Monitoring method, monitoring system and vacuum pump

Abstract

The present disclosure relates to the technical field of monitoring. Provided are a monitoring method, a monitoring system and a vacuum pump. The monitoring method comprises: acquiring an axial displacement parameter of a rotor shaft; comparing the axial displacement parameter with a set displacement alarm threshold value; and in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold value, outputting an alarm signal so as to give an alarm. Thus, the axial clearance of the rotor shaft of the vacuum pump can be monitored in real time, so as to solve the technical problem of it being difficult to monitor the risk of pump seizure of the vacuum pump.

Description

Monitoring method, monitoring system and vacuum pump

[0001] The present disclosure claims priority to the Chinese patent application No. CN202411127719.1, filed on August 16, 2024, and entitled "Monitoring method, monitoring system and vacuum pump", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of monitoring, in particular to a monitoring method, a monitoring system and a vacuum pump. BACKGROUND

[0003] The axial gap of the rotating shaft in the vacuum pump plays a crucial role as a necessary condition for its normal operation. When the vacuum pump is continuously operating, the rotating shaft inside the vacuum pump will expand due to heat, causing the axial gap to decrease, which may lead to the risk of pump jamming. SUMMARY

[0004] The present disclosure provides a monitoring method, a monitoring system and a vacuum pump, which can solve the technical problem of difficulty in monitoring the risk of pump jamming.

[0005] In a first aspect, the present disclosure provides a monitoring method for monitoring the axial displacement of a rotating shaft of a vacuum pump, comprising:

[0006] obtaining an axial displacement parameter of the rotating shaft;

[0007] comparing the axial displacement parameter with a set displacement alarm threshold;

[0008] in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold, outputting an alarm signal for alarm.

[0009] In some embodiments, the rotating shaft is sequentially provided with at least two rotors along its axial direction, and the rotors are defined as an i-th rotor based on the relative position of the rotors and a displacement sensor installed on the vacuum pump, where i is an integer greater than or equal to 1, and the rotor closest to the displacement sensor is the first rotor;

[0010] The obtaining of the axial displacement parameter of the rotating shaft comprises:

[0011] obtaining an axial displacement parameter of one end of the first rotor close to the displacement sensor.

[0012] In some embodiments, the rotors are arranged in stators, the stators are multi-stage stators, each rotor corresponds to a stator at each stage, and a partition is arranged between each adjacent two stators, and the axial gap parameter of each rotor is used to represent the axial gap size between the rotor and the corresponding partition.

[0013] The monitoring method further comprises:

[0014] obtaining a temperature parameter of a space where the rotating shaft is located, and calculating a temperature difference parameter between the temperature parameter and a set normal temperature parameter;

[0015] After the step of obtaining the axial displacement parameter of the first-stage rotor close to one end of the displacement sensor, the monitoring method further comprises:

[0016] obtaining an axial gap parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter and a preset parameter;

[0017] in response to the axial displacement parameter being less than the displacement alarm threshold, comparing the axial gap parameter of each stage rotor with a corresponding sub-threshold;

[0018] in response to the axial gap parameter of the i-th stage rotor being less than or equal to the corresponding sub-threshold of the i-th stage rotor, outputting an alarm signal for alarm.

[0019] In some embodiments, the preset parameter includes a preset assembly gap parameter of each stage rotor, an end position parameter of each stage rotor, an initial axial dimension parameter of each stage rotor and a thermal expansion coefficient of each stage rotor.

[0020] In some embodiments, the end position parameter of the rotor includes a front end parameter and a rear end parameter, the front end parameter has a value of 1, and the rear end parameter has a value of -1, wherein the front end of the rotor is close to the displacement sensor, and the rear end of the rotor is away from the displacement sensor.

[0021] In some embodiments, the obtaining of the axial gap parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter comprises:

[0022] the axial gap parameter of each stage rotor is obtained by the following formula:

[0023] ;

[0024] wherein i is the stage number of the rotor, j is the end position parameter of the rotor, the front end of the rotor corresponds to j = 1, and the rear end of the rotor corresponds to j = -1, is the axial gap parameter of the j-th end of the i-th stage rotor and the corresponding partition, is the preset assembly gap parameter of the j-th end of the i-th stage rotor and the corresponding partition, is the axial displacement parameter measured by the displacement sensor, is the thermal expansion coefficient of the i-th stage rotor, an initial axial size parameter of an i-th stage rotor, a temperature difference parameter between a temperature parameter of a space where the rotating shaft is located and a constant temperature parameter set.

[0025] In a second aspect, the embodiments of the present disclosure provide a monitoring system for monitoring an axial displacement amount of a rotating shaft of a vacuum pump, comprising:

[0026] a displacement sensor configured to obtain an axial displacement parameter of the rotating shaft;

[0027] a comparison module electrically connected to the displacement sensor and configured to compare the axial displacement parameter with a set displacement alarm threshold;

[0028] an alarm module electrically connected to the comparison module, wherein the alarm module outputs an alarm signal for alarm in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold.

[0029] In some embodiments, the monitoring system further comprises:

[0030] a signal receiving module electrically connected to the displacement sensor and configured to receive the axial displacement parameter, wherein the signal receiving module is electrically connected to the comparison module and configured to send the axial displacement parameter to the comparison module.

[0031] In some embodiments, the monitoring system is set with a constant temperature parameter, and the monitoring system further comprises:

[0032] a temperature sensor configured to obtain a temperature parameter of a space where the rotating shaft is located, wherein the temperature sensor is electrically connected to the signal receiving module;

[0033] a first calculation module electrically connected to the signal receiving module and configured to obtain a temperature difference parameter between the temperature parameter and the constant temperature parameter.

[0034] In some embodiments, the monitoring system is set with a preset parameter, and the monitoring system further comprises:

[0035] the rotating shaft is sequentially and spacedly provided with at least two rotors along an axial direction thereof, the rotors are defined as i-th stage rotors based on relative positions of the rotors and a displacement sensor mounted on the vacuum pump, wherein i is an integer greater than or equal to 1, and a rotor closest to the displacement sensor is a first stage rotor;

[0036] the displacement sensor is configured to obtain an axial displacement parameter of a side of the first stage rotor close to the displacement sensor;

[0037] The second calculation module is electrically connected with the signal receiving module and the first calculation module, and is configured to receive the axial displacement parameter and the temperature difference parameter. The second calculation module obtains the axial gap parameter of each stage rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter.

