, The failure criteria include at least one of the following: mechanical performance criteria, thermal performance criteria, oil performance criteria, and acoustic performance criteria; when any one of the criteria meets the failure criteria, the test is terminated. Among them, mechanical performance indicators include at least one of vibration signal parameters, rotational resistance torque, bearing fatigue characteristic frequency, bearing clearance, and axial movement. Thermal performance indicators include at least one of the following: temperature difference between the inner and outer rings of the bearing, bearing temperature, and rate of temperature rise; The performance indicators of lubricating oil include at least one of the following: metal element content in lubricating oil, lubricating oil viscosity, lubricating oil acid value, and fatigue spalling particles; Acoustic performance indicators include at least one of the following: sound pressure level, noise spectrum, and abnormal noise.

5. The accelerated life test method for bearings in a rotating system according to claim 1 or 4, characterized in that, A vibration sensor is fixed on the rotating system (100) to collect the original vibration signal during the accelerated test. The collected original signal is then converted into a velocity time-domain signal. Finally, the root mean square (RMS) operation is performed on the velocity time-domain signal to obtain the final vibration velocity root mean square (VRMS) parameter. The vibration velocity root mean square (VRMS) parameter is used as a failure judgment index. The failure judgment criteria are determined based on the bearing's factory technical parameters, national standards, industry standards, or the initial stable state of the test.

6. The accelerated life test method for bearings in a rotating system according to claim 1, characterized in that, Before initiating accelerated life testing, a matching process for maximum load verification is also included, specifically: Equivalent dynamic load calculation: Based on the speed constraint relationship determined in step (1), select at least one combination of turntable (200) speed and rotor (111) speed to be verified, and calculate the bearing equivalent dynamic load under the combination; Verification judgment: The calculated equivalent dynamic load is compared with the preset verification benchmark value, which is determined by the maximum bearing withstand load or the preset maximum equivalent dynamic load. If the equivalent dynamic load does not exceed the verification benchmark value, the verification is deemed to be passed and the accelerated life test can be started. If the equivalent dynamic load exceeds the verification benchmark value, the speed constraint is readjusted or a new speed combination is selected, and the process is repeated until the verification is passed.

7. The accelerated life test method for bearings in a rotating system according to claim 6, characterized in that, The process of calculating the equivalent dynamic load in step (2) includes: Parameter acquisition: Extract the moment of inertia Jz of rotor (111), the bearing spacing L at both ends of the rotating machinery, the angle θ between the axis of rotor (111) and the rotation axis of turntable (200), the combination of the rotation speed ω of turntable (200) to be verified and the rotation speed Ω of rotor (111), and at the same time obtain the initial radial load Fr0 and axial load Fa of the bearing; Gyro torque calculation: Based on the principle of rigid body rotational dynamics, the gyro torque M0 is calculated using the formula M0=Jz·(ω×Ω), where ω and Ω are vector cross products and θ is the angle between the two axes; Derivation of additional radial load: Based on the principle of lever arm balance, the additional radial load ΔFr is calculated using the formula ΔFr=M0÷L, and it is necessary to verify that ΔFr≥0; Total radial load calculation: The total radial load Fr of the bearing is calculated using the formula Fr=Fr0+ΔFr; Load factor determination: Consult the standard coefficient table for rolling bearings according to the bearing type, and determine the radial load factor X and axial load factor Y based on the ratio of Fa to Fr, Fa / Fr; if the Fa / Fr ratio does not accurately match the standard coefficient table, use the linear interpolation method for calculation. Equivalent dynamic load solution: The equivalent dynamic load P of the bearing to be verified is calculated using the formula P=X×Fr+Y×Fa.

8. The accelerated life test method for bearings in a rotating system according to claim 1, characterized in that, The turntable (200) includes a frame (220), a servo motor (221), a reducer (222), a rotary mechanism (223), and a rotary table (210). The frame (220) is used to fix the servo motor (221), the reducer (222) and the rotary mechanism (223); The servo motor (221) is connected to the reducer (222) for transmission. The pinion fixed at the output end of the reducer (222) meshes with the gear ring of the rotary mechanism (223). The rotary table (210) is fixedly connected to the rotary mechanism (223). The rotary table (210) has a clamping slot for clamping the rotary system (100) on its surface. It also includes: a status acquisition module, which includes a vibration sensor, the vibration sensor being connected to the base of the rotating system for acquiring vibration signals of the rotating system; The data processing module, connected to the state acquisition module, is used to receive the vibration signal, process it, and output the state assessment result or control parameters. A control module, connected to the data processing module, is used to generate control commands based on the state evaluation results or control parameters to adjust the operating state of the rotating system. The control module includes a PLC and a servo driver. The PLC is signal-connected to the servo driver, and the servo driver is electrically connected to the servo motor (221).

9. The accelerated life test method for bearings in a rotating system according to claim 1, characterized in that, The rotary table (210) is provided with at least two clamping structures (300) evenly distributed in the circumferential direction around its own rotation axis; the clamping structure (300) includes a base plate (310), a connecting bolt (320) is provided on the base plate (310), the head of the connecting bolt (320) is adapted to the T-slot of the table surface of the rotary table (210), and a nut (330) is screwed into the connecting bolt (320) and presses the base plate (310) tightly and fixes it on the rotary table (210); the base plate (310) is provided with a mounting wall (340) protruding from the upper surface of the base plate (310), and a through hole is provided in the mounting wall (340), and a fastening bolt for connecting with the machine base is provided in the through hole.

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