Air-suspension thrust bearing state monitoring device and control system thereof

Abstract

The application discloses a kind of gas suspension thrust bearing state monitoring devices, including shell, stator assembly and rotor assembly;The rotor assembly includes shaft, respectively installs in the front and rear end of shaft large impeller, small impeller and the thrust disc of the side of large impeller;The stator assembly is installed in shell and is set around the outer circumference of shaft, and gas suspension front radial bearing and gas suspension rear radial bearing are respectively installed at the front and rear journal of shaft, it is characterized in that, thrust bearing plate and position sensor are equipped in the front and rear end surface of thrust disc, the chamber space that thrust disc extends into is formed between thrust bearing plate, and the distance of thrust disc and thrust bearing plate is measured by position sensor.The application can effectively monitor gas suspension thrust bearing at low cost, and in the case such as overload, corresponding adjustment can be made in advance, avoid the deterioration of thrust bearing, greatly improve the operation reliability of thrust bearing, so as to improve the operation stability of whole machine.

Description

Technical Field

[0001] The present invention belongs to the field of centrifugal blower equipment, and in particular relates to an air suspension thrust bearing state monitoring device and a control system thereof. Background Art

[0002] The air-suspended high-speed direct-drive centrifugal blower integrates a permanent magnet high-speed motor, a high-efficiency three-dimensional flow impeller, stepless speed change, direct drive, and frictionless suspension support. Compared with traditional blowers such as Roots blowers, it has a very significant improvement in efficiency in key links such as motor efficiency, drive efficiency, transmission efficiency, and aerodynamic efficiency. The overall system efficiency of the whole machine system composed of such high-efficiency key links has been greatly improved. It has been widely used in the field of sewage treatment and is the development direction of high-efficiency aeration blowers.

[0003] In current practical applications, air suspension bearings, especially air suspension thrust bearings, are still a link in the entire air suspension system that is subject to high forces and has a relatively high failure rate. It is necessary to improve their reliability, thereby improving the reliability of the entire equipment.

[0004] A major drawback of existing technologies is the lack of real-time monitoring of air-suspended thrust bearings. For example, current temperature monitoring methods for air-suspended thrust bearings often have a poor response time to temperature rise. By the time the temperature reaches the monitoring value, the bearing is often already severely damaged, making it impossible to adjust in advance.

[0005] In addition, there are also some that use precision displacement sensors to monitor the position of the thrust plate. The position signal detected by this position sensor is timely and accurate. It can judge and analyze the real-time operating status of the air suspension thrust bearing based on the position signal and take timely measures to adjust it. However, this type of displacement sensor is often expensive, which directly increases the cost of the fan. More importantly, this type of displacement sensor will inevitably have a temperature drift problem during long-term use. That is, after a certain period of operation, the analog electrical signal fed back by this type of displacement sensor after detecting the same position signal will change, especially when the temperature is different. To improve this problem, the displacement sensor must be calibrated. However, calibration cannot be carried out at the fan application site, which seriously affects the continuous and long-term reliable operation of the fan equipment.

[0006] Therefore, it is necessary to have a low-cost, high-reliability monitoring solution for real-time monitoring of air-suspended thrust bearings, combined with the corresponding control system, to improve the reliability of the fan. Summary of the Invention

[0007] In order to solve the above problems, the present invention discloses an air suspension thrust bearing state monitoring device and a control system thereof, which can realize effective monitoring of the air suspension thrust bearing at low cost and greatly improve the real-time performance of monitoring.

[0008] An air-suspended thrust bearing condition monitoring device comprises a casing, a stator assembly and a rotor assembly; the rotor assembly comprises a rotating shaft, a large impeller and a small impeller respectively mounted at the front and rear ends of the rotating shaft, and a thrust plate on the side close to the large impeller; the stator assembly is mounted in the casing and arranged around the outer circumference of the rotating shaft, an air-suspended front radial bearing and an air-suspended rear radial bearing are respectively mounted at the front and rear journals of the rotating shaft, thrust bearing plates are respectively provided on the front and rear end surfaces of the thrust plate, a chamber space is formed between the two thrust bearing plates to accommodate the thrust plate extending therein, and position sensors are also provided on the opposite planes of the two thrust bearing plates, and the distance between the thrust plate and the thrust bearing plates is measured by the position sensor.

