[0038] Refer to figure 1 , The online bearing status monitoring system based on fiber vibration sensing (hereinafter sometimes referred to as “monitoring system”) in an embodiment of the present invention includes a laser 1, a pulse modulator 2, a circulator 3, an optical scanning device 4, and vibration Sensor optical cable 5, attenuator 7, photodetector 8, signal acquisition and processing module 9, and power supply module 10.
[0039] The laser light generated by the laser 1 is modulated by the pulse modulator 2 into pulsed laser light, and then enters one of the multiple (n) vibration sensing optical cables 5 through the circulator 3 and the optical scanning device 4 to detect multiple ( m) Vibration of bearing 6 under working conditions. The vibration of the bearing 6 will cause a change in the stress of the optical fiber in the vibration sensing optical cable 5, thereby causing a corresponding change in the Rayleigh scattered light signal. The Rayleigh scattered light signal with bearing vibration information is received by the photodetector 8 after passing through the optical scanning device 4 and the circulator 3 backwards (that is, in the direction opposite to the forward direction of the laser), and is converted into an electrical signal and then collected by the signal And processing module 9 processing. The laser light transmitted forward finally enters the attenuator 7 and is attenuated.
[0040] Because the distance between each bearing 6 and the photodetector 8 detected by the same vibration sensor cable 5 is different, the vibration signal of each bearing can be distinguished by the time when the signal is received. In the signal acquisition and processing module 9, the Rayleigh scattered electric signal is processed and compared with the bearing failure database to determine the working state of the bearing 6. The optical scanning device 4 is controlled to connect the circulator 3 and the vibration sensor cables 5 of different branches, so as to realize the condition monitoring of a large number of bearings.
[0041] The signal acquisition and processing module 9 may include an AD converter and a microprocessor. The signal acquisition and processing module 9 can be connected to the pulse modulator 2 to control the modulation mode of the pulse modulator 2. Although the laser 1 and the pulse modulator 2 in the present application can be replaced by a laser emitting pulsed laser, in the combination of the laser 1 and the pulse modulator 2 of the present invention, a continuous light emitting and therefore cheaper The laser 1, and through the signal acquisition and processing module 9 to control the pulse modulator 2, the pulse modulator 2 can generate pulse lasers with different modulation modes. It should be understood that the laser 1 and the pulse modulator 2 in the present application can also be referred to as a laser generating device for emitting pulsed laser light. The circulator 3 is used to transfer the pulsed laser light from the pulse modulator 2 to the optical scanning device 4 and used to transfer the scattered light signal from the optical scanning device 4 to the photodetector 8. As is well known, a circulator is an irreversible device with several terminals. In this application, the circulator 3 has at least three ends. For example, the pulsed laser from the pulse modulator 2 enters the circulator 3 from the terminal 1 and outputs from the terminal 2 to the optical scanning device 4; the scattered light signal from the optical scanning device 4 enters the circulator 3 from the terminal 2 and outputs from the terminal 3 to the circulator 3. Photodetector 8.
[0042] The signal acquisition and processing module 9 is also connected to the optical scanning device 4 to control the optical scanning device 4 to connect the circulator 3 with the vibration sensing optical cables 5 of different branches. The signal acquisition and processing module 9 can also control the optical scanning device 4 to circulate The maintaining time of the communication between the device 3 and a certain vibration sensor cable 5 is to monitor the duration of the connection of the vibration sensor cable 5 to the bearing 6. The holding time or duration can be determined according to the number of bearings 6 to which the vibration sensing optical cable 5 is connected and/or the length of the vibration sensing optical cable 5.
[0043] The power module 10 provides power for components that require power, such as the laser 1, the pulse modulator 2, the optical scanning device 4, the photodetector 8, and the signal acquisition and processing module 9.
[0044] Multiple (n) vibration sensing optical cables 5 are connected in parallel to the optical scanning device 4, and an attenuator 7 is connected to the end of each vibration sensing optical cable 5 (the front end in the laser traveling direction). The attenuator 7 can attenuate the advancing laser light, thereby preventing or reducing the reflected laser light from being formed as noise of scattered light signals.
[0045] Each vibration sensing optical cable 5 can be connected to multiple (m) bearings. Therefore, the monitoring system of the present invention can monitor the state of m×n bearings. Of course, the number of bearings 6 connected (monitored) to each vibration sensing optical cable 5 can also be different.
[0046] Such as figure 2 As shown, the optical scanning device 4 includes two plane mirrors 401A and 401B, a fixed plate 402, a motor 403, and a plurality (greater than or equal to n) laser couplers 404A, 404B, 404C,... The reflecting surfaces of the two plane mirrors 401A and 401B are arranged in parallel with each other so as to face each other. The reflecting surfaces of the two plane mirrors 401A and 401B are opposite to each other. The end faces of the two plane mirrors 401A and 401B are not on the same plane. Two plane mirrors 401A and 401B are mounted on the fixed plate 402, and their symmetry centers coincide with the center of the fixed plate 402. The fixed plate 402 is installed on the main shaft of the motor 403, and the main shaft axis of the motor 403 coincides with the fixed plate axis and passes through the symmetry centers of the two plane mirrors 401A and 401B. The laser couplers 404A, 404B, 404C, ... are respectively connected to a vibration sensing optical cable 5.
