Stick-slip vibration test system for water-lubricated nitrile rubber tail bearing

Abstract

The invention discloses a stick-slip vibration test system for a water-lubricated nitrile rubber tail bearing, which belongs to the field of water-lubricated tail bearings and comprises a high-speed camera, an LED white light lamp, two acceleration sensor bodies, a tail shaft body, a test block, a mounting bracket, a torque meter, an infrared velocimeter, a motor and a Bamp. And K is PULES. A machine vision technology is adopted to collect a tail bearing test block vibration displacement image, an acceleration sensor body is adopted to collect a vertical vibration time domain signal and a frequency domain signal of the vibration acceleration of the tail bearing test block, then a continuous coherence theory is applied to calculate the tail bearing test block vibration displacement image, and a barcode graph is generated. Topological characteristics are obtained, perfect combination of SVM, stick-slip vibration and continuous homology is achieved, classification and identification of stick-slip vibration of the tail bearing test block are finally achieved, the test block is installed through the fastening assembly, the two acceleration sensor bodies are installed through the buckle assembly, and position adjustment and installation are simple and efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of water-lubricated tail bearings, and in particular relates to a stick-slip vibration test system for a water-lubricated nitrile rubber tail bearing. Background Art

[0002] Excellent lubrication helps improve the tribological properties of water-lubricated stern bearings. However, in actual operation, especially during startup and shutdown phases, water-starved conditions, and high specific pressure and low speed conditions, water-lubricated stern bearings often operate in boundary or mixed lubrication conditions. This makes poor lubrication of the bearing-shaft friction pair extremely susceptible to slack, leading to stick-slip vibration in the stern bearing, which in turn causes a whistling sound. This seriously affects the ship's stealth and crew comfort. Although research has been conducted on stern bearing stick-slip vibration, classification and identification still rely on manual labor, which is inefficient and prone to errors and even mistakes due to inconsistent staff quality. Furthermore, the installation of test blocks and sensors requires numerous bolts, making fixation complex. Therefore, a water-lubricated nitrile rubber stern bearing stick-slip vibration test system is needed. This system uses artificial intelligence to apply persistent coherence theory to the image recognition and classification of stern bearing stick-slip vibration. This replaces manual labor with a machine, achieving excellent results in terms of efficiency, accuracy, and precision. Furthermore, the fixation of test blocks and sensors is simple and quick. Summary of the Invention

[0003] The purpose of the present invention is to provide a water-lubricated nitrile rubber tail bearing stick-slip vibration testing system, which has the advantages of using artificial intelligence to apply the theory of persistent coherence to the stick-slip vibration image recognition and classification of the tail bearing, replacing manual labor with a machine, and achieving good results in efficiency, accuracy and precision, so as to solve the above-mentioned background technical problems.

[0004] The technical solution of the present invention to solve the above technical problems is as follows: a water-lubricated nitrile rubber tail bearing stick-slip vibration test system, the test system comprising a high-speed camera, an LED white light, two acceleration sensor bodies, a tail shaft body, a test block, a mounting bracket, a torque meter, an infrared tachometer, a motor and B&K PULES;

[0005] The tail bearing test block undergoes elastic-plastic deformation under load and water lubrication, which in turn causes stick-slip and produces a whine. It is necessary to find its topological features in continuous coherence and search for useful features from these features to discover the characteristics of the tail bearing test block's whine.

[0006] The water-lubricated rubber material is processed into a rectangular test block, vulcanized with a copper outer lining, and fixed on a fixture. The acceleration sensor body (3) is a B&K acceleration sensor, which is arranged above the test block; the fixture is installed on the SSB-100 tail bearing test bench, and point T is taken on the friction surface of the sample as a measurement tracking point (about 1 mm away from the lower surface of the test block), points Ra and Rb are reference points, and the distance between the two points is 10 mm. The tail shaft speed is 20, 60 and 100 r / min, and the pressure is 0.29 MPa. The high-speed camera performs a 5 r / min test at each speed. 600 sampling points are taken in each test, and the vibration displacement amplitude of point T in the x and y directions is recorded. The data is recorded as DATA (abbreviated as "DT");

[0007] First, machine vision technology was used to capture the vibration displacement image of the tail bearing specimen, and a B&K Pulse accelerometer was used to collect the vertical vibration time domain and frequency domain signals of the tail bearing specimen's vibration acceleration. Second, the vibration displacement image of the tail bearing specimen was calculated using persistent coherence theory to generate a barcode image and obtain topological features. Finally, a support vector machine (SVM) was used to extract and identify the topological features derived from persistent coherence. The main features reflecting the stick-slip vibration process were input into the SVM. 80% of the data were selected as training samples and 20% of the data as test samples. The SVM was combined with the vibration features and persistent coherence to achieve the classification and identification of the stick-slip vibration of the tail bearing specimen.

