A motor operation noise detection device

Abstract

The application is suitable for the technical field of motor noise detection, and provides a motor operation noise detection device.The device comprises a detection chamber, the inside of the detection chamber is provided with a placing assembly, the inside of the placing assembly is provided with a motor to be detected, the outside of the motor to be detected is provided with a vibration detection assembly, the upper side of the motor to be detected is provided with a noise detection assembly, the placing assembly comprises a top cover, the lower side of the top cover is provided with a placing chamber, the inside of the top cover and the placing chamber is filled with sound insulation material, the two sides of the placing chamber are respectively provided with a set of telescopic mechanisms, and the inside of the placing chamber is provided with a mounting plate.The placing assembly provides a placing space for the motor to be detected, the detection environment is controlled within a certain range through the placing assembly, the influence of external environmental sound on noise detection is reduced, the noise detection assembly collects the sound generated by the motor to be detected, and the collected sound is used as noise detection data.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor noise detection, more particularly, it relates to a motor operation noise detection device. BACKGROUND

[0002] At present, after the motor production is completed, corresponding noise detection needs to be carried out. Noise detection of the motor is a key link to guarantee the performance, safety, reliability of the motor and meet the needs of application scenarios. Continuous abnormal noise of the motor may be accompanied by excessive vibration of parts, which will aggravate the wear of core components such as bearings and windings in the long run, shorten the service life of the motor, and even cause serious faults such as stator scanning and winding burning. Early detection can warn potential risks and reduce losses caused by sudden shutdown.

[0003] The existing motor detection method usually uses a microphone to collect sound on site, and then compares in detail according to the collected results to determine whether the motor has abnormal comparison, so as to realize detection of the motor quality.

[0004] However, the microphone can only collect the final noise signal transmitted by the air. When the detection device is set in the workshop, various sounds will be produced in the workshop. The microphone detects many sound sources, which will cause errors in the judgment of the sound source, affect the motor noise detection result, and is not conducive to the improvement of the motor. The present application provides a motor operation noise detection device to improve the existing problems. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a motor operation noise detection device.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A motor operation noise detection device, comprising a detection chamber, a placing assembly is arranged in the inside of the detection chamber, a motor to be tested is arranged in the inside of the placing assembly, a vibration detection assembly is arranged on the outside of the motor to be tested, and a noise detection assembly is arranged above the motor to be tested.

[0008] The placing assembly comprises a top cover, a placing chamber is arranged below the top cover, the inside of the top cover and the placing chamber is filled with sound insulation material, a set of telescopic mechanisms is arranged on the two sides of the placing chamber respectively, an installation plate is arranged in the inside of the placing chamber, and the motor to be tested is arranged on one side of the installation plate.

[0009] The vibration detection assembly comprises a first detection mechanism, and a second detection mechanism is arranged on the opposite side of the first detection mechanism.

[0010] The noise detection assembly comprises a first microphone, which is arranged above the motor to be tested, and a second microphone arranged on one side of the motor to be tested.

[0011] The application further provides that the placing assembly further comprises a matching plate arranged on the opposite side of the mounting plate, one side of the matching plate is provided with a connecting shaft, the output end of the motor to be tested is connected in sequence through the mounting plate, the matching plate and the connecting shaft, and the mounting plate is provided with a fixing mechanism.

[0012] The application further provides that the fixing mechanism comprises a rotary air cylinder arranged at the intermediate position of the mounting plate and the matching plate, the output end of the rotary air cylinder is connected with a fixing piece, and the shape of the fixing piece is L-shaped.

[0013] The application further provides that the first detection mechanism comprises a first supporting rod, the outer side of the first supporting rod is sleeved with a first connecting block, the lower side of the first connecting block is provided with a second connecting block, and the second connecting block is sleeved on the outer side of the first supporting rod.

[0014] The application further provides that a first placing rod is arranged through the first connecting block, the outer side of the one end of the first placing rod away from the first connecting block is sleeved with a second placing block, and the top of the second placing block is provided with a second detector.

[0015] The application further provides that a second placing rod is arranged through the second connecting block, the first placing rod and the second placing rod are arranged in a staggered manner, the outer sides of the first supporting rod, the first placing rod and the second placing rod are all provided with scales, the outer side of the one end of the second placing rod away from the second connecting block is sleeved with a first placing block, and the top of the first placing block is provided with a first detector.

[0016] The application further provides that the second detection mechanism comprises a second supporting rod, the outer side of the second supporting rod is sleeved with a third connecting block, the lower side of the third connecting block is provided with a fourth connecting block, and the fourth connecting block is sleeved on the outer side of the second supporting rod.

[0017] The application further provides that a third placing rod is arranged through the third connecting block, the outer side of the one end of the third placing rod away from the third connecting block is sleeved with a third placing block, and the top of the third placing block is provided with a third detector.

[0018] The application further provides that a fifth placing rod is arranged through the fourth connecting block, the third placing rod and the fifth placing rod are arranged in parallel, and the outer sides of the second supporting rod, the third placing rod and the fifth placing rod are all provided with scales.

[0019] The fifth placing rod is externally sleeved with a fourth placing block away from one end of the fourth connecting block, and the bottom of the fourth placing block is provided with a fourth detector arranged on the side of the third placing block away from the second supporting rod.