[0047] image 3 The working principle of the optical scanning device 4 is shown. The laser light (incident laser 101) from the circulator 3 is incident in a fixed direction, and the outgoing laser 102 reflected by the two plane mirrors 401A and 401B is parallel to the incident laser 101 and enters the laser The coupler 404A and the vibration sensor optical cable 5 connected thereto. When the motor 403 drives the plane mirrors 401A and 401B to rotate around their center of symmetry 405, that is, when the plane mirrors rotate from the positions 401A and 401B shown by the solid lines to the positions 401A' and 401B' shown by the dotted lines, the emitted laser light 102' phase Compared with the outgoing laser 102 before the rotation, it produces a parallel offset and enters the laser coupler 404B and the vibration sensor optical cable 5 connected to it. The multiple couplers 404A, 404B, 404C,... Arranged on the plane perpendicular to the outgoing laser light can couple the laser light in the free space to the vibration sensor cable 5.
[0048] The optical scanning device 4 is in the form of one input and multiple parallel outputs, and the number of output channels can range from 4 to 64. The optical scanning device 4 is configured to input the incident laser light 101 from the circulator 3 to a plurality of vibration sensing optical cables 5 time-divisionally. The optical scanning device 4 may be configured to cyclically and sequentially input the incident laser light 101 from the circulator 3 to a plurality of vibration sensing optical cables 5 (a plurality of laser couplers 404A, 404B, 404C, ...). The optical scanning device 4 can also selectively input the incident laser light 101 from the circulator 3 to the specific vibration sensing optical cable 5 according to the control of the signal acquisition and processing module 9.
[0049] It should be understood that the above "input laser 101 time-divisionally input to multiple vibration sensing optical cables 5" just means that laser light is input to only one vibration sensing optical cable 5 at the same time, and different vibration sensing optical cables 5 can be input at different times. Enter the laser. This does not mean that the laser light must be input to all the vibration sensing optical cables 5 sequentially or cyclically, nor does it mean that the laser light input time to the multiple vibration sensing optical cables 5 must be equal to each other. At a certain time point or time period, it is also possible not to input laser light to any vibration sensing optical cable 5. The action mode of the optical scanning device 4 can be appropriately controlled by the signal acquisition and processing module 9.
[0050] The structure of the optical scanning device of the present invention is not limited to the above-mentioned structure. The number of mirrors can also be one or more. The number of motors can also be one or more. The motor can rotate or move one or more mirrors, and the motor can also rotate or move some of the mirrors. The motor can also move multiple laser couplers at the same time, or move a selected laser coupler to a position that receives incident laser light. Moreover, the two mirrors do not have to be arranged in parallel.
[0051] Such as Figure 4 As shown, the vibration sensing optical cable 5 is divided into two different structural parts according to different functions. The transmission part 501 is a solid structure in which a core (also called a bare fiber) 503 is wrapped by a protective cover 504 and a cladding 505, and the sensing part 502 is a hollow structure, that is, the core 503 is suspended in the protective sleeve 504, and there is no cladding 505 between the protective sleeve 504 and the core 503.
[0052] In the length direction of the vibration sensor cable 5, the transmission part 501 and the sensor part 502 are alternately arranged. The sensing part 502 is used for mounting to the bearing to sense the vibration of the bearing. The transmission part 501 is used to transmit laser light and scattered light traveling in the reverse direction. The sensing part 502 is more suitable for sensing vibration than the transmission part 501. Of course, laser light and scattered light can also be transmitted in the sensing part 502.
[0053] It should be understood that the mounting of the sensing part 502 to the bearing covers the mounting of the sensing part 502 to the inner or outer ring of the bearing, but this is not easy to achieve in many cases. Therefore, the mounting of the sensing part 502 to the bearing also covers the mounting of the sensing part 502 to other components (such as the end cover of the bearing mentioned below) that are in contact with the bearing and receive the vibration of the bearing.
[0054] Such as Figure 5 As shown, the vibration sensing optical cable 5 can be installed to the end cover 601 of the bearing 6. The end cover 601 includes a circular ring plate 602 and a flange 603 protruding from the inner circumference of the circular ring plate 602 toward one side in the axial direction. The flange 603 is provided with a circumferential groove 604. The sensing part 502 of the vibration sensing optical cable 5 is freely wound in the circumferential groove 604 of the flange 603 of the end cap 601. The non-vibration sensing transmission part 501 of the vibration sensing optical cable 5 is fixed.
[0055] When the end cover 601 is installed on the bearing 6, the flange 603 abuts against the outer ring of the bearing 6 to receive the vibration of the bearing. The ring plate 602 can be accommodated in the bearing housing.
[0056] In the online monitoring system for bearing status based on optical fiber vibration sensing of the present invention, the host except for the vibration sensing optical cable 5 is placed approximately in the middle or center of the multiple bearings to be monitored, thereby increasing the number of monitored bearings.
[0057] The online bearing state monitoring system based on optical fiber vibration sensing of the present invention may also include a bearing failure mode database (for example, a voiceprint database). In this way, the signal acquisition and processing module 9 can compare the scattered light signal obtained by it with the data in the bearing failure mode database to determine the working state and/or failure type of the bearing. Therefore, the monitoring system of the present invention can be called a "smart" bearing state online monitoring system.
[0058] In the on-line monitoring system of the bearing condition based on optical fiber vibration sensing of the present invention, through a specially designed vibration sensing optical cable and its installation method, the layout of functional devices and the optical scanning device, the present invention provides a method for improving the vibration of the optical fiber. The sensitivity of the monitoring device and the reduction of energy loss are used to increase the number of monitored bearings, so as to realize a system of online monitoring of multiple bearings. This technical solution can greatly reduce the system cost and improve the feasibility of large-scale application of the bearing online monitoring system on high-speed trains, wind turbines and multiple machine tools.
[0059] The present invention also provides an online monitoring method for bearing state based on optical fiber vibration sensing based on the above monitoring system.
[0060] It should be understood that the above-mentioned embodiments are only exemplary and are not used to limit the present invention. Those skilled in the art can make various modifications and changes to the above-mentioned embodiments under the teaching of the present invention without departing from the scope of the present invention.