[0009] Preferably, the thrust bearing plate includes a thrust bearing front plate and a thrust bearing rear plate, both of which are arranged in the casing and are respectively installed and fixed in parallel with the corresponding positions of the front journal of the rotating shaft; the two opposite end planes of the thrust bearing rear plate and the thrust bearing front plate are respectively provided with an air-suspended rear thrust bearing and an air-suspended front thrust bearing.

[0010] Preferably, a pair of air-suspended thrust devices are provided between the thrust bearing plates, including an air-suspended rear thrust bearing and an air-suspended front thrust bearing. The thrust plate is placed between the air-suspended front and rear thrust bearings, and a compressed air film exists between the air-suspended front and rear thrust bearings on both sides. The outer diameter of the thrust plate is larger than the outer diameter of the air-suspended front and rear thrust bearings.

[0011] Preferably, the air-suspended front radial bearing is arranged on the inner arc surface of the thrust bearing rear plate and is arranged around the rotating shaft; the air-suspended rear radial bearing is arranged on the inner arc surface of the rear radial bearing seat and is arranged around the rotating shaft.

[0012] Preferably, a pair of position sensors are symmetrically installed at the relative positions of the thrust bearing front plate and the thrust bearing rear plate, namely a front position sensor and a rear position sensor, for measuring the distance between the front plate and the intermediate thrust plate.

[0013] Preferably, the position sensor includes a mounting portion, an adapter portion and a sensing portion in sequence, wherein the mounting portion and the adapter portion are arranged throughout the front position sensor, and the outer end face of the adapter portion is flush with the end face of the thrust bearing plate, and the sensing portion extends out of the front end face of the position sensor and measures the distance between the thrust plate and the thrust plate, but does not contact the front and rear thrust bearings of the air suspension; one or more independent sensing probes are arranged in the center of the sensing portion, and the sensing probes are several metal wires with insulating sheaths, and the outer ends of the metal wires remain flush and are not covered with insulation.

[0014] Preferably, the air suspension front radial bearing, the air suspension rear radial bearing, the air suspension front thrust bearing, and the air suspension rear thrust bearing are foil-type air suspension bearings.

[0015] The present invention also discloses a control system for an air-suspended thrust bearing state monitoring device, comprising a position parameter module, an aerodynamic parameter module, and a motor control module, wherein the position parameter module obtains a state signal based on the state of the induction probes of the position sensors on both sides of the thrust plate, and transmits the state signal to a host computer; the aerodynamic parameter module obtains relevant aerodynamic operating parameters, including inlet pressure, exhaust pressure, inlet temperature, exhaust temperature, and inlet flow, based on aerodynamic parameter sensors arranged at the air inlet of the large impeller and the vertebral canal exhaust port; the motor control module obtains motor operating parameters, including motor speed, motor current, motor power, and motor torque, based on a motor controller electrically connected to the motor; the host computer determines the position information of the thrust plate based on the state signal, and obtains the force load condition of the thrust bearing by looking up the built-in information table; the operating state of the motor and the pneumatic impeller at the current moment is obtained based on the aerodynamic operating parameters and the motor operating parameters; based on the actual force load condition of the thrust bearing, combined with the operating state of the motor and the pneumatic impeller at the current moment, further analyzes and diagnoses whether the current operating state is reasonable and formulates a corresponding control strategy.

[0016] Preferably, the host computer further analyzes and diagnoses whether the current operating state is reasonable based on the actual force load of the thrust bearing and the operating state of the motor and the pneumatic impeller at the current moment, and formulates a corresponding control strategy.

[0017] Preferably, the information table is a correspondence table between the position information and the load stress condition of the thrust bearing of this type, and the actual stress condition of the thrust bearing is found out according to the position information.

[0018] The present invention also discloses a control method for an air suspension thrust bearing condition monitoring device, comprising the following steps: Step 1, obtaining aerodynamic operating parameters based on aerodynamic parameter sensors provided at the air inlet of the large impeller and the exhaust port of the spinal canal, and obtaining an inlet flow rate Q, where Q = Qp(P1, T1, P2, T2), where P1 is the inlet pressure, T1 is the inlet temperature, P2 is the exhaust pressure, and T2 is the exhaust temperature;

[0019] Step 2. Obtain the impeller axial force Fp according to the speed n and flow rate Q. Fp = Fp1(n)*Fp2(Q), the unit of Fp is N, where n is the impeller speed (r / min), Q is the impeller inlet flow rate (m3 / min), Fp is the axial force on the large impeller, generally pointing from the back of the wheel to the air inlet side, Fp1(n) is the component of the axial force on the large impeller related to the speed n, and Fp2(Q) is the component of the axial force on the large impeller related to the flow rate Q, both of which are part of the axial force on the large impeller.

