An accelerated life test system for motor bearings under multiple stress actions

Abstract

The present invention is an accelerated life test system for motor bearings under the action of multiple stresses. The present invention relates to the technical field of motor bearing life test. By applying electric brushes to both ends of the inner and outer rings of the bearing, the voltage stress exerted on the bearing during normal operation of the motor can be fully simulated. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulation device can be adjusted, and a single test system can simulate the real bearing voltages borne by bearings in motors of various power ratings. The temperature of the bearing is regulated by a temperature control device, and a radial loading force is applied to the rotating shaft by a radial loading device. The data acquisition device processes the signals collected by the sensors and then transmits them to the host computer for real-time monitoring and data storage. The present invention can study the influence and action mechanism of bearing current on bearing life under multiple stresses, thereby making up for the deficiencies of the missing related test devices.

Description

Technical Field

[0001] The present invention relates to the technical field of motor bearing life testing, and is an accelerated life testing system for motor bearings under the action of multiple stresses. Background Art

[0002] Bearing damage is a high-occurrence fault in motors. In the industrial field where PWM frequency conversion modulation technology is widely used, especially in the electric drive applications with long cables, bearing electro-corrosion faults often damage the bearings earlier than mechanical faults. Long-term exposure to bearing current corrosion will cause damages such as pits, pockmarks, striated grooves and lubricant deterioration in motor bearings, resulting in problems such as abnormal vibration, increased noise and rising temperature of the motor, directly affecting the reliable operation of the motor.

[0003] At present, there are relatively few relevant studies on the action mechanism of bearing electro-corrosion damage caused by bearing current, mainly for two reasons: on the one hand, when using an actual motor for bearing life testing, the motor needs to be disassembled multiple times, and it is also difficult to place temperature, vibration and other measurement sensors in appropriate positions. When it is necessary to explore the bearing electro-corrosion damage problems of electric drive systems with different power ratings, multiple motors and inverters are required, which is troublesome to operate and has low test efficiency. On the other hand, for the test bench dedicated to bearings, most of the current bearing life test benches are based on mechanical stress loading. By applying radial and axial forces to the motor shaft, the damage of the bearings is accelerated, and there is a lack of a bearing life test bench that takes into account the bearing electrical stress loading. With the gradual adoption of SiC devices in motor controllers, the improvement of high switching frequency and switching speed makes the bearing current problem more serious. The electro-corrosion effect brought by electrical stress on motor bearings and its impact on bearing life need to be paid more attention. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, study the influence and action mechanism of bearing current on bearing life under multiple stresses, and thus make up for the deficiencies of the missing relevant test devices, the present invention provides an accelerated life testing system for motor bearings under the action of multiple stresses.

[0005] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0006] An accelerated life test system for motor bearings under multiple stress actions, the system comprising: a bearing life test bench, a motor bearing voltage simulation device, a data acquisition device and a host computer;

[0007] The bearing life test bench includes: a cast iron platform, a motor, a first coupling, a second coupling, a third coupling, a fourth coupling, a fifth coupling, a first rotating shaft, a second rotating shaft, a third rotating shaft, a fourth rotating shaft, a first test bearing, a second test bearing, a third test bearing, a first test bearing seat, a second test bearing seat, a third test bearing seat, a support bearing, a support bearing seat, a torque and speed sensor, a radial loading device, a first brush, a second brush, a third brush, a first brush fixing bracket, a second brush fixing bracket, a third brush fixing bracket, a first temperature sensor, a second temperature sensor, a third temperature sensor, a first vibration sensor, a second vibration sensor, a third vibration sensor, a first voltage sensor, a second voltage sensor, a third voltage sensor, a first current sensor, a second current sensor, a third current sensor, a first temperature control device, a second temperature control device and a third temperature control device;

[0008] The motor is fixed in the installation groove of the cast iron platform. One side shaft extension of the motor is connected to one end of the shaft of the torque and speed sensor through the first coupling. The other end of the shaft of the torque and speed sensor is connected to one end of the first rotating shaft through the second coupling. The support bearing is sleeved on the first rotating shaft and installed in the support bearing seat. The other end of the first rotating shaft is connected to one end of the second rotating shaft through the third coupling. The first test bearing is sleeved on the second rotating shaft and installed in the first test bearing seat; the base of the radial loading device is fixed on the cast iron platform, and the radial force is applied to the second rotating shaft to realize the loading of mechanical stress;

[0009] The other side shaft extension end of the motor is connected to one end of the third rotating shaft through the fourth coupling. The second test bearing is sleeved on the third rotating shaft and installed in the second test bearing seat. The other end of the third rotating shaft is connected to one end of the fourth rotating shaft through the fifth coupling. The third test bearing is sleeved on the fourth rotating shaft and installed in the third test bearing seat;