[0008] The output shaft of the motor is connected to the infrared speed meter through a flange, the infrared speed meter is connected to the torque meter through a flange, and the B&K PULES is connected to the two acceleration sensor bodies through cables. The acceleration sensor body, the tail shaft body and the test block are all installed on the mounting bracket. The mounting bracket includes a vertical pole, a cantilever rod is installed on the vertical pole, a fixed plate is installed at the bottom of the front end of the cantilever rod, and a transmission member connected to the torque meter through a flange is installed on the rear side of the fixed plate. The linkage end of the transmission member passes through the front side of the fixed plate and is fixedly installed with the tail shaft body. A snap assembly is provided between the two acceleration sensor bodies and the cantilever rod, and a fastening assembly located above the tail shaft body is provided between the test block and the fixed plate.

[0009] Preferably, the fastening assembly includes a bearing seat fixedly connected to the front side of the fixed plate, a placement cavity is opened on the bearing seat, a copper block is installed on the top of the test block, the copper block is placed in the inner cavity of the placement cavity, the bottom of the test block pair is in contact with the tail shaft body, and a lower pressure block is connected to the left side of the top of the bearing seat through a rotating shaft, and a pressure sensor is installed in the inner cavity of the lower pressure block.

[0010] Preferably, a wedge-shaped surface is provided at the end of the lower pressing block, a fixing seat is fixedly connected to the right side of the top of the supporting seat, a threaded rod is threadedly connected to the inner cavity of the fixing seat, and a wedge-shaped block adapted to the wedge-shaped surface is rotatably connected to the left end of the threaded rod.

[0011] Preferably, two symmetrical anti-slip guide blocks are fixedly connected to the right side of the top of the bearing seat, and the wedge block is slidably connected to the surfaces of the two anti-slip guide blocks.

[0012] Preferably, the snap assembly includes a vertical plate fixed to the front end of the top of the street-facing cantilever pole, the surface of the vertical plate is engaged with an elastic snap, the bottom of the front side of the elastic snap is fixedly connected to a connecting seat, the connecting seat is fixedly installed with a transverse rod, both ends of the surface of the transverse rod are provided with a shell, and the acceleration sensor body is fixedly installed on the shell.

[0013] Preferably, two arc-shaped slots are provided on the rear side of the vertical plate, and two arc-shaped protrusions adapted to the arc-shaped slots are fixedly connected to the inner side of the elastic buckle.

[0014] Preferably, two symmetrical positioning strips are fixedly connected to the front side of the vertical plate, and two positioning grooves that slide on the surface of the positioning strips are provided on the inner side of the elastic buckle.

[0015] Preferably, a movable cavity is opened inside the shell, and the inner cavity of the movable cavity is slidably connected to a fitting plate, which is adapted to the connecting seat. A pressing block is provided on the outer side of the shell, and two symmetrical push rods are fixedly connected to one side of the pressing block. One end of the push rod passes through the inner cavity of the movable cavity and is fixedly connected to the fitting plate.

[0016] Preferably, a spring is sleeved on the surface of the push rod, and two ends of the spring are fixedly connected to the inner wall of the movable cavity and the bonding plate respectively.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention uses machine vision technology to collect the vibration displacement image of the tail bearing test block, and simultaneously uses the acceleration sensor body to collect the vertical vibration time domain signal and frequency domain signal of the vibration acceleration of the tail bearing test block. Then, the vibration displacement image of the tail bearing test block is calculated using the persistent coherence theory to generate a barcode image and obtain topological features. Then, a support vector machine (SVM) is used to extract and identify the topological features obtained by the persistent coherence. The main features reflecting the stick-slip vibration process are input into the support vector machine, and appropriate samples are selected for training and testing. This achieves a perfect combination of SVM with stick-slip vibration and persistent coherence. Finally, the stick-slip vibration of the tail bearing test block is classified and identified. In addition, the test block is installed by a fastening assembly, and the two acceleration sensor bodies are installed by a snap assembly, making position adjustment and installation relatively simple and efficient.

[0019] 2. The present invention can guide the movement of the wedge block by setting the anti-slip guide block, thereby preventing the wedge block from rotating with the rotation of the threaded rod and ensuring the stability of the wedge block so that the wedge block can squeeze the pressing block.

[0020] 3. The present invention uses the arc-shaped slot and the arc-shaped protrusion in combination. When the elastic clip is sleeved on the vertical plate, the arc-shaped protrusion enters the inner cavity of the corresponding arc-shaped slot, which can limit the elastic clip and prevent the elastic clip from detaching from the surface of the vertical plate.

