Monitoring method, monitoring system and vacuum pump

Abstract

The application relates to the technical field of monitoring, and provides a monitoring method, a monitoring system and a vacuum pump. The monitoring method comprises the following steps: acquiring an axial displacement parameter of a rotating shaft; comparing the axial displacement parameter with a set displacement alarm threshold value; and performing alarm in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold value. Therefore, the axial gap of the rotating shaft of the vacuum pump can be monitored in real time, so as to improve the technical problem that the rotating shaft of the vacuum pump is stuck due to the excessively small axial gap.

Description

Technical Field

[0001] This invention relates to the field of monitoring technology, specifically to monitoring methods, monitoring systems, and vacuum pumps. Background Technology

[0002] Vacuum pumps are widely used in defense, steel, coating, microelectronics, semiconductors, biomedicine, chemicals, food, and environmental protection industries. The axial clearance of the shaft in a vacuum pump is crucial for its normal operation. Excessive axial clearance reduces pump efficiency, while insufficient clearance can lead to pump jamming. During continuous operation, the internal shaft expands due to heat, reducing the axial clearance and increasing the risk of pump jamming. Summary of the Invention

[0003] The embodiments of the present invention provide a monitoring method, a monitoring system, and a vacuum pump, which can improve the technical problem of vacuum pump jamming caused by insufficient axial clearance of the vacuum pump shaft.

[0004] In a first aspect, embodiments of the present invention provide a monitoring method for monitoring the axial displacement of the shaft of a vacuum pump, comprising:

[0005] Obtain the axial displacement parameters of the rotating shaft;

[0006] The axial displacement parameter is compared with the set displacement alarm threshold;

[0007] An alarm is triggered in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold.

[0008] In some embodiments, the rotating shaft includes at least two rotors arranged sequentially at intervals along its axial direction, the rotors being defined as i-th stage rotors based on their relative positions to displacement sensors mounted on the vacuum pump, where i is an integer greater than or equal to 1, and the rotor closer to the displacement sensor is the first stage rotor;

[0009] The process of obtaining the axial displacement parameters of the rotating shaft includes:

[0010] Obtain the axial displacement parameters of the first-stage rotor near the displacement sensor.

[0011] In some embodiments, the rotor is disposed in the stator, the stator is a multi-stage stator, each stage of the rotor corresponds to a stage of the stator, a partition is provided between each two adjacent stages of the stator, and the gap between each stage of the rotor and the corresponding partition is defined as the axial gap parameter of the rotor.

[0012] The monitoring method also includes:

[0013] Obtain the temperature parameters of the space where the rotating shaft is located, and calculate the temperature difference between the temperature parameters and the set room temperature parameters;

[0014] After the step of obtaining the axial displacement parameter of the first-stage rotor near the displacement sensor, the monitoring method further includes:

[0015] Based on the axial displacement parameter, the temperature difference parameter, and the preset parameters, the axial clearance parameter of each stage rotor is obtained.

[0016] In response to the axial displacement parameter being less than the displacement alarm threshold, the axial clearance parameter of each stage rotor is compared with the corresponding sub-threshold.

[0017] An alarm is triggered when the axial clearance parameter of level i is less than or equal to the sub-threshold of level i.

[0018] In some embodiments, the preset parameters include preset assembly clearance parameters for each stage of the rotor, end position parameters for each stage of the rotor, initial axial dimension parameters for each stage of the rotor, and thermal expansion coefficient of each stage of the rotor.

[0019] In some embodiments, the rotor's end position parameters include front-end parameters and rear-end parameters, wherein the front-end parameter is 1 and the rear-end parameter is -1, wherein the front end is the end of the rotor closer to the displacement sensor and the rear end is the end of the rotor farther from the displacement sensor.

[0020] In some embodiments, the calculation formula for obtaining the axial clearance parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter, and the preset parameter includes:

[0021] ;

[0022] Where i represents the rotor position, and j represents the rotor's end position parameter, with the front end of the rotor corresponding to j=1 and the rear end corresponding to j=-1. Let be the axial clearance parameter between the j-th end of the i-th stage rotor and the corresponding partition. The preset assembly clearance parameter is the parameter between the j-th end of the i-th stage rotor and the corresponding partition. The axial displacement parameters are measured by the displacement sensor. Let be the coefficient of thermal expansion of the i-th stage rotor. Let be the initial axial dimension parameters of the i-th stage rotor. This is the temperature difference between the temperature parameters of the space where the shaft is located and the set ambient temperature parameters.

[0023] In some embodiments, after the step of obtaining the axial clearance parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter, and the preset parameter, the method further includes:

[0024] In response to the axial displacement parameter being less than the displacement alarm threshold, each level of axial clearance parameter is compared with the corresponding sub-threshold.

[0025] An alarm is triggered in response to the i-th level axial clearance parameter being less than or equal to the i-th level sub-threshold.

[0026] Secondly, embodiments of the present invention provide a monitoring system for monitoring the axial displacement of the shaft of a vacuum pump, comprising:

[0027] A displacement sensor is used to acquire the axial displacement parameters of the rotating shaft;

[0028] The comparison module is electrically connected to the displacement sensor and is used to compare the axial displacement parameter with a set displacement alarm threshold.

[0029] An alarm module is electrically connected to the comparison module. The alarm module triggers an alarm in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold.

[0030] In some embodiments, the monitoring system further includes:

[0031] The signal receiving module is electrically connected to the displacement sensor and is used to receive the axial displacement parameters. The signal receiving module is also electrically connected to the comparison module and is used to send the axial displacement parameters to the comparison module.

[0032] In some embodiments, the monitoring system is configured with a normal temperature parameter, and the monitoring system further includes:

[0033] A temperature sensor is used to acquire the temperature parameters of the space where the rotating shaft is located;

[0034] A first calculation module is electrically connected to the temperature sensor. The first calculation module is used to obtain the temperature difference parameter between the temperature parameter and the room temperature parameter.

[0035] In some embodiments, the monitoring system is configured with preset parameters, and the monitoring system further includes:

[0036] The second calculation module is electrically connected to the signal receiving module and the first calculation module, and is used to receive the axial displacement parameter and the temperature difference parameter.

[0037] The rotating shaft includes at least two rotors arranged sequentially at intervals along its axial direction. The rotors are defined as i-th stage rotors based on their relative positions with respect to the displacement sensor, where i is an integer greater than or equal to 1, and the rotor closer to the displacement sensor is the first stage rotor.