[0038] In some embodiments, the preset parameter includes a preset assembly gap parameter of each stage rotor, an end position parameter of each stage rotor, an initial axial dimension parameter of each stage rotor and a thermal expansion coefficient of each stage rotor.

[0039] In some embodiments, the end position parameter of the rotor includes a front end parameter and a rear end parameter. The value of the front end parameter is 1, and the value of the rear end parameter is -1. The front end of the rotor is the end of the rotor close to the displacement sensor, and the rear end of the rotor is the end of the rotor away from the displacement sensor.

[0040] In some embodiments, the monitoring system further comprises:

[0041] The storage module is electrically connected with the comparison module, the first calculation module and the second calculation module. The displacement alarm threshold, the normal temperature parameter, the preset assembly gap 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 are stored in the storage module.

[0042] In some embodiments, the storage module further stores an axial gap threshold. The axial gap threshold includes at least two sub-thresholds. Based on the correspondence between the sub-thresholds and the rotors, the sub-thresholds are defined as an i-th stage sub-threshold, which corresponds to the i-th stage rotor. The comparison module further outputs an alarm signal for alarm in response to the axial gap parameter of the i-th stage rotor being less than or equal to the corresponding sub-threshold of the i-th stage rotor.

[0043] In some embodiments, the monitoring system further comprises:

[0044] The signal processing module is electrically connected with the signal receiving module, and is configured to convert the axial displacement parameter into a first digital signal. The signal processing module is also electrically connected with the temperature sensor, and is configured to convert the temperature parameter into a second digital signal. The comparison module is electrically connected with the signal processing module, and is configured to compare the first digital signal with the displacement alarm threshold. The first calculation module is electrically connected with the signal processing module, and is configured to obtain the temperature difference parameter based on the second digital signal and the normal temperature parameter.

[0045] In a third aspect, the embodiments of the present disclosure provide a vacuum pump, which is monitored by the monitoring method as described above.

[0046] The embodiments of the present disclosure have the following beneficial effects:

[0047] In the embodiments of the present disclosure, the axial displacement parameter of the rotating shaft is obtained, and it is determined whether to alarm based on the comparison result of the axial displacement parameter and the displacement alarm threshold. When the axial displacement parameter is less than the displacement alarm threshold, no alarm is given. At this time, the vacuum pump will not have the phenomenon of being stuck, and the vacuum pump can continue to work normally. When the axial displacement parameter is greater than or equal to the displacement alarm threshold, an alarm is given. At this time, the axial displacement of the rotating shaft is large, which can cause the axial gap of the rotating shaft to be too small, and the vacuum pump has the risk of being stuck. The operating personnel can detect the operating state of the vacuum pump based on the alarm information, and adjust the axial gap of the rotating shaft to prevent the vacuum pump from being stuck. Thus, the axial gap of the rotating shaft of the vacuum pump can be monitored in real time, so as to give an early warning in time when the vacuum pump has the risk of being stuck. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art without creative labor.

[0049] FIG. 1 is a flowchart of the monitoring method provided by the embodiments of the present disclosure.

[0050] FIG. 2 is a structural schematic diagram of the monitoring system provided by the embodiments of the present disclosure.

[0051] FIG. 3 is a structural schematic diagram of the vacuum pump provided by the embodiments of the present disclosure.

[0052] FIG. 4 is a structural schematic diagram of the displacement sensor installation provided by the embodiments of the present disclosure.

[0053] FIG. 5 is a sectional view of the rotating shaft and the end cover provided by the embodiments of the present disclosure.

[0054] Reference signs:

[0055] 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. Embodiments of the present application

[0056] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present disclosure. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure. In the present disclosure, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, and specifically refer to the direction of the drawing surface in the drawings; and "inner" and "outer" refer to the outline of the device.

[0057] Specifically, as shown in FIG. 1, the present application provides a monitoring method. The monitoring method is used for monitoring the axial displacement of the rotating shaft 40 of the vacuum pump. The monitoring method comprises:

[0058] Step A, obtaining the axial displacement parameter of the rotating shaft 40.

[0059] Step B, comparing the axial displacement parameter with the set displacement alarm threshold.

[0060] Step C, in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold, outputting an alarm signal for alarm.

[0061] It can be understood that by obtaining the axial displacement parameter of the rotating shaft 40, it is determined whether to alarm based on the comparison result of the axial displacement parameter and the displacement alarm threshold. When the axial displacement parameter is less than the displacement alarm threshold, the alarm signal can not be output. At this time, the vacuum pump will not appear the phenomenon of pump jamming, and the vacuum pump can continue to work normally. When the axial displacement parameter is greater than or equal to the displacement alarm threshold, the alarm signal can be output. At this time, the axial displacement of the rotating shaft 40 is large, which can cause the axial gap of the rotating shaft 40 to be too small, and the vacuum pump has the risk of pump jamming. The operating personnel can detect the running state of the vacuum pump based on the alarm information, and adjust the axial gap of the rotating shaft 40 to prevent the vacuum pump from jamming. Thus, the axial gap of the rotating shaft 40 of the vacuum pump can be monitored in real time, so as to solve the technical problem that the risk of pump jamming of the vacuum pump is difficult to monitor.

[0062] Among them, the axial displacement parameter of the rotating shaft 40 can be obtained by the displacement sensor 10. The axial displacement parameter can be compared with the set displacement alarm threshold by the comparison module 220, and in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold, an alarm signal can be output. By issuing the alarm signal to the alarm module 230, the alarm module 230 can be instructed to alarm.

[0063] In some embodiments, the displacement alarm threshold is less than the wear threshold of the rotating shaft. In this case, when the axial displacement parameter is greater than or equal to the displacement alarm threshold, the rotating shaft is likely to be in an unworn state. Therefore, the output alarm signal can be used as a risk prompt alarm to prompt the staff that the vacuum pump is at high risk of future pump seizure.