[0021] 4. The present invention uses a positioning strip and a positioning groove in combination. When the elastic clip is sleeved on the surface of the vertical plate, the positioning groove will first be sleeved on the surface of the positioning strip to guide the arc-shaped protrusion on the elastic clip, so that the arc-shaped protrusion is aligned with the arc-shaped slot, making it easier for the arc-shaped protrusion to enter the inner cavity of the arc-shaped slot. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or other advantages of the present invention will become more clear and easier to understand through the detailed description made in conjunction with the following drawings, which are only exemplary and do not limit the present invention, wherein:

[0023] Figure 1 This is a schematic diagram of the system structure of an embodiment of the present invention;

[0024] Figure 2 This is a three-dimensional schematic diagram of a mounting bracket according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of a three-dimensional disassembly of a fastening assembly and a test block according to an embodiment of the present invention;

[0026] Figure 4 This is a front-view stereoscopic disassembled schematic diagram of a buckle assembly and an acceleration sensor according to an embodiment of the present invention;

[0027] Figure 5 This is a rear-view stereoscopic disassembled schematic diagram of a buckle assembly and an acceleration sensor according to an embodiment of the present invention;

[0028] Figure 6 An embodiment of the present invention Figure 5 A partial enlarged view of point A;

[0029] Figure 7 This is a scatter plot of displacement of measuring points according to an embodiment of the present invention;

[0030] Figure 8 This is a time-domain and frequency-domain signal diagram of the vertical vibration acceleration of a tail bearing test block according to an embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the classification and identification process of stick-slip vibration of a water-lubricated stern bearing test block according to an embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram of a tail bearing vibration barcode according to an embodiment of the present invention;

[0033] Figure 11Schematic diagram of tracking point positions according to an embodiment of the present invention.

[0034] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0035] 1. High-speed camera, 2. LED white light, 3. Accelerometer body, 4. Tail shaft body, 5. Test block, 6. Mounting bracket, 61. Vertical pole, 62. Lifting rod, 63. Fixing plate, 64. Transmission part, 65. Fastening assembly, 651. Bearing seat, 652. Placement cavity, 653. Copper block, 654. Pressing block, 655. Pressure sensor, 656. Wedge surface, 657. Fixing seat, 658. Threaded rod, 659. Wedge block, 6510. Anti- Remove the guide block, 66, snap assembly, 661, vertical plate, 662, elastic snap, 663, connecting seat, 664, transverse rod, 665, sleeve, 666, arc-shaped slot, 667, arc-shaped protrusion, 668, positioning bar, 669, positioning groove, 6610, movable cavity, 6611, fitting plate, 6612, pressing block, 6613, ejector rod, 6614, spring, 7, torque meter, 8, infrared speed meter, 9, motor, 10, B&KPULES. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of a water-lubricated nitrile rubber tail bearing stick-slip vibration testing system of the present invention will be described with reference to the accompanying drawings.

[0037] The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention. They are illustrative and exemplary and should not be construed as limiting the embodiments and scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the claims and the disclosure of the specification, including technical solutions that adopt any obvious substitutions and modifications to the embodiments described herein.

[0038] The drawings in this specification are schematic diagrams that assist in illustrating the concepts of the present invention and schematically illustrate the shapes of the various components and their interrelationships. Please note that to clearly illustrate the structures of the various components of the embodiments of the present invention, the drawings are not drawn to the same scale. The same reference numerals are used to indicate the same parts.

[0039] Example 1: Figure 1-11 A water-lubricated nitrile rubber tail bearing stick-slip vibration test system according to an embodiment of the present invention is shown, the test system comprising a high-speed camera (1), an LED white light lamp (2), two acceleration sensor bodies (3), a tail shaft body (4), a test block (5), a mounting bracket (6), a torque meter (7), an infrared speed meter (8), a motor (9) and B&K PULES (10);

[0040] Figure 11 To track the point position, the tail bearing test block undergoes elastic-plastic deformation due to load and water lubrication, which in turn causes stick-slip and the resulting squealing sound. It is necessary to find its topological features in persistent coherence and search for useful features from these features to discover the characteristics of the tail bearing test block squealing sound. The 14 features commonly used in support vector machines are listed in the table below. The second column indicates whether each feature corresponds to a 0-dimensional or 1-dimensional Betti number.

