Bearing electrocorrosion detection method, system, device, equipment and medium

Abstract

The invention relates to a bearing electrocorrosion detection method, system, device and equipment and a medium. The bearing electrocorrosion detection method is applied to detection equipment, one end of the detection equipment is in contact with a test point, close to a bearing inner ring, on a rotating shaft through a rotating shaft signal lead of a test probe, and the other end of the detection equipment is in contact with a test point, close to a bearing outer ring, on a motor shell through a shell signal lead. The detection equipment detects the shaft voltage waveform of the bearing when the motor is in the target working condition, judges whether the bearing has an electro-corrosion risk under the target working condition according to the shaft voltage waveform, and if yes, after the insulating bearing is replaced, the rotating shaft signal lead and the shell signal lead are in short circuit, and the shaft current under the target working condition is detected; and evaluating the electric corrosion severity of the bearing under the target working condition according to the shaft current. By implementing the bearing electrocorrosion detection method provided by the invention, the problem of inaccurate bearing electrocorrosion detection in the prior art can be improved.

Description

Technical Field

[0001] The present application relates to the field of automobile technology, and in particular to a bearing electrical corrosion detection method, system, device, equipment and medium. Background Art

[0002] Bearing failure caused by electrical corrosion is an important cause of motor failure. Electrical corrosion of bearings refers to the corrosion and damage to bearings and related components caused by current passing through the bearings.

[0003] Currently, the shaft voltage or the shaft current can be detected and the shaft voltage can be compared with a corresponding voltage threshold, or the shaft current can be compared with a corresponding current threshold to detect whether the bearing has electrical corrosion.

[0004] However, the threshold comparison method has the problem of inaccurate detection. For shaft voltage, the breakdown voltage threshold is generally determined by the oil film thickness. However, the oil film thickness is closely related to the mechanical operation state of the motor. As the motor speed and torque change, its operating load changes greatly, causing the oil film thickness and the corresponding voltage threshold to change accordingly, which is difficult to accurately measure through theoretical methods. For shaft current, due to the limitations of the test method, the current collected by the commonly used shaft current test method is often not the actual current passing through the bearing. Therefore, the existing technology still has the problem of inaccurate electrical corrosion detection. Summary of the invention

[0005] Based on this, the present application provides a bearing electrical corrosion detection method, system, device, equipment and medium, which can improve the problem of inaccurate bearing electrical corrosion detection in the prior art.

[0006] In the first aspect, the present application provides a bearing electrical corrosion detection method, which is applied to a detection device, one end of the detection device contacts a test point on the shaft close to the inner ring of the bearing through a shaft signal lead of a test probe, and the other end contacts a test point on the motor housing close to the outer ring of the bearing through a housing signal lead. The bearing electrical corrosion detection method includes: after installing a non-insulated bearing, detecting the shaft voltage waveform of the bearing when the motor is in a target operating condition; judging whether there is an electrical corrosion risk of the bearing under the target operating condition based on the shaft voltage waveform; if there is an electrical corrosion risk under the target operating condition, short-circuiting the shaft signal lead and the housing signal lead after replacing the insulated bearing to detect the shaft current under the target operating condition; and evaluating the severity of the electrical corrosion of the bearing under the target operating condition based on the shaft current.

[0007] In combination with the first aspect, in a first possible implementation mode of the first aspect, the aforementioned step of judging whether the bearing has an electrical corrosion risk under the target operating conditions based on the shaft voltage waveform includes: identifying the shaft voltage waveform to obtain the waveform type of the shaft voltage waveform, wherein the waveform types include a resistive discharge waveform, a capacitive breakdown discharge waveform, and a capacitive non-breakdown discharge waveform; judging whether the waveform type of the shaft voltage is a capacitive non-breakdown discharge waveform; if it is not a capacitive non-breakdown discharge waveform, determining that the bearing has an electrical corrosion risk.

[0008] In combination with the first aspect, in a second possible implementation mode of the first aspect, the step of judging whether the bearing is at risk of electrical corrosion under the target operating conditions based on the shaft voltage waveform includes: detecting the number of high-frequency peaks that appear in the shaft voltage waveform per unit time; comparing the number of high-frequency peaks detected with a quantity threshold; if the number of peaks is greater than the quantity threshold, determining that the bearing is at risk of electrical corrosion.

[0009] In combination with the first aspect, in a third possible implementation manner of the first aspect, the aforementioned step of evaluating the severity of electrical corrosion of the bearing under the target operating conditions based on the shaft current includes: determining a target interval to which the numerical value of the shaft current belongs, wherein different target intervals correspond to different severity levels, and as the numerical value of the shaft current increases, the severity level of the electrical corrosion increases; obtaining the severity level corresponding to the target interval indicates the severity of the electrical corrosion.

[0010] In combination with the first aspect, in a fourth possible implementation mode of the first aspect, if there is a risk of electrical corrosion, then: record the target operating conditions when the bearing undergoes electrical corrosion, the motor operating conditions including speed and / or torque; when the motor is in the target operating conditions, indicate that the bearing has a risk of electrical corrosion and take suppression and / or avoidance measures, or perform targeted optimization during the motor design phase.

[0011] In the second aspect, the present application also provides an electrical corrosion detection system, which includes a test probe and a detection device, wherein: the test probe is fixed on the motor housing, one end of the detection device contacts a test point on the motor housing close to the outer ring of the bearing through a housing signal lead, and the other end of the detection device contacts a test point on the rotating shaft close to the inner ring of the bearing through a rotating shaft signal lead of the test probe; the detection device is used to perform a bearing electrical corrosion detection method such as the first aspect or any one embodiment of the first aspect.

[0012] In combination with the second aspect, in a first possible implementation manner of the second aspect, the electrical corrosion detection system also includes a fixing tool and a lead channel, wherein the test probe is fixed to the motor housing by the fixing tool, so that the test end of the test probe maintains a flexible contact state with the rotating shaft, and the rotating shaft signal lead is led out from the opening of the motor housing through the lead channel to connect the test equipment.