[0010] The described cast iron platform is equipped with a first brush fixing bracket, a second brush fixing bracket, and a third brush fixing bracket for respectively fixing a first brush, a second brush, and a third brush. The first brush, the second brush, and the third brush are respectively in reliable contact with a second rotating shaft, a third rotating shaft, and a fourth rotating shaft. The positive electrodes of a first voltage sensor, a second voltage sensor, and a third voltage sensor are respectively connected to the first brush, the second brush, and the third brush, and the negative electrodes are respectively connected to a first test bearing housing, a second test bearing housing, and a third test bearing housing. First current sensors, second current sensors, and third current sensors respectively pass through short wires outside the first test bearing housing, the second test bearing housing, and the third test bearing housing. First temperature sensors, second temperature sensors, and third temperature sensors are respectively installed at positions close to the outer ring of the bearing in the first test bearing housing, the second test bearing housing, and the third test bearing housing.

[0011] A first vibration sensor, a second vibration sensor, and a third vibration sensor are respectively installed on the surfaces of the first test bearing housing, the second test bearing housing, and the third test bearing housing. First temperature control devices, second temperature control devices, and third temperature control devices are respectively installed on the surfaces of the first test bearing housing, the second test bearing housing, and the third test bearing housing for controlling the temperature of the bearing housing, and thus controlling the operating temperature of the first test bearing, the second test bearing, and the third test bearing.

[0012] Preferably, the test bearing housing is made of cast iron material, and the inner surfaces of the bearing chambers of the bearing housing are all sprayed with an insulating coating of the same thickness for insulating the outer ring of the bearing and the bearing housing. At the same time, outside the bearing housing, the bearing housing and the outer ring of the bearing are connected by a short wire to provide a unique current path for the bearing current, facilitating the measurement of the bearing current.

[0013] Preferably, the motor bearing voltage simulation device includes: a main control board and a power circuit. The main control board generates a PWM drive signal for the power circuit, and the power circuit outputs 3 channels of simulated bearing voltages. The positive electrode of each channel of voltage is connected to the brush, and the negative electrode is connected to the bearing housing, thereby realizing the loading of electrical stress during the operation of the bearing.

[0014] Preferably, the power circuit includes a three-phase bridge circuit and a high-frequency common-mode transformer. The three-phase bridge circuit includes a support capacitor C1 and switching tubes M1, M2, M3, M4, M5, M6. The high-frequency common-mode transformer includes two sets of primary windings TP1, TP2 and three sets of secondary windings TS1, TS2, TS3. The same-named ends of the TP1 and TP2 windings are connected to the midpoint of the first bridge arm composed of M1 and M2. The different-named end of the TP1 winding is connected to the midpoint of the second bridge arm composed of M3 and M4. The different-named end of the TP2 winding is connected to the midpoint of the third bridge arm composed of M5 and M6. The same-named ends of the three sets of windings TS1, TS2, TS3 on the secondary side of the transformer are respectively connected to the three brushes, and the different-named ends are respectively connected to the three test bearing housings.

[0015] Preferably, the number of turns of the primary windings TP1 and TP2 of the high-frequency common-mode transformer are N P1 and N P2 respectively, and the number of turns of the three sets of secondary windings are the same, all being N S , and the turns ratio relationship is N P1 / N S = 6:1, N P2 / N S = 2:1.

[0016] Preferably, voltage, current, temperature, and vibration sensors are connected to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to a host computer for data storage. The rotation speed of the motor is controlled through the host computer interface, the sensor data information is monitored in real time, the noise spectrum of the vibration sensor is observed, and the operating condition of the bearing is judged.

[0017] Preferably, an insulating coupling is used for the coupling.

[0018] A method for accelerating the life test of a motor bearing under multiple stresses, the method comprising the following steps:

[0019] Collect the temperature of the motor bearing through a temperature sensor, collect the vibration intensity of the motor bearing through a vibration sensor, and control the temperature of the bearing housing through a temperature control device;

[0020] Generate a PWM drive signal through a main control board to a power circuit. The power circuit outputs 3 channels of analog bearing voltages. The positive pole of each voltage is connected to a brush, and the negative pole is connected to the bearing housing, so as to realize the loading of electrical stress during the operation of the bearing;

[0021] Connect voltage, current, temperature, and vibration sensors to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to a host computer for data storage. At the same time, the rotation speed of the motor can be controlled through the host computer interface, the sensor data information can be monitored in real time, the noise spectrum of the vibration sensor can be observed, and the operating condition of the bearing can be judged.

[0022] A computer-readable storage medium, on which a computer program is stored, and the program is executed by a processor to be used to implement a method for accelerating the life test of a motor bearing under multiple stresses.