[0041]

[0042]

[0043] The water-lubricated rubber material was processed into a rectangular test block, vulcanized with a copper outer lining, and fixed on a fixture. The acceleration sensor was a B&K acceleration sensor, which was arranged above the test block. The fixture was installed on the SSB-100 tail bearing test bench. Point T was taken on the friction surface of the specimen as the measurement tracking point (about 1 mm away from the lower surface of the test block). Points Ra and Rb were reference points with a distance of 10 mm between the two points. The tail shaft speed was 20, 60 and 100 r / min, and the pressure was 0.29 MPa. A high-speed camera was used to conduct a 5 r / min test at each speed. 600 sampling points were taken in each test. The vibration displacement amplitude of point T in the x and y directions was recorded, and the data was recorded as DATA (abbreviated as "DT"). The test data is described in the following table. Figure 7 Shown is a scatter plot of displacement of measuring points;

[0044]

[0045] The vertical vibration acceleration of the tail bearing test block measured by acceleration sensor 3 is as follows: Figure 8 As shown;

[0046] like Figure 7 As shown in (a), at a speed of 20 r / min, the displacement of the measuring point is highly dispersed, and the displacement values fluctuate in both the x-direction (horizontal direction) and the y-direction (vertical direction). The displacement fluctuation amplitude of the measuring point in the x-direction is mainly concentrated between -0.2 and 0.2 mm, and the displacement fluctuation amplitude of the measuring point in the y-direction is mainly concentrated between -0.2 and 0.3 mm. The fluctuation amplitude is large, and it is preliminarily determined that the lubrication of the tail bearing is poor. Poor lubrication can easily lead to stick-slip vibration, causing "screaming" sound. Further research is needed. Figure 8 (a) and Figure 8 (d) It was found that under the working condition of 20r / min, both the time domain signal and the frequency domain signal showed large fluctuations; the amplitude of the vibration acceleration of the time domain signal in 0.15~0.40s was greater than that under the working condition of 100r / min ( Figure 8 (f)) significantly increased; contrast Figure 8 (a) and Figure 8 (c) Frequency domain curves: In the 0-3kHz range, the number of vibration acceleration peaks at 20 r / min is significantly greater than that at 100 r / min. The maximum amplitude of vibration acceleration at 20 r / min is 14.5 mm / s², which is greater than the 9.7 mm / s² at 100 r / min. Both the time and frequency domain signals exhibit large fluctuations, and a harsh "screaming" sound can be heard from the tail bearing during the test. This indicates that stick-slip vibration occurred in the tail bearing under this operating condition.

[0047] At a speed of 60r / min, the displacement scatter plot of the measuring point ( Figure 7 (b) The amplitude in the x and y directions is between 20 r / min and 100 r / min; Observe Figure 7 (b) The amplitude of the tail bearing vibration acceleration and frequency domain signal was found to be between 20 and 100 r / min, and no "screaming" sound was heard during the test. It was determined that under this operating condition, the tail bearing did not experience stick-slip vibration.

[0048] like Figure 7 As shown in (c), the displacement concentration of the tail bearing measuring point is high at 100 r / min, and the displacement value fluctuation is mainly concentrated in the x direction. The displacement fluctuation amplitude of the measuring point in the x direction is mainly concentrated in -0.1~0.1mm, and the fluctuation amplitude is small. During the test, it was found that the tail bearing did not make any "screaming" sound, and it was preliminarily determined that the tail bearing was well lubricated. Further research is needed. Figure 8 (c) and Figure 8 (f) It was found that the time and frequency domain signals of the tail bearing at 100 r / min were relatively stable, without large fluctuations, and no "screaming" sound was heard during the test. It can be concluded that under this operating condition, the tail bearing did not experience stick-slip vibration;

[0049] First, machine vision technology is used to collect the vibration displacement image of the tail bearing test block, and the B&K Pulse accelerometer is used to collect the vertical vibration time domain signal and frequency domain signal of the vibration acceleration of the tail bearing test block. Secondly, the vibration displacement image of the tail bearing test block is calculated using the persistent coherence theory to generate a barcode map and obtain the topological features. Finally, the support vector machine (SVM) is used to extract and identify the topological features obtained by persistent coherence. The main features reflecting the stick-slip vibration process are input into the SVM. 80% of the data are selected as training samples and 20% of the data are selected as test samples. The SVM is combined with the vibration features and persistent coherence to realize the classification and identification of the stick-slip vibration of the tail bearing test block. The specific process is as follows: Figure 9 As shown;

[0050] DT1, DT6, DT2 of water-lubricated rubber tail bearing specimens at 20, 60 and 100 r / min and 0.29 MPa 11The stick-slip vibration barcode diagram of the test data is as follows Figure 10 As shown;