[0020] Step 3: Obtain the thrust plate position d based on the position sensor signal, using 0 and 1 to represent the open and closed states of the sensor. A combination of 0 and 1 represents different state combinations of several position sensors, corresponding to different operating state information.

[0021] Step 4: Calculate the thrust plate's bearing capacity Ft based on the thrust plate's position d and speed n: Ft = Ft1(n)*Ft2(d), where Ft is expressed in N, n is the impeller speed (r / min), Ft1 is the component of the thrust plate's bearing capacity Ft that is related to the speed n, and Ft2 is the component of the thrust plate's bearing capacity Ft that is related to the thrust plate's position d.

[0022] Step 5: Based on the current pressure value, flow rate, temperature and motor power parameters, compare the impeller axial force Fp and the bearing load capacity Ft to determine whether the current impeller operation is in the normal range. If not, make corresponding adjustments.

[0023] Preferably, the position change of the thrust plate and its further change trend are judged based on the change of the position signal of d, especially the change speed; at the same time, the change also reflects the change of the axial position of the impeller, which is used as a criterion for the stability of the impeller operation and transmitted to the upper computer to timely grasp the impeller operation status and make timely adjustments.

[0024] Preferably, when the speed, flow rate, and impeller axial force change relatively little while the bearing capacity of the thrust plate increases relatively more and the speed is relatively fast, it indicates that the thrust bearing load is rapidly increasing and is not in the normal range. Adjustment measures need to be taken. Specifically, increase the speed and exhaust pressure to see if the bearing capacity of the thrust plate can be reduced. If it does not decrease or even increases further, operate the pneumatic control components and sound an alarm at the same time, and check the inlet and exhaust pipe conditions.

[0025] Beneficial effects:

[0026] (1) The present invention realizes effective monitoring of the air suspension thrust bearing through a simple and reliable position sensor, greatly improving the real-time monitoring performance;

[0027] (2) The present invention monitors the air-suspended thrust bearing and can make corresponding adjustments in advance in the event of overload, thereby avoiding deterioration of the thrust bearing and significantly improving the operational reliability of the thrust bearing, thereby improving the operational stability of the entire machine;

[0028] (3) The present invention uses a low-cost position sensor, which basically does not increase the cost of the fan equipment and has excellent economic efficiency;

[0029] (4) The position sensor used in the present invention is stable and reliable, has a simple internal structure, does not contain complex precision components, does not have the sensor "temperature drift" phenomenon that is easy to occur after long-term use, and does not require recalibration maintenance work. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the cross-sectional structure of a centrifugal blower;

[0031] Figure 2 This is a partial enlarged view including the position sensor and thrust bearing;

[0032] Figure 3 This is a schematic diagram of the position sensor structure (the sensing part includes 1 sensing probe);

[0033] Figure 4 This is a schematic diagram of the position sensor structure (the sensing part includes 4 sensing probes);

[0034] Figure 5 It is an air suspension front thrust bearing (with 6 sensors installed);

[0035] Figure 6 It is an air suspension rear thrust bearing (with 6 sensors installed);

[0036] Figure 7 It is the control system block diagram.

[0037] Reference numerals:

[0038] 1 Casing, 2 Stator assembly, 2-1 Stator core, 2-2 Copper wire winding, 2-3 Lead wire, 3 Rear radial bearing plate, 4 Rear radial bearing seat, 4-1 Air suspension rear radial bearing, 5 Rear casing, 6 Rotor assembly, 6-1 Rotating shaft, 6-2 Small impeller, 6-3 Thrust plate, 6-4 Large impeller, 7 Volute, 8 Air inlet, 9 Large impeller back plate, 10 Thrust bearing front plate, 10-1 Front thrust bearing, 10-2 Front position sensor, 10-21 Sensing part, 10-22 Sensing probe, 10-220 Sensing probe outer end face, 10-220x outer end face, 10-23 Mounting part, 10-24 Adapter part, 10-240 Adapter part outer end face, 11 Lead wire, 12 Thrust bearing rear plate, 12-1 Rear position sensor, 12-2 Air suspension rear thrust bearing, 12-3 Air suspension front radial bearing. DETAILED DESCRIPTION

[0039] Further detailed description will be given with reference to the accompanying drawings.