[0064] In some embodiments, the displacement alarm threshold is equal to the wear threshold of the rotating shaft. In this case, when the axial displacement parameter is greater than or equal to the displacement alarm threshold, the rotating shaft has already worn. The alarm information can be used as a failure prompt alarm to prompt the staff to shut down the vacuum pump for maintenance.

[0065] In some embodiments, the rotating shaft 40 is sequentially provided with at least two rotors along its axial direction. The rotor is defined as an i-th rotor, where i is an integer greater than or equal to 1, and the rotor closest to the displacement sensor 10 is the first rotor.

[0066] The rotating shaft 40 in the pump body assembly 510 of the vacuum pump is provided with a plurality of rotors along its axial direction, and there is a gap between adjacent two rotors.

[0067] When the vacuum pump is continuously operated, each rotor can be deformed due to the increase of ambient temperature, and thus the axial gap between each rotor and the corresponding stator can change. In order to facilitate the subsequent calculation of the axial gap of each rotor, the grade of each rotor can be defined respectively.

[0068] In some embodiments, the axial displacement parameter of the rotating shaft 40 is obtained, comprising:

[0069] The axial displacement parameter of the first rotor close to the displacement sensor 10 is obtained.

[0070] Since the first rotor is the rotor closest to the displacement sensor 10, the displacement sensor 10 will act on the first rotor. The first rotor has a front end close to the displacement sensor 10 and a rear end away from the displacement sensor 10. The displacement sensor 10 is used to obtain the axial displacement parameter of the front end of the first rotor.

[0071] In some embodiments, the rotor is arranged in the stator, and the stator is a multi-stage stator. Each rotor corresponds to a stator, and a partition is arranged between each adjacent two stages of stators. The axial gap parameter of each rotor is used to represent the axial gap size of the rotor and the corresponding partition.

[0072] It can be understood that, since the number of rotors is at least two, the stators can also be provided as at least two. Based on the corresponding relationship between the stators and the rotors, the stators can be defined as the i-th stator. The two adjacent stators are separated by a partition. The partition is a circular ring-shaped partition, so that the shaft can pass through each partition. The axial gap parameter of the rotor is defined as the gap between each rotor and the corresponding partition. It can be understood that, in order to prevent the partition from interfering with the rotation of the rotor, the rotor needs to form a gap with the partition. When the rotor abuts against the partition, it can cause a pump jamming phenomenon.

[0073] In some embodiments, the monitoring method further comprises: obtaining a temperature parameter of the space where the shaft 40 is located, and calculating a temperature difference parameter between the temperature parameter and a set normal temperature parameter.

[0074] It can be understood that, by obtaining the temperature parameter of the space where the shaft 40 is located and the set normal temperature parameter, the temperature difference parameter of the shaft 40 can be obtained. Based on the thermal expansion and contraction phenomenon, it can be known that the shaft 40 will expand after being heated. The temperature difference parameter of the shaft 40 can be used to measure the change of the axial gap parameter of each rotor caused by the thermal expansion and contraction phenomenon.

[0075] After obtaining the axial displacement parameter of the first rotor close to one end of the displacement sensor 10, the monitoring method further comprises:

[0076] Based on the axial displacement parameter, the temperature difference parameter and the preset parameter, the axial gap parameter of each rotor is obtained.

[0077] In response to the axial displacement parameter being less than the displacement alarm threshold, the axial gap parameter of each rotor is compared with the corresponding sub-threshold.

[0078] In response to the axial gap parameter of the i-th rotor being less than or equal to the corresponding sub-threshold of the i-th rotor, an alarm signal is outputted for alarm.

[0079] It can be understood that, by obtaining the axial gap parameter of each rotor in real time, the real-time monitoring of the axial gap of each rotor can be realized, so as to prevent the pump from being jammed due to the too small axial gap of the rotor.

[0080] That is to say, when the axial displacement parameter does not trigger the alarm, the axial gap parameter of each rotor can be further compared to realize multi-dimensional alarm monitoring.

[0081] For example, the axial gap parameter of the i-th rotor can be compared with the sub-threshold corresponding to the i-th rotor. If the axial gap parameter of the i-th rotor is greater than the sub-threshold corresponding to the i-th rotor, no alarm signal is output. At this time, the vacuum pump will not be stuck, and the vacuum pump can continue to work normally. If the axial gap parameter of the i-th rotor is less than or equal to the sub-threshold corresponding to the i-th rotor, an alarm signal is output. At this time, the axial gap of the i-th rotor is too small, and the vacuum pump has the risk of being stuck. The operator can detect the i-th rotor of the vacuum pump based on the alarm signal, and adjust the axial gap of the i-th rotor to prevent the vacuum pump from being stuck.

[0082] Therefore, based on the comparison of the axial gap parameter of the i-th rotor and the sub-threshold corresponding to the i-th rotor, the axial gap of each rotor of the vacuum pump can be monitored in real time, and the i-th rotor with problems can be accurately repaired. The technical problem that the risk of the vacuum pump being stuck is difficult to monitor can be solved, risk alarm can be realized, and the repair efficiency can be improved.

[0083] In the comparison of the axial gap parameter of each rotor and the corresponding sub-threshold, the axial gap parameter of each rotor and the corresponding sub-threshold can be compared synchronously. If the axial gap parameter of any i-th rotor is less than or equal to the corresponding sub-threshold, an alarm signal is output for alarm.

[0084] In some embodiments, the preset parameters include a preset assembly gap parameter of each rotor, an end position parameter of each rotor, an initial axial size parameter of each rotor, and a thermal expansion coefficient of each rotor.

[0085] The initial axial size parameter of each rotor is the initial length of the rotor. For example, the initial axial size parameter of the second rotor is the initial length parameter of the second rotor.

[0086] The thermal expansion coefficient of each rotor is related to the material of the rotor. When each rotor of the rotating shaft 40 is made of the same material, the thermal expansion coefficients of each rotor are the same. When each rotor of the rotating shaft 40 is made of different materials, the thermal expansion coefficients of each rotor are different.

[0087] The end position parameter of the rotor includes a front end parameter and a rear end parameter, the value of the front end parameter is 1, and the value of the rear end parameter is -1. The front end of the rotor is the end of the rotor close to the displacement sensor 10, and the rear end of the rotor is the end of the rotor away from the displacement sensor 10.