[0038] The displacement sensor is used to obtain the axial displacement parameter of the first stage rotor near the displacement sensor end. The second calculation module obtains the axial clearance parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter.

[0039] In some embodiments, the preset parameters include preset assembly clearance parameters for each stage of the rotor, end position parameters for each stage of the rotor, initial axial dimension parameters for each stage of the rotor, and thermal expansion coefficient of each stage of the rotor.

[0040] In some embodiments, the rotor's end position parameters include front-end parameters and rear-end parameters, wherein the front-end parameter is 1 and the rear-end parameter is -1, wherein the front end is the end of the rotor closer to the displacement sensor and the rear end is the end of the rotor farther from the displacement sensor.

[0041] In some embodiments, the monitoring system further includes:

[0042] The storage module is electrically connected to the comparison module, the first calculation module and the second calculation module. The displacement alarm threshold, the room temperature parameter, the preset assembly gap parameter of each stage of the rotor, the end position parameter of each stage of the rotor, the initial axial dimension parameter of each stage of the rotor and the thermal expansion coefficient of each stage of the rotor are all stored in the storage module.

[0043] In some embodiments, the storage module further stores an axial clearance threshold, which includes at least two sub-thresholds. The sub-thresholds are defined as i-th level sub-thresholds based on their correspondence with the rotor, and the i-th level sub-thresholds correspond to the i-th level rotor. The comparison module further outputs an alarm signal based on the i-th level axial clearance parameter being less than or equal to the i-th level sub-threshold.

[0044] In some embodiments, the monitoring system further includes:

[0045] The signal processing module is electrically connected to the signal receiving module and is used to convert the axial displacement parameter into a first digital signal. The signal processing module is also electrically connected to the temperature sensor and is used to convert the temperature parameter into a second digital signal. The comparison module is electrically connected to the signal processing module and is used to compare the first digital signal with the displacement alarm threshold. The first calculation module is electrically connected to the signal processing module to obtain the temperature difference parameter based on the second digital signal and the room temperature parameter.

[0046] Thirdly, embodiments of the present invention provide a vacuum pump, wherein the vacuum pump uses the monitoring method described above to monitor the axial displacement of the rotating shaft.

[0047] The beneficial effects of the embodiments of the present invention are as follows:

[0048] In embodiments of the present invention, the axial displacement parameter of the rotating shaft is acquired, and an alarm is triggered based on a comparison between the axial displacement parameter and a displacement alarm threshold. When the axial displacement parameter is less than the displacement alarm threshold, no alarm is triggered. In this case, the vacuum pump will not jam, and it can continue to operate normally. When the axial displacement parameter is greater than or equal to the displacement alarm threshold, an alarm is triggered. In this case, the axial displacement of the rotating shaft is large, which may cause the axial clearance of the shaft to be too small, posing a risk of vacuum pump jamming. Operators can detect the vacuum pump based on the alarm information and adjust the axial clearance of the rotating shaft to prevent vacuum pump jamming. Therefore, the axial clearance of the vacuum pump shaft can be monitored in real time, improving the technical problem of vacuum pump jamming caused by insufficient axial clearance. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a flowchart illustrating the monitoring method provided in an embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram of the monitoring system provided in an embodiment of the present invention.

[0052] Figure 3 This is a schematic diagram of the structure of a vacuum pump provided in an embodiment of the present invention.

[0053] Figure 4 This is a schematic diagram of the displacement sensor installation structure provided in an embodiment of the present invention.

[0054] Figure 5 This is a cross-sectional view of the shaft and end cap provided in an embodiment of the present invention.

[0055] Figure label:

[0056] 10-Displacement sensor, 20-Controller, 210-Signal receiving module, 220-Comparison module, 230-Alarm module, 240-First calculation module, 250-Second calculation module, 260-Storage module, 270-Signal processing module, 280-Display module, 30-Temperature sensor, 40-Rotating shaft, 510-Pump body assembly, 520-First bearing plate, 530-Second bearing plate, 540-End cover, 550-Measuring hole, 560-Motor assembly, 570-Gearbox assembly. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention. In the present invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0058] Specifically, such as Figure 1 As shown in the figure, this application provides a monitoring method. This monitoring method is used to monitor the axial displacement of the shaft 40 of a vacuum pump. The monitoring method includes:

[0059] Step A: Obtain the axial displacement parameters of the rotating shaft 40.

[0060] Step B: Compare the axial displacement parameters with the set displacement alarm threshold.

[0061] Step C: An alarm is triggered in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold.

[0062] Understandably, by acquiring the axial displacement parameters of the rotating shaft 40, an alarm is triggered based on a comparison between these parameters and a displacement alarm threshold. When the axial displacement parameters are less than the threshold, no alarm is triggered. In this case, the vacuum pump will not jam, and it can continue to operate normally. When the axial displacement parameters are greater than or equal to the threshold, an alarm is triggered. In this case, the axial displacement of the rotating shaft 40 is large, which can cause the axial clearance of the shaft to be too small, posing a risk of pump jamming. Operators can use the alarm information to inspect the vacuum pump and adjust the axial clearance of the rotating shaft 40 to prevent jamming. Therefore, the axial clearance of the vacuum pump's rotating shaft 40 can be monitored in real time, improving the technical problem of vacuum pump jamming caused by insufficient axial clearance.

[0063] The axial displacement parameters of the rotating shaft 40 can be obtained through the displacement sensor 10. The axial displacement parameters can be compared with the set displacement alarm threshold through the comparison module 220. An alarm can be triggered through the alarm module 230.

[0064] In some embodiments, the displacement alarm threshold is less than the wear threshold of the shaft. It is understood that when an alarm is triggered in response to an axial displacement parameter being greater than or equal to the displacement alarm threshold, the shaft is in a non-wearing state. This alarm information can then serve as a risk warning, alerting operators to the potential risk of the vacuum pump jamming.

[0065] In some embodiments, the displacement alarm threshold is equal to the wear threshold of the shaft. It is understood that when an alarm is triggered in response to an axial displacement parameter exceeding or equal to the displacement alarm threshold, the shaft has already experienced wear. This alarm message can then serve as a fault indication, prompting personnel to stop the machine for maintenance.

[0066] In some embodiments, the shaft 40 includes at least two rotors arranged sequentially at intervals along its axial direction. The rotors are defined as i-th stage rotors based on their relative positions to the displacement sensor 10 mounted on the vacuum pump, where i is an integer greater than or equal to 1, and the rotor closer to the displacement sensor 10 is the first stage rotor.

