Motor operation noise detection device

Abstract

The invention is suitable for the technical field of motor noise detection, and provides a motor operation noise detection device, which comprises a detection chamber, a placement assembly is arranged in the detection chamber, a to-be-detected motor is arranged in the placement assembly, and a vibration detection assembly is arranged on the outer side of the to-be-detected motor. A noise detection assembly is arranged above the to-be-detected motor, the placement assembly comprises a top cover, a placement chamber is arranged below the top cover, the top cover and the placement chamber are filled with sound insulation materials, the two sides of the placement chamber are each provided with a telescopic mechanism, and a mounting plate is arranged in the placement chamber; the placement assembly is arranged to provide a placement space for the to-be-detected motor, the detection environment is controlled within a certain range through the placement assembly, the influence of external environment sound in noise detection is reduced, the sound generated by the to-be-detected motor is collected through the noise detection assembly, and the collected sound serves 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 parts 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: A motor operation noise detection device, comprising a detection chamber, a placing assembly is arranged inside the detection chamber, a to-be-tested motor is arranged inside the placing assembly, a vibration detection assembly is arranged on the outside of the to-be-tested motor, and a noise detection assembly is arranged above the to-be-tested motor.

[0007] The placing assembly comprises a top cover, a placing chamber is arranged below the top cover, sound insulation materials are filled in the inside of the top cover and the placing chamber, 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 to-be-tested motor is arranged on one side of the installation plate.

[0008] 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.

[0009] The noise detection assembly comprises a first microphone, the first microphone is arranged above the to-be-tested motor, and a second microphone is arranged on one side of the to-be-tested motor.

[0010] The application is further provided with: the placing assembly further comprises a matching plate, the matching plate is 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.

[0011] The application is further provided with: the fixing mechanism comprises a rotary air cylinder, the rotary air cylinder is 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 arranged as L-shaped.

[0012] The application is further provided with: 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.

[0013] The application is further provided with: 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.

[0014] The application is further provided with: 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 mode, 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.

[0015] The application is further provided with: 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.

[0016] The application is further provided with: 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.

[0017] The application is further provided with: 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.

[0018] 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.

[0019] To sum up, the present application includes at least one of the following beneficial technical effects: (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.

[0020] (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.

[0021] (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 improve the production quality of the motor.

[0022] (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

[0023] Figure 1 It is a structural schematic view of a motor operation noise detection device in the present application.

[0024] Figure 2 It is a structural schematic view of a placing assembly in the present application.

[0025] Figure 3 It is Figure 2 an exploded structural schematic view.

[0026] Figure 4 It is a structural schematic view of a vibration detection assembly in the present application.

[0027] Figure 5 It is a structural schematic diagram of the first detection mechanism in the application.

[0028] Figure 6 It is a structural schematic diagram of the second detection mechanism in the application.

[0029] Figure 7 It is an analysis diagram of the double microphone coherence function, the first microphone spectrum and the second microphone spectrum in the application.

[0030] Figure 8 It is a spectrum diagram of the four groups of detectors in the application.

[0031] Figure 9 It is a noise spectrum diagram of any group of microphones in the application.

[0032] Legend: 1, detection chamber; 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; 3, motor to be detected; 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; 5, noise detection assembly; 51, first microphone; 52, second microphone. DETAILED DESCRIPTION

[0033] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] It should be noted that, unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0035] Please refer to Figures 1-9 The present application provides the following technical solutions: Embodiment one, please 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 a detection chamber 1, the inside of the detection chamber 1 is provided with a placing assembly 2, the inside of the placing assembly 2 is provided with a motor to be tested 3, the upper side of the motor to be tested 3 is provided with a noise detection assembly 5.

[0036] By setting the placing assembly 2 to provide a placing space for the motor to be tested 3, and by controlling the detection environment within a certain range through the placing assembly 2, the influence of external environmental sound on noise detection is reduced, and by setting the noise detection assembly 5 to collect the sound generated by the motor to be tested 3, the collected sound is used as noise detection material.

[0037] The specific structure of the placing assembly 2 is as follows: Refer to Figure 2 and Figure 3 , the placing assembly 2 includes a top cover 21, the lower side of the top cover 21 is provided with a placing chamber 22, the inside of the top cover 21 and the placing chamber 22 is filled with sound insulation material, the two sides of the placing chamber 22 are respectively provided with a set of telescopic mechanisms 23, the inside of the placing chamber 22 is provided with a mounting plate 24, and the motor to be tested 3 is arranged on one side of the mounting plate 24.