[0020] To sum up, the present application includes at least one of the following beneficial technical effects:

[0021] (1) The placing assembly provides a placing space for the motor to be tested, and controls the detection environment within a certain range, thereby reducing the influence of external environmental sound on noise detection. The noise detection assembly collects the sound generated by the motor to be tested, and uses the collected sound as noise detection material.

[0022] (2) When the sound signals of the first microphone and the second microphone have high correlation, i.e., the similarity of the sound signals is high, the sound of the first microphone and the second microphone comes from the same vibration source, i.e., the collected noise is structural noise at this time. Conversely, when the correlation of the sound signals of the first microphone and the second microphone is low, the noise is air noise at this time. By comparing the sound of the first microphone and the second microphone, the source of the noise can be determined, and the motor can be further improved.

[0023] (3) The first detector, the second detector, the third detector, and the fourth detector are arranged to detect the main points of the motor to be tested, so as to achieve the purpose of detecting the vibration signal of the motor to be tested. Through further analysis of the vibration signal, the source of the motor noise can be accurately determined, the motor can be further repaired, and the improvement of the motor is facilitated, which is beneficial to improving the production quality of the motor.

[0024] (4) The first supporting rod, the first placing rod, the second placing rod, the second supporting rod, the third placing rod, and the fifth placing rod are all provided with scales, so that the detection points can be accurately determined, the process of measuring the position with a ruler is reduced, and the efficiency of motor noise detection is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a structural schematic view of a motor operation noise detection device in the present application.

[0026] Figure 2 It is a structural schematic view of a placing assembly in the present application.

[0027] Figure 3 It is an exploded structural schematic view. Figure 2

[0028] Figure 4 It is a structural schematic view of a vibration detection assembly in the present application. ​

[0029] Figure 5 It is a structure schematic view of the first detection mechanism in the application.

[0030] Figure 6 It is a structure schematic view of the second detection mechanism in the application.

[0031] Figure 7 It is an analysis view of the double microphone coherence function, the first microphone spectrum and the second microphone spectrum in the application.

[0032] Figure 8 It is a spectrum view of the four groups of detectors in the application.

[0033] Figure 9 It is a noise spectrum view of any group of microphones in the application.

[0034] Reference signs: 1, detection chamber;

[0035] 2, placing assembly; 21, top cover; 22, placing chamber; 23, telescopic mechanism; 24, mounting plate; 25, matching plate; 26, connecting shaft; 27, fixing mechanism; 271, rotary air cylinder; 272, fixing piece;

[0036] 3, motor to be detected;

[0037] 4, vibration detection assembly; 41, first detection mechanism; 411, first support rod; 412, first connecting block; 413, second connecting block; 414, first placing rod; 415, second placing rod; 416, first placing block; 417, first detector; 418, second placing block; 419, second detector; 42, second detection mechanism; 421, second support rod; 422, third connecting block; 423, fourth connecting block; 424, third placing rod; 425, fifth placing rod; 426, third placing block; 427, third detector; 428, fourth placing block; 429, fourth detector;

[0038] 5, noise detection assembly; 51, first microphone; 52, second microphone. DETAILED DESCRIPTION

[0039] It should be noted that the embodiments and the features in the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0040] It should be noted that, unless otherwise specified, all the technical and scientific terms used in the present application have the same meaning as that generally understood by the ordinary skilled person in the technical field to which the present application belongs.

[0041] Please refer to Figures 1-9 The present application provides the following technical solutions:

[0042] Embodiment one, refer to Figure 1 , in order to solve the microphone sound detection motor noise in the process, the influence of multiple sound sources on the detection result, the embodiment includes detection chamber 1, the inside of detection chamber 1 is provided with placing assembly 2, the inside of placing assembly 2 is provided with motor to be tested 3, the upper side of motor to be tested 3 is provided with noise detection assembly 5.

[0043] By setting placing assembly 2 to provide a space for motor to be tested 3, and by placing assembly 2 to control the detection environment within a certain range, reduce the influence of external environmental sound in noise detection, by setting noise detection assembly 5 to collect the sound generated by motor to be tested 3, the collected sound is used as the material for noise detection.

[0044] The specific structure of placing assembly 2 is as follows:

[0045] Refer to Figure 2 and Figure 3 , placing assembly 2 includes top cover 21, the lower side of top cover 21 is provided with placing chamber 22, the inside of top cover 21 and placing chamber 22 is filled with sound insulation material, the two sides of placing chamber 22 are respectively provided with a set of telescopic mechanism 23, the inside of placing chamber 22 is provided with mounting plate 24, motor to be tested 3 is arranged on one side of mounting plate 24.

[0046] Among them, top cover 21 and placing chamber 22 are connected through hinge, telescopic mechanism 23 includes hinged mounting block, telescopic cylinder, output shaft, connecting rod, connecting seat, hinged mounting block is installed in the inside of detection chamber 1, the bottom of telescopic cylinder is hinged with hinged mounting block, the output end of telescopic cylinder is connected with output shaft, connecting rod is arranged on output shaft in a penetrating manner, connecting rod is rotatably connected with output shaft, the end of connecting rod away from output shaft is connected with connecting seat, connecting seat is arranged on the side wall of top cover 21.

[0047] Start telescopic cylinder, top cover 21 can move along the hinge connected with placing chamber 22 under the drive of telescopic cylinder, and then realize the opening and closing of top cover 21 and placing chamber 22, by setting two sets of telescopic mechanism 23, the opening and closing of top cover 21 and placing chamber 22 can be realized, the combination of top cover 21 and placing chamber 22 forms a closed space, which provides airtight environment for motor noise detection, reduces the influence of external environmental sound on noise detection analysis.