[0067] The shaft 40 within the pump body assembly 510 of the vacuum pump includes a plurality of rotors arranged sequentially at intervals along the axial direction.

[0068] When a vacuum pump operates continuously, each rotor may deform due to increased ambient temperature. This can alter the axial clearance between each rotor and its corresponding stator. Therefore, defining the rotor for each stage facilitates subsequent calculations of the axial clearance for that stage.

[0069] In some embodiments, obtaining the axial displacement parameters of the rotating shaft 40 includes:

[0070] Obtain the axial displacement parameters of the first-stage rotor near the displacement sensor 10.

[0071] Since the first-stage rotor is the rotor closest to the displacement sensor 10, the displacement sensor 10 will act on the first-stage rotor. The first-stage rotor has a front end close to the displacement sensor 10 and a rear end far from the displacement sensor 10. The displacement sensor 10 is used to acquire the axial displacement parameters of the front end of the first-stage rotor.

[0072] In some embodiments, the rotor is disposed within the stator, which is a multi-stage stator, with each stage of rotor corresponding to one stage of stator. A partition is provided between each pair of adjacent stages of stator. The gap between each stage of rotor and its corresponding partition is defined as the axial clearance parameter of that rotor.

[0073] Understandably, if the number of rotors is set to at least two, then the number of stators is also set to at least two. At least two stators can be defined as the i-th stage stator based on the corresponding rotor. Adjacent stator stages are separated by partitions. These partitions are annular partitions, allowing the rotor shaft to pass through each partition. The axial clearance parameter of the rotor is defined as the clearance between each stage rotor and its corresponding partition. Understandably, the rotor needs to form a clearance with the partition to prevent the partition from interfering with rotor rotation. If the rotor comes into contact with the partition, it can cause phenomena such as pump jamming.

[0074] In some embodiments, the monitoring method further includes: acquiring the temperature parameters of the space where the rotating shaft 40 is located, and calculating the temperature difference parameter between the temperature parameters and the set room temperature parameter.

[0075] Understandably, by obtaining the temperature parameters of the space where the shaft 40 is located and calculating the difference with the set ambient temperature parameters, the temperature difference parameter of the shaft 40 can be obtained. Based on the phenomenon of thermal expansion and contraction, it can be known that the shaft 40 will expand after heating. Obtaining the temperature difference parameter facilitates the subsequent calculation of the axial clearance of each stage rotor.

[0076] After obtaining the axial displacement parameters of the first-stage rotor near the displacement sensor 10, the monitoring method also includes:

[0077] Based on axial displacement parameters, temperature difference parameters, and preset parameters, the axial clearance parameters of each stage rotor are obtained.

[0078] In response to the axial displacement parameter being less than the displacement alarm threshold, the axial clearance parameter of each level is compared with the corresponding sub-threshold.

[0079] An alarm is triggered when the axial clearance parameter of level i is less than or equal to the sub-threshold of level i.

[0080] Understandably, after obtaining the axial clearance parameters of each stage of the rotor, real-time monitoring of each stage of the rotor can be performed to prevent the axial clearance of the rotor far from the displacement sensor 10 from being too small, which could cause the vacuum pump to jam.

[0081] Understandably, if the axial displacement parameter does not trigger an alarm, the axial clearance parameter at each level can be further compared to achieve multi-dimensional alarm monitoring.

[0082] The axial clearance parameter of the i-th stage is compared with the i-th stage sub-threshold. If the axial clearance parameter of the i-th stage is greater than the i-th stage sub-threshold, no alarm is triggered. In this case, the vacuum pump will not jam and can continue to operate normally. If the axial clearance parameter of the i-th stage is less than or equal to the i-th stage sub-threshold, an alarm is triggered. In this case, the axial clearance of the i-th stage rotor is too small, and the vacuum pump is at risk of jamming. Operators can use the alarm information to detect the i-th stage rotor of the vacuum pump and adjust the axial clearance of the i-th stage rotor to prevent the vacuum pump from jamming.

[0083] Therefore, based on the comparison between the axial clearance parameter of the i-th stage and the sub-threshold of the i-th stage, the axial clearance of each stage rotor of the vacuum pump can be monitored in real time, and the i-th stage rotor with problems can be accurately repaired. This can improve the technical problem of vacuum pump jamming caused by the insufficient axial clearance of the shaft 40 of the vacuum pump, realize risk alarm, and improve maintenance efficiency.

[0084] Specifically, when comparing the axial clearance parameter at each level with the corresponding sub-threshold, the comparison is performed synchronously. If the axial clearance parameter at any level is less than or equal to the corresponding sub-threshold, an alarm is triggered.

[0085] In some embodiments, the preset parameters include the preset assembly clearance parameter of each stage rotor, the end position parameter of each stage rotor, the initial axial dimension parameter of each stage rotor, and the thermal expansion coefficient of each stage rotor.

[0086] The initial axial dimension parameter of each stage rotor is the initial length of that rotor. For example, the initial axial dimension parameter of the second stage rotor is the initial length parameter of the second stage rotor.

[0087] The coefficient of thermal expansion of each stage of the rotor is related to the material of that stage. When each stage of the rotor on the shaft 40 is made of the same material, the coefficient of thermal expansion of each stage of the rotor is... The same. When each stage of the rotor of shaft 40 is made of a different material, the coefficient of thermal expansion of each stage of the rotor is the same. different.

[0088] The rotor's end position parameters include front-end parameters and rear-end parameters. The front-end parameter takes the value of 1, and the rear-end parameter takes the value of -1. The front end is the end of the rotor that is closer to the displacement sensor 10, and the rear end is the end of the rotor that is farther away from the displacement sensor 10.

[0089] In some embodiments, a calculation formula for the axial clearance parameter of each stage rotor is obtained based on axial displacement parameters, temperature difference parameters, and preset parameters, including:

[0090] .

[0091] Where i represents the rotor position, and j represents the rotor's end position parameter. The front end of the rotor corresponds to j=1, and the rear end corresponds to j=-1. denoted as axial clearance parameter between the j-th end of the i-th stage rotor and the corresponding partition. The preset assembly clearance parameter is the j-th end of the i-th stage rotor and the corresponding partition. The axial displacement parameters are measured by displacement sensor 10. is the coefficient of thermal expansion of the i-th stage rotor. Let be the initial axial dimension parameters of the i-th stage rotor. This is the temperature difference parameter between the temperature parameters of the space where the rotating shaft 40 is located and the set ambient temperature parameter.