[0013] In the third aspect, the present application also provides a detection device, which includes a detection unit for detecting the shaft voltage waveform of the bearing when the motor is in a target operating condition after installing a non-insulated bearing; a judgment unit for judging whether there is a risk of electrical corrosion of the bearing under the target operating condition based on the shaft voltage waveform; the detection unit is also used to short-circuit the shaft signal lead and the housing signal lead after replacing the insulating bearing if there is a risk of electrical corrosion under the target operating condition to detect the shaft current under the target operating condition; and an evaluation unit for evaluating the severity of electrical corrosion of the bearing under the target operating condition based on the shaft current.

[0014] In combination with the third aspect, in a first possible implementation mode of the third aspect, the judgment unit is specifically used to: identify the shaft voltage waveform to obtain the waveform type of the shaft voltage waveform, wherein the waveform type includes a resistive discharge waveform, a capacitive breakdown discharge waveform, and a capacitive non-breakdown discharge waveform; judge whether the waveform type of the shaft voltage is a capacitive non-breakdown discharge waveform; if it is not a capacitive non-breakdown discharge waveform, it is determined that there is a risk of electrical corrosion in the bearing.

[0015] In combination with the third aspect, in a second possible implementation mode of the third aspect, the judgment unit is specifically used to: detect the number of high-frequency peaks that appear in the shaft voltage waveform per unit time; compare the number of high-frequency peaks detected with a quantity threshold; if the number of peaks is greater than the quantity threshold, it is determined that there is a risk of electrical corrosion in the bearing.

[0016] In combination with the third aspect, in a third possible implementation mode of the third aspect, the evaluation unit is specifically used to: determine a target interval to which the numerical value of the shaft current belongs, wherein different target intervals correspond to different severity levels, and as the numerical value of the shaft current increases, the severity level of the electrical corrosion increases; obtaining the severity level corresponding to the target interval indicates the severity of the electrical corrosion.

[0017] In combination with the third aspect, in a fourth possible implementation manner of the third aspect, the detection device also includes a prompt unit, which is used to: if there is a risk of electrical corrosion, then: record the target operating conditions when the bearing is electrically corroded, the motor operating conditions including speed and / or torque; when the motor is in the target operating conditions, prompt that the bearing has a risk of electrical corrosion and take suppression measures and / or avoidance measures, or perform targeted optimization during the motor design stage.

[0018] In a fourth aspect, the present application also provides a detection device, which includes a processor and a memory, and the processor and the memory are connected via a bus; the processor is used to execute multiple instructions; the memory is used to store multiple instructions, and the instructions are suitable for being loaded by the processor and a bearing electrical corrosion detection method such as the first aspect or any one embodiment of the first aspect.

[0019] In a fifth aspect, the present application further provides a computer-readable storage medium storing a plurality of instructions, wherein the instructions are suitable for being loaded by a processor and executed by a bearing electrical corrosion detection method such as the first aspect or any one embodiment of the first aspect.

[0020] In summary, the present application provides a bearing electrical corrosion detection method, system, device, equipment and medium, wherein the bearing electrical corrosion detection method is applied to the detection equipment, one end of the detection equipment contacts the test point on the shaft close to the inner ring of the bearing through the shaft signal lead of the test probe, and the other end contacts the test point on the motor housing close to the outer ring of the bearing through the housing signal lead, so that the detection equipment can detect the shaft voltage waveform of the bearing under the target working condition when the motor is installed with a conventional non-insulated bearing, and judge whether the bearing has an electrical corrosion risk under the target working condition based on the shaft voltage waveform. If there is an electrical corrosion risk, the shaft current of the bearing is further detected by replacing the insulating bearing and short-circuiting the shaft signal lead and the housing signal lead, and the severity of the electrical corrosion of the bearing under the target working condition is evaluated based on the numerical value of the shaft current. Therefore, the present application can conveniently detect the shaft voltage waveform and the shaft current, and accurately detect the electrical corrosion of the bearing under the target working condition by combining the shaft voltage waveform and the shaft current, thereby improving the problem of inaccurate bearing electrical corrosion detection in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a flow chart of a bearing electrical corrosion detection method in one embodiment of the present application;

[0022] Figure 2 A schematic diagram of the shape of a resistive discharge waveform in one embodiment of the present application;

[0023] Figure 3 A schematic diagram of the shape of a capacitive breakdown discharge waveform in an embodiment of the present application;

[0024] Figure 4 A schematic diagram of the shape of a capacitive non-breakdown discharge waveform in an embodiment of the present application;

[0025] Figure 5 This is a schematic diagram of the structure of a test probe in an embodiment of the present application;

[0026] Figure 6 A schematic diagram of the modification of a motor housing in an embodiment of the present application;

[0027] Figure 7 A rendering of a motor housing modification in one embodiment of the present application;

[0028] Figure 8 A front view of a test probe fixed on a fixed tool in an embodiment of the present application;

[0029] Fig. 9 It is a left view of a test probe fixed on a fixed tool in one embodiment of the present application;

[0030] Fig.10 This is an oblique view of a test probe fixed on a fixed tool in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] The prior art detects whether electrical corrosion has occurred in the bearing by detecting the shaft voltage or shaft current and comparing the detected shaft voltage or shaft current with the corresponding voltage threshold or current threshold. However, the threshold comparison method has the problem of inaccurate electrical corrosion detection. One reason is that with the change of motor speed and torque, the oil film thickness is difficult to accurately measure, which leads to the inaccuracy of the voltage threshold determined according to the oil film thickness. Another reason is that the method of detecting single current is inaccurate. The current method of detecting shaft current is usually to short-circuit the shaft and the ground or the shell through a lead, and measure the current passing through the short-circuited lead; or to detect the current passing through the shaft through a Rogowski coil. When the bearing is in the oil film breakdown conduction state, the shaft current will be released through the bearing. Therefore, the current passing through the short-circuit lead is not the real shaft current, and the numerical relationship between the current and the shaft current is affected by many factors and is difficult to determine; and the shaft current detected by the Rogowski coil inevitably contains differential mode current (differential mode current only flows through the shaft, not the current flowing through the bearing), and the differential mode current will not directly cause electrical corrosion to the bearing. Only the common mode current flowing through the bearing will cause electrical corrosion to the bearing. Therefore, it is impossible to directly judge whether the bearing has the risk of electrical corrosion based on the numerical value of the shaft current. In addition, in some other existing technologies, there are methods for testing shaft current based on magnetic field detection, but in the bench test environment of automotive motors, it will be interfered by a large number of electromagnetic signals, so there are high requirements for engineering technology and test environment, and the measured shaft current still has the problem of inaccuracy.