[0040] like Figure 1As shown, the air suspension thrust bearing state monitoring device of the present invention mainly includes a casing 1, a stator assembly 2, a rear radial bearing plate 3, a rear radial bearing seat 4, a rear casing 5, a rotor assembly 6, a volute 7, an air inlet 8, a large impeller back plate 9, a thrust bearing front plate 10, a lead wire 11, a thrust bearing rear plate 12 and other parts.

[0041] Figure 1 The rotor assembly 6 in the figure primarily comprises a rotating shaft 6-1, a thrust plate 6-3 mounted on the rotating shaft 6-1 near the volute 7, a large impeller 6-4, and a small impeller 6-2 mounted at the rear end. The stator assembly 2 comprises a stator core 2-1, copper wire windings 2-2, and lead wires 2-3. The stator assembly 2 is mounted within the casing 1 and arranged around the outer circumference of the rotor midsection. A rear radial bearing plate 3 is mounted at the rear end of the casing 1, with a rear radial bearing seat 4 mounted on its inner circumference. An air-suspended rear radial bearing 4-1 is mounted on the inner side of the rear radial bearing seat 4 around the rear journal of the rotating shaft 6-1. The volute 7 is mounted at the front end of the casing 1 and is equipped with an air inlet 8.

[0042] like Figure 2 As shown, the large impeller backplate 9 is mounted on the inner front end of the casing 1. A thrust bearing front plate 10 and a thrust bearing rear plate 12 are fixedly mounted in parallel at positions corresponding to the front journal of the rotating shaft 6-1. An air-suspended rear thrust bearing 12-2 and an air-suspended front thrust bearing 10-1 are mounted on opposing end surfaces of the thrust bearing rear plate 12 and the thrust bearing front plate 10, respectively. A chamber is formed between the air-suspended front and rear thrust bearings to accommodate the thrust plate 6-3. A compressed air film forms between the thrust plate 6-3 and the air-suspended front and rear thrust bearings on either side. The outer diameter of the thrust plate 6-3 is larger than the outer diameters of the air-suspended front and rear thrust bearings, typically by 6-10 mm. An air-suspended front radial bearing 12-3 is mounted on the inner arc surface of the thrust bearing rear plate 12, surrounding the rotating shaft 6-1. An air-suspended rear radial bearing 4-1 is mounted on the inner arc surface of the rear radial bearing seat 4, surrounding the rotating shaft 6-1.

[0043] A pair of position sensors, front position sensor 10-2 and rear position sensor 12-1, are symmetrically mounted on the thrust bearing front plate 10 and thrust bearing rear plate 12. These sensors measure the distance to the intermediate thrust plate 6-3. Sensor lead wires 11 from front position sensor 10-2 and rear position sensor 12-1 are routed outside housing 1.

[0044] like Figure 3As shown, the front position sensor 10-2 and the rear position sensor are of the same type, comprising a mounting portion 10-23, an adapter portion 10-24, a sensing portion 10-21, and a lead wire 11. The mounting portion 10-23 is fixedly connected to the mounting location. The front end of the adapter portion 10-24 is the sensing portion 10-21, which houses the sensing probe 10-22. The distance between the outer end surface 10-240 of the adapter portion and the outer end surface 10-220 of the sensing probe is H1, which is generally 0.80 to 1.40 mm. After the position sensors are installed, the outer end surface of the adapter portion of the front position sensor 10-2 is required to be flush with the motor-side end surface of the thrust bearing front plate 10, with the sensing portion 10-21 facing the thrust plate. The outer end surface of the adapter portion of the rear position sensor 12-1 is required to be flush with the impeller-side end surface of the thrust bearing rear plate 12, with the sensing portion facing the thrust plate. The sensing probes 10-22 are two metal wires with good insulation sheaths. The ends of the two metal wires maintain a strictly equal height H1. The end faces of the wires are also the outer end faces of the sensing probes, and the wires have no insulation covering at the outer end faces.

[0045] like Figures 4 to 6 As shown, the sensing portion 10-21 of the position sensor may include one or more sensing probes 10-22, each sensing probe is independent of each other, and the distance between the outer end surface of the adapter portion and the outer end surface 10-220x of each sensing probe may be different, denoted as Hx, and each Hx generally takes a value of 0.80 to 1.40 mm.