[0092] Understandably, based on the above calculation formula, the axial clearance parameter at each end of each stage of the rotor can be calculated. This allows for real-time monitoring of the axial clearance parameter of each stage of the rotor.

[0093] For example, when it is necessary to obtain the axial clearance parameter of the front end of the fifth-stage rotor relative to the fifth-stage stator, then i=5, j=1. Substituting into the formula, we get: .

[0094] For example, when it is necessary to obtain the axial clearance parameter at the rear end of the third-stage rotor, then i=3, j=-1. Substituting into the formula, we get: .

[0095] On the other hand, such as Figure 2 As shown in the illustration, this application also provides a monitoring system. This monitoring system is used to monitor the axial displacement of the shaft 40 of a vacuum pump. The monitoring system includes a displacement sensor 10, a comparison module 220, and an alarm module 230. The displacement sensor 10 is used to acquire the axial displacement parameters of the shaft 40. The comparison module 220 is electrically connected to the displacement sensor 10 and is used to compare the axial displacement parameters with a set displacement alarm threshold. The alarm module 230 is electrically connected to the comparison module 220. The alarm module 230 triggers an alarm in response to the axial displacement parameters being greater than or equal to the displacement alarm threshold.

[0096] Understandably, the axial displacement parameter of the rotating shaft 40 is acquired by the displacement sensor 10, and the comparison module 220 determines whether to send an alarm signal to the alarm module 230 based on the comparison result between the axial displacement parameter and the displacement alarm threshold. When the axial displacement parameter is less than the displacement alarm threshold, no alarm is triggered. At this time, the vacuum pump will not experience pump jamming and can continue to operate normally. When the axial displacement parameter is greater than or equal to the displacement alarm threshold, an alarm is triggered. At this time, the axial displacement of the rotating shaft 40 is large, which may cause the axial clearance of the rotating shaft 40 to be too small, and the vacuum pump may jam. Operators can detect the vacuum pump based on the alarm information and adjust the axial clearance of the rotating shaft 40 to prevent the vacuum pump from jamming. Thus, the axial clearance of the vacuum pump's rotating shaft 40 can be monitored in real time to improve the technical problem of vacuum pump jamming caused by the rotating shaft 40 being too small.

[0097] In some embodiments, the displacement sensor 10 may be one or more of the following: inductive displacement sensor, capacitive displacement sensor, photoelectric displacement sensor, ultrasonic displacement sensor, Hall effect displacement sensor, and magnetostrictive displacement sensor. The axial displacement of the rotating shaft 40 is the axial offset of the rotating shaft 40 relative to the stator surrounding the region.

[0098] The monitoring system can be based on a controller 20 as a central control unit. The controller 20 can receive axial displacement parameters monitored by the displacement sensor 10. The controller 20 can be wirelessly connected to the displacement sensor 10, for example, via Wi-Fi or Bluetooth. Alternatively, the controller 20 can also be wiredly connected to the displacement sensor 10, for example, via a data cable.

[0099] The rotating shaft 40 can move towards the displacement sensor 10, in which case the axial displacement parameter acquired by the displacement sensor 10 is a positive value. The rotating shaft 40 can also move away from the displacement sensor 10, in which case the axial displacement parameter acquired by the displacement sensor 10 is a negative value. Typically, the rotating shaft 40 will generate heat due to continuous operation, causing a certain amount of axial expansion. For the end of the rotating shaft 40 facing the displacement sensor 10, the end of the rotating shaft 40 will move closer to the displacement sensor 10. The greater the displacement, the smaller the axial clearance of the rotating shaft 40 will be, which may cause the vacuum pump to jam.

[0100] In some embodiments, the displacement alarm threshold set within the controller 20 can be 0.1 mm, 0.5 mm, 1 mm, or any value between the two. For example, if the displacement alarm threshold is set to 0.5 mm, no alarm will sound when the acquired axial displacement parameter is less than 0.5 mm. In this case, the vacuum pump will not jam, and it can continue to operate normally. An alarm will sound when the acquired axial displacement parameter is greater than or equal to 0.5 mm.

[0101] Understandably, after receiving the axial displacement parameter, the controller 20 can send the axial displacement parameter to the comparison module 220. The comparison module 220 compares the parameter with a set displacement alarm threshold and outputs an alarm signal to the alarm unit based on the comparison result. The alarm unit responds to the alarm signal and can then sound an alarm to prompt the operator to check the vacuum pump.

[0102] The comparison module 220 can be configured as a comparator, primarily used for magnitude comparison. After receiving the axial displacement parameter, the comparison module 220 compares the value with a preset displacement alarm threshold. If the axial displacement parameter is less than the displacement alarm threshold, the comparison module 220 does not send an alarm signal to the alarm module 230. If the axial displacement parameter is greater than or equal to the displacement alarm threshold, the comparison module 220 sends an alarm signal to the alarm module 230.

[0103] The alarm module 230 can be configured as an alarm device, such as a buzzer alarm, a flashing alarm light, or an audible and visual alarm. The alarm module 230 can generate an alarm sound and / or an alarm light based on an alarm signal to alert operators to check the vacuum pump.

[0104] In some embodiments, the monitoring system further includes a signal receiving module 210. The signal receiving module 210 is electrically connected to the displacement sensor 10 and is used to receive axial displacement parameters. The signal receiving module 210 is also electrically connected to a comparison module 220 and is used to send the axial displacement parameters to the comparison module 220.

[0105] Understandably, after receiving the axial displacement parameter, the signal receiving module 210 can send the axial displacement parameter to the comparison module 220. The comparison module 220 compares the parameter with a set displacement alarm threshold and outputs an alarm signal to the alarm unit based on the comparison result. The alarm unit responds to the alarm signal and can then sound an alarm to prompt the operator to check the vacuum pump.

[0106] The signal receiving module 210 can be configured as a signal receiver. The signal receiving module 210 can receive the axial displacement parameters monitored by the displacement sensor 10. Specifically, the signal receiving module 210 can be wirelessly connected to the displacement sensor 10. For example, the signal receiving module 210 and the displacement sensor 10 can be connected via Wi-Fi or Bluetooth. Alternatively, the signal receiving module 210 can also be wiredly connected to the displacement sensor 10. For example, the signal receiving module 210 and the displacement sensor 10 can be connected via a data cable.