[0033] In this regard, the present application provides a bearing electrical corrosion detection method, which is applied to a detection device, and the detection device improves the detection accuracy of electrical corrosion by combining the shaft voltage waveform and the shaft current. The bearing electrical corrosion detection method is applied to the detection device. In order to improve the accuracy and simplicity of detecting the shaft voltage and shaft current, one end of the detection device contacts the test point on the shaft close to the inner ring of the bearing through the shaft signal lead of the test probe, so that the detection device and the shaft are flexibly connected while the shaft is running, and the other end contacts the test point on the motor housing close to the outer ring of the bearing through the housing signal lead. For example, the test point can be located at the connection and fixing place between the motor end cover and the bearing, so as to be as close to the outer ring of the bearing as possible, thereby improving the accuracy of detecting the shaft voltage and shaft current. The shaft current is quickly and easily detected by replacing the non-insulated bearing with an insulated bearing, short-circuiting the shaft signal lead and the housing signal lead, and detecting the current on the short-circuit wire.

[0034] Specifically, after installing the non-insulated bearing, the detection equipment detects the shaft voltage waveform of the bearing when the motor is in the target operating condition; based on the shaft voltage waveform, it is determined whether there is a risk of electrical corrosion of the bearing under the target operating condition; if so, after replacing the insulated bearing, the shaft current of the bearing under the target operating condition is detected; based on the shaft current, the severity of electrical corrosion of the bearing under the target operating condition is evaluated.

[0035] It should be noted that the present application first determines whether the bearing has an electrical corrosion risk through the shaft voltage waveform, because the shaft voltage waveform reflects the change of the shaft voltage over a period of time. Compared with only detecting the shaft voltage at a certain point in time, it can more accurately determine whether the bearing has an electrical corrosion risk, and the shaft current needs to be detected only when there is an electrical corrosion risk, otherwise there is no need to detect the shaft current, which simplifies the detection process. If there is an electrical corrosion risk, the non-insulated bearing is replaced with an insulated bearing, so that the shaft current of the bearing can be quickly and easily detected, and the severity of the bearing electrical corrosion can be evaluated according to the numerical value of the shaft current, so as to evaluate the specific impact on the service life of the bearing and other information.

[0036] It should also be noted that the detection equipment proposed in this application can be an oscilloscope that integrates a processing chip and memory and has a certain computing power, or a special detection equipment, etc. This application does not limit this. In addition, the detection equipment can exchange data with other equipment, etc., and execute the bearing electrical corrosion detection method proposed in this application.

[0037] In order to better understand the bearing electrical corrosion detection method proposed in this application, this application also provides an embodiment of the bearing electrical corrosion detection method, such as Figure 1 As shown, next, this application uses the detection equipment as the execution subject to explain the bearing electrical corrosion detection method, specifically:

[0038] 110: After installing the non-insulated bearing, detect the shaft voltage waveform of the bearing when the motor is in the target operating condition;

[0039] 120: Determine whether the bearing has electrical corrosion risk under the target working condition based on the shaft voltage waveform;

[0040] 130: If there is a risk of electrical corrosion under the target operating conditions, short-circuit the shaft signal lead and the housing signal lead after replacing the insulating bearing to detect the shaft current under the target operating conditions;

[0041] 140: Evaluate the severity of electrical corrosion of bearings under target operating conditions based on shaft current.

[0042] In step 110, one end of the detection device is connected to the shaft signal lead, and the other end is connected to the housing signal lead. The present application installs a non-insulated bearing so that the detection device can test and obtain the shaft voltage waveform of the bearing when the motor is in the target operating condition.

[0043] It should be noted that the occurrence of electrical corrosion in bearings is related to the motor working conditions, including the motor speed and torque, especially the torque. The magnitude of the torque directly affects the bearing stress and the formation of the oil film. Large torque may cause the bearing to be squeezed more, thus affecting the thickness and quality of the oil film. Under low speed and high torque conditions, the oil film is difficult to form or the oil film quality is poor. The bearing is more susceptible to the influence of shaft voltage and electrical corrosion. Because under low speed and high torque conditions, the centrifugal force is not enough to overcome the weight of the motor rotor or the bearing is squeezed, and an effective oil film may not be formed between the ball and the raceway, resulting in direct contact. At this time, a good low-impedance conductive path is formed from the inner ring to the outer ring of the bearing. The shaft voltage is basically released in the form of resistive discharge through this low-impedance path. Although it will not produce spark attack, it mainly affects the bearing in the form of current heating. Long-term accumulation may form frosted marks and produce operating noise when it is serious to a certain extent.

[0044] Under medium to high speed and low torque conditions, a continuous oil film will form in the motor bearings. The thickness and quality of the oil film are crucial to resisting shaft voltage breakdown. If the oil film is thick enough and of good quality, its withstand voltage value is high and it can withstand the shaft voltage without breakdown. At this time, there is no electrical corrosion in the bearings. However, even if there is no penetrating discharge in the oil film, there may be local discharges in the oil film. These local discharges will gradually erode the quality of the oil film and reduce its voltage resistance. After a long period of accumulation, when the voltage resistance of the oil drops to a certain level, the shaft voltage that was previously able to withstand may become unbearable, and then breakdown discharge occurs, causing electrical corrosion of the bearings.