[0046] In this embodiment, a position sensor is provided that includes four sensing probes, 10-221 through 10-224. The distance between the outer end surface 10-240 of the adapter portion 10-24 and the outer end surface 10-220x of each sensing probe 10-22 is denoted as Hx, and can be set to H1 = 1.4 mm, H2 = 1.2 mm, H3 = 1.0 mm, and H4 = 0.8 mm, respectively. When the fan is under different operating conditions, the thrust plate gradually increases in load. As the thrust plate approaches the side thrust bearing, it will contact the sensing probes 10-221, 10-222, 10-223, and 10-224 at different locations, causing the corresponding sensing probes of the sensor to change from an open state to a conductive state. The corresponding position information is then analyzed by the host computer in combination with other relevant information, and a corresponding judgment is made and appropriate adjustment measures are taken.

[0047] The air suspension front radial bearing 12 - 3 , the air suspension rear radial bearing 4 - 1 , the air suspension front thrust bearing 10 - 1 , and the air suspension rear thrust bearing 12 - 5 may be foil-type air suspension bearings or air suspension bearings of other types of structures.

[0048] like Figure 7As shown, the present invention also discloses a control system for an air suspension thrust bearing state monitoring device, comprising a position parameter module, an aerodynamic parameter module, and a motor control module. The position parameter module obtains a state signal based on the state of the induction probes of the position sensors on both sides of the thrust plate, and transmits the state signal to a host computer; the aerodynamic parameter module obtains relevant aerodynamic operating parameters based on the aerodynamic parameter sensors, including inlet pressure, exhaust pressure, inlet temperature, exhaust temperature, and inlet flow rate, wherein the inlet pressure and inlet temperature aerodynamic parameter sensors are arranged at the air inlet of the large impeller, and the exhaust pressure and exhaust temperature aerodynamic parameter sensors are arranged on the vertebral tube connected to the volute outlet; the motor control module obtains motor operating parameters based on a motor controller electrically connected to the motor, including motor speed, motor current, motor power, and motor torque.

[0049] The principle of the position sensor is that when the sensor probe is not in contact with the thrust plate, the two metal wires inside the sensor probe are in an open circuit state. When the thrust plate and the sensor probe are close enough to contact, the two metal wires inside the sensor probe become connected. Position signal processing can detect and process the state of each sensor probe, whether it is open or connected, and forward this status signal to the position logic processing and then transmit it to the host computer.

[0050] The host computer determines the position of the thrust plate based on feedback from the position sensor. This position reflects the position between the thrust plate and the thrust bearing, and also reflects the load conditions of the thrust bearing. Specifically, the host computer obtains the position information between the thrust plate and the thrust bearing based on feedback from the position sensor. Using a built-in table that maps the position information and load conditions of this type of thrust bearing, the host computer can determine the actual load conditions of the thrust bearing based on this position information.

[0051] The host computer can calculate the current operating status of the fan based on the motor operating parameters and pneumatic operating parameters, and derive the current operating status of the high-speed motor and pneumatic impeller.

[0052] Importantly, the position change of the thrust plate can be judged according to the change of the position signal of d, especially the speed of the position change, as a key criterion for the bearing capacity of the thrust bearing; the speed of the position change also reflects the axial position change of the impeller, which can generally be used as a key criterion for the stability of the impeller operation, helping the host computer to grasp the impeller operation status in time and make timely adjustments to avoid further deterioration of the situation and causing serious consequences, thereby greatly improving the operation stability.

[0053] At this point, the host computer can further analyze and diagnose whether the current operating status is reasonable based on the actual force of the thrust bearing and the current operating status of the motor and pneumatic impeller, and formulate corresponding control strategies and make corresponding adjustments in a timely manner, including (1) adjusting the motor operating status, (2) adjusting the pneumatic control components, and (3) outputting relevant notification information to the HMI touch screen. Among them, (1) adjusting the motor includes: motor speed, motor current, motor torque, motor control mode, etc.; (2) adjusting the pneumatic control components includes: exhaust port vent valve, outlet guide vane and inlet guide vane (if installed), etc.