[0048] In addition, the inside of top cover 21 and placing chamber 22 is filled with sound insulation material, the sound insulation material can be sound insulation cotton, because the inside of top cover 21 and placing chamber 22 is provided with sound insulation material, the combination of top cover 21 and placing chamber 22 forms a sound insulation environment, which further reduces the influence of external environmental sound on motor noise detection.

[0049] Refer to Figure 2 and Figure 3The placing assembly 2 further comprises a matching plate 25 arranged on the opposite side of the mounting plate 24, and a connecting shaft 26 is arranged on one side of the matching plate 25, and the output end of the motor 3 to be measured is connected to the connecting shaft 26 in sequence through the mounting plate 24 and the matching plate 25, and a fixing mechanism 27 is arranged on the mounting plate 24.

[0050] The fixing column is arranged between the matching plate 25 and the mounting plate 24, and the stability between the mounting plate 24 and the matching plate 25 is increased or decreased through the fixing column, and the side wall of the mounting plate 24 is provided with a jack, and the motor 3 to be measured can be directly inserted into the jack for fixation, and then the fixing mechanism 27 is started to further fix the motor 3 to be measured, thereby reducing the influence of shaking of the motor 3 to be measured during detection.

[0051] In addition, the connecting shaft 26 penetrates the side wall of the placing chamber 22, and the end of the connecting shaft 26 away from the placing chamber 22 can be connected to a load to increase the content of detection.

[0052] The specific structure of the fixing mechanism 27 is as follows:

[0053] Referring to Figure 4 The fixing mechanism 27 comprises a rotary air cylinder 271 arranged at the middle position between the mounting plate 24 and the matching plate 25, and a fixing piece 272 connected to the output end of the rotary air cylinder 271, and the shape of the fixing piece 272 is arranged as L-shaped.

[0054] The fixing piece 272 with L-shaped structure can further fix the motor 3 to be measured, the rotary air cylinder 271 is started, and the fixing piece 272 rotates under the driving of the rotary air cylinder 271, and the motor 3 to be measured is fixed after the rotary air cylinder 271 rotates.

[0055] After the motor 3 to be measured is fixed, the motor 3 to be measured can be detected by the noise detection assembly 5.

[0056] The specific structure of the noise detection assembly 5 is as follows:

[0057] Referring to Figure 4 The noise detection assembly 5 comprises a first microphone 51 arranged above the motor 3 to be measured, and a second microphone 52 arranged on one side of the motor 3 to be measured.

[0058] The top of the mounting plate 24 is provided with a support, the shape of the support is L-shaped, the first microphone 51 is arranged at the bottom of the support, the first microphone 51 can collect sound from above the motor to be tested 3, the second microphone 52 is arranged below the first microphone 51, and the second microphone 52 is on one side of the motor to be tested 3, the second microphone 52 can collect sound from the other side, the detection results of the first microphone 51 and the second microphone 52 can be compared to improve the reliability of the data, the vertical distance between the first microphone 51 and the top surface of the motor to be tested 3 is 100±5mm, the horizontal distance between the second microphone 52 and the side surface of the motor to be tested 3 is 100±5mm, and the microphone sensitivity is set to 50mV / Pa to ensure signal acquisition consistency.

[0059] The L-shaped support of the first microphone 51 is connected with the mounting plate 24 through a rubber shock pad, and the support of the second microphone 52 also adopts the same shock absorbing measure; the thickness of the shock pad is 5±1mm, which can inhibit the vibration conduction of 10-1000Hz, so that the microphone only collects the noise signal propagated by air, and avoids the interference of support vibration.

[0060] During the motor detection process, the microphone can only collect the final noise signal propagated by air, therefore, the sound signals received by the first microphone 51 and the second microphone 52 are all the sound in the closed environment formed by the top cover 21 and the placement chamber 22, and the comparison of the sound signals of the first microphone 51 and the second microphone 52 can determine whether the sound is air sound or structure sound, the sound generated by the surface vibration of the motor is structure sound, and the noise generated by the fan vortex is air sound.

[0061] When the sound signals of the first microphone 51 and the second microphone 52 have high correlation, i.e. the similarity of the sound signals is high, the sound of the first microphone 51 and the second microphone 52 comes from the same vibration source, i.e. the noise collected at this time is structure sound; on the contrary, when the correlation of the sound signals of the first microphone 51 and the second microphone 52 is low, the noise at this time is air sound.

[0062] The comparison of the sound of the first microphone 51 and the second microphone 52 can determine the source of the noise, and the motor can be further improved.

[0063] In the second embodiment, after the noise detection assembly 5 can preliminarily determine the collected noise, in order to more carefully analyze the structure sound, the structure noise can be further classified into electromagnetic noise and mechanical noise, and the mechanical noise can be further divided into rotor imbalance noise and bearing noise.

[0064] Among them, electromagnetic noise is mainly caused by the alternating electromagnetic force generated by the uneven magnetic field between the stator and rotor in the motor, which causes the motor vibration; rotor imbalance noise is mainly caused by the centrifugal force caused by rotor imbalance, misalignment, and shaft bending, which causes motor vibration; bearing noise is the sound generated by the periodic impact of the rolling elements with the inner and outer raceways of the bearing, as well as the friction and impact between the rolling elements and the cage.

