Ultrasonic continuous measurement device and method for rotor compressor bearing oil film

Abstract

The application relates to a rotor compressor bearing oil film ultrasonic continuous measuring device and method, wherein the device comprises: two ultrasonic sensors symmetrically arranged at the proximal end of the bearing; two first temperature sensors arranged in blind holes and close to the oil film; two second temperature sensors attached to the outer wall of the bearing and close to the ultrasonic sensors; a sound velocity calibration device connected with the compressor pump body through a high-pressure pipeline, containing a temperature control unit and a signal output unit; a control device connected with the sensors and the calibration device, acquiring a first temperature control sound velocity calibration, acquiring a second temperature, and performing temperature compensation on the reference signal, and combining the measuring signal to invert the oil film thickness. Through the differential design of the double temperature sensors, the required temperatures for sound velocity calibration and temperature compensation are clearly distinguished for the first time, the problem that the same temperature value cannot effectively serve two systems is solved, and the measuring precision is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of compressor condition monitoring and non-destructive testing technology, and in particular to an ultrasonic continuous measurement device and method for oil film of rotor compressor bearings. Background Technology

[0002] Rotary compressors are widely used in refrigeration equipment such as air conditioners and heat pumps due to their compact structure, high volumetric efficiency, and high reliability. As the supporting structure for key moving components of the compressor, the main bearing and auxiliary bearing play crucial roles in transmitting power and maintaining the rotor's operational accuracy. During compressor operation, a micron-sized lubricating oil film forms between the bearing and the crankshaft, serving to bear the load and reduce friction and wear. The dynamic change in oil film thickness directly reflects the lubrication state of the bearing; too thin a film can lead to boundary lubrication or even dry friction, causing bearing failure and seizure; too thick a film can cause oil leakage and reduced volumetric efficiency. Therefore, achieving real-time, continuous, and accurate monitoring of the oil film thickness of the main and auxiliary bearings is a core technical requirement for ensuring the safe and efficient operation of the compressor and for conducting predictive maintenance.

[0003] Currently, methods for measuring the oil film thickness of sliding bearings mainly include eddy current method, capacitance method, and ultrasonic method. Among them, the ultrasonic method has become a research hotspot in recent years due to its advantages such as non-invasive installation, fast response speed, and insensitivity to the conductivity of the oil. Its basic principle is to utilize the reflection characteristics of ultrasonic waves at the solid-oil-solid multi-layer medium interface, and to invert the oil film thickness by extracting information such as the amplitude and phase of the reflected echo. However, when this technology is applied to the high-temperature and high-pressure actual operating conditions of rotary compressors, it faces the following insurmountable technical bottlenecks: In the high-temperature, high-pressure, and enclosed operating environment of a rotary compressor, a large amount of refrigerant gas dissolves in the lubricating oil, forming a special oil-gas mixture. This causes a significant drift in the sound velocity, a core parameter for ultrasonic thickness measurement. Existing methods mostly use the static sound velocity of pure lubricating oil at normal temperature and pressure as the calculation benchmark, ignoring the differences in physical properties caused by drastic changes in the medium composition. This inevitably introduces a systematic bias that is difficult to eliminate in the oil film thickness inversion.

[0004] Meanwhile, the intense frictional heat generated during compressor operation, combined with ambient heat transfer, causes a rapid increase in oil temperature (reaching 50-120℃), leading to multiple measurement errors. On one hand, the nonlinear temperature change directly alters the velocity of sound in the lubricating oil; on the other hand, the high temperature causes thermal expansion of the sensor probe and substrate materials, resulting in unpredictable drift in the amplitude and phase of the reference incident signal. Faced with such dynamic changes over a wide temperature range, traditional single-temperature-point calibration methods are simply incapable of achieving real-time and accurate error compensation.

[0005] In response, some existing technologies provide methods for calibrating the velocity of sound. For example, Chinese patent CN 122217235 A discloses a method for calibrating the velocity of sound in lubricating oil that takes into account the dissolution of refrigerant. This method can measure the velocity of sound in lubricating oil by taking into account the dissolution of refrigerant.

