A monitoring method for determining in situ when a gearbox system has reached thermal equilibrium

Abstract

The application relates to a monitoring method for judging whether a gear box system reaches thermal equilibrium on site, and relates to a monitoring method for judging whether a gear box device reaches a whole thermal equilibrium state in continuous operation, so as to solve the problem that existing monitoring methods cannot directly judge whether a gear box reaches thermal equilibrium through quantitative real-time monitoring data. In the application, the oil inlet temperature, the oil return temperature, the first bearing temperature and the second bearing temperature of the gear box are respectively acquired at equal interval time, and v m The corresponding first-order shaft displacement amplitude and first-order phase angle are obtained; and whether the gear box system reaches thermal equilibrium is judged through quantitative real-time monitoring data. The gear box system can be directly judged to reach thermal equilibrium state through quantitative real-time monitoring data, and the on-site dynamic balancing operation efficiency and success rate of a vibration test technician are greatly improved.

Description

Technical Field

[0001] This invention relates to a monitoring method for determining whether a gearbox device has reached an overall thermal equilibrium state during continuous operation. Background Technology

[0002] In practical engineering, all gearbox rotor systems exhibit imbalance. For a new gearbox system, if an inherent imbalance is detected during initial operation, and the resulting vibration exceeds the specified allowable range, balancing is required. If the rotor where the imbalance occurs is suitable for on-site dynamic balancing, on-site vibration testing technicians must perform the on-site dynamic balancing operation by calculating the balancing weights and their installation phase angles. This process needs to be performed at least twice, thus requiring repeatability. This necessitates that, apart from the different balancing weights installed each time, the gearbox's dynamic stiffness must remain relatively constant. Factors such as speed, temperature, and load can cause changes in the equipment's dynamic stiffness unrelated to the imbalance, especially changes in internal equipment temperature, including inlet oil temperature, return oil temperature, and bearing temperature.

[0003] Previously, when performing on-site dynamic balancing on a gearbox system, if the vibration analysis software showed a significant difference in the displacement values ​​of two time-domain shafts perpendicularly arranged at the same bearing section (especially if one amplitude exceeded 50 μm), the system would be stopped for on-site dynamic balancing after maintaining this state for no more than 10 minutes. However, sometimes even after two or more operations, the results were still unsatisfactory. This is because the duration of the initial imbalance state was too short, and the temperature changes in various parts of the equipment were still significant, resulting in a noticeable change in the dynamic stiffness of the equipment. Consequently, the corresponding shaft displacement values ​​and phase angles read in the testing software still showed significant changes. In other words, the imbalance had not yet reached a relatively fixed level, thus making each balancing process unrepeatable, and therefore making it difficult to reduce the gearbox vibration state to an ideal level.

[0004] Therefore, a gearbox system needs to operate for a sufficiently long time to reach thermal equilibrium before the imbalance can be relatively stabilized. Current literature lacks information on how to directly determine whether a gearbox system has reached thermal equilibrium in the field using quantified real-time monitoring data. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that existing monitoring methods cannot directly determine whether a gearbox has reached thermal equilibrium through quantitative real-time monitoring data, and to propose a monitoring method for determining whether a gearbox system has reached thermal equilibrium on-site.

[0006] The monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium, as described in this invention, includes the following steps:

[0007] Step 1: Obtain the time-domain peak-to-peak value of the axial displacement v of the four bearings inside the gearbox. m m = 1, 2, 3, 4, 5, 6, 7, 8, where m represents the peak-to-peak value of the time-domain axis displacement of the m-th axis; two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement are obtained for each bearing; Δ1 = |v1 - v2|, Δ2 = |v3 - v4|, Δ3 = |v5 - v6|, and Δ4 = |v7 - v8| are calculated, where Δ1 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the first bearing, Δ2 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the second bearing, Δ3 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the third bearing, and Δ4 is ​​the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the fourth bearing. If at least one of Δ1 to Δ4 is ​​greater than the first threshold, or v m If at least one of them is greater than the second threshold, proceed to step two; otherwise, continue with step one.