[0023] A computer device, comprising a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes according to a method for accelerating the life test of a motor bearing under multiple stresses.

[0024] The present invention has the following beneficial effects:

[0025] The accelerated life test system for motor bearings proposed by the present invention can simultaneously apply electrical stress and mechanical stress, making the bearing accelerated life test more in line with the actual working conditions of motor operation.

[0026] The accelerated life test system for motor bearings proposed by the present invention can, when no mechanical stress is applied, separately conduct experimental research on the electrical corrosion mechanism and fault characteristics of bearings, providing experimental platform support for the current research on the electrical corrosion fault mechanism of motor bearings.

[0027] The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the real bearing voltages borne by bearings in motors of various power ratings, greatly saving the cost of experimental equipment and improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0029] Figure 1 It is the system structure and function block diagram of the present invention;

[0030] Figure 2 It is the circuit schematic diagram of the power circuit in the motor bearing voltage simulation device of the present invention;

[0031] Figure 3 It is the equivalent circuit schematic diagram of the power circuit of the present invention in working mode 1;

[0032] Figure 4 It is the equivalent circuit schematic diagram of the power circuit of the present invention in working mode 2;

[0033] Figure 5 It is the equivalent circuit schematic diagram of the power circuit of the present invention in working mode 3;

[0034] Figure 6 It is the equivalent circuit schematic diagram of the power circuit of the present invention in working mode 4;

[0035] Figure 7 It is the switching states of each power switch tube of the power circuit of the present invention in 4 working modes;

[0036] Figure 8This is the waveform diagram of a single-channel analog bearing voltage output by the bearing voltage simulation device of the present invention within a single switching cycle. Detailed implementation manners

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] The present invention is described in detail below with reference to specific embodiments. Specific Embodiment 1:

[0043] According to Figures 1 to 8 As shown, the specific optimized technical solution adopted by the present invention to solve the above technical problems is: The present invention relates to a motor bearing accelerated life test system under multiple stress actions.

[0044] A motor bearing accelerated life test system under multiple stress actions, the system includes: a bearing life test bench, a motor bearing voltage simulation device, a data acquisition device, and a host computer;

[0045] The bearing life test bench includes: a cast iron platform 101, a motor 102, a first coupling 103, a second coupling 104, a third coupling 105, a fourth coupling 106, a fifth coupling 107, a first rotating shaft 108, a second rotating shaft 109, a third rotating shaft 110, a fourth rotating shaft 111, a first test bearing 112, a second test bearing 113, a third test bearing 114, a first test bearing seat 115, a second test bearing seat 116, a third test bearing seat 117, a support bearing 118, a support bearing seat 119, a torque and speed sensor 120, a radial loading device 121, a first brush 122, a second brush 123, a third brush 124, a first brush fixing bracket 125, a second brush fixing bracket 126, a third brush fixing bracket 127, a first temperature sensor 128, a second temperature sensor 129, a third temperature sensor 130, a first vibration sensor 131, a second vibration sensor 132, a third vibration sensor 133, a first voltage sensor 134, a second voltage sensor 135, a third voltage sensor 136, a first current sensor 137, a second current sensor 138, a third current sensor 139, a first temperature control device 140, a second temperature control device 141, and a third temperature control device 142;

[0046] The motor 102 is fixed in the installation groove of the cast iron platform 101. One end of the shaft extension on one side of the motor 102 is connected to one end of the rotating shaft of the torque and speed sensor 120 through the first coupling 103. The other end of the rotating shaft of the torque and speed sensor 120 is connected to one end of the first rotating shaft 108 through the second coupling 104. The support bearing 118 is sleeved on the first rotating shaft 108, and the support bearing 118 is installed in the support bearing seat 119. The other end of the first rotating shaft 108 is connected to one end of the second rotating shaft 109 through the third coupling 105. The first test bearing 112 is sleeved on the second rotating shaft 109, and the first test bearing 112 is installed in the first test bearing seat 109; The base of the radial loading device 121 is fixed to the cast iron platform 101, and by applying a radial force to the second rotating shaft 109, the loading of mechanical stress is realized;

[0047] The shaft extension end on the other side of the motor 102 is connected to one end of the third rotating shaft 110 through the fourth coupling 106. The second test bearing 113 is sleeved on the third rotating shaft 110, and the second test bearing 113 is installed in the second test bearing seat 116. The other end of the third rotating shaft 110 is connected to one end of the fourth rotating shaft 111 through the fifth coupling 107. The third test bearing 114 is sleeved on the fourth rotating shaft 111, and the third test bearing 114 is installed in the third test bearing seat 117;