[0054] Specifically, when the air suspension thrust bearing operates normally, a compressed air film forms between the thrust plate and the thrust bearing, preventing contact between the two. A certain clearance exists between the two bearings. The distance between the outer end face of the position sensor's adapter 10-24 and the thrust plate is defined as L0. During normal operation, L0 is typically 1.0 to 1.8 mm. As the fan operates in different states, the clearance between the thrust plate and the thrust bearing varies accordingly, and so does L0. When L0 changes, H1 is the distance between the outer end face of the adapter 10-240 and the outer end face of the sensing probe 10-220. H1 is typically 0.80 to 1.40 mm.

[0055] More specifically, assume that H1 of a position sensor is set to 1.2 mm. Under a certain operating state, L0 = 1.5 mm. At this point, the gap between the outer end face 10-220 of the position sensor's sensing probe and the thrust plate is L0-H1 = 0.3 mm. As the wind turbine's operating state changes, the thrust plate's load increases and it moves closer to the thrust bearing, reducing L0. When L0 decreases to 1.2 mm, L0-H1 = 0 mm. The outer end face 10-220 of the sensing probe 10-22 contacts the thrust plate. At this point, both metal wires within the position sensor's sensing probe 10-22 contact the thrust plate, causing the sensor's state to change from open to short. The position signal change from the position sensor is processed through position signal and position logic, and then transmitted to the host computer. The host computer will use ① the position signal, ② the corresponding motor operating status of the high-speed motor and motor controller, ③ the pneumatic operating status of the pneumatic sensor and pneumatic operating logic processing, and ④ the corresponding table of the position information and load stress of the built-in air suspension thrust bearing. After integrating the information of ①, ②, ③, and ④, the host computer can accurately judge the real-time operating status of the fan, especially the load condition of the air suspension thrust bearing, make an accurate judgment, and take appropriate adjustment measures at the same time. The measures include: (1) adjusting the motor operating status, (2) adjusting the pneumatic control components, and (3) outputting relevant notice information to the HMI touch screen. Among them, (1) adjusting the motor includes: motor speed, motor current, motor torque, motor control mode, etc.; (2) adjusting the pneumatic control components includes: exhaust port vent valve, outlet guide vane and inlet guide vane (if installed), etc.

[0056] For example, during fan operation, if for some reason, such as a blockage in the outlet pipe, the fan outlet pressure increases and the flow rate decreases, the fan rapidly enters the "surge zone," the load on the air suspension thrust bearing increases dramatically, and the gap between the thrust plate and the front thrust bearing decreases sharply. Both metal wires in the position sensor's sensing probe 10-22 will come into contact with the thrust plate, and the position sensor's sensing probe 10-22 will transition from an open-circuit state to a short-circuit state. The host computer comprehensively determines that the fan is operating abnormally and makes timely adjustments, opening the bleed valve to increase the fan flow rate, reduce the outlet pressure, and keep the fan out of the "surge zone," ensuring reliable and stable operation.

[0057] In addition, the sensing portion 10-21 of the position sensor may include a sensing probe 10-22, and multiple sensors may be installed on the front plate and the rear plate of the thrust bearing for use in combination.

[0058] Specifically, such as Figures 5 and 6As shown, six position sensors are installed on the front and rear thrust plates, respectively. H1 for each sensor can be set to different values: H11 = 1.4 mm, H12 = 1.3 mm, H13 = 1.2 mm, H14 = 1.1 mm, H15 = 1.0 mm, and H16 = 0.9 mm. When the fan is operating under different conditions, the thrust plate gradually increases in load. As it approaches the thrust bearing, it contacts the sensor probes at different locations, causing the corresponding sensor probes to transition from open to conductive. The corresponding position information is then analyzed by the host computer in conjunction with other relevant information, which then determines the appropriate position and takes appropriate adjustments.

[0059] The present invention also discloses a control method for an air suspension thrust bearing state monitoring device, comprising the following steps:

[0060] (1) According to the pneumatic fluid law / pneumatic operating parameters, the inlet flow rate Q = Qp (P1, T1,

[0061] P2, T2), where P1 is the inlet pressure, T1 is the inlet temperature, P2 is the exhaust pressure, and T2 is the exhaust temperature.

[0062] (2) According to the impeller model, speed n and flow Q, the impeller axial force Fp = Fp1(n)*Fp2

[0063] (Q), the unit is N, where n is the impeller speed (r / min), Q is the impeller inlet flow

[0064] (m^3 / min).

[0065] (3) According to the setting of the position sensor, the relationship between the position sensor signal and the thrust plate position can be obtained.