[0006] In addition, some existing technologies have proposed using reference temperature to compensate for acoustic signals. For example, Chinese patent CN112033315 A proposes a real-time temperature compensation method for reference signals in ultrasonic measurement of oil film thickness. The method calculates the time shift factor Δt of the reference signal based on the elastic deformation of the matrix A-lubricating oil-matrix B structure and the temperature correlation of sound velocity. By monitoring the scaling ratio of the initial wave signal during film thickness measurement, the waveform scaling factor b of the reference signal is obtained. The amplitude attenuation factor a is obtained through the waveform scaling factor b, and then the reference signal at the measured temperature is obtained by compensating the initial reference signal.

[0007] However, those skilled in the art encounter the following problems when applying the above two solutions: 1. The calibration scheme provided by Chinese patent CN 122217235 A is an offline calibration scheme. Therefore, it is necessary to pre-calibrate the combination of all types, lubricating oil states, refrigerant states, and refrigerant types. This is not practical for refrigeration equipment that has been in service for a long time and lacks effective maintenance. Therefore, it is not possible to continuously measure the speed of sound in the lubricating oil of refrigeration equipment that has been in service for a long time and lacks effective maintenance.

[0008] 2. Both calibration and compensation methods require sound velocity measurement. When combining these methods, those skilled in the art generally use a homogeneous design, which involves designing one or more temperature sensors, then having all the temperature sensors output a final temperature value, which is then provided to both systems simultaneously. However, this method has not proven effective in practice, and the error remains relatively large. Summary of the Invention

[0009] The inventors of this application discovered through research that the temperature used for sound velocity calibration and the temperature used for temperature compensation are actually not the same temperature, and the difference is huge. In the entire compressor bearing, the radial temperature variation is large. Sound velocity calibration actually requires the oil film temperature to be collected, so a blind hole design is required. On the other hand, temperature compensation requires the temperature of the ultrasonic sensor installation location, so it must be set on the surface. Based on this, the purpose of this invention is to solve the above-mentioned defects of the prior art and provide a continuous ultrasonic measurement device and method for rotor compressor bearing oil film. By designing the first sensor and the second sensor respectively and clarifying the specific setting method, temperature compensation and sound velocity calibration can be effectively integrated to obtain more accurate oil film measurement results.

[0010] The objective of this invention can be achieved through the following technical solutions: An ultrasonic continuous measurement device for bearing oil film of a rotary compressor, comprising: Two ultrasonic sensors are symmetrically arranged along the circumference near the end of the bearing. Two first temperature sensors are respectively arranged axially on one side of the two ultrasonic sensors near the bearing end, and are located in blind holes. The blind holes are set from the outer side wall of the bearing towards the inner side wall, and the blind holes do not penetrate the inner side wall. Two second temperature sensors are respectively arranged axially on one side of the two ultrasonic sensors near the bearing root and attached to the outer wall of the bearing; The sound velocity calibration device is connected to the compressor pump body through a high-pressure pipeline, forming an oil circulation loop and a gas phase balance loop. It includes a temperature control unit for adjusting the lubrication temperature inside the sound velocity calibration device, and a signal output unit for outputting the sound velocity calibration value. The control device, connected to the ultrasonic sensor, the first temperature sensor, the second temperature sensor, the temperature control unit, and the signal output unit respectively, is configured as follows: The system acquires the first temperature collected by the first temperature sensor, sends it to the temperature control unit as the temperature control target, and receives the sound velocity of the lubricating oil corresponding to the first temperature value output by the signal output unit. The second temperature is acquired by the second temperature sensor and the measurement signal is acquired by the continuous or ultrasonic sensor. The reference signal is temperature compensated based on the second temperature, and the oil film thickness is obtained by inversion calculation combined with the measurement signal.

[0011] The distance between the blind hole and the inner wall of the bearing is 1 mm.

[0012] The projected length of the distance between the first temperature sensor and the corresponding ultrasonic sensor in the bearing axis direction, and the projected length of the distance between the second temperature sensor and the corresponding ultrasonic sensor in the bearing axis direction, are both less than the first set threshold length.