[0065] Based on the above analysis, structural noise can be further analyzed. Structural noise can be summarized and classified into: electromagnetic noise, rotor imbalance noise, and bearing noise.

[0066] To enable structural sound analysis, a vibration detection component 4 is installed on the outside of the motor 3 under test. By installing the vibration detection component 4, further analysis can be performed on the noise detection component 5, increasing the diversity of data and improving the reliability of the data.

[0067] The specific structure of vibration detection component 4 is as follows:

[0068] See Figure 4 The vibration detection component 4 includes a first detection mechanism 41, and a second detection mechanism 42 is provided on the opposite side of the first detection mechanism 41.

[0069] See Figure 5 The first detection mechanism 41 includes a first support rod 411, a first connecting block 412 is sleeved on the outside of the first support rod 411, and a second connecting block 413 is provided below the first connecting block 412. The second connecting block 413 is sleeved on the outside of the first support rod 411.

[0070] See Figure 5 A first placement rod 414 is provided through the first connecting block 412. A second placement block 418 is sleeved on the outer side of the end of the first placement rod 414 away from the first connecting block 412. A second detector 419 is provided on the top of the second placement block 418.

[0071] See Figure 5 A second placement rod 415 is provided through the second connecting block 413. The second placement rod 415 and the first placement rod 414 are arranged alternately. The outer sides of the first support rod 411, the first placement rod 414 and the second placement rod 415 are all provided with scales. The outer side of the end of the second placement rod 415 away from the second connecting block 413 is fitted with a first placement block 416. The top of the first placement block 416 is provided with a first detector 417.

[0072] See Figure 6The second detection mechanism 42 comprises a second supporting rod 421, a third connecting block 422 is sleeved outside the second supporting rod 421, a fourth connecting block 423 is arranged below the third connecting block 422, and the fourth connecting block 423 is sleeved outside the second supporting rod 421.

[0073] Referring to Figure 6 A third placing rod 424 is arranged through the third connecting block 422, a third placing block 426 is sleeved outside one end of the third placing rod 424 away from the third connecting block 422, and a third detector 427 is arranged at the top of the third placing block 426.

[0074] Referring to Figure 6 A fifth placing rod 425 is arranged through the fourth connecting block 423, the third placing rod 424 and the fifth placing rod 425 are arranged in parallel, and the second supporting rod 421, the third placing rod 424 and the fifth placing rod 425 are all provided with scales outside.

[0075] Referring to Figure 6 The fourth placing block 428 is sleeved outside one end of the fifth placing rod 425 away from the fourth connecting block 423, a fourth detector 429 is arranged at the bottom of the fourth placing block 428, and the fourth detector 429 is arranged on the side of the third placing block 426 away from the second supporting rod 421.

[0076] The first connecting block 412 and the second connecting block 413 can slide and rotate along the first supporting rod 411, the first placing block 416 and the second placing block 418 can slide and rotate along the second placing rod 415 and the first placing rod 414 respectively, when the first connecting block 412, the second connecting block 413, the first placing block 416 and the second placing block 418 slide and rotate to appropriate positions respectively, the first connecting block 412, the second connecting block 413, the first placing block 416 and the second placing block 418 are all provided with bolt fixing points, and the first connecting block 412, the second connecting block 413, the first placing block 416 and the second placing block 418 can be fixed by bolts respectively, so that shaking in detection is reduced, and the stability of data detection is increased.

[0077] Similarly, the third connecting block 422 and the fourth connecting block 423 can slide and rotate along the second supporting rod 421, the third placing block 426 and the fourth placing block 428 can slide and rotate along the third placing rod 424 and the fifth placing rod 425 respectively, when the third connecting block 422, the fourth connecting block 423, the third placing block 426 and the fourth placing block 428 slide and rotate to appropriate positions respectively, the third connecting block 422, the fourth connecting block 423, the third placing block 426 and the fourth placing block 428 are all provided with bolt fixing points, and the third connecting block 422, the fourth connecting block 423, the third placing block 426 and the fourth placing block 428 can be fixed by bolts respectively, so that shaking in detection is reduced, and the stability of data detection is increased.

[0078] Meanwhile, since the first support rod 411, the first placement rod 414, the second placement rod 415, and the second support rod 421, the third placement rod 424, and the fifth placement rod 425 are all provided with scales, the detection points can be more accurately determined, the process of measuring the positions with a ruler is reduced, and the efficiency of motor noise detection is improved.

[0079] In actual application, the detection positions can be adjusted in advance according to motors of different sizes before starting detection, so as to adapt to the positions of the motors, improve the accuracy of detection, and improve the detection efficiency.

[0080] During the detection of the motor, the positions of the motor that generate noise are mainly the drive end bearing, the non-drive end bearing, and the vibration of the motor shell. Since the drive end bearing is connected with the load, the first detection mechanism 41 is arranged at the drive end bearing for detection. More specifically, the second detector 419 is arranged to detect the radial condition of the drive end bearing, and the first detector 417 is arranged to detect the axial condition of the drive end bearing. The fourth detector 429 is arranged at the non-drive end bearing to detect the radial condition thereof. The third detector 427 is arranged at the position of the motor shell for detection. The third detector 427 is directly opposite the midpoint of the shell of the motor to be detected, that is, the distance between the third detector 427 and the output end and the non-output end of the motor to be detected is equal, and the deviation is not more than ±5 mm.