[0066] 0 and 1 are used to represent the open state and the conductive state of the sensor, that is, different state combinations of the position sensor can be represented by the combination of 0 and 1.

[0067] In this embodiment, there are 6 sets of position sensors, and the distances between their sensing probes and the mounting end surfaces are

[0068] 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm. When the fan is in different operating conditions, the thrust plate load gradually increases. In the process of approaching the side thrust bearing, it will contact the sensing probe at different positions, causing the corresponding state of the sensor to change from the open state to the conductive state. The open state of the position sensor can be set to 0 and the conductive state to 1. Then, the 6 groups of position sensors are combined in the order from 1.4mm to 0.9mm. Considering that the thrust plate contacts the probe in this order, there are 7 states in total, namely 000000, 100000, 110000, 111000,

[0069] 111100, 111110, 111111. Also, when the thrust plate is in the center position, the distance between the thrust plate's circular surface and the sensor mounting end face is set to 1.8 mm. The relationship between the position sensor state combination and operating status is shown in Table 1 below.

[0070] (4) Based on the bearing model, d, and speed n, the thrust plate bearing capacity Ft = Ft1(n)*Ft2(d) is calculated in N, where n is the impeller speed (r / min) and d is the distance between the circular surface on one side of the thrust plate and the sensor mounting end face on that side (mm).

[0071] (5) By comparing the current pressure, flow, temperature, motor power and other parameters, the impeller axial force Fp and the bearing load capacity Ft can be used to determine whether the current operation of the impeller is within the normal range. If necessary, corresponding adjustments can be made.

[0072] Table 1 Relationship between position sensor state combination and operating state

[0073]

[0074]

[0075] It should be emphasized that this method determines the position change of the thrust plate based on the change in the position signal of d, especially the speed of the position change. At the same time, the speed of the change in d also reflects the change in the axial position of the impeller. It can generally serve as a key criterion for impeller operation stability, helping the host computer to timely understand the impeller operation status and make timely adjustments, avoiding further deterioration and serious consequences, and significantly improving operation stability. Specific adjustment measures are shown in Table 2.

[0076] Table 2 Relationship between aerodynamic parameters, position parameters and adjustment measures

[0077]

[0078]

[0079]

[0080]

[0081] The present invention is not limited to the specific embodiments described above. That is, those skilled in the art will be able to make various changes and modifications to the present invention without departing from the scope of the appended claims, and all suitable changes and equivalents of such changes and modifications are intended to fall within the scope of the present invention.

[0082] The basic structure, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles and structures of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An air suspension thrust bearing condition monitoring device, comprising a housing (1), a stator assembly (2) and a rotor assembly (6); the rotor assembly (6) comprises a rotating shaft (6-1), a large impeller (6-4) respectively mounted at the front and rear ends of the rotating shaft (6-1), a small impeller (6-2) and a thrust plate (6-3) close to the large impeller (6-4); the stator assembly (2) is mounted in the housing (1) and arranged around the outer circumference of the rotating shaft (6-1), and an air suspension front radial bearing (12-3) and an air suspension rear radial bearing (4-1) are respectively mounted at the front and rear journals of the rotating shaft (6-1); thrust bearing plates are provided on the front and rear end surfaces of the thrust plate (6-3) to form a chamber space for accommodating the thrust plate (6-3) to extend into, characterized in that: A position sensor is provided on the thrust bearing plate, and the distance between the thrust plate (6-3) and the thrust bearing plate is measured by the position sensor; The thrust bearing plates are arranged in the housing (1) and are respectively fixed and mounted in parallel with corresponding positions of the front journals of the rotating shaft (6-1). The thrust bearing plates include a thrust bearing front plate (10) and a thrust bearing rear plate (12), and an air-suspended rear thrust bearing (12-2) and an air-suspended front thrust bearing (10-1) are respectively provided on opposite end planes of the two thrust bearing plates. The thrust plate (6-3) is placed between the air suspension front and rear thrust bearings, and a compressed air film exists between the air suspension front and rear thrust bearings on both sides, and the outer diameter of the thrust plate (6-3) is larger than the outer diameters of the air suspension front and rear thrust bearings; A pair of position sensors are symmetrically installed at the relative positions of the thrust bearing front plate (10) and the thrust bearing rear plate (12), namely a front position sensor (10-2) and a rear position sensor (12-1), for measuring the distance between the front plate (10) and the intermediate thrust plate (6-3); The position sensor comprises a mounting portion, an adapter portion and a sensing portion in sequence, wherein the mounting portion and the adapter portion are arranged through the front position sensor, and the outer end face of the adapter portion is flush with the end face of the thrust bearing plate; the sensing portion extends out of the front end face of the position sensor and measures the distance between the thrust plate (6-3) and the thrust plate toward the thrust plate, but does not contact the front and rear thrust bearings of the air suspension; one or more independent sensing probes are arranged in the center of the sensing portion, and the sensing probes are a plurality of metal wires with insulating sheaths, and the outer ends of the metal wires remain flush and are not covered with insulation.