[0051] Depend on Figure 10 (a) It can be seen that under the working conditions of 20r / min and 0.29MPa, the 0-dimensional Betty number is distributed in a stepped manner as a whole. Most of the points with ε greater than 0.01 are located in the upper layer, and the maximum ε is 0.042. The displacement data of the measuring point becomes looser and the amplitude is larger; the ε of the lower layer of the measuring point is in the interval [0, 0.01], indicating that the displacement data of the measuring point is compact and the amplitude is small; the displacement amplitude of the measuring point is random as a whole, indicating that at a speed of 20r / min (the lowest speed that the test bench can reach), the tail shaft-tail bearing friction pair is in a mixed lubrication state, the friction pair has intermittent shaft seizure, resulting in stick-slip phenomenon, which in turn induces chatter and The 1D Betty number is distributed as a line, with a large number of lines of varying lengths, indicating that the measuring point has formed many 1D rings around the origin. Since the tail bearing is made of highly viscoelastic material, stick-slip motion occurs between it and the tail shaft during the test. In the direction of rotation, the measuring point is pulled away from the origin by friction and then pulled back to the origin by the elastic restoring force of the rubber, forming a ring in the two-dimensional plane. Due to the stick-slip phenomenon, the measuring point is pulled away from the origin at different distances, forming rings of different sizes, resulting in different lengths of lines in the 1D Betty number diagram. The maximum radius of the 1D ring in the 1D Betty number diagram is 0.018, and the minimum is 0.001.

[0052] Observation 10(b) shows that compared with Figure 10 (a) Barcode diagram, Figure 10 The ε of the 0-dimensional Betty number in (b) is less than 0.0125, and the amplitude becomes smaller, indicating that with the increase of the speed, the lubrication state of the tail bearing changes from mixed lubrication to elastic hydrodynamic lubrication, and no stick-slip vibration or hum occurs. The 1-dimensional Betty number is tighter than that at 20 r / min, and the maximum ε drops to 0.005. This shows that at 60 r / min, due to the improvement of the lubrication state, the ring formed by the tail bearing displacement amplitude is tighter and the distribution is more concentrated.

[0053] observe Figure 10 (c) It is found that the data in the lower layer of the 0-dimensional Betty number increases slightly, but the change is not obvious, indicating that the tail bearing lubrication film has been fully established, the tail bearing is in good lubrication condition, and no stick-slip vibration occurs; the 1-dimensional Betty number is not much different from the 60r / min, and is still relatively close. More Betty numbers fall in the [0, 0.05] interval, indicating that the radius of the 1-dimensional ring formed by the measuring point around the origin is smaller, and the tail bearing operation is more stable;

[0054] Overall, the 0-dimensional Betty number trend in these three stages is from varying lengths at the beginning to gradually becoming regular and orderly. This indicates that as the speed increases, the tail bearing amplitude decreases, transitioning from mixed lubrication to complete lubrication, and from vibrating hum to no hum. The 1-dimensional Betty number trend is that the lines are long and sparse at the beginning, with fewer and longer-lasting 1-dimensional holes. As the speed increases, the lines become shorter and tighter. This indicates that as the speed increases, the tail bearing reaches a fully lubricated state, the amplitude decreases, and the operation gradually stabilizes.

[0055] DT1~DT4,DT6~DT9,DT 11 ~DT 14 Data as training samples, DT5, DT 10 , DT 15 The data was used as a test sample to predict vibrations. Feature 8 (the length of the longest line of the 1-dimensional Betty number barcode) in the first table was trained and learned. Feature 8 is the quantity that best reflects the persistent coherent topological characteristics. The support vector machine prediction results are listed in the following table. In the following table, Y is the predicted value of the support vector machine; J is the feature value extracted by the persistent coherence calculation; W is the error between the predicted value and the calculated value.

[0056]

[0057]

[0058] The output of the support vector machine is the prediction result of machine learning based on persistent coherence. Feature 8 reflects the stick-slip vibration of the water-lubricated rubber tail bearing specimen under the same load and different speeds. As shown in the table above, the maximum error value of Feature 8 is less than 3%, indicating that the use of persistent coherence-based machine learning to classify and predict the squealing sound caused by the stick-slip phenomenon of the tail bearing specimen is highly accurate.

[0059] The output shaft of the motor 9 is connected to the infrared speed meter 8 through a flange, the infrared speed meter 8 is connected to the torque meter 7 through a flange, and the B&K PULES 10 is connected to the two acceleration sensor bodies 3 through cables. The acceleration sensor body 3, the tail shaft body 4 and the test block 5 are all installed on the mounting bracket 6. The mounting bracket 6 includes a vertical pole 61, and a lifting rod 62 is installed on the vertical pole 61. A fixing plate 63 is installed at the bottom of the front end of the lifting rod 62. A transmission member 64 is installed on the rear side of the fixing plate 63 and is connected to the torque meter 7 through a flange. The linkage end of the transmission member 64 passes through the front side of the fixing plate 63 and is fixed to the tail shaft body 4. A snap assembly 66 is provided between the two acceleration sensor bodies 3 and the lifting rod 62, and a fastening assembly 65 located above the tail shaft body 4 is provided between the test block 5 and the fixing plate 63.