[0038] Among them, the top cover 21 and the placing chamber 22 are connected through a hinge, the telescopic mechanism 23 includes a hinged mounting block, a telescopic cylinder, an output shaft, a connecting rod and a connecting seat, the hinged mounting block is installed in the inside of the detection chamber 1, the bottom of the telescopic cylinder is hinged with the hinged mounting block, the output end of the telescopic cylinder is connected with the output shaft, the connecting rod is penetratingly arranged on the output shaft, the connecting rod and the output shaft are rotationally connected, and the end of the connecting rod away from the output shaft is connected with the connecting seat, and the connecting seat is arranged on the side wall of the top cover 21.

[0039] Start the telescopic cylinder, the top cover 21 can move along the hinge connected with the placing chamber 22 under the driving of the telescopic cylinder, thereby realizing the opening and closing of the top cover 21 and the placing chamber 22, and by arranging two sets of telescopic mechanisms 23, the opening and closing of the top cover 21 and the placing chamber 22 can be realized, and the combination of the top cover 21 and the placing chamber 22 forms a closed space, which provides a sealed environment for motor noise detection and reduces the influence of external environmental sound on noise detection analysis.

[0040] In addition, the inside of the top cover 21 and the placing chamber 22 is filled with sound insulation material, and the sound insulation material can be sound insulation cotton, and the combination of the top cover 21 and the placing chamber 22 forms a sound insulation environment due to the arrangement of sound insulation material in the top cover 21 and the placing chamber 22, thereby further reducing the influence of external environmental sound on motor noise detection.

[0041] 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 one side of the matching plate 25 is provided with a connecting shaft 26, the output end of the motor 3 to be measured 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.

[0042] The fixing column is arranged between the matching plate 25 and the mounting plate 24, the stability between the mounting plate 24 and the matching plate 25 is increased or decreased through the fixing column, the side wall of the mounting plate 24 is provided with a jack, 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, so as to reduce the influence of shaking of the motor 3 to be measured in the detection process.

[0043] 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 with a load, so as to increase the detection content.

[0044] The specific structure of the fixing mechanism 27 is as follows: 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 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.

[0045] The fixing piece 272 with L-shaped structure can further fix the motor 3 to be measured, the rotary air cylinder 271 is started, 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.

[0046] After the motor 3 to be measured is fixed, the motor 3 to be measured can be detected by the noise detection assembly 5.

[0047] The specific structure of the noise detection assembly 5 is as follows: 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.

[0048] 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.

[0049] 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.

[0050] 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 placing 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.

[0051] 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.

[0052] 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.

[0053] In the second embodiment, after the noise detection assembly 5 preliminarily determines the collected noise, in order to analyze the structure sound more carefully, the structure sound 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The specific structure of vibration detection component 4 is as follows: 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] See Figure 6 The second detection mechanism 42 includes a second support rod 421, a third connecting block 422 is sleeved on the outside of the second support rod 421, and a fourth connecting block 423 is provided below the third connecting block 422. The fourth connecting block 423 is sleeved on the outside of the second support rod 421.

[0062] Referring to Figure 6 , the third adapter block 422 is provided with a third placement rod 424 penetratingly arranged thereon, and a third placement block 426 is arranged outside the end of the third placement rod 424 away from the third adapter block 422, and the top of the third placement block 426 is provided with a third detector 427.

[0063] Referring to Figure 6 , the fourth adapter block 423 is provided with a fifth placement rod 425 penetratingly arranged thereon, and the third placement rod 424 and the fifth placement rod 425 are arranged in parallel, and the outer sides of the second support rod 421, the third placement rod 424 and the fifth placement rod 425 are provided with scales.

[0064] Referring to Figure 6 , the fifth placement rod 425 is provided with a fourth placement block 428 arranged outside the end of the fifth placement rod 425 away from the fourth adapter block 423, and the bottom of the fourth placement block 428 is provided with a fourth detector 429, and the fourth detector 429 is arranged on the side of the third placement block 426 away from the second support rod 421.