[0107] In some embodiments, the monitoring system further includes a temperature sensor 30. The temperature sensor 30 is used to acquire temperature parameters of the space where the rotating shaft 40 is located. The monitoring system is set with a normal temperature parameter. The monitoring system also includes a first calculation module 240. The first calculation module 240 is electrically connected to the temperature sensor 30. The first calculation module 240 is used to acquire the temperature difference parameter between the temperature parameter and the normal temperature parameter.

[0108] Understandably, by obtaining the temperature parameters of the space where the shaft 40 is located and calculating the difference with the set ambient temperature parameters, the temperature difference parameter of the shaft 40 can be obtained. Based on the phenomenon of thermal expansion and contraction, it can be known that the shaft 40 will expand after heating. Obtaining the temperature difference parameter facilitates the subsequent calculation of the axial clearance of each stage rotor.

[0109] The rotating shaft 40 is typically located within the pump body assembly 510 of the vacuum pump. The temperature sensor 30 can acquire the internal temperature of the pump body assembly 510 to reflect the temperature parameters of the space where the rotating shaft 40 is located. Therefore, the temperature sensor 30 is typically directly installed inside the cavity of the pump body assembly 510.

[0110] In some embodiments, the temperature sensor 30 may be one or more of a thermocouple temperature sensor, a thermistor temperature sensor, and an infrared radiation temperature sensor.

[0111] The ambient temperature parameter can be the room temperature parameter. This parameter can be obtained through an external temperature probe and then input into the controller 20 to form a preset ambient temperature parameter. Alternatively, the ambient temperature parameter can be set directly, for example, to 25 degrees Celsius.

[0112] The first calculation module 240 can be configured as a difference calculator. It obtains the temperature difference parameter based on the input temperature parameter and the ambient temperature parameter. The calculation formula of the first calculation module 240 is: Temperature parameter = Temperature parameter - Ambient temperature parameter.

[0113] In some embodiments, preset parameters are set within the monitoring system. The monitoring system also includes a second calculation module 250. The second calculation module 250 is electrically connected to the signal receiving module 210 and the first calculation module 240, and is used to receive axial displacement parameters and temperature difference parameters. The rotating shaft 40 includes at least two rotors arranged sequentially at intervals along its axial direction. The rotors are defined as i-th stage rotors based on their relative position to the displacement sensor 10. Here, i is an integer greater than or equal to 1, and the rotor closer to the displacement sensor 10 is the first stage rotor. The displacement sensor 10 is used to acquire the axial displacement parameters of the first stage rotor at the end closest to the displacement sensor 10. The second calculation module 250 acquires the axial clearance parameters of each stage rotor based on the axial displacement parameters, temperature difference parameters, and preset parameters.

[0114] Understandably, the second calculation module 250 can receive axial displacement parameters and temperature parameters. The second calculation module 250 contains calculation logic that can calculate the axial clearance parameter of each stage of the rotor based on preset parameters, axial displacement parameters, and temperature parameters. Therefore, real-time monitoring of each stage of the rotor can be performed to prevent the axial clearance of rotors far from the displacement sensor 10 from becoming too small, which could cause the vacuum pump to jam.

[0115] The shaft 40 within the pump body assembly 510 of the vacuum pump includes a plurality of rotors arranged sequentially at intervals along the axial direction. Each rotor is fixedly sleeved on the shaft.

[0116] When a vacuum pump operates continuously, each rotor may deform due to increased ambient temperature. This can alter the axial clearance between each rotor and its corresponding stator. If the change in axial clearance is too large, it may cause the clearance to become too small, leading to pump jamming. Therefore, the second calculation module 250 can directly obtain the axial clearance parameters of each stage rotor relative to each stage stator, facilitating the monitoring of each stage rotor.

[0117] For example, the rotating shaft 40 includes three rotors arranged sequentially at intervals along its axial direction. Along the direction away from the displacement sensor 10, the three rotors are sequentially designated as a first-stage rotor, a second-stage rotor, and a third-stage rotor. The displacement sensor 10 is used to acquire the axial displacement parameters of the first-stage rotor near the end of the first-stage rotor. The second calculation module 250 can acquire the first-stage axial clearance parameters of the first-stage rotor, the second-stage axial clearance parameters of the second-stage rotor, and the third-stage axial clearance parameters of the third-stage rotor based on the axial displacement parameters, temperature difference parameters, and preset parameters.

[0118] The second computing module 250 can be configured as a microcontroller with a corresponding computing program programmed into it. This computing program can be:

[0119] .

[0120] Where i represents the rotor position, and j represents the rotor's end position parameter. The front end of the rotor corresponds to j=1, and the rear end corresponds to j=-1. denoted as axial clearance parameter between the j-th end of the i-th stage rotor and the corresponding partition. The preset assembly clearance parameter is the j-th end of the i-th stage rotor and the corresponding partition. The axial displacement parameters are measured by displacement sensor 10. is the coefficient of thermal expansion of the i-th stage rotor. Let be the initial axial dimension parameters of the i-th stage rotor. This is the temperature difference parameter between the temperature parameters of the space where the rotating shaft 40 is located and the set ambient temperature parameter.

[0121] In some embodiments, the preset parameters include the preset assembly clearance parameter of each stage rotor, the end position parameter of each stage rotor, the initial axial dimension parameter of each stage rotor, and the thermal expansion coefficient of each stage rotor.

[0122] For example, the second calculation module 250 can calculate the i-th axial clearance parameter between the i-th stage rotor and the corresponding partition based on the axial displacement parameter, temperature difference parameter, preset assembly gap parameter of each stage rotor, end position parameter of each stage rotor, initial axial dimension parameter of each stage rotor, and thermal expansion coefficient of each stage rotor.

[0123] It is understandable that each stage rotor, after being assembled into the vacuum pump, will have a corresponding assembly clearance value. This assembly clearance value is used as the preset assembly clearance parameter for the corresponding rotor.

[0124] The initial axial dimension parameter for each stage of the rotor is the length of that rotor. For example, the initial axial dimension parameter for the second stage rotor is the length of the second stage rotor.

[0125] The coefficient of thermal expansion of each stage of the rotor is related to the material of that stage. When each stage of the rotor of the shaft 40 is made of the same material, the coefficient of thermal expansion of each stage of the rotor is the same. When each stage of the rotor of the shaft 40 is made of different materials, the coefficient of thermal expansion of each stage of the rotor is different.