[0081] The first detector 417, the second detector 419, the third detector 427, and the fourth detector 429 are all laser vibration detectors. The laser vibration detector emits a beam of laser to the surface of the motor to be detected. If the surface of the motor to be detected is static, the frequency of the reflected laser does not change. If the surface of the motor to be detected is moving, that is, the motor to be detected vibrates, the frequency of the reflected laser will change. The faster the vibration speed, the greater the frequency shift. Therefore, the first detector 417, the second detector 419, the third detector 427, and the fourth detector 429 are arranged to detect the main points of the motor to be detected respectively, so as to achieve the purpose of detecting the vibration signal of the motor to be detected.

[0082] It should be noted that the laser beam of the first detector 417, the second detector 419, the third detector 427, and the fourth detector 429 needs to be perpendicular to the measured surface of the motor to be detected. If the deviation exceeds the range, the position of the related connection part needs to be adjusted to make the angle meet the requirements.

[0083] In the third embodiment, the corresponding detection equipment can be installed according to the above structure to meet the requirements of noise detection. However, after collecting the noise data, the corresponding data needs to be further analyzed. The analysis process is specifically designed in this embodiment.

[0084] The specific process of motor noise detection is as follows:

[0085] First, the motor to be tested 3 and the hole on the mounting plate 24, that is, the motor to be tested 3 is inserted into the mounting plate 24, the telescopic mechanism 23 is started, the top cover 21 is closed with the placement chamber 22 under the action of the telescopic mechanism 23, the fixing mechanism 27 is started to fix the motor to be tested 3, the rated load of the motor to be tested 3 is loaded on the connecting shaft 26, and the standard load motor is used for loading. The detection of noise is adapted, after loading the rated load, 5±1 minutes are required to wait, the motor vibration and noise signal is stable, then the noise detection assembly 5 and the vibration detection assembly 4 start to detect the started motor to be tested 3, the vibration detection assembly 4 and the noise detection assembly 5 are externally connected with an information processing system, the information processing system can process the received information to judge whether the performance of the motor to be tested 3 meets the standard.

[0086] Among them, the vibration detection assembly 4 and the noise detection assembly 5 use a unified information processing system, so that all information receiving channels are synchronized, and a speed sensor is further arranged on the motor to be tested 3. The speed sensor can detect the real-time speed of the motor to be tested 3.

[0087] The externally connected information processing system includes a data acquisition module, a fast Fourier analysis module, a coherence function calculation module and a peak value identification module.

[0088] The sampling frequency of the data acquisition module is not less than 20 kHz, which meets the sampling requirement of high-frequency noise in the motor, and the sampling accuracy is 16 bits.

[0089] The frequency resolution of the fast Fourier analysis module is set to 1 Hz, and the spectrum average number is set to 10 times. The random noise interference is reduced by multiple settings, and the analysis frequency band covers 20-2000 Hz.

[0090] The coherence function calculation module calculates the coherence coefficient of the vibration signal and the noise signal at each frequency point The calculation window uses a Hanning window.

[0091] The sidelobe attenuation rate of the Hanning window can effectively suppress the spectrum leakage, and compared with the rectangular window, the frequency resolution and the coherence coefficient calculation accuracy can be improved. If it is necessary to further improve the analysis accuracy of the narrowband frequency, the information processing system can be switched to a Blackman window.

[0092] The Hanning window and the Blackman window are the default window functions of the coherence function calculation in the scheme, which are used for analyzing related data.

[0093] The peak value identification module automatically identifies the frequency point corresponding to the amplitude in the spectrum, and matches the theoretical characteristic frequency, the rotating frequency, the bearing fault frequency and the power frequency. The matching error is allowed to be within ±1 Hz.

[0094] The priority judgment logic of the peak value identification is as follows:

[0095] The bearing fault frequency is the most influential to the motor life, and is the first to be determined; the power frequency electromagnetic noise is easy to cause winding overheating, and is the second to be determined; the rotation frequency and the frequency of rotor imbalance and misalignment are the last to be determined; if multiple theoretical frequencies are matched at the same time, the coherence coefficients of each frequency are calculated respectively, and the one with higher coherence coefficient is determined as the main noise source.

[0096] For the information received by the vibration detection assembly 4 and the noise detection assembly 5, the information received by the noise detection assembly 5 is processed first. If the coherence of the first microphone 51 and the second microphone 52 in the main noise frequency band is high, the noise is structural noise, and the next step of noise source determination is performed. Otherwise, if the coherence is low, the noise is air noise, and the fan system of the motor to be tested 3 is detected to modify the motor to be tested 3.

[0097] If the above two conditions are within the normal range, the motor quality is qualified.

[0098] The specific process of analyzing air noise and structural noise by the first microphone 51 and the second microphone 52 is as follows:

[0099] The noise frequency band is 20-2000Hz, covering the common noise frequency band of the motor, electromagnetic noise 50-300Hz, rotor imbalance noise 1-100Hz, and low-frequency bearing noise 100-2000Hz. When the coherence coefficient of the first microphone 51 and the second microphone 52 is , it is determined that the noise is structural noise, i.e. generated by the surface vibration of the motor; when , it is determined that the noise is air noise, i.e. generated by the fan vortex; when the coherence coefficient is , the data is re-collected, and the environmental interference is excluded for re-analysis.

[0100] It should be noted that the coherence coefficient is calculated by the coherence function analysis module of the external information processing system. The frequency resolution is set to 1Hz, and the average number is set to 10 times during analysis.