[0088] In some embodiments, based on the axial displacement parameter, the temperature difference parameter, and the preset parameter, the axial gap parameter of each rotor is obtained, including: ​

[0089] The axial gap parameter of each stage rotor is obtained by the following formula:

[0090] 。

[0091] wherein i is the stage number of the rotor. j is the end position parameter of the rotor. The front end of the rotor corresponds to j = 1. The rear end of the rotor corresponds to j = -1. is the axial gap parameter of the jth end of the ith stage rotor and the corresponding partition. is the preset assembly gap parameter of the jth end of the ith stage rotor and the corresponding partition. is the axial displacement parameter measured by the displacement sensor 10. is the thermal expansion coefficient of the ith stage rotor. is the initial axial size parameter of the ith stage rotor. is the temperature difference parameter between the temperature parameter of the space where the shaft 40 is located and the set normal temperature parameter.

[0092] It can be understood that based on the above calculation formula, the axial gap parameter of each end of each stage rotor can be calculated. Thus, the real-time monitoring of the axial gap parameter of each stage rotor is realized.

[0093] For example, when the axial gap parameter of the front end of the fifth stage rotor relative to the fifth stage stator needs to be obtained, i = 5, j = 1. The formula is: 。

[0094] For example, when the axial gap parameter of the rear end of the third stage rotor needs to be obtained, i = 3, j = -1. The formula is: 。

[0095] On the other hand, as shown in FIG. 2, the application also provides a monitoring system. The monitoring system is used for monitoring the axial displacement amount of the shaft 40 of the vacuum pump. The monitoring system comprises a displacement sensor 10, a comparison module 220 and an alarm module 230. The displacement sensor 10 is used for obtaining the axial displacement parameter of the shaft 40. The comparison module 220 is electrically connected with the displacement sensor 10, and is used for comparing the axial displacement parameter with a set displacement alarm threshold. The alarm module 230 is electrically connected with the comparison module 220. The alarm module 230 outputs an alarm signal for alarm in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold.

[0096] It can be understood that the axial displacement parameter of the rotating shaft 40 is acquired by the displacement sensor 10, and the comparison module 220 determines whether to transmit an alarm signal to the alarm module 230 based on the comparison result of the axial displacement parameter and the displacement alarm threshold. When the axial displacement parameter is less than the displacement alarm threshold, no alarm signal is output. At this time, the vacuum pump will not have the pump jamming phenomenon, and the vacuum pump can continue to work normally. When the axial displacement parameter is greater than or equal to the displacement alarm threshold, the alarm signal is output. At this time, the axial displacement of the rotating shaft 40 is large, thereby causing the axial gap of the rotating shaft 40 to be too small, and the vacuum pump has a risk of pump jamming. The operator can detect the vacuum pump based on the alarm information, thereby adjusting the axial gap of the rotating shaft 40 to prevent the vacuum pump from being jammed. Thus, the axial gap of the rotating shaft 40 of the vacuum pump can be monitored in real time, thereby solving the technical problem that the risk of pump jamming of the vacuum pump is difficult to monitor.

[0097] In some embodiments, the displacement sensor 10 can adopt one or more of an inductive displacement sensor, a capacitive displacement sensor, an optoelectronic displacement sensor, an ultrasonic displacement sensor, a Hall displacement sensor, and a magnetostrictive displacement sensor. The axial displacement of the rotating shaft 40 is the offset of the rotating shaft 40 relative to the stator around the area in the axial direction.

[0098] The monitoring system can take a controller 20 as a central control unit. The controller 20 can receive the axial displacement parameter monitored by the displacement sensor 10. The controller 20 can be connected to the displacement sensor 10 in a wireless manner. For example, the controller 20 is connected to the displacement sensor 10 in a wireless fidelity (WiFi) manner or a Bluetooth manner. Alternatively, the controller 20 can also be connected to the displacement sensor 10 in a wired manner. For example, the controller 20 is connected to the displacement sensor 10 through a data line.

[0099] The rotating shaft 40 can displace towards the displacement sensor 10, and at this time, the axial displacement parameter acquired by the displacement sensor 10 is a positive value. The rotating shaft 40 can also displace away from the displacement sensor 10, and at this time, the axial displacement parameter acquired by the displacement sensor 10 is a negative value. Generally, the rotating shaft 40 will heat based on continuous work, causing the rotating shaft 40 to expand in the axial direction. For the end of the rotating shaft 40 towards the displacement sensor 10, the end of the rotating shaft 40 displaces towards the displacement sensor 10. The greater the displacement, the smaller the axial gap of the rotating shaft 40, and the higher the risk of pump jamming of the vacuum pump.

[0100] In some embodiments, the displacement alarm threshold value set in the controller 20 can be 0.1 mm, 0.5 mm, 1 mm, or any value between 0.1 mm and 1 mm. For example, the displacement alarm threshold value is set to 0.5 mm. When the value of the axial displacement parameter obtained is less than 0.5 mm, no alarm signal is output. At this time, the vacuum pump does not have the risk of pump jamming, and the vacuum pump can continue to work normally. When the value of the axial displacement parameter obtained is greater than or equal to 0.5 mm, an alarm signal is output. At this time, the axial displacement of the rotating shaft 40 is large, which causes the axial gap of the rotating shaft 40 to be too small, and the vacuum pump has the risk of pump jamming.

[0101] It can be understood that after the controller 20 receives the axial displacement parameter, the axial displacement parameter can be sent to the comparison module 220. The comparison module 220 compares the comparison module 220 with the set displacement alarm threshold value, and determines whether to output an alarm signal to the alarm module based on the comparison result. The alarm module responds to the received alarm signal and alarms to prompt the operator to detect the vacuum pump.

[0102] The comparison module 220 can be set as a comparator, which is mainly used for size comparison. After the comparison module 220 receives the axial displacement parameter, the value is compared with the preset displacement alarm threshold value. If the axial displacement parameter is less than the displacement alarm threshold value, 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 value, the comparison module 220 sends an alarm signal to the alarm module 230.

[0103] The alarm module 230 can be set as an alarm device. For example, a buzzer alarm, a stroboscopic alarm lamp, an audible and visual alarm, etc. The alarm module 230 can generate an alarm sound and / or an alarm light based on the alarm signal to prompt the operator to detect the vacuum pump.