[0126] In some embodiments, the rotor end position parameters include front end parameters and rear end parameters. The front end parameter has a value of 1, and the rear end parameter has a value of -1. The front end is the end of the rotor that is closer to the displacement sensor 10, and the rear end is the end of the rotor that is farther away from the displacement sensor 10.

[0127] It is understandable that the rotor has two opposite ends, defined as the front end and the rear end. When the rotor expands due to heat, both the front and rear ends will shift, causing changes in the axial clearance values ​​of the front and rear ends. Therefore, based on the introduced end position parameters of the rotor, the axial clearance parameters of the front and rear ends of each stage of the rotor can be calculated.

[0128] For example, the rotating shaft 40 includes three rotors arranged sequentially at intervals along its axial direction. Along the direction away from the displacement sensor 10, the three rotors are sequentially designated as a first-stage rotor, a second-stage rotor, and a third-stage rotor. The displacement sensor 10 is used to acquire the axial displacement parameters of the first-stage rotor at the end closest to the displacement sensor 10. The second calculation module 250 can acquire the first-stage front end axial clearance parameters and the first-stage rear end axial clearance parameters of the first-stage rotor, the second-stage front end axial clearance parameters and the second-stage rear end axial clearance parameters of the second-stage rotor, and the third-stage front end axial clearance parameters and the third-stage rear end axial clearance parameters of the third-stage rotor, based on the axial displacement parameters, temperature difference parameters, preset assembly clearance parameters for each stage rotor, end position parameters for each stage rotor, initial axial dimension parameters for each stage rotor, and thermal expansion coefficient of each stage rotor.

[0129] In some embodiments, the monitoring system further includes a storage module 260. The storage module 260 is electrically connected to the comparison module 220, the first calculation module 240, and the second calculation module 250. Displacement alarm thresholds, ambient temperature parameters, preset assembly gap parameters for each stage of the rotor, end position parameters for each stage of the rotor, initial axial dimension parameters for each stage of the rotor, and thermal expansion coefficients for each stage of the rotor are all stored in the storage module 260.

[0130] Understandably, the storage module 260 is used for data storage, including displacement alarm thresholds, ambient temperature parameters, preset assembly gap parameters for each rotor stage, end position parameters for each rotor stage, initial axial dimension parameters for each rotor stage, and thermal expansion coefficient for each rotor stage.

[0131] The storage module 260 is electrically connected to the first calculation module 240 and is used to send room temperature parameters to the first calculation module 240. Of course, the first calculation module 240 can also send the calculated temperature difference parameters to the storage module 260 for storage, so that the temperature difference data can be viewed during maintenance.

[0132] The storage module 260 is electrically connected to the second calculation module 250 and is used to send the preset assembly clearance parameters, end position parameters, initial axial dimension parameters, and thermal expansion coefficient of each rotor stage to the second calculation module 250. Alternatively, the second calculation module 250 can also send the calculated axial clearance parameters of the i-th rotor stage and the corresponding i-th stage partition to the storage module 260 for storage, so as to store the axial clearance parameters of each rotor stage in real time, which is beneficial for determining the time of fault occurrence during maintenance.

[0133] The storage module 260 is also electrically connected to the comparison module 220 and is used to send the displacement alarm threshold to the comparison module 220. Of course, the comparison module 220 can also send alarm signals to the storage module 260 to record the time of each alarm.

[0134] In some embodiments, the storage module 260 may be configured as a solid-state memory, such as a solid-state drive. The storage module 260 may also be configured as a read-only memory, enabling it to retain data even when power is lost.

[0135] In some embodiments, the storage module 260 further stores an axial clearance threshold. The axial clearance threshold includes at least two sub-thresholds. The sub-thresholds are defined as i-th level sub-thresholds based on their correspondence with the rotor. The i-th level sub-threshold corresponds to the i-th level rotor. The comparison module 220 further outputs an alarm signal based on the i-th level axial clearance parameter being less than or equal to the i-th level sub-threshold.

[0136] Understandably, based on the calculations performed by the aforementioned second calculation module 250, the axial clearance parameter of each stage of the rotor can be obtained. When judging each stage of the rotor, it is necessary to compare the axial clearance threshold of each stage. Therefore, the storage module 260 stores at least two sub-thresholds corresponding to the rotors. The axial clearance parameter of the i-th stage is compared with the i-th stage sub-threshold. If the axial clearance parameter of the i-th stage is greater than the i-th stage sub-threshold, no alarm is triggered. In this case, the vacuum pump will not jam, and it can continue to operate normally. If the axial clearance parameter of the i-th stage is less than or equal to the i-th stage sub-threshold, an alarm is triggered. In this case, the axial clearance of the i-th stage rotor is too small, and the vacuum pump is at risk of jamming. Operators can use the alarm information to detect the i-th stage rotor of the vacuum pump and adjust the axial clearance of the i-th stage rotor to prevent the vacuum pump from jamming.

[0137] Therefore, based on the comparison between the axial clearance parameter of the i-th stage and the sub-threshold of the i-th stage, the axial clearance of each stage rotor of the vacuum pump can be monitored in real time, and the i-th stage rotor with problems can be accurately repaired. This can improve the technical problem of vacuum pump jamming caused by the excessive axial clearance of the shaft 40 of the vacuum pump, and improve the maintenance efficiency.

[0138] In some embodiments, the monitoring system further includes a signal processing module 270. The signal processing module 270 is electrically connected to the signal receiving module 210 and is used to convert the axial displacement parameter into a first digital signal. The signal processing module 270 is also electrically connected to the temperature sensor 30 and is used to convert the temperature parameter into a second digital signal. A comparison module 220 is electrically connected to the signal processing module 270 and is used to compare the first digital signal with a displacement alarm threshold. A first calculation module 240 is electrically connected to the signal processing module 270 to obtain a temperature difference parameter based on the second digital signal and the room temperature parameter.

[0139] It is understood that the axial displacement parameters acquired by the displacement sensor 10 and the temperature parameters acquired by the temperature sensor 30 are both analog signals. The signal processing module 270 can perform analog-to-digital conversion. The signal processing module 270 converts the axial displacement parameters into a first digital signal and the temperature parameters into a second digital signal to achieve digital comparison, digital calculation, and digital display.

[0140] The signal processing module 270 can be a digital-to-analog converter (DAC). For example, the signal processing module 270 can be an integrating DAC, a successive approximation DAC, or a parallel comparator / serial-parallel DAC.