[0060] Example 2: Basically the same as Example 1, furthermore: the fastening assembly 65 includes a bearing seat 651 fixedly connected to the front side of the fixing plate 63, a placement cavity 652 is opened on the bearing seat 651, a copper block 653 is installed on the top of the test block 5, the copper block 653 is placed in the inner cavity of the placement cavity 652, the bottom of the test block 5 is in contact with the tail shaft body 4, the left side of the top of the bearing seat 651 is rotatably connected to a lower pressing block 654 through a rotating shaft, a pressure sensor 655 is installed in the inner cavity of the lower pressing block 654, a wedge-shaped surface 656 is opened at the end of the lower pressing block 654, and the right side of the top of the bearing seat 651 is fixedly connected to the fixing seat 6 57. The inner cavity of the fixed seat 657 is threadedly connected to a threaded rod 658, and the left end of the threaded rod 658 is rotatably connected to a wedge block 659 adapted to the wedge surface 656. The right side of the top of the supporting seat 651 is fixedly connected to two symmetrical anti-slip guide blocks 6510, and the wedge blocks 659 are slidably connected to the surfaces of the two anti-slip guide blocks 6510. Through the setting of the anti-slip guide blocks 6510, the movement of the wedge blocks 659 can be guided, so as to avoid the wedge blocks 659 from rotating with the rotation of the threaded rod 658 and ensure the stability of the wedge blocks 659 so that the wedge blocks 659 can squeeze the pressing block 654.

[0061] Example 3: Basically the same as Example 1, further: the buckle assembly 66 includes a vertical plate 661 fixed to the top front end of the street-facing word pick rod 62, the surface of the vertical plate 661 is engaged with an elastic buckle 662, the bottom of the front side of the elastic buckle 662 is fixedly connected to a connecting seat 663, the connecting seat 663 is fixedly installed with a transverse rod 664 through the connecting seat 663, both ends of the surface of the transverse rod 664 are provided with a sleeve 665, the acceleration sensor body 3 is fixedly installed on the sleeve 665, and the rear side of the vertical plate 661 is provided with two arc-shaped slots 6 66, the inner side of the elastic clip 662 is fixedly connected to two arc-shaped protrusions 667 that are adapted to the arc-shaped slots 666. Through the coordinated use of the arc-shaped slots 666 and the arc-shaped protrusions 667, when the elastic clip 662 is sleeved on the vertical plate 661, the arc-shaped protrusions 667 enter the inner cavity of the corresponding arc-shaped slots 666, which can limit the elastic clip 662 and prevent the elastic clip 662 from being separated from the surface of the vertical plate 661. The front side of the vertical plate 661 is fixedly connected to two symmetrical positioning strips 668. The elastic clip 662 The inner side of the housing 665 is provided with two positioning grooves 669 that slide on the surface of the positioning strip 668. Through the cooperation of the positioning strip 668 and the positioning groove 669, when the elastic buckle 662 is sleeved on the surface of the vertical plate 661, the positioning groove 669 will first be sleeved on the surface of the positioning strip 668, guiding the arc-shaped protrusion 667 on the elastic buckle 662, so that the arc-shaped protrusion 667 is aligned with the arc-shaped slot 666, so that the arc-shaped protrusion 667 can enter the inner cavity of the arc-shaped slot 666. The interior of the housing 665 is provided with an active cavity 6610. The active cavity The inner cavity of 6610 is slidably connected with a fitting plate 6611, which is adapted to the connecting seat 663. A pressing block 6612 is provided on the outer side of the sleeve 665. Two symmetrical push rods 6613 are fixedly connected to one side of the pressing block 6612. One end of the push rod 6613 passes through the inner cavity of the movable cavity 6610 and is fixedly connected to the fitting plate 6611. A spring 6614 is provided on the surface of the push rod 6613. The two ends of the spring 6614 are respectively fixedly connected to the inner wall of the movable cavity 6610 and the fitting plate 6611.