[0048] The described cast iron platform 101 is equipped with a first brush fixing bracket 125, a second brush fixing bracket 126, and a third brush fixing bracket 127 for respectively fixing a first brush 122, a second brush 123, and a third brush 124. The first brush 122, the second brush 123, and the third brush 124 are respectively in reliable contact with a second rotating shaft 109, a third rotating shaft 110, and a fourth rotating shaft 111. The positive electrodes of a first voltage sensor 134, a second voltage sensor 135, and a third voltage sensor 136 are respectively connected to the first brush 122, the second brush 123, and the third brush 124, and the negative electrodes are respectively connected to a first test bearing seat 115, a second test bearing seat 116, and a third test bearing seat 117. First current sensors 137, second current sensors 138, and third current sensors 139 respectively pass through short wires outside the first test bearing seat 115, the second test bearing seat 116, and the third test bearing seat 117. First temperature sensors 128, second temperature sensors 129, and third temperature sensors 130 are respectively installed at positions close to the outer ring of the bearing in the first test bearing seat 115, the second test bearing seat 116, and the third test bearing seat 117;

[0049] A first vibration sensor 131, a second vibration sensor 132, and a third vibration sensor 133 are respectively installed on the surfaces of the first test bearing seat 115, the second test bearing seat 116, and the third test bearing seat 117. A first temperature control device 150, a second temperature control device 151, and a third temperature control device 152 are respectively installed on the surfaces of the first test bearing seat 115, the second test bearing seat 116, and the third test bearing seat 117 for controlling the temperature of the bearing seat, and thus controlling the operating temperature of the first test bearing 112, the second test bearing 113, and the third test bearing 114.

[0050] Refer to Figures 3 to 6 As shown, they are respectively 4 working modes of the power circuit (22). Within one switching period, the voltage values output by the secondary side of the transformer in each working mode are shown in Figure 7 As shown, the drive signals S1, S2, S3, S4, S5, and S6 of the 6 switching tubes in the circuit are all high level to control the tubes to turn on and low level to control the tubes to turn off. The voltages Ub1, Ub2, and Ub3 output by the three sets of windings on the secondary side of the high-frequency common-mode transformer correspond to the three-way analog bearing voltages output by the bearing voltage simulation device, and the waveform of each output analog bearing voltage is as shown in Figure 8 As shown, the waveform is a typical 4-level stepped wave, and this analog bearing voltage waveform is the same as the bearing voltage waveform of the motor in the three-phase two-level PWM variable-frequency drive system widely used in the industrial field. Therefore, the electrical stress borne by the bearings of the test bench in the present invention can fully simulate the electrical stress borne by the bearings during the normal operation of the actual motor.

[0051] It should be further noted that the simulated bearing voltage waveform in the present invention can be changed according to the modulation method of the actual motor drive system. If the actual motor controller adopts the space vector pulse width modulation strategy (SVPWM), the present invention can inject a third harmonic component into the program of the main control board 21 to simulate the low-frequency fluctuation characteristics of 3 times the modulation frequency of the actual bearing voltage, without the need for hardware modification. In addition, according to the power of the actual motor to be simulated and the jump speed of the actual bearing voltage level, by controlling the magnitude of the power supply voltage Ubus of the power circuit 22 and the switching frequency of the switching tubes, the control of the output simulated bearing voltage amplitude and rising speed is achieved.

[0052] The motor bearing accelerated life test system proposed by the present invention can simultaneously apply electrical stress and mechanical stress, making the bearing accelerated life test more in line with the actual operating conditions of the motor.

[0053] The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the simulated voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the true bearing voltages borne by bearings in motors of multiple power ratings, greatly saving the cost of experimental equipment and improving the test efficiency. Specific Embodiment 2:

[0055] The difference between the second embodiment of the present application and the first embodiment is only that:

[0056] The test bearing housing is made of cast iron material, and the inner surface of the bearing chamber of the bearing housing is sprayed with an insulating coating of the same thickness to insulate the outer bearing ring from the bearing housing. At the same time, outside the bearing housing, the bearing housing and the outer bearing ring are connected by a short wire to provide the only current path for the bearing current, facilitating the measurement of the bearing current.

[0057] The motor bearing accelerated life test system proposed by the present invention can, when no mechanical stress is applied, independently conduct experiments on the mechanism of bearing electrical corrosion and fault characteristics, providing experimental platform support for the current research on the mechanism of motor bearing electrical corrosion faults. Specific Embodiment 3:

[0059] The difference between the third embodiment of the present application and the second embodiment is only that:

[0060] The motor bearing voltage simulation device includes: a main control board 21 and a power circuit 22. The main control board 21 generates a PWM drive signal for the power circuit 22, and the power circuit 22 outputs 3 channels of simulated bearing voltages. The positive pole of each channel of voltage is connected to the brush, and the negative pole is connected to the bearing housing, thereby realizing the loading of electrical stress during the operation of the bearing.