[0141] In some embodiments, the signal processing module 270 may also have functions such as interference isolation, signal amplification, and filtering. For example, the signal processing module 270 integrates a digital-to-analog converter, a signal amplifier, and a filter.

[0142] In some embodiments, the monitoring system further includes a display module 280. The display module 280 is electrically connected to the signal processing module 270 and is used to receive a first digital signal and a second digital signal to digitally display the axial displacement parameters and the temperature parameters of the space where the rotating shaft 40 is located.

[0143] It is understandable that after receiving the first digital signal and the second digital signal, the display module 280 can directly display the axial displacement parameters and temperature parameters digitally, so as to directly observe the axial displacement values ​​and temperature values.

[0144] The display module 280 can be a display screen, a touch screen, etc.

[0145] In some embodiments, the display module 280 may also be electrically connected to the first calculation module 240 to receive temperature parameters. Thus, the difference between the internal temperature of the cavity and the external ambient temperature can be displayed on the display module 280.

[0146] In some embodiments, the display module 280 may also be electrically connected to the second calculation module 250 to receive the axial clearance parameters of each stage of the rotor. Thus, the current axial clearance parameters of each stage of the rotor can be displayed on the display module 280.

[0147] like Figures 3 to 5 As shown in the embodiments, this application also provides a vacuum pump. This vacuum pump uses the monitoring method described in the foregoing embodiments to monitor the axial displacement of a rotating shaft. The vacuum pump includes a pump body assembly 510 and a monitoring system as described in the foregoing embodiments. The rotating shaft 40 is mounted within the pump body assembly 510.

[0148] Understandably, the axial displacement parameters of the rotating shaft 40 are acquired through the displacement sensor 10, and an alarm is triggered based on a comparison between these parameters and a displacement alarm threshold. When the axial displacement parameter is less than the threshold, no alarm is triggered. In this case, the vacuum pump will not jam, and it can continue to operate normally. When the axial displacement parameter is greater than or equal to the threshold, an alarm is triggered. In this case, the axial displacement of the rotating shaft 40 is large, which can cause the axial clearance of the shaft to be too small, posing a risk of pump jamming. Operators can use the alarm information to check the vacuum pump and adjust the axial clearance of the shaft 40 to prevent pump jamming. Therefore, the axial clearance of the vacuum pump's rotating shaft 40 can be monitored in real time, improving the technical problem of vacuum pump jamming caused by insufficient axial clearance.

[0149] The pump body assembly 510 may include a lower housing and an upper housing that covers the lower housing. The upper housing and the lower housing may be fixedly connected by fasteners such as bolts. After the upper housing and the lower housing are closed, a cavity is formed inside, and the rotating shaft 40 is disposed in the cavity.

[0150] like Figure 3 As shown, in some embodiments, the vacuum pump further includes a first bearing plate 520 and a second bearing plate 530. The first bearing plate 520 and the second bearing plate 530 are disposed on opposite sides of the pump body assembly 510. The two ends of the rotating shaft 40 are rotatably connected to the first bearing plate 520 and the second bearing plate 530, respectively.

[0151] The first bearing plate 520 and the second bearing plate 530 are respectively connected to both sides of the pump body assembly 510 so that both ends of the rotating shaft 40 can be connected to the bearing. The first bearing plate 520 can be fixed to one side of the pump body assembly 510 by bolts or other fasteners, and the second bearing plate 530 can be fixed to the other side of the pump body assembly 510 by bolts or other fasteners.

[0152] In some embodiments, the first bearing plate 520 may include a first plate body and a first bearing. The first plate body has at least one first mounting hole, and a first bearing is installed in each first mounting hole. The second bearing plate 530 may include a second plate body and a second bearing. The second plate body has at least one second mounting hole, and a second bearing is installed in each second mounting hole. The two ends of the rotating shaft 40 may be connected to the first bearing and the second bearing, respectively.

[0153] like Figure 3 and Figure 4 As shown, in some embodiments, the vacuum pump further includes an end cap 540. The end cap 540 is connected to a first bearing plate 520 or a second bearing plate 530. The end cap 540 is configured with a measuring hole 550. The measuring hole 550 is coaxially arranged with the rotating shaft 40. A displacement sensor 10 is mounted in the measuring hole 550.

[0154] End cap 540 can seal the side of the vacuum pump away from motor assembly 560. When motor assembly 560 is connected to first bearing plate 520, end cap 540 is connected to second bearing plate 530. When motor assembly 560 is connected to second bearing plate 530, end cap 540 is connected to first bearing plate 520. Measuring hole 550 constructed on end cap 540 is used to install displacement sensor 10, thereby monitoring the axial displacement of internal shaft 40 through displacement sensor 10 to obtain axial displacement parameters of shaft 40.

[0155] like Figure 5 As shown, the measuring hole 550 is coaxially arranged with the rotating shaft 40, that is, the center of the measuring hole 550 is collinear with the axis of the rotating shaft 40, so as to ensure the accuracy of the displacement sensor 10 in measuring the axial displacement.

[0156] like Figure 4 As shown, in some embodiments, at least two shafts 40 are provided. The at least two shafts 40 are arranged radially apart. At least two measuring holes 550 are spaced apart on the end cap 540. A displacement sensor 10 is installed in each measuring hole 550. Each displacement sensor 10 acquires the axial displacement parameter of a shaft 40.

[0157] At least two rotating shafts 40 can form a shaft system assembly for a vacuum pump to achieve multi-axis drive. For each rotating shaft 40, a displacement sensor 10 is provided in each measuring hole 550 to monitor each rotating shaft 40 separately.

[0158] In some embodiments, the vacuum pump further includes a motor assembly 560 and a gearbox assembly 570. The gearbox assembly 570 is connected to the motor assembly 560. The output shaft of the motor assembly 560 is drive-connected to a first end of the gearbox assembly 570, and the rotating shaft 40 is drive-connected to a second end of the gearbox assembly 570.

[0159] The motor assembly 560 serves as a drive structure, driving the gears in the gearbox assembly 570 to rotate. The gearbox assembly 570 can house a transmission gear pair, functioning as a reduction gearbox to change the rotational speed. After the drive gear on the output shaft of the motor assembly 560 rotates, the gearbox assembly 570 can change its speed and transmit it to the rotating shaft 40 at an appropriate speed, thus achieving the rotation of the rotating shaft 40.