[0045] In step 120, if the detection device determines that the bearing does not have the risk of electrical corrosion under the target working condition based on the shaft voltage waveform, the oil film capacitor is not broken down at this time, and the shaft current is not detected, thereby simplifying the process; if the detection device determines that the bearing has the risk of electrical corrosion under the target working condition based on the shaft voltage waveform, step 130 is executed to further evaluate the severity of the electrical corrosion of the bearing based on the shaft current of the bearing, because the lubricating oil or grease of the bearing itself will form an oil film capacitor in the bearing when the motor is running. At this time, the shaft current flowing through the bearing is a charging and discharging shaft current that is charged and released on both sides of the oil film capacitor. This type of current is generally small in value and only passes through the outer ring of the bearing and will not enter the oil film. However, when the shaft voltage of the bearing is too large, the oil film capacitor will be broken down, the shaft current will increase, and a large amount of heat will be released when passing through the bearing, causing the bearing metal to melt. Therefore, after the detection device qualitatively determines that the bearing has the risk of electrical corrosion based on the shaft voltage waveform, it can quantitatively evaluate the severity of the electrical corrosion of the bearing based on the shaft current of the bearing.

[0046] It should be noted that the present application can determine whether there is a risk of electrical corrosion of the bearing by detecting the smoothness of the shaft voltage waveform, because the smoothness of the shaft voltage waveform reflects the discharge of the bearing. If the shaft voltage waveform is not smooth and has many peaks or fluctuations, these may be signs of breakdown and discharge of the bearing oil film, which in turn leads to electrical corrosion of the bearing. Based on this, the present application provides two possible implementation methods of step 120:

[0047] In one possible implementation, the present application identifies the shaft voltage waveform of the bearing by image recognition or manual observation. The shaft voltage waveform can be divided into three categories, including resistive discharge waveform, capacitive breakdown discharge waveform and capacitive non-breakdown discharge waveform. When the shaft voltage waveform is a resistive discharge waveform or a capacitive breakdown discharge waveform, the shaft voltage waveform is not smooth and has more peaks or fluctuations, indicating that the possibility of bearing discharge is greater, and thus it is considered that there is a risk of electrical corrosion. When the shaft voltage waveform is a capacitive non-breakdown discharge waveform, the shaft voltage waveform is relatively smooth and has fewer peaks or fluctuations, indicating that the possibility of bearing discharge is less, and thus it is considered that there is no risk of electrical corrosion. Specifically, step 120 includes: identifying the shaft voltage waveform to obtain the waveform type of the shaft voltage waveform, wherein the waveform types include resistive discharge waveform, capacitive breakdown discharge waveform and capacitive non-breakdown discharge waveform; judging whether the waveform type of the shaft voltage is a capacitive non-breakdown discharge waveform; if it is not a capacitive non-breakdown discharge waveform, determining that the bearing is at risk of electrical corrosion.

[0048] The characteristics of several types of bearing shaft voltages mentioned in this application are as follows:

[0049] Resistive discharge waveform Figure 2As shown in the figure, the shaft voltage remains at 0 in the steady state, and a non-zero voltage exists only at the moment of violent oscillation. The shaft voltage at this moment is a high-frequency, instantaneous, high-value quasi-sine wave based on the steady-state voltage. This means that the bearing has not formed a steady-state oil film at this time, the bearing balls are in direct contact with the inner and outer rings of the bearing, and the shaft current characteristics are reflected as resistive discharge, which poses a risk of electrical corrosion to the bearing.

[0050] Capacitive breakdown discharge waveform is as follows Figure 3 As shown in the figure, the shaft voltage of the bearing has a continuous non-zero waveform, but it is not stable. It may reset to 0 after the voltage oscillates. The shaft voltage during oscillation is a high-frequency, instantaneous, high-value quasi-sine wave based on the steady-state voltage. This shows that a steady-state oil film has been formed in the bearing, but the shaft voltage is greater than the breakdown threshold of the oil film. At the moment of breakdown, the oil film is resistive, and the shaft voltage characteristics are reflected as resistive discharge. There is still a risk of electrical corrosion of the bearing.

[0051] Capacitive non-breakdown discharge waveform is as follows Figure 4 As shown, the shaft voltage of the bearing exhibits a stable trapezoidal waveform. After the voltage oscillation, the new steady-state voltage rises or falls regularly relative to the previous steady-state voltage, and the shaft voltage at this moment exhibits a step rise / fall based on the steady-state voltage, indicating that a steady-state oil film has been formed in the bearing, and the shaft voltage is lower than the breakdown threshold of the oil film. The shaft voltage characteristic is reflected as capacitive discharge, and there is no risk of electrical corrosion of the bearing.

[0052] In another practicable manner, the present application provides a method for quickly determining whether a bearing has a risk of electrical corrosion based on a shaft voltage waveform, that is, determining whether a bearing has a risk of electrical corrosion by checking the number of shaft voltage peaks per unit time. Specifically, step 120 includes: detecting the number of high-frequency peaks that appear in the shaft voltage waveform per unit time; comparing the number of high-frequency peaks detected with a number threshold; if the number of peaks is greater than the number threshold, determining that the bearing has a risk of electrical corrosion.

[0053] It should be noted that the number and frequency of the peaks in the shaft voltage waveform reflect the discharge condition of the bearing. The more peaks appearing per unit time, the more frequently the oil film breakdown occurs in the bearing, and the higher the risk of electrical corrosion. This application determines whether the bearing has an electrical corrosion risk by comparing the number and frequency of high-frequency spikes. If there is an electrical corrosion risk, it is necessary to further detect the shaft current and evaluate the severity of the electrical corrosion based on the numerical value of the shaft current. Otherwise, there is no need to detect the shaft current.