[0065] Among them, the first adapter block 412 and the second adapter block 413 can slide and rotate along the first support rod 411, and the first placement block 416 and the second placement block 418 can slide and rotate along the second placement rod 415 and the first placement rod 414 respectively, when the first adapter block 412, the second adapter block 413, the first placement block 416 and the second placement block 418 are slid and rotated to the appropriate positions respectively, since the first adapter block 412, the second adapter block 413, the first placement block 416 and the second placement block 418 are all provided with bolt fixing points, they can be fixed by bolts respectively, so as to reduce the shaking in detection and increase the stability of data detection.

[0066] Similarly, the third adapter block 422 and the fourth adapter block 423 can slide and rotate along the second support rod 421, and the third placement block 426 and the fourth placement block 428 can slide and rotate along the third placement rod 424 and the fifth placement rod 425 respectively, when the third adapter block 422, the fourth adapter block 423, the third placement block 426 and the fourth placement block 428 are slid and rotated to the appropriate positions respectively, since the third adapter block 422, the fourth adapter block 423, the third placement block 426 and the fourth placement block 428 are all provided with bolt fixing points, they can be fixed by bolts respectively, so as to reduce the shaking in detection and increase the stability of data detection.

[0067] At the same time, since the first support rod 411, the first placement rod 414 and 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 judged, the process of measuring the position with a ruler is also reduced, and the efficiency of motor noise detection is improved.

[0068] In practical applications, the detection position can be adjusted in advance before starting detection according to different sizes of the motor, so as to adapt to the position of the motor, improve the accuracy of detection, and improve the detection efficiency.

[0069] During the detection of the motor, the positions where the motor generates noise are mainly the drive end bearing, the non-drive end bearing, and the vibration of the motor shell. Among them, the first detection mechanism 41 is arranged at the drive end bearing 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, and the third detector 427 is arranged at the position of the motor shell to detect the midpoint of the shell of the motor to be tested. That is, the distance between the third detector 427 and the output end and the non-output end of the motor to be tested is equal, and the deviation is not more than ±5 mm.

[0070] 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 tested. If the surface of the motor to be tested is stationary, the frequency of the reflected laser does not change. If the surface of the motor to be tested is in motion, i.e., the motor to be tested vibrates, the frequency of the reflected laser will change. The faster the vibration speed, the greater the frequency shift. Therefore, by arranging the first detector 417, the second detector 419, the third detector 427, and the fourth detector 429 to detect the main points of the motor to be tested respectively, the purpose of detecting the vibration signal of the motor to be tested is achieved.

[0071] 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 tested. If the deviation exceeds the range, the position of the related connection part needs to be adjusted to make the angle meet the requirements.

[0072] In example three, the corresponding detection equipment can be installed through the above structure to meet the requirements of noise detection. However, after collecting noise data, further analysis of the corresponding data is needed. This embodiment specifically designs the analysis process.

[0073] The specific process of motor noise detection is as follows: First, the motor to be tested 3 and the hole on the mounting plate 24 are matched, that is, the motor to be tested 3 is inserted into the socket on the mounting plate 24, the telescopic mechanism 23 is started, the top cover 21 is driven by the telescopic mechanism 23 to form a closed space with the placement chamber 22, 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 as the loading mode to adapt to the detection of noise. After loading the rated load, 5±1 minutes are required to wait for the motor vibration and noise signal to be stable, and 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, and the information processing system can process the received information to judge whether the performance of the motor to be tested 3 meets the standard.

[0074] 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 rotating speed sensor is further arranged on the motor to be tested 3, which can detect the real-time rotating speed of the motor to be tested 3.

[0075] 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.

[0076] 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.

[0077] The frequency resolution of the fast Fourier analysis module is set to 1 Hz, and the spectrum average number is set to 10 times. Random noise interference is reduced through multiple settings, and the analysis frequency band covers 20 Hz-2000 Hz.

[0078] The coherence function calculation module calculates the coherence coefficient of the vibration signal and the noise signal at each frequency point , and the calculation window uses a Hanning window.

[0079] The sidelobe attenuation rate of the Hanning window can effectively suppress spectrum leakage, and compared with a 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 narrow-band frequency, the information processing system can be switched to a Blackman window.

[0080] The Hanning window and the Blackman window are the default window functions for coherence function calculation in the scheme, which are used for analyzing related data.

[0081] The peak value identification module automatically identifies the frequency point corresponding to the amplitude in the spectrum, and matches it with the theoretical characteristic frequency, the rotating frequency, the bearing fault frequency and the power frequency multiplication. The matching error is allowed to be within ±1 Hz.