[0160] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A monitoring method for monitoring an amount of axial displacement of a rotation shaft of a vacuum pump, characterized by, The rotating shaft includes at least two rotors spaced apart along its axial direction. Each rotor is defined as an i-th stage rotor based on its relative position to a displacement sensor mounted on the vacuum pump, where i is an integer greater than or equal to 1. The rotor closest to the displacement sensor is the first stage rotor. The rotors are disposed within a stator, which is a multi-stage stator. Each stage of the rotor corresponds to a stage of the stator. A partition is provided between each pair of adjacent stages of the stator. The gap between each stage of the rotor and its corresponding partition is defined as the axial clearance parameter of that rotor. The monitoring method includes: The axial displacement parameters of the first-stage rotor near the displacement sensor are obtained, as well as the temperature parameters of the space where the shaft is located, and the temperature difference parameters between the temperature parameters and the set room temperature parameters are calculated. Based on the axial displacement parameter, the temperature difference parameter, and the preset parameters, the axial clearance parameter of each stage rotor is obtained. The axial displacement parameter is compared with the set displacement alarm threshold; An alarm is triggered when the axial displacement parameter is greater than or equal to the displacement alarm threshold; when the axial displacement parameter is less than the displacement alarm threshold, the axial clearance parameter of each stage rotor is compared with the corresponding sub-threshold, and an alarm is triggered in response to the axial clearance parameter of the i-th stage being less than or equal to the i-th stage sub-threshold. The preset parameters include the preset assembly clearance parameters of each stage of the rotor, the end position parameters of each stage of the rotor, the initial axial dimension parameters of each stage of the rotor, and the thermal expansion coefficient of each stage of the rotor.

2. The monitoring method according to claim 1, characterized in that, The rotor's end position parameters include front-end parameters and rear-end parameters. The front-end parameter has a value of 1, and the rear-end parameter has a value of -1. The front end is the end of the rotor that is closer to the displacement sensor, and the rear end is the end of the rotor that is farther away from the displacement sensor.

3. The monitoring method according to claim 1, characterized in that, The calculation formula for obtaining the axial clearance parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter, and the preset parameter includes: ； Where i represents the rotor position, and j represents the rotor's end position parameter, with the front end of the rotor corresponding to j=1 and the rear end corresponding to j=-1. Let be the axial clearance parameter between the j-th end of the i-th stage rotor and the corresponding partition. The preset assembly clearance parameter is the parameter between the j-th end of the i-th stage rotor and the corresponding partition. The axial displacement parameters are measured by the displacement sensor. Let be the coefficient of thermal expansion of the i-th stage rotor. Let be the initial axial dimension parameters of the i-th stage rotor. This is the temperature difference between the temperature parameters of the space where the shaft is located and the set ambient temperature parameters.

4. A monitoring system for monitoring the axial displacement of the shaft of a vacuum pump, characterized in that, The monitoring system is used to perform the monitoring method as described in any one of claims 1 to 3, and the monitoring system includes: A displacement sensor is used to acquire the axial displacement parameters of the rotating shaft; The comparison module is electrically connected to the displacement sensor and is used to compare the axial displacement parameter with a set displacement alarm threshold. An alarm module is electrically connected to the comparison module. The alarm module triggers an alarm in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold.

5. The monitoring system according to claim 4, characterized in that, The monitoring system also includes: The signal receiving module is electrically connected to the displacement sensor and is used to receive the axial displacement parameters. The signal receiving module is also electrically connected to the comparison module and is used to send the axial displacement parameters to the comparison module.

6. The monitoring system according to claim 5, characterized in that, The monitoring system is set with a normal temperature parameter, and the monitoring system also includes: A temperature sensor is used to acquire the temperature parameters of the space where the rotating shaft is located, and the temperature sensor is electrically connected to the signal receiving module. The first calculation module is electrically connected to the signal receiving module and is used to obtain the temperature difference parameter between the temperature parameter and the room temperature parameter.

7. The monitoring system according to claim 6, characterized in that, The monitoring system is configured with preset parameters, and the monitoring system further includes: The second calculation module is electrically connected to the signal receiving module and the first calculation module, and is used to receive the axial displacement parameter and the temperature difference parameter. The rotating shaft includes at least two rotors arranged sequentially at intervals along its axial direction. The rotors are defined as i-th stage rotors based on their relative positions with respect to the displacement sensor, where i is an integer greater than or equal to 1, and the rotor closer to the displacement sensor is the first stage rotor. The displacement sensor is used to obtain the axial displacement parameter of the first stage rotor near the displacement sensor end. The second calculation module obtains the axial clearance parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter. The preset parameters include the preset assembly clearance parameters of each stage of the rotor, the end position parameters of each stage of the rotor, the initial axial dimension parameters of each stage of the rotor, and the thermal expansion coefficient of each stage of the rotor.

8. The monitoring system according to claim 7, characterized in that, The rotor's end position parameters include front-end parameters and rear-end parameters. The front-end parameter has a value of 1, and the rear-end parameter has a value of -1. The front end is the end of the rotor that is closer to the displacement sensor, and the rear end is the end of the rotor that is farther away from the displacement sensor.

9. The monitoring system according to claim 7, characterized in that, The monitoring system also includes: The storage module is electrically connected to the comparison module, the first calculation module and the second calculation module. The displacement alarm threshold, the room temperature parameter, the preset assembly gap parameter of each stage of the rotor, the end position parameter of each stage of the rotor, the initial axial dimension parameter of each stage of the rotor and the thermal expansion coefficient of each stage of the rotor are all stored in the storage module.

10. The monitoring system according to claim 9, characterized in that, The storage module also stores an axial clearance threshold, which includes at least two sub-thresholds. The sub-thresholds are defined as i-th level sub-thresholds based on their correspondence with the rotor. The i-th level sub-threshold corresponds to the i-th level rotor. The comparison module also outputs an alarm signal based on the i-th level axial clearance parameter being less than or equal to the i-th level sub-threshold.

11. The monitoring system according to any one of claims 6-10, characterized in that, The monitoring system also includes: The signal processing module is electrically connected to the signal receiving module and is used to convert the axial displacement parameter into a first digital signal. The signal processing module is also electrically connected to the temperature sensor and is used to convert the temperature parameter into a second digital signal. The comparison module is electrically connected to the signal processing module and is used to compare the first digital signal with the displacement alarm threshold. The first calculation module is electrically connected to the signal processing module to obtain the temperature difference parameter based on the second digital signal and the room temperature parameter.

12. A vacuum pump, characterized in that, The vacuum pump uses the monitoring method described in any one of claims 1-3 to monitor the axial displacement of the shaft.

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