[0008] Step 2: Obtain the frequency domain displacement waveform windows corresponding to the peak-to-peak values ​​of the two time-domain shaft displacements on the first bearing and the frequency domain displacement waveform windows corresponding to the peak-to-peak values ​​of the two time-domain shaft displacements on the second bearing; at the same time, determine whether the frequency corresponding to the maximum displacement value is the rated rotational frequency or its harmonic. If both are true, proceed to Step 3; otherwise, return to Step 1.

[0009] Step 3: Obtain the oil inlet temperature T of the gearbox at equal time intervals. 1～n Oil return temperature T 2～n First bearing temperature T 3～n Second bearing temperature T 4～n And obtain v m The corresponding first-order axial displacement amplitude x m～n and first-order phase angle Φ m～n Where n represents the nth record retrieval;

[0010] If at time t n With t n-1 In comparison, simultaneously satisfying:

[0011] 1)Δ 进油温度 =|T 1～n -T 1～(n-1) |≤1.5℃; where, Δ 进油温度 Let time t n With time t n-1 The difference in oil inlet temperature;

[0012] 2)Δ 回油温度 =|T 2～n -T 2～(n-1) |≤1.5℃; where, Δ 回油温度 Let time t n With time t n-1The return oil temperature difference;

[0013] 3)Δ 第一轴承温度 =|T 3～n -T 3～(n-1) |≤1.5℃; where, Δ 第一轴承温度 Let time t n With time t n-1 The temperature difference of the first bearing;

[0014] 4)Δ 第二轴承温度 =|T 4～n -T 4～(n-1) |≤1.5℃; where, Δ 第二轴承温度 Let time t n With time t n-1 The temperature difference of the second bearing;

[0015] 5)Δ 一阶轴位移幅值 =|x m～n -x m～(n-1) |≤1μmm=1,2,3,4; where, Δ 一阶轴位移幅值 Let time t n With time t n-1 The difference in the first-order axial displacement amplitude;

[0016] 6)Δ 一阶相位角 =|Φ m～n -Φ m～(n-1) |≤1°m=1,2,3,4;where, Δ 一阶相位角 Let time t n With time t n-1 The difference in the first-order phase angle;

[0017] Then the gearbox system reaches a state of thermal equilibrium.

[0018] Furthermore, the first threshold in step one is 15 μm.

[0019] Furthermore, the second threshold in step one is 38 μm or 50 μm.

[0020] Furthermore, the time-domain peak-to-peak value of the axial displacement v of the four bearings within the gearbox... mVibration data are obtained using a first-axis displacement vibration sensor, a second-axis displacement vibration sensor, a third-axis displacement vibration sensor, a fourth-axis displacement vibration sensor, a fifth-axis displacement vibration sensor, a sixth-axis displacement vibration sensor, a seventh-axis displacement vibration sensor, and an eighth-axis displacement vibration sensor. Specifically, the first and second-axis displacement vibration sensors are mounted perpendicularly to each other on a first bearing; the third and fourth-axis displacement vibration sensors are mounted perpendicularly to each other on a second bearing; the fifth and sixth-axis displacement vibration sensors are mounted perpendicularly to each other on a third bearing; and the seventh and eighth-axis displacement vibration sensors are mounted perpendicularly to each other on a fourth bearing.

[0021] Furthermore, the temperature T of the first bearing 3～n The temperature T of the second bearing is obtained through a third temperature sensor. 4～n The temperature is obtained through a fourth temperature sensor.

[0022] Furthermore, v m The corresponding first-order axial displacement amplitude x m～n and first-order phase angle Φ m～n Acquired via a bond phase sensor;

[0023] The key phase sensor is arranged on the input shaft of the gearbox.

[0024] Furthermore, the gearbox's oil inlet temperature T 1～n The temperature is obtained through a first temperature sensor; the first temperature sensor is installed on the oil inlet line of the gearbox.

[0025] Gearbox return oil temperature T 2～n The temperature is obtained through a second temperature sensor, which is installed on the return oil line of the gearbox.