[0082] The priority judgment logic of the peak value identification is as follows: The bearing fault frequency is the most influential to the motor life, and is judged first; the power frequency electromagnetic noise is easy to cause the winding overheating, and is judged second; the rotation frequency and the bearing unbalance are judged last; if multiple theoretical frequencies are matched simultaneously, the coherence coefficients of each frequency are calculated respectively, and the one with higher coherence coefficient is judged as the main noise source.

[0083] 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.

[0084] If the above two conditions are within the normal range, the motor quality is qualified.

[0085] The specific process of analyzing air noise and structural noise by the first microphone 51 and the second microphone 52 is as follows: The noise frequency band is 20-2000Hz, covering the common noise frequency band of the motor, the electromagnetic noise is 50-300Hz, the rotor unbalance noise is 1-100Hz, and the low-frequency bearing noise is 100-2000Hz, the coherence coefficient of the first microphone 51 and the second microphone 52 , it is determined that the noise is structural noise, that is, it is generated by the surface vibration of the motor; when , it is determined that the noise is air noise, that is, it is generated by the fan vortex; when the coherence coefficient is , the data is collected again, and the environmental interference is excluded for reanalysis.

[0086] It should be noted that the coherence coefficient is calculated by the coherence function analysis module of the external information processing system, and the frequency resolution is set to 1Hz and the average number is set to 10 times during analysis.

[0087] In order to more clearly illustrate the relationship between the related 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 .

[0088] As shown in Figure 9 , the noise spectrum diagram exceeding 2000Hz in the detection process is also given in the drawing, and under this waveform display, the motor operation is in a normal state.

[0089] After the noise of the motor to be tested 3 is judged as structural noise by the first microphone 51 and the second microphone 52, the noise is further determined by the detection data of the vibration detection assembly 4, that is, the source of the noise is determined.

[0090] 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 detected 3. According to the four groups of detection devices, the related data can be obtained.

[0091] 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 to obtain the related frequency spectrum, and the related frequency spectrum is further analyzed.

[0092] The structural sound source analysis includes data processing principle and data analysis two processes, and the data processing process is as follows: The main content of the data processing principle is as follows: The rotational frequency of the motor to be detected 3, the characteristic frequency of the inner ring, the outer ring, the retainer and the rolling element of the bearing of the motor to be detected 3 are calculated.

[0093] The rotational frequency f1 of the motor to be detected 3 is calculated:

[0094] Wherein, f1 is the rotational frequency of the motor to be detected 3, and N0 is the real-time rotational speed of the motor to be detected 3.

[0095] According to the existing known bearing type and rotational frequency of the motor to be detected 3, the bearing fault frequency is calculated: The calculation formula of the inner ring characteristic frequency is:

[0096] 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 diameter of the bearing pitch circle, The contact angle is

[0097] The bearing rotational speed N is consistent with the real-time rotational speed N0 of the motor to be detected 3, that is, The diameter of the bearing pitch circle is the diameter of the rolling element center track, that is, 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.

[0098] According to the official technical manual of the bearing matched with the motor to be detected 3, the number of rolling elements n, the diameter of the rolling element d, the diameter of the bearing pitch circle D, and the contact angle If the above parameters are not marked in the manual, the 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 3 different rolling bodies, D is the center distance between the outer circle of the inner ring and the inner circle of the outer ring multiplied by 2, the bearing contact angle measuring instrument with an accuracy of ±0.5° is used to measure .

[0099] The calculation formula of the outer ring characteristic frequency is:

[0100] Wherein, BPFO is the outer ring characteristic frequency, N is the bearing speed, n is the number of rolling bodies, d is the rolling body diameter, D is the bearing pitch diameter, is the contact angle.

[0101] The calculation formula of the rolling body characteristic frequency is:

[0102] Wherein, BSF is the rolling body characteristic frequency, N is the bearing speed, n is the number of rolling bodies, d is the rolling body diameter, D is the bearing pitch diameter, is the contact angle.

[0103] The calculation formula of the cage characteristic frequency is:

[0104] Wherein, FTF is the cage characteristic frequency, N is the bearing speed, n is the number of rolling bodies, d is the rolling body diameter, D is the bearing pitch diameter, is the contact angle.

[0105] The noise source of the motor to be measured 3 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.

[0106] Referring to Figure 7 and Figure 8 , since the structural sound includes electromagnetic noise, bearing fault noise and rotor imbalance noise, the characteristics and spectrum diagram of the three kinds of noise and the coherence coefficient are analyzed to determine which kind of noise it is.