[0061] The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the real bearing voltages borne by bearings in motors of various power ratings, greatly saving the cost of experimental equipment and improving the test efficiency. Specific Embodiment Four:

[0063] The difference between the fourth embodiment of the present application and the third embodiment is only that:

[0064] The power circuit 22 includes a three-phase bridge circuit and a high-frequency common-mode transformer. The three-phase bridge circuit includes a support capacitor C1 and switching tubes M1, M2, M3, M4, M5, and M6. The high-frequency common-mode transformer includes two sets of primary windings TP1 and TP2 and three sets of secondary windings TS1, TS2, and TS3. The same-name ends of the TP1 and TP2 windings are connected to the midpoint of the first bridge arm composed of M1 and M2. The different-name end of the TP1 winding is connected to the midpoint of the second bridge arm composed of M3 and M4. The different-name end of the TP2 winding is connected to the midpoint of the third bridge arm composed of M5 and M6. The same-name ends of the three sets of windings TS1, TS2, and TS3 on the secondary side of the transformer are respectively connected to three brushes, and the different-name ends are respectively connected to three test bearing seats.

[0065] The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the real bearing voltages borne by bearings in motors of various power ratings, greatly saving the cost of experimental equipment and improving the test efficiency. Specific Embodiment Five:

[0067] The difference between the fifth embodiment of the present application and the fourth embodiment is only that:

[0068] The number of turns of the primary windings TP1 and TP2 of the high-frequency common-mode transformer are N P1 and N P2 , respectively. The number of turns of the three sets of secondary windings is the same, all being N S . The turns ratio relationship is N P1 / N S =6:1, N P2 / N S =2:1.

[0069] The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the true bearing voltages borne by bearings in motors of various power levels, greatly saving the cost of experimental equipment and improving the test efficiency. Specific Embodiment Six:

[0071] The difference between the sixth embodiment of this application and the fifth embodiment is only that:

[0072] The voltage, current, temperature, and vibration sensors are connected to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to the upper computer for data storage. The rotation speed of the motor is controlled through the upper computer interface, the sensor data information is monitored in real time, the noise spectrum of the vibration sensor is observed, and the bearing operating condition is judged.

[0073] The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the true bearing voltages borne by bearings in motors of various power levels, greatly saving the cost of experimental equipment and improving the test efficiency. Specific Embodiment Seven:

[0075] The difference between the seventh embodiment of this application and the sixth embodiment is only that:

[0076] The coupling uses an insulating coupling. The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the true bearing voltages borne by bearings in motors of various power levels, greatly saving the cost of experimental equipment and improving the test efficiency. Specific Embodiment Eight:

[0078] The difference between the eighth embodiment of this application and the seventh embodiment is only that:

[0079] The present invention provides a method for accelerating the life test of a motor bearing under multiple stress actions. The method is based on a system for accelerating the life test of a motor bearing under multiple stress actions. The system includes: a bearing life test bench, a motor bearing voltage simulation device, a data acquisition device, and an upper computer;

[0080] The bearing life test bench includes: a cast iron platform, a motor, a first coupling, a second coupling, a third coupling, a fourth coupling, a fifth coupling, a first rotating shaft, a second rotating shaft, a third rotating shaft, a fourth rotating shaft, a first test bearing, a second test bearing, a third test bearing, a first test bearing seat, a second test bearing seat, a third test bearing seat, a support bearing, a support bearing seat, a torque and speed sensor, a radial loading device, a first brush, a second brush, a third brush, a first brush fixing bracket, a second brush fixing bracket, a third brush fixing bracket, a first temperature sensor, a second temperature sensor, a third temperature sensor, a first vibration sensor, a second vibration sensor, a third vibration sensor, a first voltage sensor, a second voltage sensor, a third voltage sensor, a first current sensor, a second current sensor, a third current sensor, a first temperature control device, a second temperature control device, and a third temperature control device;

[0081] The motor is fixed in the installation groove of the cast iron platform. One shaft extension of the motor is connected to one end of the shaft of the torque and speed sensor through the first coupling. The other end of the shaft of the torque and speed sensor is connected to one end of the first rotating shaft through the second coupling. The support bearing is sleeved on the first rotating shaft and installed in the support bearing seat. The other end of the first rotating shaft is connected to one end of the second rotating shaft through the third coupling. The first test bearing is sleeved on the second rotating shaft and installed in the first test bearing seat; The base of the radial loading device is fixed on the cast iron platform, and the mechanical stress is loaded by applying a radial force to the second rotating shaft;