[0054] It should also be noted that the purpose of detecting the number of high-frequency spikes per unit time in this application is to more accurately detect the risk of electrical corrosion of the bearing, because high-frequency spikes have the characteristics of concentrated energy, difficult to protect, and cumulative effect, and are the most serious damage to the bearing. First of all, the frequent appearance of spike signals means that the oil film is unstable at this moment and cannot act as a capacitor to absorb the bearing current. Moreover, high-frequency spikes have the characteristics of high frequency and rapid change, which makes the exothermic energy highly concentrated in a short time. This energy concentration phenomenon has a greater destructive force inside the bearing. In addition, the damage of high-frequency spikes to the bearing is a long-term cumulative process. Even if the degree of damage each time is not large, as time goes by and the number of damages increases, the performance of the bearing will gradually decline until it fails. Therefore, in general, this application can more accurately evaluate the risk of electrical corrosion of the bearing by detecting the number of high-frequency spikes that appear in the shaft voltage waveform per unit time. Moreover, compared with technologies such as image recognition, this embodiment is simpler and easier to operate, and has lower requirements on the computing power of the equipment. Even an oscilloscope with simple computing power can implement this method.

[0055] In step 130, since the detection device determines that the bearing has an electrical corrosion risk under the target working condition based on the shaft voltage waveform, in order to further evaluate the severity of the electrical corrosion, the present application replaces the insulating bearing so that the detection device can test the shaft current of the bearing when the motor is in the target working condition. Because the bearing behaves as a benign conductor when the oil film capacitor is broken down, the present application replaces the bearing with an insulating bearing, and connects the shaft signal lead and the housing signal lead to short-circuit to obtain a branch in parallel with the bearing, and detects the current passing through the branch to obtain the shaft current, and then judges the severity of the electrical corrosion based on the value of the shaft current. In addition, according to the bearing characteristics, resistors, capacitors and other devices can be added to the branch to ensure that the electrical characteristics of the branch are the same as the original circuit of the bearing.

[0056] Furthermore, generally, bearings are used in pairs, including front-end bearings and rear-end bearings. In order to detect the electrical corrosion of the front-end bearings and the rear-end bearings, the two bearings can be tested separately, that is, when testing the front-end bearing, it is necessary to set the test probe at the test point of the motor shaft close to the front-end bearing, set the housing signal lead at the test point close to the front-end bearing, and when it is determined that the front-end bearing has an electrical corrosion risk according to the shaft voltage waveform of the front-end bearing, replace the front-end bearing with an insulating bearing, and test the shaft current of the front-end bearing; similarly, when testing the rear-end bearing, it is necessary to set the test probe at the test point of the motor shaft close to the rear-end bearing, set the housing signal lead at the test point close to the rear-end bearing, and when it is determined that the rear-end bearing has an electrical corrosion risk according to the shaft voltage waveform of the rear-end bearing, replace the rear-end bearing with an insulating bearing, and test the shaft current of the rear-end bearing. On motor equipment with more than two bearings, each bearing can also be tested separately according to this method. It can be seen that the detection method provided by the present application has the advantages of being simple and operable.

[0057] It should be noted that the existing accurate shaft current test method is usually: add an insulating layer to the motor bearing seat or housing to block the shaft current path, and embed a lead wire in the bearing seat or housing without destroying the insulation state. One end of the lead wire is short-circuited with the outer ring of the bearing, and the other end is short-circuited with the motor housing. The current passing through the lead wire is the shaft current. However, the process of embedding the bearing lead wire is relatively complicated, and has very high requirements on the technical ability of engineers and product quality. The present application can solve this problem better, because the present application converts the bearing current into a current passing through a branch circuit by replacing the non-insulated bearing with an insulated bearing and connecting an external branch circuit. Compared with conventional testing methods, this method greatly reduces the difficulty of process modification, and the shaft current test can be directly performed by replacing the shaft voltage test prototype bearing without the need for other modifications; since the bearing balls and inner and outer rings are good conductors themselves, the bearing oil film also exhibits resistance when the current breaks through the bearing oil film, so there is theoretical support for the circuit equivalent replacement of the bearing resistance with leads under resistive discharge and breakdown discharge conditions; and under capacitive discharge, the shaft current will not pass through the bearing, and there is no risk of bearing electrical corrosion, so there is no need to test the shaft current.

[0058] In addition, the present application uses a fixing tool to fix the test probe to the motor. Compared with directly processing the probe fixing device on the motor, the material selection of the fixing tool is more flexible, the processing technology is simpler, and in some scenarios it can be directly provided by the test probe supplier; for the motor housing, it is only necessary to process simple connection structures such as screw holes based on the original motor, eliminating the cost of re-molding the housing.

[0059] It can be seen that the motor structure modification involved in this application does not pose any special technical difficulties to technicians, and does not have strict requirements on the test site and test materials. The test verification can be completed smoothly at an acceptable cost using the patented method.

[0060] In step 140, when the detection device evaluates the severity of the electrical corrosion of the bearing, the detection device may perform the evaluation according to the target interval to which the numerical value of the shaft current belongs, or according to the change trend of the numerical value of the shaft current. Specifically:

[0061] In one practicable manner, the detection device determines the target interval to which the numerical value of the shaft current belongs, wherein different target intervals correspond to different severity levels, and as the numerical value of the shaft current increases, the severity level of the electrical corrosion increases; obtaining the severity level corresponding to the target interval indicates the severity of the electrical corrosion. The larger the shaft current, the more severe the bearing discharge, and thus the more severe the electrical corrosion. For example, assuming that there are three intervals of current, they include the first interval, the second interval, and the third interval in order from small to large, corresponding to the severity levels of "mild", "relatively severe", and "very severe", respectively.

[0062] In another feasible method, the detection equipment draws a change trend graph of the shaft current according to the numerical value of the shaft current, and determines the severity of the electrical corrosion according to the change rate of the numerical value of the shaft current, wherein different change rates correspond to different severity levels, and the greater the change rate of the shaft current, the higher the severity of the electrical corrosion.