[0107] Before detection, the actual power frequency of the detection environment is measured by using the power grid frequency detector with an accuracy of ±0.1 Hz , the measurement time is 10s, and the average value is taken, and the integer multiple of the measured , is taken as the characteristic frequency of the electromagnetic noise; if the noise spectrum and the vibration spectrum appear peak values at , , and the coherence coefficient of the corresponding frequency is , it is determined that the electromagnetic noise is determined.

[0108] It should be noted that in the process of judging whether it is electromagnetic noise, the interference caused by the load also needs to be ruled out. The method for ruling out the load interference is: After loading the rated load, record the vibration and noise peak value at the frequency multiplication of the power supply; then reduce the load to 50% of the rated load, and record the peak value at this frequency again; if the deviation of the two peak values is <10%, it means that the peak value is caused by electromagnetic noise and is not related to the load; if the deviation is >10%, the electromagnetic compatibility of the load motor needs to be checked.

[0109] According to the above content, the data processing principle of noise detection can be known, and the corresponding analysis graph can be generated by collecting the corresponding data information of the double microphone and the four groups of detectors. In the specific data analysis process, the data is processed by two parts of individual analysis and comprehensive analysis.

[0110] First, analyze each case separately.

[0111] The analysis process of the electromagnetic noise of the motor to be tested 3 is as follows: Since the electromagnetic force directly acts on the stator and the shell, the electromagnetic noise is most obvious on the motor shell. The electromagnetic noise is directly related to the power frequency, which is 50Hz. When analyzing the frequency spectrum graph, 50Hz and its harmonics, such as 100Hz and 150Hz, can be analyzed.

[0112] As shown in Figure 7 , according to the coherence function of the double microphone, the coherence coefficients at 50Hz, 100Hz and 150Hz can be observed , to judge that the noise structure sound generated by the motor to be tested 3 at this time.

[0113] As shown in Figure 8 , further analyze the frequency spectrum graph of the detector. In the frequency spectrum graph of the third detector 427, the motor shell, it can be seen that the 50Hz and its harmonic positions appear obvious peak values, which are typical electromagnetic noise characteristics. According to the detector frequency spectrum graph and the double microphone coherence coefficient, it can be judged that the noise generated at this time is electromagnetic noise.

[0114] It should be noted that according to the double microphone coherence function analysis, the coherence is low between 1Hz-50Hz, and obvious peak values appear in the detector frequency spectrum graph. At this time, the noise generated is air noise.

[0115] The analysis process of the electromagnetic noise of the motor to be tested 3 is as follows: Referring to Figure 8 , since the motor to be tested 3 has two bearings, the frequency 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 frequency spectrum graph matches the theoretical BPFI / BPFO / BSF / FTF, and If yes, it is determined that there is a bearing failure problem.

[0116] It should be noted that the low frequency signal is only applicable to severe bearing failure, such as large area spalling of the raceway and fracture of the rolling element; for early and slight failure such as micro pitting of the raceway and wear of the rolling element, the spectrum of the mid-high frequency band vibration signal needs to be analyzed, that is, the vibration signal of the bearing point position second detector 419 and the fourth detector 429 is processed by the information processing system to extract the fault characteristic frequency of the mid-high frequency band, and if the frequency matches the theoretical BPFI / BPFO / BSF / FTF and , it is determined as early and slight bearing failure.

[0117] The analysis process of the rotor unbalance noise of the motor to be tested 3 is as follows: When judging the rotor unbalance 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 f1 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 are the maximum values among all frequency components, and the coherence coefficient of the two at f1 is , it is preliminarily determined as rotor unbalance; if the peak amplitude reaches more than 50% of the peak amplitude of f1, it is determined as rotor misalignment failure.

[0118] Referring to Figure 8 , in the embodiment, the speed is 1800 rpm, the corresponding data is substituted into , and the calculation formula can obtain that the rotational frequency f1 is 30 Hz. In all vibration detectors, the rotational frequency component is very obvious, and 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 there are high-order harmonics of the rotational frequency, such as 60 Hz and 90 Hz. Based on the above, it is determined that the noise is rotor unbalance noise.

[0119] Secondly, since there are multiple groups of detectors in the embodiment, the detection results at specific positions also need to be further analyzed, that is, the analysis is comprehensively performed.