[0082] The other shaft extension end of the motor is connected to one end of the third rotating shaft through the fourth coupling. The second test bearing is sleeved on the third rotating shaft and installed in the second test bearing seat. The other end of the third rotating shaft is connected to one end of the fourth rotating shaft through the fifth coupling. The third test bearing is sleeved on the fourth rotating shaft and installed in the third test bearing seat;

[0083] The cast iron platform is installed with a first brush fixing bracket, a second brush fixing bracket, and a third brush fixing bracket for respectively fixing the first brush, the second brush, and the third brush. The first brush, the second brush, and the third brush are respectively in reliable contact with the second rotating shaft, the third rotating shaft, and the fourth rotating shaft. The positive poles of the first voltage sensor, the second voltage sensor, and the third voltage sensor are respectively connected to the first brush, the second brush, and the third brush, and the negative poles are respectively connected to the first test bearing seat, the second test bearing seat, and the third test bearing seat; The first current sensor, the second current sensor, and the third current sensor respectively pass through the short wires outside the first test bearing seat, the second test bearing seat, and the third test bearing seat; The first temperature sensor, the second temperature sensor, and the third temperature sensor are respectively installed at positions close to the outer ring of the bearing in the first test bearing seat, the second test bearing seat, and the third test bearing seat;

[0084] The first vibration sensor, the second vibration sensor, and the third vibration sensor are respectively installed on the surfaces of the first test bearing housing, the second test bearing housing, and the third test bearing housing; the first temperature control device, the second temperature control device, and the third temperature control device are respectively installed on the surfaces of the first test bearing housing, the second test bearing housing, and the third test bearing housing to control the temperature of the bearing housing, and thus control the operating temperatures of the first test bearing, the second test bearing, and the third test bearing. The method includes the following steps:

[0085] Collect the temperature of the motor bearing through a temperature sensor, collect the vibration intensity of the motor bearing through a vibration sensor, and control the temperature of the bearing housing through a temperature control device;

[0086] Generate a PWM drive signal through the main control board to the power circuit. The power circuit outputs three channels of analog bearing voltages. The positive pole of each voltage is connected to the brush, and the negative pole is connected to the bearing housing, so as to realize the loading of electrical stress during the operation of the bearing;

[0087] Connect the voltage, current, temperature, and vibration sensors to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to the upper computer for data storage. At the same time, the upper computer interface can control the speed of the motor, monitor the sensor data information in real time, observe the noise spectrum of the vibration sensor, and judge the operating condition of the bearing.

[0088] The test system and the method for generating electrical stress proposed by the present invention are applicable to the three-phase two-level inverter variable frequency speed regulation system widely used in the current industrial and new energy vehicle fields. The number of levels, amplitude, frequency, and switching speed of the analog voltage generated by the bearing voltage simulator can be adjusted. One test system can simulate the real bearing voltages borne by bearings in motors of multiple power levels, greatly saving the cost of experimental equipment and improving the test efficiency. Specific Embodiment Nine:

[0090] The difference between Embodiment Nine and Embodiment Eight of this application is only that:

[0091] The present invention provides a computer-readable storage medium, on which a computer program is stored. The program is executed by a processor to be used to implement a method for accelerating the life test of a motor bearing under multiple stress actions. The method specifically is: collect the temperature of the motor bearing through a temperature sensor, collect the vibration intensity of the motor bearing through a vibration sensor, and control the temperature of the bearing housing through a temperature control device;

[0092] Generate a PWM drive signal through the main control board to the power circuit. The power circuit outputs three channels of analog bearing voltages. The positive pole of each voltage is connected to the brush, and the negative pole is connected to the bearing housing, so as to realize the loading of electrical stress during the operation of the bearing;

[0093] Connect voltage, current, temperature, and vibration sensors to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to the host computer for data storage. At the same time, the host computer interface can control the speed of the motor, monitor the sensor data information in real time, observe the noise spectrum of the vibration sensor, and judge the operating condition of the bearing. Specific Embodiment Ten:

[0095] The difference between the tenth embodiment and the ninth embodiment of this application is only that:

[0096] The present invention provides a computer device, including a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a method for accelerating the life test of a motor bearing under multiple stress actions.

[0097] The method is specifically as follows: Collect the temperature of the motor bearing through a temperature sensor, collect the vibration intensity of the motor bearing through a vibration sensor, and control the temperature of the bearing housing through a temperature control device;

[0098] Generate a PWM drive signal through the main control board to the power circuit. The power circuit outputs 3 channels of analog bearing voltages. The positive pole of each voltage is connected to the brush, and the negative pole is connected to the bearing housing, so as to realize the loading of electrical stress during the operation of the bearing;

[0099] Connect voltage, current, temperature, and vibration sensors to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to the host computer for data storage. At the same time, the host computer interface can control the speed of the motor, monitor the sensor data information in real time, observe the noise spectrum of the vibration sensor, and judge the operating condition of the bearing.