[0062] The test block 5 and the copper block 653 are placed as a whole in the inner cavity of the placement cavity 652, and then the lower pressing block 654 is turned over so that the lower pressing block 654 covers the top of the bearing seat 651 and the pressure sensor 655 in the inner cavity of the fastening assembly 65 is against the top of the copper block 653. Then the threaded rod 658 is operated to rotate. The thread causes the threaded rod 658 to rotate and move, and the threaded rod 658 drives the wedge block 659 to move until the wedge block 659 contacts the wedge surface 656 on the lower pressing block 654, which will cause the lower pressing block 654 to move downward and squeeze the copper block 653. The pressure sensor 655 will feedback the pressure at this time. After the pressure is within the appropriate range, the test block 5 can be installed above the tail shaft body 4, and then the elastic clip 662 is guided downward according to the limit of the positioning bar 668 and the positioning groove 669. It is put on the surface of the vertical plate 661 so that the arc-shaped protrusion 667 enters the inner cavity of the arc-shaped slot 666 to ensure the stability of the lifting rod 62. At this time, the acceleration sensor body 3 can be installed, and the pressing block 6612 is pressed so that the top rod 6613 pushes the fitting plate 6611 to slide in the inner cavity of the movable cavity 6610 and break away from the contact with the transverse rod 664. At this time, the spring 6614 is in a stretched state. The user can push the shell 665 to move and rotate on the surface of the transverse rod 664 to adjust the position of the acceleration sensor body 3 and cancel the pressure on the pressing block 6612. The restoring force of the spring 6614 makes the fitting plate 6611 contact the transverse rod 664 again, ensuring the position and state of the acceleration sensor body 3 at this time. The acceleration sensor body 3 and the test block 5 are installed in this way, which is simple and efficient.

[0063] In summary, the water-lubricated nitrile rubber tail bearing stick-slip vibration test system uses machine vision technology to collect the vibration displacement image of the tail bearing test block, and uses the acceleration sensor body 3 to collect the vertical vibration time domain signal and frequency domain signal of the vibration acceleration of the tail bearing test block. Then, the vibration displacement image of the tail bearing test block is calculated using the persistent coherence theory to generate a barcode image and obtain topological features. Then, the support vector machine (SVM) is used to extract and identify the topological features obtained by the persistent coherence. The main features reflecting the stick-slip vibration process are input into the support vector machine, and appropriate samples are selected for training and testing to achieve a perfect combination of SVM with stick-slip vibration and persistent coherence. Finally, the stick-slip vibration of the tail bearing test block is classified and identified. In addition, the test block 5 is installed by the fastening component 65, and the two acceleration sensor bodies 3 are installed by the snap assembly 66. The position adjustment and installation are relatively simple and efficient.

[0064] The technical features disclosed above are not limited to the disclosed combinations with other features. Those skilled in the art may also make other combinations between the technical features according to the purpose of the invention to achieve the purpose of the invention.

Claims

1. Water-lubricated nitrile rubber tail bearing stick-slip vibration test system, characterized by: The test system includes a high-speed camera (1), an LED white light (2), two acceleration sensor bodies (3), a tail shaft body (4), a test block (5), a mounting bracket (6), a torque meter (7), an infrared speed meter (8), a motor (9) and B&K PULES (10); The tail bearing test block is subjected to load and water lubrication, which causes elastic-plastic deformation, and then stick-slip phenomenon occurs, resulting in the occurrence of squealing sound; it is necessary to find its topological characteristics in continuous synchronization, Useful features are searched from these features to find the characteristics of the tail bearing test block's squealing sound; The water-lubricated rubber material is processed into a rectangular test block, vulcanized with a copper outer lining, and fixed on a fixture. The acceleration sensor body (3) is a B&K acceleration sensor, which is arranged above the test block; the fixture is installed on the SSB-100 tail bearing test bench, and point T is taken on the friction surface of the sample as a measurement tracking point (about 1 mm away from the lower surface of the test block), points Ra and Rb are reference points, and the distance between the two points is 10 mm. The tail shaft speed is 20, 60 and 100 r / min, and the pressure is 0.29 MPa. The high-speed camera performs a 5 r / min test at each speed. 600 sampling points are taken in each test, and the vibration displacement amplitude of point T in the x and y directions is recorded. The data is recorded as DATA (abbreviated as "DT"); First, machine vision technology was used to collect the vibration displacement image of the tail bearing specimen, and the vertical vibration time domain signal and frequency domain signal of the tail bearing specimen's vibration acceleration were collected using a B&KPulse accelerometer. Second, the vibration displacement image of the tail bearing specimen was calculated using the persistent coherence theory to generate a barcode image and obtain topological features. Finally, a support vector machine (SVM) was used to extract and identify the topological features obtained by persistent coherence. The main features reflecting the stick-slip vibration process were input into the SVM. 80% of the data were selected as training samples and 20% of the data were selected as test samples. The SVM was combined with the vibration features and persistent coherence to achieve the classification and identification of the stick-slip vibration of the tail bearing specimen. The output shaft of the motor (9) is connected to the infrared speed meter (8) through a flange, and the infrared speed meter (8) is connected to the torque meter (7) through a flange. The PULES (10) is connected to two acceleration sensor bodies (3) through cables. The acceleration sensor bodies (3), the tail shaft body (4) and the test block (5) are all installed on a mounting bracket (6). The mounting bracket (6) includes a vertical rod (61). A lifting rod (62) is installed on the vertical rod (61). A fixing plate (63) is installed at the bottom of the front end of the lifting rod (62). A transmission member (64) connected to the torque meter (7) through a flange is installed on the rear side of the fixing plate (63). The linkage end of the transmission member (64) passes through the front side of the fixing plate (63) and is fixedly installed with the tail shaft body (4). A snap assembly (66) is provided between the two acceleration sensor bodies (3) and the lifting rod (62). A fastening assembly (65) located above the tail shaft body (4) is provided between the test block (5) and the fixing plate (63).