[0063] After determining in step 140 that the target working condition has the risk of electrical corrosion of the bearing, the detection device also proposes countermeasures for the target working condition, such as reducing the working time of the motor under the target working condition, or taking inhibitory measures and / or avoidance measures for the electrical corrosion of the bearing, or performing targeted optimization in the motor design stage. Specifically, if there is a risk of electrical corrosion, the detection device records the target working condition when the bearing is electrocorroded, and the motor working condition includes speed and / or torque; when the motor is in the target working condition, it prompts the bearing to have the risk of electrical corrosion and takes inhibitory measures and / or avoidance measures, or performs targeted optimization in the motor design stage. By prompting the existence of the risk of electrical corrosion of the bearing, the detection device prompts the technician to adjust the speed and / or torque of the motor, thereby reducing the working time of the motor under the target working condition. For example, when the motor is in a low-speed and high-torque working condition, the oil film quality is poor, and the bearing is prone to electrical corrosion. At this time, the motor may be in a heavy-loaded working condition. At this time, the technician can reduce the working time of the motor under the low-speed and high-torque working condition by increasing the speed and reducing the load. However, when the motor needs to maintain the target operating conditions under certain special circumstances, such as in special scenarios with heavy loads such as cranes, winches, metallurgical equipment, mining equipment, or special environments such as high altitudes and low temperatures, the motor needs to maintain the target operating conditions of low speed and high torque. At this time, technicians can take measures to ensure the safe operation of the motor. The measures include: 1. Optimize the motor design: reduce the generation of shaft voltage through measures such as motor electromagnetic balance design and inverter output waveform optimization; 2. Use insulating bearings: coat the outer or inner ring surface of the bearing with insulating materials, or use insulating bearings such as ceramic ball bearings to block the path of current passing through the bearing; 3. Install conductive rings: install conductive rings at the motor shaft end to guide the shaft voltage to the ground or other low potential points to reduce the potential difference and discharge at both ends of the bearing; 4. Regular inspection and maintenance: regularly inspect and maintain the motor and bearings to promptly detect and deal with potential electrical corrosion problems.

[0064] In summary, the present application provides a method for easily detecting shaft voltage and shaft current, by contacting one end of the detection device with a test point on the shaft close to the inner ring of the bearing through the shaft signal lead of the test probe, and contacting the other end with a test point on the motor housing close to the outer ring of the bearing through the housing signal lead, so that the shaft voltage waveform of the bearing can be accurately and easily detected, and based on the shaft voltage waveform of the bearing, it can be judged whether the bearing has the risk of electrical corrosion under the target working conditions, and then by replacing the insulating bearing and short-circuiting the shaft signal lead and the housing signal lead, the bearing can be accurately and easily detected. The shaft current can be measured to further evaluate the severity of the bearing electrical corrosion according to the numerical value of the shaft current. Therefore, by implementing the bearing electrical corrosion detection method of the present application, the difficulty of testing the shaft voltage and shaft current can be reduced, and the shaft current and shaft voltage with high accuracy can be conveniently detected, which reduces the difficulty of testing and saves time and effort. Moreover, compared with threshold comparison, or single voltage detection or current detection, the present application combines the shaft voltage waveform and the shaft current to accurately detect the electrical corrosion under the target working condition, thus improving not only the problem of inconvenient detection, but also the problem of inaccurate electrical corrosion detection. In general, the present application improves the problems of inaccurate and inconvenient electrical corrosion detection in the prior art.

[0065] In addition, the present application also provides an electrical corrosion detection system, which includes a test probe and a detection device, wherein the test probe is used to detect the electrical signal of the rotating shaft, and the detection device is used to perform the bearing electrical corrosion detection method in any of the above embodiments or implementations. Figure 5 As shown; the test probe is fixed on the motor housing, and the test end of the test probe contacts the test point on the rotating shaft close to the inner ring of the bearing; one end of the detection device contacts the test point on the motor housing close to the outer ring of the bearing through the housing signal lead, and the other end contacts the test point on the rotating shaft close to the inner ring of the bearing through the shaft signal lead of the test probe; in other words, one end of the shaft signal lead of the test probe is pulled out of the housing and connected to the detection device, and the other end of the shaft signal lead is connected to the test end of the test probe, and the test end of the test probe contacts the rotating shaft. Except for the bare metal wire at the test end, the other parts of the shaft signal lead need to maintain good insulation and shielding.

[0066] It should be noted that in order to ensure that the probe can continuously detect the electrical signal of the rotating shaft, the motor housing is modified and an opening is set in the motor housing. By fixing the test probe on the motor housing and contacting the test end of the test probe with the test point on the rotating shaft close to the inner ring of the bearing, continuous flexible contact between the test probe and the rotating shaft is achieved. The test point is as close to the inner ring of the bearing as possible, and can be specifically set near the connection between the rotating shaft and the bearing. In order to ensure that the test end of the housing signal lead is in contact with the test point on the motor housing close to the outer ring of the bearing, the test end of the housing signal lead can be connected to the test point on the motor housing close to the outer ring of the bearing by winding, gluing, bolting, etc. The test point should be as close to the outer ring of the bearing as possible, for example, it can be set on the housing near the connection between the inner end cover of the motor and the bearing.

[0067] In order to further ensure that the test end of the test probe maintains contact with the test point, the present application also provides an implementation method of the electrical corrosion detection system, such as Figure 6 As shown, the electrical corrosion detection system also includes a fixing fixture and a lead channel, wherein the test probe is fixed to the motor housing through the fixing fixture so that the test end of the test probe maintains a flexible contact state with the shaft, and the shaft signal lead is led out from the opening of the motor housing through the lead channel to connect to the test equipment. In addition, multiple test probes can be set for one bearing, such as Figure 6 As shown, two sets of tooling and lead channels are provided to fix two test probes. When one of the test probes fails, the other probe can be used as a backup.

[0068] It should be noted that for the convenience of setting, the present application can set lead channels on the motor housing respectively for the shaft signal lead and the housing signal lead, so that the housing signal lead and the shaft signal lead are led out from the lead channel to respectively connect the two ports of the detection device, but they can also be led out without passing through the lead channel. For example, the housing signal lead and the shaft signal lead can also be led out and fixed by surface mounting.