[0026] Compared with the prior art, the present invention has the following beneficial effects: by performing the steps in the above invention, the gearbox system on site can reach a thermal equilibrium state, and the thermal equilibrium state is directly determined by quantitative real-time monitoring data. The thermal equilibrium state makes the dynamic stiffness of the gearbox system relatively constant, thereby fixing the original imbalance of the gearbox system. This will greatly improve the efficiency and success rate of the on-site dynamic balancing operation of vibration testing technicians. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the gearbox system in Specific Implementation Method 1;

[0028] Among them, 1 is the starter motor; 2 is the first-stage test speed-increasing gearbox; 3 is the gearbox; 4 is the lubrication station; 5 is the oil inlet pipe; 6 is the oil return pipe; 7 is the input shaft high-speed rotor system; 8 is the output shaft low-speed rotor system; C1 is the starter motor end coupling; C2 is the test gearbox input end coupling; B1 is the first bearing; B2 is the second bearing; B3 is the third bearing; B4 is the fourth bearing; T1 is the first temperature sensor; T2 is the second temperature sensor; T3 is the third temperature sensor; T4 is the fourth temperature sensor; T5 is the fifth temperature sensor; T6 is the sixth temperature sensor; V1 is the first shaft displacement vibration sensor; V2 is the second shaft displacement vibration sensor; V3 is the third shaft displacement vibration sensor; V4 is the fourth shaft displacement vibration sensor; V5 is the fifth shaft displacement vibration sensor; V6 is the sixth shaft displacement vibration sensor; V7 is the seventh shaft displacement vibration sensor; V8 is the eighth shaft displacement vibration sensor; V9 is the key phase sensor. Detailed Implementation

[0029] Specific Implementation Method 1: Combination Figure 1 This embodiment describes a monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium, which includes the following steps:

[0030] Step 1: Obtain the time-domain peak-to-peak value of the axial displacement v of the four bearings inside gearbox 3. m m = 1, 2, 3, 4, 5, 6, 7, 8, where m represents the peak-to-peak value of the time-domain axis displacement of the m-th axis; two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement are obtained for each bearing; Δ1 = |v1 - v2|, Δ2 = |v3 - v4|, Δ3 = |v5 - v6|, and Δ4 = |v7 - v8| are calculated, where Δ1 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the first bearing B1, Δ2 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the second bearing B2, Δ3 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the third bearing B3, and Δ4 is ​​the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the fourth bearing B4. If at least one of Δ1 to Δ4 is ​​greater than the first threshold, or v m If at least one of them is greater than the second threshold, proceed to step two; otherwise, continue with step one.

[0031] Step 2: Obtain the frequency domain displacement waveform windows corresponding to the peak-to-peak values ​​of the two time-domain shaft displacements on the first bearing B1 and the frequency domain displacement waveform windows corresponding to the peak-to-peak values ​​of the two time-domain shaft displacements on the second bearing B2; at the same time, determine whether the frequency corresponding to the maximum displacement value is the rated rotational frequency or its harmonic. If both are true, proceed to Step 3; otherwise, return to Step 1.

[0032] Step 3: Obtain the oil inlet temperature T of gearbox 3 at equal time intervals. 1～nOil return temperature T 2～n Temperature T of the first bearing B1 3～n Second bearing B2 temperature T 4～n And obtain v m The corresponding first-order axial displacement amplitude x m～n and first-order phase angle Φ m～n Where n represents the nth record retrieval;

[0033] If at time t n With t n-1 In comparison, simultaneously satisfying:

[0034] 1)Δ 进油温度 =|T 1～n -T 1～(n-1) |≤1.5℃; where, Δ 进油温度 Let time t n With time t n-1 The difference in oil inlet temperature;

[0035] 2)Δ 回油温度 =|T 2～n -T 2～(n-1) |≤1.5℃; where, Δ 回油温度 Let time t n With time t n-1 The temperature difference between the return and return temperatures;

[0036] 3)Δ 第一轴承温度 =|T 3～n -T 3～(n-1) |≤1.5℃; where, Δ 第一轴承温度 Let time t n With time t n-1 The temperature difference of the first bearing B1;

[0037] 4)Δ 第二轴承温度 =|T 4～n -T 4～(n-1) |≤1.5℃; where, Δ 第二轴承温度 Let time t n With time t n-1 The temperature difference of the second bearing B2;

[0038] 5)Δ 一阶轴位移幅值 =|x m～n -x m～(n-1) |≤1μmm=1,2,3,4; where, Δ 一阶轴位移幅值 Let time t n With time t n-1 The difference in the first-order axial displacement amplitude;

[0039] 6)Δ 一阶相位角 =|Φ m～n -Φ m～(n-1)|≤1°m=1,2,3,4;where, Δ 一阶相位角 Let time t n With time t n-1 The difference in the first-order phase angle;

[0040] Then the gearbox system reaches a state of thermal equilibrium.