[0101] In order to more clearly illustrate the relationship between the relevant data, the noise frequency band adopted in this embodiment is 20-300Hz, and the coherence function diagram of the double microphones is as shown in Figure 8 .

[0102] As shown in Figure 9 , the noise spectrum diagram exceeding 2000Hz in the detection process is also given in the drawing. Under this waveform display, the motor operation is in a normal state.

[0103] When the noise of the motor to be tested 3 is judged to be structure-borne sound through the first microphone 51 and the second microphone 52, the source of the noise is further determined through the detection data of the vibration detection assembly 4, that is, the source of the noise is determined.

[0104] The second detector 419 detects the vibration of the driving end bearing, the fourth detector 429 detects the vibration of the non-driving end bearing, and the third detector 427 detects the vibration of the shell of the motor to be tested 3. According to the four groups of detection devices, the related data can be obtained.

[0105] In the specific vibration signal data analysis, the microphone data and the detection device data are analyzed by fast Fourier transform, that is, the data obtained by the first microphone 51, the second microphone 52, the first detector 417, the second detector 419, the third detector 427 and the fourth detector 429 are analyzed by fast Fourier transform, and the related frequency spectrum is obtained. Further analysis is carried out according to the related frequency spectrum.

[0106] The structure-borne sound source analysis includes data processing principle and data analysis two processes, and the data processing process is as follows:

[0107] The main content of the data processing principle is as follows:

[0108] The rotational frequency of the motor to be tested 3, the characteristic frequency of the inner ring, the outer ring, the retainer and the rolling element of the bearing related to the motor to be tested 3 are calculated.

[0109] The rotational frequency f1 of the motor to be tested 3 is calculated:

[0110]

[0111] Wherein, f1 is the rotational frequency of the motor to be tested 3, and N0 is the real-time rotational speed of the motor to be tested 3.

[0112] According to the known bearing type and rotational frequency of the motor to be tested 3, the bearing fault frequency is calculated:

[0113] The calculation formula of the inner ring characteristic frequency is:

[0114]

[0115] Wherein, BPFI is the inner ring characteristic frequency, N is the bearing rotational speed, n is the number of rolling elements, d is the diameter of the rolling element, D is the pitch diameter of the bearing, is the contact angle.

[0116] The bearing rotational speed N is consistent with the real-time rotational speed N0 of the motor to be tested 3, that is, The bearing pitch diameter is the diameter of the center track of the rolling element, i.e., twice the distance between the center of the inner ring raceway and the center of the outer ring raceway, and the contact angle is the angle between the normal direction of the contact point of the rolling element and the raceway and the radial direction of the bearing.

[0117] According to the official technical manual of the bearing matched with the motor to be measured, the number of rolling elements n, the diameter of the rolling element d, the bearing pitch diameter D, and the contact angle are obtained. If the above parameters are not marked in the manual, a digital vernier caliper with an accuracy of not less than 0.01 mm is used to measure d and D, d is the average value of the measurements of three different rolling elements, D is the center distance between the outer circle of the inner ring and the inner circle of the outer ring multiplied by 2, and a bearing contact angle measuring instrument with an accuracy of ±0.5° is used to measure .

[0118] The calculation formula of the outer ring characteristic frequency is:

[0119]

[0120] where BPFO is the outer ring characteristic frequency, N is the bearing speed, n is the number of rolling elements, d is the diameter of the rolling element, D is the bearing pitch diameter, and is the contact angle.

[0121] The calculation formula of the rolling element characteristic frequency is:

[0122]

[0123] where BSF is the rolling element characteristic frequency, N is the bearing speed, n is the number of rolling elements, d is the diameter of the rolling element, D is the bearing pitch diameter, and is the contact angle.

[0124] The calculation formula of the cage characteristic frequency is:

[0125]

[0126] where FTF is the cage characteristic frequency, N is the bearing speed, n is the number of rolling elements, d is the diameter of the rolling element, D is the bearing pitch diameter, and is the contact angle.

[0127] The noise source of the motor to be measured is analyzed by the microphone signal and the vibration signal, and the coherence coefficient of the microphone signal and the vibration signal needs to be analyzed.

[0128] Referring to Figure 7 and Figure 8 , since the structural noise includes electromagnetic noise, bearing fault noise, and rotor imbalance noise, the characteristics of the three types of noise, the frequency spectrum and the coherence coefficient are analyzed to determine which type of noise it is.

[0129] Before testing, the actual power frequency of the testing environment was measured using a power grid frequency meter with an accuracy of ±0.1Hz. The measurement time was 10 seconds, and the average value was taken. The actual measurement was used as the benchmark. multiples of , As a characteristic harmonic of electromagnetic noise; if the noise spectrum and the vibration spectrum are in , Peaks are observed at all locations, and the coherence coefficients at the corresponding frequencies are... If so, it is determined to be electromagnetic noise.

[0130] It is important to note that in determining whether the noise is electromagnetic, it is also necessary to eliminate interference from the load. The method for eliminating load interference is as follows:

[0131] After applying the rated load, record the peak vibration and noise at the power supply's double frequency. Then reduce the load to 50% of the rated load and record the peak value at that frequency again. If the difference between the two peak values ​​is less than 10%, it indicates that the peak value is caused by electromagnetic noise and is unrelated to the load. If the difference is greater than 10%, the electromagnetic compatibility of the load motor needs to be checked.