[0069] It should also be noted that the test point can be inside the motor or outside the motor, and this application does not limit this. Figure 7 As shown, the test end of the shaft signal lead contacts the test point on the shaft outside the motor close to the inner ring of the bearing, so that one end of the detection device contacts the test point on the shaft outside the motor close to the inner ring of the bearing through the shaft signal lead of the test probe; the test end of the shell signal lead contacts the test point on the motor housing close to the outer ring of the bearing, so that the other end of the test device contacts the test point on the motor housing close to the outer ring of the bearing through the shell signal lead. Similarly, the setting scheme of the test point inside the motor can be obtained, which will not be repeated in this article.

[0070] In order to make the test probe as close to the inner ring of the bearing as possible, a fixed fixture is set on the rotating shaft close to the inner ring of the bearing. The test probe is fixedly connected to the fixed fixture by riveting, bolting or other connection methods, and can also be fixedly connected to the motor housing by riveting, bolting or other connection methods, so that the test end of the test probe maintains a stable and continuous flexible contact state with the test point. The shaft signal lead of the test probe passes through the lead channel and the opening of the motor housing in turn. Figure 8 , Fig. 9 as well as Fig.10 , which are the front view, left view and oblique view of the test probe fixed on the fixed fixture.

[0071] Since the placement of the test probe and the fixing tooling may affect the motor structure, the present application can also lengthen the motor shaft and thicken the motor end cover, etc., to reduce the interference of the test equipment on the motor's mechanical structure and electromagnetic performance. Furthermore, the present application also insulates the coupling of the motor and the dynamometer to prevent the shaft voltage from being discharged along the dynamometer shaft end.

[0072] In addition, the specific installation method of the test probe can be flexibly changed according to the actual situation of the motor and the assembly process. Specifically: adjust the selection and installation position of the test probe according to the specific motor characteristics. For example, for some small motors, it may be necessary to use a smaller test probe and install it in a position that is easy to access and has the least impact on the motor performance; according to changes in working conditions, such as temperature, humidity, vibration, etc., select test probes that adapt to these conditions to reduce the impact of these external factors on the test results; adjust the installation position or method of the test probe according to the requirements of the assembly process, such as integrating the test probe into the assembly equipment to achieve automatic testing and monitoring, thereby improving production efficiency and reducing manual intervention.

[0073] The present application also provides a detection device. The embodiment of the present application can divide the functional modules of the device according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one module. The above integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. Specifically, the detection device includes a detection unit for detecting the shaft voltage waveform of the bearing when the motor is in the target working condition after installing a non-insulated bearing; a judgment unit for judging whether there is an electrical corrosion risk of the bearing under the target working condition according to the shaft voltage waveform; the detection unit is also used to short-circuit the shaft signal lead and the housing signal lead after replacing the insulating bearing if there is an electrical corrosion risk under the target working condition to detect the shaft current under the target working condition; an evaluation unit for evaluating the severity of electrical corrosion of the bearing under the target working condition according to the shaft current.

[0074] In another implementable manner, the judgment unit is specifically used to: identify the shaft voltage waveform to obtain the waveform type of the shaft voltage waveform, wherein the waveform types include resistive discharge waveform, capacitive breakdown discharge waveform and capacitive non-breakdown discharge waveform; judge whether the waveform type of the shaft voltage is a capacitive non-breakdown discharge waveform; if it is not a capacitive non-breakdown discharge waveform, it is determined that there is a risk of electrical corrosion in the bearing.

[0075] In another implementable manner, the judgment unit is specifically used to: detect the number of high-frequency peaks that appear in the shaft voltage waveform per unit time; compare the number of high-frequency peaks detected with a quantity threshold; if the number of peaks is greater than the quantity threshold, it is determined that there is a risk of electrical corrosion in the bearing.

[0076] In another implementable manner, the evaluation unit is specifically used to: determine the target interval to which the numerical value of the shaft current belongs, wherein different target intervals correspond to different severity levels, and as the numerical value of the shaft current increases, the severity level of the electrical corrosion increases; obtaining the severity level corresponding to the target interval indicates the severity of the electrical corrosion.

[0077] In another practicable manner, the detection device also includes a prompt unit, which is used to: if there is a risk of electrical corrosion, then: record the target operating conditions when the bearing is electrically corroded, the motor operating conditions including speed and / or torque; when the motor is in the target operating conditions, prompt that the bearing has a risk of electrical corrosion and take suppression measures and / or avoidance measures, or perform targeted optimization during the motor design stage.

[0078] The present application also provides a detection device, which may include: a processor and a memory. The processor and the memory are connected via a bus. The processor is used to execute multiple instructions; the memory is used to store multiple instructions, which are suitable for the processor to load and execute the bearing electrical corrosion detection method in the above embodiment.

[0079] The processor may be an electronic control unit (ECU), a central processing unit (CPU), a general processor, a coprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of 5SP and a microprocessor, etc. In this embodiment, the processor may be a single-chip microcomputer, and various control functions may be implemented by programming the single-chip microcomputer. The processor has the advantages of powerful computing power and fast processing. Specifically, the processor is used to execute the function of the detection unit, which is used to detect the shaft voltage waveform of the bearing when the motor is in the target operating condition after the non-insulated bearing is installed; the processor is also used to execute the function of the judgment unit, which is used to judge whether there is a risk of electrical corrosion of the bearing under the target operating condition based on the shaft voltage waveform. If so, after replacing the insulated bearing, the shaft current of the bearing under the target operating condition is detected; the processor is also used to execute the function of the evaluation unit, which is used to evaluate the severity of electrical corrosion of the bearing under the target operating condition based on the shaft current.

[0080] In another implementable manner, the processor is specifically used to: identify the shaft voltage waveform to obtain the waveform type of the shaft voltage waveform, wherein the waveform types include a resistive discharge waveform, a capacitive breakdown discharge waveform, and a capacitive non-breakdown discharge waveform; determine whether the waveform type of the shaft voltage is a capacitive non-breakdown discharge waveform; if it is not a capacitive non-breakdown discharge waveform, determining that the bearing is at risk of electrical corrosion.