[0041] In this embodiment, the gearbox system includes a starter motor 1, a first-stage test speed-increasing gearbox 2, a gearbox 3, a lubrication station 4, an oil inlet pipe 5, an oil return pipe 6, a starter motor end coupling C1, and a test gearbox input end coupling C2; the gearbox 3 contains an input shaft 7 and an output shaft 8, with a first bearing B1 and a second bearing B2 mounted on the input shaft 7, and a third bearing B3 and a fourth bearing B4 mounted on the output shaft 8;

[0042] The oil inlet of the gearbox 3 is connected to the oil outlet of the lubricating oil station 4 through the oil inlet pipe 5, and the oil outlet of the gearbox 3 is connected to the oil return port of the lubricating oil station 4 through the oil return pipe 6.

[0043] The gearbox 3 is driven by the starter motor 1, and is connected to the first-stage test speed-increasing gearbox 2 through the starter motor end coupling C1 to match the input speed. It is then connected to the input shaft 7 of the gearbox 3 through the test gearbox input end coupling C2.

[0044] A first temperature sensor T1 is installed on the oil inlet pipe 5 of the gearbox 3 to monitor the oil inlet temperature T1; a second temperature sensor T2 is installed on the oil return pipe 6 to monitor the oil return temperature T2.

[0045] Inside the gearbox 3, each bearing is equipped with one temperature sensor Tm (m = 3, 4, 5, 6) and two mutually perpendicular shaft displacement vibration sensors Vm (m = 1, 2, 3, 4, 5, 6, 7, 8), which are used to monitor bearing temperature and shaft vibration, respectively. The monitored shaft vibration includes time-domain displacement peak-to-peak value and frequency-domain displacement waveform components. A key phase sensor V9 is installed at the journal of the input shaft 7 (outside the gearbox) for the order analysis module, including monitoring first-order shaft displacement and first-order phase angle.

[0046] In the test gearbox 3, the oil inlet temperature is monitored by temperature sensor T1, and the oil return temperature is monitored by temperature sensor T2; the temperature of bearing B1 located on the input shaft 7 is monitored by bearing temperature sensor T3, and the temperature of bearing B2 is monitored by bearing temperature sensor T4; the temperature of bearing B3 located on the output shaft 8 is monitored by bearing temperature sensor T5, and the temperature of bearing B4 is monitored by bearing temperature sensor T6.

[0047] In the test gearbox 3, the shaft vibration of the input shaft is monitored by shaft displacement vibration sensors V1, V2, V3 and V4, and the shaft vibration of the output shaft is monitored by shaft displacement sensors V5, V6, V7 and V8. The monitored shaft vibration includes time-domain displacement peak-to-peak value and frequency-domain displacement waveform components. The key phase sensor V9 is used for the order analysis module, including monitoring the first-order shaft displacement and the first-order phase angle.

[0048] According to the test outline:

[0049] 1) Rated operating conditions: Input shaft 5416 rpm, corresponding output shaft 3000 rpm, no load;

[0050] 2) Vibration index: The peak-to-peak displacement values ​​of all time-domain axes located on the input axis (i.e., v1, v2, v3 and v4) do not exceed 38 μm.