[0120] The comprehensive judgment process is as follows: 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 perform similarly at the rotational 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 those of other positions, mainly showing electromagnetic noise and structural transmission vibration.

[0121] Frequency characteristics: the dominant component in the low frequency band is the rotating frequency and its harmonics, reflecting the rotor imbalance problem; the medium frequency band is the bearing fault characteristic frequency region; the high frequency band has increased broadband noise, reflecting bearing surface damage and impact noise.

[0122] Spectrum analysis: the response of microphone spectrum and vibration spectrum at the fault frequency is obviously different, the vibration sensor can capture bearing fault characteristics more clearly, while the microphone is greatly affected by environmental noise.

[0123] Analysis results: the bearing has inner ring fault, which needs to be closely monitored for development, the rotor has obvious imbalance, dynamic balance correction should be considered, electromagnetic noise is obvious, the power quality and electromagnetic state of the motor need to be checked.

[0124] According to the corresponding analysis results, the corresponding positions of the motor to be tested 3 can be checked, which is also conducive to the further improvement of motor production.

[0125] 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 skilled in the art without creative labor should belong to the scope of protection of the present application.

Claims

1. A motor operating noise detection device, characterized in that: The device includes a testing chamber (1), inside which a placement component (2) is installed, inside which a motor to be tested (3) is installed, outside of which a vibration detection component (4) is installed, and above which a noise detection component (5) is installed. The placement component (2) includes a top cover (21), and a placement chamber (22) is provided below the top cover (21). The top cover (21) and the placement chamber (22) are both filled with sound insulation material. A set of telescopic mechanisms (23) are provided on both sides of the placement chamber (22). An installation plate (24) is provided inside the placement chamber (22). The motor to be tested (3) is located 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 provided 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 drive end bearing of the motor (3) under test. The second detection mechanism (42) includes a third detector (427) for detecting the housing of the motor (3) under test and a fourth detector (429) for detecting the non-drive end bearing of the motor (3) under test. The noise detection component (5) includes a first microphone (51) which is positioned above the motor (3) under test, and a second microphone (52) is positioned on one side of the motor (3) under test.

2. The motor operating noise detection device according to claim 1, characterized in that: The placement component (2) also includes a mating plate (25), which is located on the opposite side of the mounting plate (24). A connecting shaft (26) is provided on one side of the mating plate (25). The output end of the motor under test (3) passes through the mounting plate (24), the mating plate (25) and the connecting shaft (26) in sequence. A fixing mechanism (27) is provided on the mounting plate (24).

3. The motor operating noise detection device according to claim 2, characterized in that: The fixing mechanism (27) includes a rotary cylinder (271), which is located in the middle of the mounting plate (24) and the mating plate (25). The output end of the rotary cylinder (271) is connected to a fixing member (272), which is L-shaped.

4. The motor operating noise detection device according to claim 1, characterized in that: 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), and the second connecting block (413) is sleeved on the outside of the first support rod (411).

5. The motor operating noise detection device according to claim 4, characterized in that: A first placement rod (414) is provided through the first connecting block (412), and 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).

6. The motor operating noise detection device according to claim 5, characterized in that: 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 in an alternating manner. 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 second placement rod (415) away from the second connecting block (413) is fitted with a first placement block (416).

7. The motor operating noise detection device according to claim 1, characterized in that: The second detection mechanism (42) includes a second support rod (421), a third connecting block (422) is sleeved on the outside of the second support rod (421), and a fourth connecting block (423) is provided below the third connecting block (422), and the fourth connecting block (423) is sleeved on the outside of the second support rod (421).

8. The motor operating noise detection device according to claim 7, characterized in that: A third placement rod (424) is provided through the third connecting block (422), and a third placement block (426) is sleeved on the outer side of the end of the third placement rod (424) away from the third connecting block (422).

9. The motor operating noise detection device according to claim 8, characterized in that: A fifth placement rod (425) is provided through the fourth connecting block (423). The third placement rod (424) and the fifth placement rod (425) are arranged in parallel. The outer sides of the second support rod (421), the third placement rod (424), and the fifth placement rod (425) are all provided with scales.

10. The motor operating noise detection device according to claim 9, characterized in that: The fifth placement rod (425) is fitted with a fourth placement block (428) on the outer side of the end away from the fourth connecting block (423), and the fourth detector (429) is located on the side of the third placement block (426) away from the second support rod (421).

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