[0104] In some embodiments, the monitoring system further comprises a signal receiving module 210. The signal receiving module 210 is electrically connected with the displacement sensor 10 and is used for receiving the axial displacement parameter. The signal receiving module 210 is electrically connected with the comparison module 220 and is used for sending the axial displacement parameter to the comparison module 220.

[0105] It can be understood that after the signal receiving module 210 receives the axial displacement parameter, the axial displacement parameter can be sent to the comparison module 220. The comparison module 220 compares the comparison module 220 with the set displacement alarm threshold value, and outputs an alarm signal to the alarm module based on the comparison result. The alarm module responds to the alarm signal and can alarm to prompt the operator to detect 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 parameter monitored by the displacement sensor 10. The signal receiving module 210 can be connected to the displacement sensor 10 in a wireless manner. For example, the signal receiving module 210 is connected to the displacement sensor 10 in a WIFI manner or a Bluetooth manner. Alternatively, the signal receiving module 210 can also be connected to the displacement sensor 10 in a wired manner. For example, the signal receiving module 210 is connected to the displacement sensor 10 through a data line.

[0107] In some embodiments, the monitoring system further comprises a temperature sensor 30. The temperature sensor 30 is configured to obtain a temperature parameter of a space where the rotating shaft 40 is located. The monitoring system is provided with a normal temperature parameter. The monitoring system further comprises a first calculation module 240. The first calculation module 240 is electrically connected to the temperature sensor 30. The first calculation module 240 is configured to obtain a temperature difference parameter between the temperature parameter and the normal temperature parameter.

[0108] It can be understood that by obtaining the temperature parameter of the space where the rotating shaft 40 is located and the normal temperature parameter, the temperature difference parameter of the rotating shaft 40 can be obtained by difference calculation. Based on the thermal expansion and contraction phenomenon, it can be known that the rotating shaft 40 will expand after being heated. The temperature difference parameter of the rotating shaft 40 can be used to measure the change of the axial gap parameter of each stage rotor caused by the thermal expansion and contraction phenomenon.

[0109] The rotating shaft 40 is usually arranged in a pump body assembly 510 of a vacuum pump. The temperature sensor 30 can obtain the temperature inside the pump body assembly 510 to reflect the temperature parameter of the space where the rotating shaft 40 is located. Therefore, the temperature sensor 30 is usually directly installed in a cavity of the pump body assembly 510.

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

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

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

[0113] In some embodiments, the monitoring system is provided with preset parameters. The monitoring system further comprises a second calculation module 250. The second calculation module 250 is electrically connected with the signal receiving module 210 and the first calculation module 240, and is configured to receive the axial displacement parameter and the temperature difference parameter. The rotating shaft 40 comprises at least two rotors which are sequentially and spacedly arranged along the axial direction of the rotating shaft 40. The rotor is defined as an i-th rotor based on the relative position between the rotor and the displacement sensor 10. Wherein, i is an integer greater than or equal to 1, and the rotor closest to the displacement sensor 10 is the first rotor. The displacement sensor 10 is configured to obtain the axial displacement parameter of the first rotor close to one end of the displacement sensor 10. The second calculation module 250 obtains the axial gap parameter of each rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter.

[0114] It can be understood that the second calculation module 250 can receive the axial displacement parameter and the temperature parameter. The second calculation module 250 is provided with a calculation logic. The calculation logic can calculate the axial gap parameter of each rotor based on the preset parameter, the axial displacement parameter and the temperature parameter. Thus, each rotor can be monitored in real time to prevent the pump from being stuck due to the too small axial gap of the rotor.

[0115] The rotating shaft 40 in the pump body assembly 510 of the vacuum pump comprises a plurality of rotors which are sequentially and spacedly arranged along the axial direction. Each rotor is fixedly sleeved on the rotating shaft 40.

[0116] When the vacuum pump is continuously working, each rotor can be deformed due to the increase of the ambient temperature. Therefore, the axial gap between each rotor and the corresponding stator can be changed. If the change value of the axial gap between the corresponding rotor and the stator is too large, the axial gap between the rotor and the stator can be too small, which can cause the pump to be stuck. Therefore, the second calculation module 250 can directly obtain the axial gap parameter of each rotor relative to each stator, so as to monitor each rotor.

[0117] For example, the rotating shaft 40 comprises three rotors which are sequentially and spacedly arranged along the axial direction. In the direction away from the displacement sensor 10, the three rotors are sequentially the first rotor, the second rotor and the third rotor. The displacement sensor 10 is configured to obtain the axial displacement parameter of the first rotor close to one end of the displacement sensor 10. The second calculation module 250 can obtain the first axial gap parameter of the first rotor, the second axial gap parameter of the second rotor and the third axial gap parameter of the third rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter.

[0118] The second calculation module 250 can be a single-chip microcomputer programmed with a corresponding calculation program. The calculation program can be:

[0119] ​

[0120] wherein i is the stage number of the rotor. j is the end position parameter of the rotor. The front end of the rotor corresponds to j = 1. The rear end of the rotor corresponds to j = -1. is the axial gap parameter of the jth end of the ith stage rotor and the corresponding partition. is the preset assembly gap parameter of the jth end of the ith stage rotor and the corresponding partition. is the axial displacement parameter measured by the displacement sensor 10. is the thermal expansion coefficient of the ith stage rotor. is the initial axial dimension parameter of the ith stage rotor. is the temperature difference parameter between the temperature parameter of the space where the shaft 40 is located and the set normal temperature parameter.

[0121] In some embodiments, the preset parameters include the preset assembly gap 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 ith stage axial gap parameter of the ith stage rotor and the corresponding partition based on the axial displacement parameter, the temperature difference parameter, the preset assembly gap 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.

[0123] It can be understood that each stage rotor has a corresponding assembly gap value after being assembled in the vacuum pump. The assembly gap value is taken as the preset assembly gap parameter of the corresponding rotor.

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

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

[0126] In some embodiments, the end position parameter of the rotor includes a front end parameter and a rear end parameter, the value of the front end parameter is 1, and the value of the rear end parameter is -1, wherein the front end of the rotor is the end of the rotor close to the displacement sensor 10, and the rear end of the rotor is the end of the rotor away from the displacement sensor 10.