[0051] After completing the gearbox system layout as described above and debugging the lubrication station 4 and vibration test software interface, start the starter motor 1 to run the gearbox system, gradually increasing the speed to the rated operating condition mentioned above, and then proceed with the following steps:

[0052] S1 - Located in the time-domain displacement curve interface of the vibration testing software, it allows real-time observation and recording of all time-domain axial displacement peak-to-peak values ​​(v). m (m = 1, 2, 3, 4), organize the read data (keeping the integers) into the following table:

[0053] Shaft vibration sensor V1 V2 V3 V4 Corresponding time-domain axis displacement variable <![CDATA[v1]]> <![CDATA[v2]]> <![CDATA[v3]]> <![CDATA[v4]]> Peak-to-peak size (μm) 23 14 48 26

[0054] It is clear that v3 has exceeded the targets specified in the outline, so S2 will be implemented;

[0055] S2 - Located in the frequency domain displacement curve interface of the vibration testing software, observe v respectively. m The frequency domain displacement waveform windows corresponding to (m=1,2,3,4) are summarized in the following table:

[0056]

[0057] It is obvious that the frequencies corresponding to all maximum displacement values ​​are the rated rotational frequencies of the input shaft, so proceed with S3;

[0058] S3 is located in the order analysis interface of the vibration testing software. Since only v3 exceeded the limit when executing S1, we only need to focus on the corresponding x in the field. 3～n and Φ 3～n That's it. Simultaneously, begin observing the temperature control interface and record the series of temperatures, along with the first-order axis displacement and phase angle, in the table below (the initial recording time on-site was 9:53):

[0059]

[0060] Based on this, the above variables are recorded repeatedly every 5 minutes, as shown in the table below:

[0061]

[0062]

[0063] After 45 minutes and a total of 10 records, it's not hard to see that:

[0064] 1)Δ 进油温度 =|T 1～n -T 1～(n-1) |<1℃;Δ 回油温度 =|T 2～n -T 2～(n-1) |<1℃;Δ 轴承温度 =|T 3～n -T 3～(n-1) |<1℃;

[0065] Δ 轴承温度 =|T 4～n -T 4～(n-1) |<1℃;

[0066] 2)Δ 一阶轴位移 =|x 3～n -x 3～(n-1) |<0.5μm;

[0067] 3)Δ 一阶相位角 =|Φ 3～n -Φ 3～(n-1) |<1°.

[0068] Therefore, the gearbox system has reached thermal equilibrium.

[0069] Specific Implementation Method Two: This implementation method further defines the monitoring method for determining on-site that a gearbox system has reached thermal equilibrium as described in Specific Implementation Method One. In this implementation method, the first threshold in step one is 15 μm.

[0070] In this embodiment, the first threshold was determined through multiple experiments, and in this embodiment, the first threshold should not be too large, otherwise subsequent operations will not be possible.

[0071] Specific Implementation Method 3: This implementation method further defines the monitoring method for determining on-site that a gearbox system has reached thermal equilibrium as described in Specific Implementation Method 1. In this implementation method, the second threshold in step one is 38μm or 50μm.

[0072] In this embodiment, 38μm or 50μm is the upper limit specified in the test outline.

[0073] Specific Implementation Method Four: This implementation method further defines the monitoring method for determining the thermal equilibrium of a gearbox system on-site, as described in Specific Implementation Method One. In this implementation method, the peak-to-peak value of the time-domain axial displacement v of the four bearings within the gearbox 3 is... m Vibration data are obtained using a first axial displacement vibration sensor V1, a second axial displacement vibration sensor V2, a third axial displacement vibration sensor V3, a fourth axial displacement vibration sensor V4, a fifth axial displacement vibration sensor V5, a sixth axial displacement vibration sensor V6, a seventh axial displacement vibration sensor V7, and an eighth axial displacement vibration sensor V8. Specifically, the first axial displacement vibration sensor V1 and the second axial displacement vibration sensor V2 are mounted perpendicularly to each other on a first bearing B1; the third axial displacement vibration sensor V3 and the fourth axial displacement vibration sensor V4 are mounted perpendicularly to each other on a second bearing B2; the fifth axial displacement vibration sensor V5 and the sixth axial displacement vibration sensor V6 are mounted perpendicularly to each other on a third bearing B3; and the seventh axial displacement vibration sensor V7 and the eighth axial displacement vibration sensor V8 are mounted perpendicularly to each other on a fourth bearing B4.