2. The air suspension thrust bearing state monitoring device according to claim 1, characterized in that: The air-suspended front radial bearing (12-3) is arranged on the inner arc surface of the thrust bearing rear plate (12) and is arranged around the rotating shaft (6-1); the air-suspended rear radial bearing (4-1) is arranged on the inner arc surface of the rear radial bearing seat (4) and is arranged around the rotating shaft (6-1).

3. The control system of the air suspension thrust bearing state monitoring device according to claim 1, characterized in that: The control system includes a position parameter module, a pneumatic parameter module and a motor control module, wherein the position parameter module obtains a status signal based on the status of the sensing probes of the position sensors on both sides of the thrust plate and transmits the status signal to the host computer; The aerodynamic parameter module obtains relevant aerodynamic operating parameters based on aerodynamic parameter sensors arranged at the air inlet of the large impeller and the exhaust port of the spinal canal, including inlet pressure, exhaust port pressure, inlet temperature, exhaust port temperature and inlet flow rate; The motor control module obtains motor operating parameters, including motor speed, motor current, motor power and motor torque, based on a motor controller electrically connected to the motor; The upper computer determines the position information of the thrust plate based on the status signal, and obtains the force load condition of the thrust bearing by looking up the built-in information table; obtains the operating status of the motor and pneumatic impeller at the current moment based on the pneumatic operating parameters and motor operating parameters; based on the actual force load condition of the thrust bearing, combined with the operating status of the motor and pneumatic impeller at the current moment, further analyzes and diagnoses whether the current operating status is reasonable and formulates corresponding control strategies.

4. The control method of the air suspension thrust bearing state monitoring device according to claim 1, characterized in that: The method comprises the following steps: Step 1, obtaining aerodynamic operation parameters according to aerodynamic parameter sensors provided at the air inlet of the large impeller and the exhaust port of the spinal canal, and obtaining an inlet flow rate Q, Q = Qp (P1, T1, P2, T2), where P1 is the inlet pressure, T1 is the inlet temperature, P2 is the exhaust pressure, and T2 is the exhaust temperature; Step 2: Obtain the impeller axial force Fp according to the speed n and flow Q. Fp=Fp1(n)*Fp2(Q). The unit of Fp is N, where n is the impeller speed in r / min and Q is the impeller inlet flow in m. 3 / min, Fp1 and Fp2 are different components of the axial force of the large impeller; Fp1 (n) is the component of the axial force Fp of the large impeller related to the speed n, and Fp2 (Q) is the component of the axial force Fp of the large impeller related to the flow rate Q; Step 3: Obtain the thrust plate position d based on the position sensor signal, using 0 and 1 to represent the open and closed states of the sensor. A combination of 0 and 1 represents different state combinations of several position sensors, corresponding to different operating state information. Step 4: Calculate the thrust plate capacity Ft based on the thrust plate position d and the speed n: Ft = Ft1(n) * Ft2(d), where Ft is expressed in N, n is the impeller speed in r / min, Ft1 is the component of the thrust plate capacity Ft related to the speed n, and Ft2 is the component of the thrust plate capacity Ft related to the thrust plate position d. Step 5: Based on the current pressure value, flow rate, temperature and motor power parameters, compare the impeller axial force Fp and the bearing load capacity Ft to determine whether the current impeller operation is in the normal range. If not, make corresponding adjustments.

5. The control method of the air suspension thrust bearing state monitoring device according to claim 4, characterized in that: The position change and change trend of the thrust plate are determined based on the change of the position signal d. At the same time, the change also reflects the change of the axial position of the impeller, which is used as the criterion for the stability of the impeller operation and transmitted to the host computer to timely grasp the impeller operation status and make timely adjustments.

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