[0127] It can be understood that the rotor has two opposite ends, which are defined as front end and rear end respectively. When the rotor is heated and expanded, the front end and the rear end of the rotor will both produce displacement, thereby causing the axial gap value of the front end of the rotor and the axial gap value of the rear end of the rotor to change. By introducing the end position parameter of the rotor, the axial gap parameters of the front end and the rear end of each stage of the rotor can be conveniently calculated.

[0128] For example, the rotating shaft 40 includes three rotors which are sequentially and spaced apart along the axial direction thereof. In the direction away from the displacement sensor 10, the three rotors are sequentially a first stage rotor, a second stage rotor and a third stage rotor. The displacement sensor 10 is used to obtain the axial displacement parameter of the first stage rotor close to one end of the displacement sensor 10. The second calculation module 250 can obtain the first stage front end axial gap parameter and the first stage rear end axial gap parameter of the first stage rotor, the second stage front end axial gap parameter and the second stage rear end axial gap parameter of the second stage rotor, and the third stage front end axial gap parameter and the third stage rear end axial gap parameter of the third stage rotor based on the axial displacement parameter, the temperature difference 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 size parameter of each stage of the rotor and the thermal expansion coefficient of each stage of the rotor.

[0129] In some embodiments, the monitoring system further includes a storage module 260. The storage module 260 is electrically connected with the comparison module 220, the first calculation module 240 and the second calculation module 250. The displacement alarm threshold, the normal 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 size 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 260.

[0130] It can be understood that the storage module 260 is used for data storage to store the displacement alarm threshold, the normal 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 size parameter of each stage of the rotor and the thermal expansion coefficient of each stage of the rotor.

[0131] The storage module 260 is electrically connected with the first calculation module 240, and is used to send the normal temperature parameter to the first calculation module 240. Of course, the first calculation module 240 can also send the calculated temperature difference parameter to the storage module 260 for storage, so as to facilitate the viewing of the temperature difference data during the maintenance process.

[0132] The storage module 260 is electrically connected with the second calculation module 250, and is configured to send the preset assembly gap 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 to the second calculation module 250. Of course, the second calculation module 250 can also send the calculated i-th stage rotor and the corresponding i-th stage axial gap parameter to the storage module 260 for storage, so as to store the axial gap parameter of each stage rotor in real time, and facilitate the judgment of the time point of failure in the maintenance process.

[0133] The storage module 260 is also electrically connected with the comparison module 220, and is configured to send the displacement alarm threshold to the comparison module 220. Of course, the comparison module 220 can also send the alarm signal to the storage module 260, so as to record the alarm time each time.

[0134] In some embodiments, the storage module 260 can be configured as a solid-state storage, such as a solid-state hard disk. The storage module 260 can also be configured as a read-only memory, so as to have the function of not losing power-off data.

[0135] In some embodiments, the storage module 260 also stores the axial gap threshold. Since the shaft is provided with at least two rotors along the axial direction, the axial gap threshold can include at least two sub-thresholds corresponding to the at least two rotors. Based on the corresponding relationship between the sub-threshold and the rotor, the sub-threshold is defined as an i-th stage sub-threshold. The i-th stage sub-threshold corresponds to the i-th stage rotor. The comparison module 220 also outputs an alarm signal in response to that the axial gap parameter of the i-th stage rotor is less than or equal to the i-th stage sub-threshold corresponding to the i-th stage rotor.

[0136] It can be understood that based on the calculation of the aforementioned second calculation module 250, the axial gap parameter of each stage rotor can be obtained. When each stage rotor is judged, the axial gap threshold of each stage rotor needs to be compared. Therefore, the storage module 260 can store the sub-thresholds corresponding to the at least two rotors, and compare the axial gap parameter of the i-th stage rotor with the i-th stage sub-threshold corresponding to the i-th stage rotor. If the axial gap parameter of the i-th stage rotor is greater than the i-th stage sub-threshold corresponding to the i-th stage rotor, no alarm signal is output. At this time, the vacuum pump does not appear to be stuck, and the vacuum pump can continue to work normally. If the axial gap parameter of the i-th stage rotor is less than or equal to the i-th stage sub-threshold corresponding to the i-th stage rotor, an alarm signal is output. At this time, the axial gap of the i-th stage rotor is too small, and the vacuum pump has the risk of being stuck. The operator can detect the i-th stage rotor of the vacuum pump based on the alarm information, so as to adjust the axial gap of the i-th stage rotor to prevent the vacuum pump from being stuck.

[0137] Therefore, based on the comparison between the axial gap parameter of the i-th rotor and the sub-threshold corresponding to the i-th rotor, the axial gap of each rotor of the vacuum pump can be monitored in real time, and the i-th rotor with problems can be accurately repaired, thereby solving the technical problem that the pump blocking risk of the vacuum pump is difficult to monitor, and improving the repair efficiency.

[0138] In some embodiments, the monitoring system further comprises a signal processing module 270. The signal processing module 270 is electrically connected with the signal receiving module 210, for converting the axial displacement parameter into a first digital signal. The signal processing module 270 is also electrically connected with the temperature sensor 30, for converting the temperature parameter into a second digital signal. The comparison module 220 is electrically connected with the signal processing module 270, for comparing the first digital signal with the displacement alarm threshold. The first calculation module 240 is electrically connected with the signal processing module 270, for obtaining a temperature difference parameter based on the second digital signal and the normal temperature parameter.

[0139] It can be understood that the axial displacement parameter obtained by the displacement sensor 10 and the temperature parameter obtained by the temperature sensor 30 are both analog signals. The signal processing module 270 can realize analog-to-digital conversion. The signal processing module 270 converts the axial displacement parameter into a first digital signal and converts the temperature parameter into a second digital signal, so as to realize digital comparison, digital calculation and digital display.

[0140] The signal processing module 270 can be an analog-to-digital converter. For example, the signal processing module 270 can adopt an integral type analog-to-digital converter, a successive approximation type analog-to-digital converter, a parallel comparison type / serial-parallel type analog-to-digital converter, etc.