[0074] In this embodiment, within the gearbox 3, the first bearing B1 and the second bearing B2 are mounted on the input shaft 7, and the third bearing B3 and the fourth bearing B4 are mounted on the output shaft 8. A first shaft displacement vibration sensor V1 and a second shaft displacement vibration sensor V2, perpendicular to each other, are mounted on the first bearing B1. A third shaft displacement vibration sensor V3 and a fourth shaft displacement vibration sensor V4, perpendicular to each other, are mounted on the second bearing B2. A fifth shaft displacement vibration sensor V5 and a sixth shaft displacement vibration sensor V6, perpendicular to each other, are mounted on the third bearing B3. A seventh shaft displacement vibration sensor V7 and an eighth shaft displacement vibration sensor V8, perpendicular to each other, are mounted on the fourth bearing B4.

[0075] Specific Implementation Method Five: This implementation method further defines the monitoring method for determining the thermal equilibrium of a gearbox system in the field, as described in Specific Implementation Method One. In this implementation method, the temperature T of the first bearing B1... 3～n Temperature T of the second bearing B1 is obtained via the third temperature sensor T3. 4～n The temperature is obtained through the fourth temperature sensor, T4.

[0076] In this embodiment, a temperature sensor T3 is installed at the first bearing B1; and a temperature sensor T4 is installed at the second bearing B2.

[0077] Specific Implementation Method Six: This implementation method further defines the monitoring method for determining on-site thermal equilibrium of a gearbox system described in Specific Implementation Method One. In this implementation method, v m The corresponding first-order axial displacement amplitude x m～nand first-order phase angle Φ m～n Acquired via the key phase sensor V9;

[0078] The key phase sensor V9 is arranged on the input shaft 7 of the gearbox 3.

[0079] In this embodiment, a key phase sensor V9 is installed on the journal (outside the gearbox body) of the input shaft 7 of the gearbox 3; the key phase sensor V9 is used in the order analysis module, including monitoring the first-order shaft displacement amplitude x. m～n and first-order phase angle Φ m～n .

[0080] Specific Implementation Method Seven: This implementation method further defines the monitoring method for determining the thermal equilibrium of a gearbox system in the field, as described in Specific Implementation Method One. In this implementation method, the oil inlet temperature T of the gearbox 3... 1～n The temperature is obtained through the first temperature sensor T1; the first temperature sensor T1 is installed on the oil inlet pipe 5 of the gearbox 3.

[0081] The return oil temperature T of gearbox 3 2～n The temperature is obtained through the second temperature sensor T2; the second temperature sensor T2 is installed on the oil return line 6 of the gearbox 3.

[0082] In this embodiment, the oil inlet of the gearbox 3 is connected to the oil outlet of the lubricating oil station 4 via the oil inlet pipe 5, and the oil outlet of the test gearbox is connected to the oil return port of the lubricating oil station 4 via the oil return pipe 6; a temperature sensor T1 is installed on the oil inlet pipe 5 of the test gearbox 3 to monitor the oil inlet temperature T1; a temperature sensor T2 is installed on the oil return pipe 6 to monitor the oil return temperature T2.