[0100] The present invention belongs to the field of motor bearing life testing. The invention includes: a bearing life test bench, a bearing voltage simulation device, a data acquisition device and a host computer. The bearing life test bench includes a motor, an insulating coupling, a test bearing and a bearing housing, etc. Temperature, vibration, voltage and current sensors are installed on each bearing housing. The motor bearing voltage simulation device can generate multiple channels of simulated voltages that are consistent with the actual motor bearing voltage waveform, and load them onto both ends of the inner and outer rings of the bearing through brushes, which can fully simulate the voltage stress received by the bearing during normal operation of the motor. The number of levels, amplitude, frequency and switching speed of the simulated voltage generated by the bearing voltage simulation device can be adjusted, and a test system can simulate the real bearing voltages borne by bearings in motors of multiple power levels. The temperature of the bearing is regulated by a temperature control device, and a radial loading force is applied to the rotating shaft by a radial loading device. The data acquisition device processes the signals collected by the sensors and then transmits them to the host computer for real-time monitoring and data storage. The present invention can study the influence and action mechanism of bearing current on bearing life under multiple stresses, thereby making up for the deficiencies of missing relevant test devices.

[0101] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of these features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined. Any process or method description shown in the flowchart or described in other ways herein can be understood to represent a module, segment, or part of code including one or more N executable instructions for implementing a customized logical function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in the reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present invention belong. The logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a sequenced list of executable instructions for implementing a logical function, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion (electronic device) having one or N wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM).In addition, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing when necessary, and then stored in a computer memory. It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0102] Those of ordinary skill in the art can understand that all or part of the steps carried by the method of the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments. In addition, in each embodiment of the present invention, the functional units can be integrated in a processing module, or each unit can exist physically alone, or two or more units can be integrated in a module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0103] The above is only a preferred embodiment of a motor bearing accelerated life test system based on multiple stress actions. The protection scope of a motor bearing accelerated life test system based on multiple stress actions is not limited to the above embodiments. Any technical solutions falling within this concept belong to the protection scope of the present invention. It should be noted that for those skilled in the art, several improvements and changes made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. An accelerated life test system for motor bearings under multiple stress actions, characterized in that: The system includes: a bearing life test bench, a motor bearing voltage simulation device, a data acquisition device, and a host computer; The bearing life test bench includes: a cast iron platform, a motor, a first coupling, a second coupling, a third coupling, a fourth coupling, a fifth coupling, a first rotating shaft, a second rotating shaft, a third rotating shaft, a fourth rotating shaft, a first test bearing, a second test bearing, a third test bearing, a first test bearing seat, a second test bearing seat, a third test bearing seat, a support bearing, a support bearing seat, a torque and speed sensor, a radial loading device, a first brush, a second brush, a third brush, a first brush fixing bracket, a second brush fixing bracket, a third brush fixing bracket, a first temperature sensor, a second temperature sensor, a third temperature sensor, a first vibration sensor, a second vibration sensor, a third vibration sensor, a first voltage sensor, a second voltage sensor, a third voltage sensor, a first current sensor, a second current sensor, a third current sensor, a first temperature control device, a second temperature control device, and a third temperature control device; The motor is fixed in the installation groove of the cast iron platform. One shaft extension of the motor is connected to one end of the rotating shaft of the torque and speed sensor through the first coupling. The other end of the rotating shaft of the torque and speed sensor is connected to one end of the first rotating shaft through the second coupling. The support bearing is sleeved on the first rotating shaft and installed in the support bearing seat. The other end of the first rotating shaft is connected to one end of the second rotating shaft through the third coupling. The first test bearing is sleeved on the second rotating shaft and installed in the first test bearing seat; The base of the radial loading device is fixed on the cast iron platform, and the radial force is applied to the second rotating shaft to realize the loading of mechanical stress; The other shaft extension end of the motor is connected to one end of the third rotating shaft through the fourth coupling. The second test bearing is sleeved on the third rotating shaft and installed in the second test bearing seat. The other end of the third rotating shaft is connected to one end of the fourth rotating shaft through the fifth coupling. The third test bearing is sleeved on the fourth rotating shaft and installed in the third test bearing seat; The cast iron platform is installed with a first brush fixing bracket, a second brush fixing bracket, and a third brush fixing bracket for respectively fixing the first brush, the second brush, and the third brush. The first brush, the second brush, and the third brush are respectively in reliable contact with the second rotating shaft, the third rotating shaft, and the fourth rotating shaft. The positive poles of the first voltage sensor, the second voltage sensor, and the third voltage sensor are respectively connected to the first brush, the second brush, and the third brush, and the negative poles are respectively connected to the first test bearing seat, the second test bearing seat, and the third test bearing seat; The first current sensor, the second current sensor, and the third current sensor respectively pass through the short wires outside the first test bearing seat, the second test bearing seat, and the third test bearing seat; The first temperature sensor, the second temperature sensor, and the third temperature sensor are respectively installed at positions close to the outer ring of the bearing in the first test bearing seat, the second test bearing seat, and the third test bearing seat; The first vibration sensor, the second vibration sensor, and the third vibration sensor are respectively installed on the surfaces of the first test bearing housing, the second test bearing housing, and the third test bearing housing; the first temperature control device, the second temperature control device, and the third temperature control device are respectively installed on the surfaces of the first test bearing housing, the second test bearing housing, and the third test bearing housing, and are used to control the temperature of the bearing housing, so as to control the operating temperature of the first test bearing, the second test bearing, and the third test bearing. The test bearing housing is made of cast iron material, and the inner surfaces of the bearing chambers of the bearing housing are all sprayed with an insulating coating of the same thickness, which is used to insulate the outer ring of the bearing from the bearing housing. At the same time, outside the bearing housing, the bearing housing and the outer ring of the bearing are connected by a short wire to provide the only current path for the bearing current, which is convenient for measuring the bearing current. The motor bearing voltage simulation device includes: a main control board and a power circuit. The main control board generates a PWM drive signal for the power circuit, and the power circuit outputs 3 channels of simulated bearing voltages. The positive pole of each voltage is connected to the brush, and the negative pole is connected to the bearing housing, so as to realize the loading of electrical stress during the operation of the bearing. The power circuit includes a three-phase bridge circuit and a high-frequency common-mode transformer. The three-phase bridge circuit includes a support capacitor C1 and switching tubes M1, M2, M3, M4, M5, and M6. The high-frequency common-mode transformer includes two sets of primary windings TP1 and TP2 and three sets of secondary windings TS1, TS2, and TS3. The same-named ends of the TP1 and TP2 windings are connected to the midpoint of the first bridge arm composed of M1 and M2. The different-named end of the TP1 winding is connected to the midpoint of the second bridge arm composed of M3 and M4. The different-named end of the TP2 winding is connected to the midpoint of the third bridge arm composed of M5 and M6. The same-named ends of the three sets of windings TS1, TS2, and TS3 on the secondary side of the transformer are respectively connected to three brushes, and the different-named ends are respectively connected to three test bearing housings.