[0141] In some embodiments, the signal processing module 270 can also have the functions of interference isolation, signal amplification, filtering, etc. For example, the signal processing module 270 is integrated with an analog-to-digital converter, a signal amplifier, a filter, etc.

[0142] In some embodiments, the monitoring system further comprises a display module 280. The display module 280 is electrically connected with the signal processing module 270, for receiving the first digital signal and the second digital signal, so as to digitally display the axial displacement parameter and the temperature parameter of the space where the shaft 40 is located.

[0143] It can be understood that after the display module 280 receives the first digital signal and the second digital signal, the axial displacement parameter and the temperature parameter can be directly digitally displayed, so as to directly observe the axial displacement value and the temperature value.

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

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

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

[0147] As shown in FIGS. 3-5, the present application also provides a vacuum pump. The vacuum pump applies the monitoring method as in the foregoing embodiments to monitor the axial displacement of the rotating shaft. The vacuum pump includes a pump body assembly 510 and a monitoring system as in the foregoing embodiments. The rotating shaft 40 is installed in the pump body assembly 510.

[0148] It can be understood that the axial displacement parameter of the rotating shaft 40 is obtained by the displacement sensor 10, and whether to output an alarm signal is determined based on the comparison result of the axial displacement parameter and the displacement alarm threshold. When the axial displacement parameter is less than the displacement alarm threshold, no alarm signal is output. At this time, the vacuum pump does not have the risk of pump jamming, and the vacuum pump can continue to work normally. When the axial displacement parameter is greater than or equal to the displacement alarm threshold, an alarm signal is output. At this time, the axial displacement of the rotating shaft 40 is large, which can cause the axial gap of the rotating shaft 40 to be too small, and the vacuum pump has the risk of pump jamming. The operating personnel can detect the vacuum pump based on the alarm information, so as to adjust the axial gap of the rotating shaft 40 to prevent the vacuum pump from jamming. Thus, the axial gap of the rotating shaft 40 of the vacuum pump can be monitored in real time, so as to solve the technical problem that the risk of pump jamming of the vacuum pump is difficult to monitor.

[0149] The pump body assembly 510 can include a lower shell and an upper shell which is combined above the lower shell. The upper shell and the lower shell can be fixedly connected by bolts or other fasteners. The upper shell and the lower shell are combined to form a cavity in the interior, and the rotating shaft 40 is arranged in the cavity.

[0150] As shown in FIG. 3, 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 arranged on opposite sides of the pump body assembly 510. The two ends of the rotating shaft 40 are rotatably connected with 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 connected to the two sides of the pump body assembly 510, respectively, so that the two ends of the rotating shaft 40 can be connected with the bearings. 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 can include a first plate body and first bearings. The first plate body is configured with at least one first mounting hole, and each first mounting hole is mounted with a first bearing. The second bearing plate 530 can include a second plate body and second bearings. The second plate body is configured with at least one second mounting hole, and each second mounting hole is mounted with a second bearing. The two ends of the shaft 40 can be connected to the first bearing and the second bearing, respectively.

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

[0154] The end cover 540 can seal the side of the vacuum pump away from the motor assembly 560. When the motor assembly 560 is connected to the first bearing plate 520, the end cover 540 is connected to the second bearing plate 530. When the motor assembly 560 is connected to the second bearing plate 530, the end cover 540 is connected to the first bearing plate 520. The measurement hole 550 configured on the end cover 540 is used to mount the displacement sensor 10, so as to monitor the axial displacement of the shaft 40 inside by the displacement sensor 10, to obtain the axial displacement parameter of the shaft 40.

[0155] As shown in FIG. 5, the measurement hole 550 is coaxially arranged with the shaft 40, i.e. the hole center of the measurement hole 550 is collinear with the axial direction of the shaft 40, to ensure the accuracy of the axial displacement measurement by the displacement sensor 10.

[0156] As shown in FIG. 4, in some embodiments, the shaft 40 is provided as at least two. The at least two shafts 40 are arranged along the radial direction. The end cover 540 is configured with at least two measurement holes 550 at intervals. Each measurement hole 550 is mounted with a displacement sensor 10. Each displacement sensor 10 obtains an axial displacement parameter of a shaft 40, respectively.

[0157] The at least two shafts 40 can form a shafting assembly of the vacuum pump, to realize multi-shaft transmission. For each shaft 40, a displacement sensor 10 is arranged in each measurement hole 550, to monitor each shaft 40, respectively.

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

[0159] The motor assembly 560 is used as a driving structure to drive the rotation of the gear in the gear box assembly 570. The gear box assembly 570 can be provided with a transmission connected gear pair, and the gear box assembly 570 can be used as a speed reducer to change the rotation speed. After the driving gear of the output shaft of the motor assembly 560 rotates, the gear box assembly 570 can change the rotation speed and then transmit the rotation at a proper rotation speed to the rotating shaft 40, so as to realize the rotation of the rotating shaft 40.

[0160] The above describes the embodiments of the present disclosure in detail, and the principles and implementation manners of the present disclosure are described by using specific examples. The above description of the embodiments is only used to help understand the method of the present disclosure and its core idea; meanwhile, for those skilled in the art, according to the idea of the present disclosure, the specific implementation manners and application ranges can be changed, and the above description of the present disclosure should not be understood as a limitation.

Claims

1. A monitoring method for monitoring an amount of axial displacement of a rotation shaft of a vacuum pump, characterized by, The method comprises: obtaining an axial displacement parameter of the rotating shaft; comparing the axial displacement parameter with a set displacement alarm threshold value; in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold value, outputting an alarm signal for alarm.

2. The monitoring method according to claim 1, characterized in that, The rotating shaft is sequentially provided with at least two rotors along the axial direction thereof, and the rotors are defined as an i-th rotor based on the relative positions of the rotors and a displacement sensor mounted on the vacuum pump, wherein i is an integer greater than or equal to 1, and the rotor closest to the displacement sensor is the first rotor; The method of obtaining the axial displacement parameter of the rotating shaft comprises: obtaining an axial displacement parameter of the first rotor at one end close to the displacement sensor.