[0083] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium, characterized in that, Includes the following steps: Step 1: Obtain the time-domain peak-to-peak value of the axial displacement v of the four bearings inside the gearbox (3). m m = 1, 2, 3, 4, 5, 6, 7, 8, where m represents the peak-to-peak value of the time-domain axis displacement of the m-th axis; two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement are obtained for each bearing; Δ1 = |v1 - v2|, Δ2 = |v3 - v4|, Δ3 = |v5 - v6| and Δ4 = |v7 - v8| are calculated, where Δ1 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the first bearing (B1), Δ2 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the second bearing (B2), Δ3 is the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the third bearing (B3), and Δ4 is ​​the difference between the two mutually perpendicular peak-to-peak values ​​of the time-domain axis displacement on the fourth bearing (B4). If at least one of Δ1 to Δ4 is ​​greater than the first threshold, or v m If at least one of them is greater than the second threshold, proceed to step two; otherwise, continue with step one. Step 2: Obtain the frequency domain displacement waveform windows corresponding to the peak-to-peak values ​​of the two time-domain shaft displacements on the first bearing (B1) and the frequency domain displacement waveform windows corresponding to the peak-to-peak values ​​of the two time-domain shaft displacements on the second bearing (B2); at the same time, determine whether the frequency corresponding to the maximum displacement value is the rated rotational frequency or its harmonic. If both are true, proceed to Step 3; otherwise, return to Step 1. Step 3: Obtain the oil inlet temperature T of the gearbox (3) at equal time intervals. 1～n Oil return temperature T 2～n Temperature T of the first bearing (B1) 3～n Temperature T of the second bearing (B2) 4～n And obtain v m The corresponding first-order axial displacement amplitude x m～n and first-order phase angle Φ m～n Where n represents the nth record retrieval; If at time t n With t n-1 In comparison, simultaneously satisfying: 1)Δ 进油温度 =|T 1～n -T 1～(n-1) |≤1.5℃; where, Δ 进油温度 Let time t n With time t n-1 The difference in oil inlet temperature; 2)Δ 回油温度 =|T 2～n -T 2～(n-1) |≤1.5℃; where, Δ 回油温度 Let time t n With time t n-1 The return oil temperature difference; 3)Δ 第一轴承温度 =|T 3～n -T 3～(n-1) |≤1.5℃; where, Δ 第一轴承温度 Let time t n With time t n-1 The temperature difference of the first bearing (B1); 4)Δ 第二轴承温度 =|T 4～n -T 4～(n-1) |≤1.5℃; where, Δ 第二轴承温度 Let time t n With time t n-1 The temperature difference value of the second bearing (B2); 5)Δ 一阶轴位移幅值 =|x m～n -x m～(n-1) |≤1μm(m=1,2,3,4); where, Δ 一阶轴位移幅值 Let time t n With time t n-1 The difference in the first-order axial displacement amplitude; 6)Δ 一阶相位角 =|Φ m～n -Φ m～(n-1) |≤1°(m=1,2,3,4); where, Δ 一阶相位角 Let time t n With time t n-1 The difference in the first-order phase angle; Then the gearbox system reaches a state of thermal equilibrium.

2. The monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium, as described in claim 1, is characterized in that... The first threshold in step one is 15μm.

3. The monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium, as described in claim 1, is characterized in that... The second threshold in step one is 38 μm or 50 μm.

4. The monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium according to claim 1, characterized in that, The peak-to-peak value of the time-domain axial displacement of the four bearings in the gearbox (3) m Vibration data are obtained using a first axial displacement vibration sensor (V1), a second axial displacement vibration sensor (V2), a third axial displacement vibration sensor (V3), a fourth axial displacement vibration sensor (V4), a fifth axial displacement vibration sensor (V5), a sixth axial displacement vibration sensor (V6), a seventh axial displacement vibration sensor (V7), and an eighth axial displacement vibration sensor (V8). Specifically, the first axial displacement vibration sensor (V1) and the second axial displacement vibration sensor (V2) are mounted perpendicularly to each other on a first bearing (B1); the third axial displacement vibration sensor (V3) and the fourth axial displacement vibration sensor (V4) are mounted perpendicularly to each other on a second bearing (B2); the fifth axial displacement vibration sensor (V5) and the sixth axial displacement vibration sensor (V6) are mounted perpendicularly to each other on a third bearing (B3); and the seventh axial displacement vibration sensor (V7) and the eighth axial displacement vibration sensor (V8) are mounted perpendicularly to each other on a fourth bearing (B4).

5. A monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium, as described in claim 1, characterized in that, Temperature T of the first bearing (B1) 3～n The temperature T of the second bearing (B1) is obtained through the third temperature sensor (T3). 4～n The temperature is obtained through the fourth temperature sensor (T4).

6. The monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium according to claim 1, characterized in that, v m The corresponding first-order axial displacement amplitude x m～n and first-order phase angle Φ m～n Acquired via a key phase sensor (V9); The key phase sensor (V9) is arranged on the input shaft (7) of the gearbox (3).

7. The monitoring method for determining on-site whether a gearbox system has reached thermal equilibrium according to claim 1, characterized in that, The oil inlet temperature T of the gearbox (3) 1～n The temperature is obtained by the first temperature sensor (T1); the first temperature sensor (T1) is installed on the oil inlet pipe (5) of the gearbox (3); The return oil temperature T of the gearbox (3) 2～n The temperature is obtained by a second temperature sensor (T2); the second temperature sensor (T2) is installed on the return oil line (6) of the gearbox (3).

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