2. The accelerated life test system for motor bearings under multiple stress actions according to claim 1, wherein: The number of turns of the primary windings TP1 and TP2 of the high-frequency common-mode transformer are N P1 and N P2 respectively. The number of turns of the three sets of secondary windings are the same, all being N S . The turns ratio relationship is N P1 / N S = 6:1, N P2 / N S = 2:

1.

3. A motor bearing accelerated life test system under multiple stress actions according to claim 2, characterized in that: The voltage, current, temperature, and vibration sensors are connected to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to the upper computer for data storage. The rotation speed of the motor is controlled through the upper computer interface, and the sensor data information is monitored in real time. The noise spectrum of the vibration sensor is observed to judge the operating condition of the bearing.

4. The accelerated life test system for motor bearings under multiple stress actions according to claim 3, wherein: The coupling uses an insulating coupling.

5. A method for accelerating the life test of a motor bearing under multiple stress actions, which is implemented based on the motor bearing accelerating life test system under multiple stress actions according to claim 1, and is characterized in that: The method includes the following steps: Collect the temperature of the motor bearing through a temperature sensor, collect the vibration intensity of the motor bearing through a vibration sensor, and control the temperature of the bearing housing through a temperature control device. Generate a PWM drive signal for the power circuit through the main control board. The power circuit outputs 3 channels of simulated bearing voltages. The positive pole of each voltage is connected to the brush, and the negative pole is connected to the bearing housing, so as to realize the loading of electrical stress during the operation of the bearing. Connect the voltage, current, temperature, and vibration sensors to a 12-channel data acquisition device. The data acquisition device processes the signals and then transmits them to the upper computer for data storage. At the same time, the rotation speed of the motor is controlled through the upper computer interface, and the sensor data information is monitored in real time. The noise spectrum of the vibration sensor is observed to judge the operating condition of the bearing.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by a processor to be used for implementing a method for accelerating the life test of a motor bearing under multiple stress actions as described in claim 5.

7. A computer device, characterized in that, It includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a method for accelerating the life test of a motor bearing under multiple stresses according to claim 5.

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