3. The monitoring method according to claim 2, characterized in that, The rotors are arranged in stators, and the stators are multi-stage stators, each rotor corresponds to one stage of stator, and an interval is arranged between each adjacent two stages of stators, and an axial gap parameter of each rotor is used to represent the axial gap size between the rotor and the corresponding interval; The monitoring method further comprises: obtaining a temperature parameter of a space where the rotating shaft is located, and calculating a temperature difference parameter between the temperature parameter and a set normal temperature parameter; After the step of obtaining the axial displacement parameter of the first rotor at one end close to the displacement sensor, the monitoring method further comprises: based on the axial displacement parameter, the temperature difference parameter and a set preset parameter, obtaining an axial gap parameter of each rotor; in response to the axial displacement parameter being less than the displacement alarm threshold value, comparing the axial gap parameter of each rotor with a corresponding sub-threshold value; in response to the axial gap parameter of the i-th rotor being less than or equal to the corresponding sub-threshold value of the i-th rotor, outputting an alarm signal for alarm.

4. The monitoring method according to claim 3, characterized in that, The preset parameter comprises a preset assembly gap parameter of each rotor, an end position parameter of each rotor, an initial axial size parameter of each rotor and a thermal expansion coefficient of each rotor.

5. The monitoring method according to claim 4, characterized in that, The end position parameter of the rotor comprises a front end parameter and a rear end parameter, the value of the front end parameter is 1, and the value of the rear end parameter is -1, wherein the front end of the rotor is one end close to the displacement sensor, and the rear end of the rotor is one end away from the displacement sensor.

6. The monitoring method of claim 4, wherein, The method of obtaining the axial gap parameter of each rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter comprises: the axial gap parameter of each rotor is obtained by the following formula: ； where i is the stage number of the rotor, and j is the end position parameter of the rotor, the front end of the rotor corresponds to j = 1, and the rear end of the rotor corresponds to j = -1, an axial gap parameter of the jth end of the ith stage rotor and the corresponding partition, a preset assembly gap parameter for the jth end of the ith stage rotor and the corresponding partition, an axial displacement parameter measured by a displacement sensor, the thermal expansion coefficient of the i-th stage rotor, initial axial size parameter for the i-th stage rotor, is the temperature difference parameter between the temperature parameter of the space where the rotating shaft is located and the set normal temperature parameter.

7. A monitoring system for monitoring an amount of axial displacement of a rotation shaft of a vacuum pump, characterized by, The method comprises: a displacement sensor for obtaining an axial displacement parameter of the rotating shaft; a comparison module electrically connected with the displacement sensor, configured to compare the axial displacement parameter with a set displacement alarm threshold value; an alarm module electrically connected with the comparison module, the alarm module outputs an alarm signal for alarm in response to the axial displacement parameter being greater than or equal to the displacement alarm threshold value.

8. The monitoring system of claim 7, wherein, The monitoring system further comprises: The signal receiving module is electrically connected with the displacement sensor and is configured to receive the axial displacement parameter.

9. The monitoring system of claim 8, wherein, The monitoring system is provided with a normal temperature parameter, and the monitoring system further comprises: A temperature sensor is configured to acquire a temperature parameter of a space where the rotating shaft is located, and the temperature sensor is electrically connected with the signal receiving module. A first calculation module is electrically connected with the signal receiving module and is configured to acquire a temperature difference parameter between the temperature parameter and the normal temperature parameter.

10. The monitoring system of claim 9, wherein, The monitoring system is provided with a preset parameter, and the monitoring system further comprises: The rotating shaft is provided with at least two rotors which are arranged along the axial direction of the rotating shaft in sequence, and the rotors are defined as an i-th rotor based on the relative positions of the rotors and a displacement sensor installed on the vacuum pump, where i is an integer greater than or equal to 1, and the rotor closest to the displacement sensor is a first rotor; The displacement sensor is configured to acquire an axial displacement parameter of an end of the first rotor close to the displacement sensor; A second calculation module is electrically connected with the signal receiving module and the first calculation module and is configured to receive the axial displacement parameter and the temperature difference parameter, and the second calculation module is configured to acquire an axial gap parameter of each rotor based on the axial displacement parameter, the temperature difference parameter and the preset parameter.

11. The monitoring system of claim 10, wherein, The preset parameter comprises a preset assembly gap parameter of each rotor, an end position parameter of each rotor, an initial axial size parameter of each rotor and a thermal expansion coefficient of each rotor.

12. The monitoring system of claim 10, wherein, The end position parameter of the rotor comprises a front end parameter and a rear end parameter, the value of the front end parameter is 1, and the value of the rear end parameter is -1, where the front end of the rotor is an end of the rotor close to the displacement sensor, and the rear end of the rotor is an end of the rotor away from the displacement sensor.

13. The monitoring system of claim 11, wherein, The monitoring system further comprises: A storage module is electrically connected with the comparison module, the first calculation module and the second calculation module, and the displacement alarm threshold, the normal temperature parameter, the preset assembly gap parameter of each rotor, the end position parameter of each rotor, the initial axial size parameter of each rotor and the thermal expansion coefficient of each rotor are stored in the storage module.

14. The monitoring system of claim 13, wherein, The storage module further stores an axial gap threshold, the axial gap threshold comprises at least two sub-thresholds, the sub-thresholds are defined as i-th sub-thresholds based on the corresponding relationship between the sub-thresholds and the rotors, and the i-th sub-threshold corresponds to the i-th rotor, where the comparison module further outputs an alarm signal for alarm in response to the axial gap parameter of the i-th rotor being less than or equal to the sub-threshold corresponding to the i-th rotor.

15. The monitoring system according to any one of claims 9-14, characterized in that, The monitoring system further comprises: The signal processing module is electrically connected with the signal receiving module, and is configured to convert the axial displacement parameter into a first digital signal. The signal processing module is also electrically connected with the temperature sensor, and is configured to convert the temperature parameter into a second digital signal. The comparison module is electrically connected with the signal processing module, and is configured to compare the first digital signal with the displacement alarm threshold. The first calculation module is electrically connected with the signal processing module, and is configured to obtain the temperature difference parameter based on the second digital signal and the normal temperature parameter.

16. A vacuum pump, characterized by The vacuum pump applies the monitoring method of any one of claims 1-6 to monitor the axial displacement of the rotating shaft.

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