[0132] Based on the above, the data processing principle of noise detection is known. At the same time, the data collected by the dual microphones and four detectors can generate corresponding analysis charts. The specific data analysis process includes two parts: individual analysis and comprehensive analysis to process the data.

[0133] First, we need to analyze each case individually.

[0134] The analysis process for the electromagnetic noise of the motor under test 3 is as follows:

[0135] Since electromagnetic force acts directly on the stator and the housing, electromagnetic noise is most noticeable on the motor housing. Electromagnetic noise is directly related to the power supply frequency. When analyzing the spectrum, the 50Hz frequency and its harmonics can be the focus, and the harmonics can be 100Hz, 150Hz, etc.

[0136] like Figure 7 As shown, the coherence coefficients at 50Hz, 100Hz, and 150Hz can be observed based on the dual-microphone coherence function. Determine the structural noise generated by the motor 3 under test at this time.

[0137] like Figure 8 As shown, further analysis of the detector's spectrum reveals that in the spectrum of the third detector 427 and the motor housing, there are obvious peaks at 50Hz and its harmonic positions, which are typical electromagnetic noise characteristics. Based on the detector's spectrum and the coherence coefficient of the dual microphones, it can be determined that the noise generated at this time is electromagnetic noise.

[0138] It should be noted that according to the double microphone coherence function analysis, the coherence is low between 1 Hz-50 Hz, and obvious peaks appear in the detector spectrum, at this time the noise generated is air sound.

[0139] The analysis process of the electromagnetic noise of the motor to be tested 3 is as follows:

[0140] Referring to Figure 8 , since the motor to be tested 3 has two sets of bearings, the spectrum of the radial second detector 419 of the driving end bearing and the radial fourth detector 429 of the non-driving end bearing can be observed, if the frequency in the spectrum matches the theoretical BPFI / BPFO / BSF / FTF, and , it is judged that there is a bearing fault problem.

[0141] It should be noted that low-frequency signals are only suitable for severe bearing faults, such as large-area spalling of the raceway and fracture of the rolling element; for early and slight faults such as micro-point corrosion of the raceway and wear of the rolling element, the spectrum of the middle and high frequency band vibration signals needs to be analyzed, that is, the vibration signals of the bearing point position second detector 419 and the fourth detector 429 are processed by the information processing system to extract the fault characteristic frequency of the middle and high frequency band, if the frequency matches the theoretical BPFI / BPFO / BSF / FTF, and , it can be determined as an early and slight bearing fault.

[0142] The analysis process of the rotor imbalance noise of the motor to be tested 3 is as follows:

[0143] When judging the rotor imbalance noise, first, the real-time speed N0 of the motor to be tested 3 is measured by the speed sensor, and the 1 times rotational frequency is calculated, if the peak amplitude of the noise spectrum and the peak amplitude of the bearing radial vibration spectrum, including the driving end bearing and the non-driving end bearing, at f1 is the maximum value among all frequency components, and the coherence coefficient of the two at f1 is , it is preliminarily determined that the rotor is unbalanced; if the peak amplitude reaches more than 50% of the peak amplitude of f1, it is determined that there is a rotor misalignment fault.

[0144] Referring to Figure 8 , in this embodiment, the speed is 1800 rpm, the corresponding data is substituted into , and the calculation formula can obtain the rotational frequency f1 as 30 Hz, in all vibration detectors, the rotational frequency component is very obvious, the rotational frequency component in the axial first detector 417 of the driving end bearing is particularly prominent, indicating that there is obvious unbalance force, and the high-order harmonics of the rotational frequency, such as 60 Hz and 90 Hz, also exist, and it can be judged that the noise is rotor imbalance noise.

[0145] Secondly, since there are multiple groups of detectors in the embodiment, further analysis of the detection results at specific positions is also needed, i.e. comprehensive analysis.

[0146] The comprehensive judgment process is as follows:

[0147] Position analysis: the vibration amplitude of the driving end bearing second detector 419 is obviously higher than that of the non-driving end fourth detector 429; the axial vibration first detector 417 and the radial vibration second detector 419 show similar performance at the rotation frequency, but the radial vibration is more obvious at the high frequency band; the vibration spectrum of the motor shell third detector 427 is obviously different from that of other positions, mainly showing electromagnetic noise and structural transmitted vibration.

[0148] Frequency characteristics: the dominant component in the low frequency band is the rotation frequency and its harmonics, reflecting the rotor imbalance problem; the middle frequency band is the bearing fault characteristic frequency region; the high frequency band has increased wideband noise, reflecting bearing surface damage and impact noise.

[0149] Spectrum analysis: the response of the microphone spectrum and the vibration spectrum at the fault frequency is obviously different, and the vibration sensor can more clearly capture the bearing fault characteristics, while the microphone is greatly affected by environmental noise.

[0150] Analysis result: the bearing has inner ring fault, which needs to be closely monitored for development; the rotor has obvious imbalance, and dynamic balance correction should be considered; electromagnetic noise is obvious, and the power quality and electromagnetic state of the motor need to be checked.

[0151] According to the corresponding analysis result, the corresponding position of the motor to be measured 3 can be checked, which is also conducive to the further improvement of motor production.

[0152] Obviously, the above-described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should belong to the scope of protection of the present application.