2. The stick-slip vibration test system of the water-lubricated nitrile rubber tail bearing according to claim 1 is characterized in that: The fastening assembly (65) includes a bearing seat (651) fixedly connected to the front side of the fixing plate (63), a placement cavity (652) is provided on the bearing seat (651), a copper block (653) is installed on the top of the test block (5), and the copper block (653) is placed in the inner cavity of the placement cavity (652), the bottom of the test block (5) is in contact with the tail shaft body (4), and a lower pressing block (654) is rotatably connected to the left side of the top of the bearing seat (651) through a rotating shaft, and a pressure sensor (655) is installed in the inner cavity of the lower pressing block (654).

3. The stick-slip vibration test system of the water-lubricated nitrile rubber tail bearing according to claim 2 is characterized in that: The end of the lower pressure block (654) is provided with a wedge-shaped surface (656), the right side of the top of the supporting seat (651) is fixedly connected to a fixing seat (657), the inner cavity of the fixing seat (657) is threadedly connected to a threaded rod (658), and the left end of the threaded rod (658) is rotatably connected to a wedge-shaped block (659) adapted to the wedge-shaped surface (656).

4. The stick-slip vibration test system of the water-lubricated nitrile rubber tail bearing according to claim 3 is characterized in that: Two symmetrical anti-slip guide blocks (6510) are fixedly connected to the right side of the top of the bearing seat (651), and the wedge block (659) is slidably connected to the surfaces of the two anti-slip guide blocks (6510).

5. The stick-slip vibration test system of the water-lubricated nitrile rubber tail bearing according to claim 4 is characterized in that: The buckle assembly (66) comprises a vertical plate (661) fixed to the front end of the top of the street-facing cantilever rod (62); an elastic buckle (662) is engaged on the surface of the vertical plate (661); a connecting seat (663) is fixedly connected to the bottom of the front side of the elastic buckle (662); a transverse rod (664) is fixedly installed on the connecting seat (663); both ends of the surface of the transverse rod (664) are provided with a sleeve (665); and the acceleration sensor body (3) is fixedly installed on the sleeve (665).

6. The stick-slip vibration test system of the water-lubricated nitrile rubber tail bearing according to claim 5, characterized in that: Two arc-shaped slots (666) are provided on the rear side of the vertical plate (661), and two arc-shaped protrusions (667) adapted to the arc-shaped slots (666) are fixedly connected to the inner side of the elastic buckle (662).

7. The stick-slip vibration test system of the water-lubricated nitrile rubber tail bearing according to claim 6, characterized in that: Two symmetrical positioning strips (668) are fixedly connected to the front side of the vertical plate (661), and two positioning grooves (669) are provided on the inner side of the elastic buckle (662) for sliding on the surface of the positioning strips (668).

8. The stick-slip vibration test system for a water-lubricated nitrile rubber tail bearing according to claim 7, characterized in that: A movable cavity (6610) is provided inside the sleeve (665), and the inner cavity of the movable cavity (6610) is slidably connected to a fitting plate (6611), and the fitting plate (6611) is adapted to the connecting seat (663). A pressing block (6612) is provided on the outer side of the sleeve (665), and two symmetrical push rods (6613) are fixedly connected to one side of the pressing block (6612), and one end of the push rod (6613) passes through the inner cavity of the movable cavity (6610) and is fixedly connected to the fitting plate (6611).

9. The stick-slip vibration test system of the water-lubricated nitrile rubber tail bearing according to claim 8, characterized in that: The surface of the push rod (6613) is sleeved with a spring (6614), and the two ends of the spring (6614) are fixedly connected to the inner wall of the movable cavity (6610) and the fitting plate (6611) respectively.

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