[0081] In another implementable manner, the processor is specifically used to: detect the number of high-frequency peaks that appear in the shaft voltage waveform per unit time; compare the number of high-frequency peaks detected with a quantity threshold; if the number of peaks is greater than the quantity threshold, it is determined that there is a risk of electrical corrosion in the bearing.

[0082] In another implementable manner, the processor is specifically used to: determine the target interval to which the numerical value of the shaft current belongs, wherein different target intervals correspond to different severity levels, and as the numerical value of the shaft current increases, the severity level of the electrical corrosion increases; obtaining the severity level corresponding to the target interval indicates the severity of the electrical corrosion.

[0083] In another practicable manner, the processor is also used to execute the function of a prompt unit, specifically for: if there is a risk of electrical corrosion, then: record the target operating conditions when the bearing is electrically corroded, the motor operating conditions including speed and / or torque; when the motor is in the target operating conditions, prompt that the bearing has a risk of electrical corrosion and take suppression measures and / or avoidance measures, or perform targeted optimization during the motor design stage.

[0084] In one embodiment, the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a plurality of instructions, which are suitable for being loaded by a processor and executing the method in any of the aforementioned embodiments. The processor is used to execute the plurality of instructions; the memory is used to store the plurality of instructions, which are loaded by the processor and executed by the bearing electrical corrosion detection method in the aforementioned embodiment.

[0085] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A bearing electrical corrosion detection method, applied to a detection device, characterized in that: One end of the detection device contacts a test point on the shaft close to the inner ring of the bearing through a shaft signal lead of the test probe, and the other end contacts a test point on the motor housing close to the outer ring of the bearing through a housing signal lead. The bearing electrical corrosion detection method includes: After installing the non-insulated bearing, detect the shaft voltage waveform of the bearing when the motor is in the target operating condition; Determining whether the bearing has an electrical corrosion risk under the target operating condition according to the shaft voltage waveform; If there is a risk of electrical corrosion under the target working condition, after replacing the insulating bearing, the shaft signal lead and the housing signal lead are short-circuited to detect the shaft current under the target working condition; The severity of the electrical corrosion of the bearing under the target operating condition is evaluated based on the shaft current.

2. The method according to claim 1, characterized in that: The step of judging whether the bearing has an electrical corrosion risk under the target working condition according to the shaft voltage waveform comprises: Identifying the shaft voltage waveform to obtain a waveform type of the shaft voltage waveform, wherein the waveform type includes a resistive discharge waveform, a capacitive breakdown discharge waveform, and a capacitive non-breakdown discharge waveform; Determining whether the waveform type of the shaft voltage is the capacitive non-breakdown discharge waveform; If it is not the capacitive non-breakdown discharge waveform, it is determined that the bearing has the risk of electrical corrosion.

3. The method according to claim 1, characterized in that The step of judging whether the bearing has an electrical corrosion risk under the target working condition according to the shaft voltage waveform comprises: Detecting the number of high-frequency peaks that appear in the shaft voltage waveform per unit time; comparing the number of spikes of the detected high-frequency spikes with a number threshold; If the number of the peaks is greater than the number threshold, it is determined that the bearing has a risk of electrical corrosion.

4. The method according to claim 1, characterized in that: The step of evaluating the severity of the electrical corrosion of the bearing under the target working condition according to the shaft current comprises: Determining a target interval to which the value of the shaft current belongs, wherein different target intervals correspond to different severity levels, and as the value of the shaft current increases, the severity level of the electrical corrosion increases; Obtaining the severity level corresponding to the target interval indicates the severity of the electrical corrosion.

5. The method according to claim 1, characterized in that If there is a risk of galvanic corrosion: Recording target operating conditions when electrical corrosion occurs in the bearing, wherein the motor operating conditions include speed and / or torque; When the motor is in the target operating condition, it is prompted that the bearing has the risk of electrical corrosion and suppression measures and / or avoidance measures are taken, or targeted optimization is performed in the motor design stage.

6. An electrical corrosion detection system, characterized in that: Includes test probes and testing equipment, including: The test probe is fixed on the motor housing, one end of the detection device contacts a test point on the motor housing close to the outer ring of the bearing through a housing signal lead, and the other end of the detection device contacts a test point on the shaft close to the inner ring of the bearing through a shaft signal lead of the test probe; the detection device is used to perform the bearing electrical corrosion detection method as described in any one of claims 1 to 5.

7. The system according to claim 6, characterized in that The electrical corrosion detection system also includes a fixing tool and a lead channel, wherein the test probe is fixed to the motor housing by the fixing tool so that the test end of the test probe maintains a flexible contact state with the rotating shaft, and the rotating shaft signal lead is led out from the opening of the motor housing through the lead channel to connect to the test equipment.

8. A detection device, characterized in that: The detection device comprises: A detection unit, used to detect the shaft voltage waveform of the bearing when the motor is in a target operating condition after the non-insulated bearing is installed; A judgment unit, used for judging whether there is an electrical corrosion risk of the bearing under the target working condition according to the shaft voltage waveform; The detection unit is further used to short-circuit the shaft signal lead and the housing signal lead after replacing the insulating bearing if there is a risk of electrical corrosion under the target working condition, so as to detect the shaft current under the target working condition; An evaluation unit is used to evaluate the severity of the electrical corrosion of the bearing under the target working condition according to the shaft current.

9. A detection device, characterized in that: The detection device includes a processor and a memory, and the processor and the memory are connected via a bus; the processor is used to execute multiple instructions; the memory is used to store the multiple instructions, and the instructions are suitable for being loaded by the processor and executing the bearing electrical corrosion detection method described in any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that a plurality of instructions are stored in the computer-readable storage medium, and the instructions are suitable for being loaded by a processor and executing the bearing electrical corrosion detection method according to any one of claims 1 to 5.

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