Claims

1. An electric motor operating noise detection apparatus, characterized by: Including detection chamber (1), the inside of detection chamber (1) is provided with placement assembly (2), the inside of placement assembly (2) is provided with to be measured motor (3), the outside of to be measured motor (3) is provided with vibration detection assembly (4), the top and one side of to be measured motor (3) are provided with noise detection assembly (5); The vibration detection assembly (4) and noise detection assembly (5) are externally connected with an information processing system; The placement assembly (2) includes a top cover (21), a placement chamber (22) is arranged below the top cover (21), the inside of the top cover (21) and the placement chamber (22) is filled with sound insulation material, a set of telescopic mechanisms (23) are arranged on both sides of the placement chamber (22), an installation plate (24) is arranged in the inside of the placement chamber (22), and the to-be-tested motor (3) is arranged on one side of the installation plate (24). The vibration detection assembly (4) includes a first detection mechanism (41), and a second detection mechanism (42) is arranged on the opposite side of the first detection mechanism (41). The first detection mechanism (41) includes a first detector (417) and a second detector (419) for detecting the axial and radial directions of the bearing of the driving end of the to-be-tested motor (3). The second detection mechanism (42) includes a third detector (427) for detecting the shell of the to-be-tested motor (3) and a fourth detector (429) for detecting the bearing of the non-driving end of the to-be-tested motor (3). The first detection mechanism (41) further includes a first support rod (411), a first placement rod (414), a second placement rod (415), a first connecting block (412) and a second connecting block (413) slidingly rotating along the first support rod (411), a first placement block (416) slidingly rotating along the second placement rod (415), and a second placement block (418) slidingly rotating along the first placement rod (414), and all of which are provided with scales on the outer sides. The second detection mechanism (42) further includes a second support rod (421), a third placement rod (424), a fifth placement rod (425), a third connecting block (422) and a fourth connecting block (423) slidingly rotating along the second support rod (421), a third placement block (426) slidingly rotating along the third placement rod (424), and a fourth placement block (428) slidingly rotating along the fifth placement rod (425), and all of which are provided with scales on the outer sides. The noise detection assembly (5) includes a first microphone (51) arranged above the to-be-tested motor (3), and a second microphone (52) arranged on one side of the to-be-tested motor (3). After determining that the noise of the to-be-tested motor (3) is structural noise through the first microphone (51) and the second microphone (52), the vibration detection assembly (4) is used to further determine the source of the noise. The structural noise includes electromagnetic noise, bearing fault noise, and rotor imbalance noise, and the specific type is analyzed according to the noise characteristics, frequency spectrum, and coherence coefficient.

2. A motor operating noise detection apparatus according to claim 1, characterised in that: The placing assembly (2) further comprises a matching plate (25) arranged on the opposite side of the mounting plate (24), one side of the matching plate (25) is provided with a connecting shaft (26), the output end of the motor (3) to be tested is connected with the connecting shaft (26) in sequence through the mounting plate (24) and the matching plate (25), and the mounting plate (24) is provided with a fixing mechanism (27).

3. An apparatus for detecting motor operating noise according to claim 2, characterized in that: The fixing mechanism (27) comprises a rotary air cylinder (271), the rotary air cylinder (271) is arranged at the intermediate position of the mounting plate (24) and the matching plate (25), and the output end of the rotary air cylinder (271) is connected with a fixing piece (272), and the shape of the fixing piece (272) is arranged as L-shaped.

4. The apparatus of claim 1, wherein: The first detection mechanism (41) comprises a first supporting rod (411), a first connecting block (412) is arranged on the outer side of the first supporting rod (411), a second connecting block (413) is arranged below the first connecting block (412), and the second connecting block (413) is arranged on the outer side of the first supporting rod (411).

5. An apparatus for detecting motor operating noise according to claim 4, characterized in that: A first placing rod (414) is arranged on the first connecting block (412) in a penetrating mode, and a second placing block (418) is arranged on the outer side of the end of the first placing rod (414) away from the first connecting block (412).

6. An apparatus for detecting motor operating noise according to claim 5, characterized in that: A second placing rod (415) is arranged on the second connecting block (413) in a penetrating mode, the first placing rod (414) and the second placing rod (415) are arranged in an interlaced mode, the outer sides of the first supporting rod (411), the first placing rod (414) and the second placing rod (415) are provided with scales, and a first placing block (416) is arranged on the outer side of the end of the second placing rod (415) away from the second connecting block (413).

7. The apparatus of claim 1, wherein: The second detection mechanism (42) comprises a second supporting rod (421), a third connecting block (422) is arranged on the outer side of the second supporting rod (421), a fourth connecting block (423) is arranged below the third connecting block (422), and the fourth connecting block (423) is arranged on the outer side of the second supporting rod (421).

8. A motor operating noise detection apparatus according to claim 7, characterised in that: A third placing rod (424) is arranged on the third connecting block (422) in a penetrating mode, and a third placing block (426) is arranged on the outer side of the end of the third placing rod (424) away from the third connecting block (422).

9. An electrical machine operating noise detection apparatus according to claim 8, characterised in that: A fifth placing rod (425) is arranged on the fourth connecting block (423) in a penetrating mode, the third placing rod (424) and the fifth placing rod (425) are arranged in parallel, and the outer sides of the second supporting rod (421), the third placing rod (424) and the fifth placing rod (425) are provided with scales.

10. An apparatus for detecting motor operating noise according to claim 9, wherein: The fourth detector (429) is arranged on the side of the third placing block (426) away from the second supporting rod (421).

Images