[0013] The back of the ultrasonic sensor is coated with a damping protective layer made of AB glue.

[0014] The control device achieves a sealed connection with the ultrasonic sensor, the first temperature sensor, and the second temperature sensor via an aviation socket and plug.

[0015] A measurement method based on an ultrasonic continuous measurement device for oil film in rotor compressor bearings, the measurement method comprising: Step S1: Construct a temperature correction model that includes an amplitude variation factor and a time shift factor; Step S2: After starting the rotor compressor and making it reach a stable operating state under each target working condition, acquire the measurement signal collected by the ultrasonic sensor, the first temperature collected by the first temperature sensor, and the second temperature collected by the second temperature sensor. Step S3: Send the first temperature to the temperature control unit as the temperature control target, and receive the sound velocity of the lubricating oil corresponding to the first temperature value output by the signal output unit as the calibration sound velocity. Step S4: Extract the first oil film interface reflection pulse as the oil film reflection signal based on the measurement signal acquired by the ultrasonic sensor; Step S5: Compensate the temperature correction model based on the second temperature to obtain the compensated reference signal; Step S6: Determine the amplitude spectrum and phase spectrum of the reflection coefficient based on the oil film reflection signal and the compensated reference signal; Step S7: Use the amplitude spectrum and phase spectrum of the reflection coefficient to calibrate the sound velocity and obtain the oil film thickness.

[0016] The temperature correction model is as follows: in: For temperature T Lower time-domain reference signal, t For a moment, a The amplitude variation factor, room temperature T Time-domain compensated signal at 0, This is the time shift factor.

[0017] The amplitude and phase of the compensated reference signal are as follows: Where: T2 is the second temperature. The frequency domain amplitude spectrum of the reference signal at the second temperature. room temperature T The frequency domain amplitude spectrum of the reference signal at 0. The frequency domain phase spectrum of the reference signal at the second temperature. This is the amplitude variation factor corresponding to the second temperature. room temperature T The frequency domain phase spectrum of the reference signal at 0. For signal frequency, This is the time shift factor corresponding to the second temperature.

[0018] The amplitude spectrum and phase spectrum of the reflection coefficient are as follows: in: The amplitude spectrum of the reflection coefficient, The amplitude spectrum of the oil film reflection signal. The phase spectrum of the reflection coefficient. This represents the phase spectrum of the oil film reflection signal.

[0019] In step S7, if the amplitude spectrum of the reflection coefficient is less than 0.95, the oil film thickness is calculated by inversion using the spring model; otherwise, the oil film thickness is calculated using the composite model. The oil film thickness calculated based on the spring model is: in: h 1 represents the oil film thickness. For the density of lubricating oil, c 2 represents the calibrated speed of sound. For the acoustic impedance of the bearing medium, The acoustic impedance of the crankshaft medium; The oil film thickness calculated based on the composite model is: in: The oil film thickness is calculated based on the composite model. V 12 The interface reflectance coefficient, z 2 represents the acoustic velocity impedance of the lubricating oil film layer.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. On the one hand, the differentiated design of dual temperature sensors can solve the core contradiction. By setting a first temperature sensor embedded in a blind hole near the oil film and a second temperature sensor attached to the outer wall near the ultrasonic sensor, the temperature required for sound velocity calibration and the temperature required for temperature compensation are clearly distinguished for the first time. This design directly solves the fundamental problem of using a single temperature value to serve two systems simultaneously with poor results, and significantly improves measurement accuracy. On the other hand, the sound velocity calibration device is integrated and connected to the compressor pump body through a high-pressure pipeline, realizing online and continuous calibration of the sound velocity of lubricating oil affected by refrigerant dissolution. Compared with the offline calibration scheme, this method can track the changes in oil state in real time without pre-calibrating all operating condition combinations, making it more practical and universal.

[0021] 2. If the distance is too large, the measured temperature will deviate from the true oil film temperature, reducing the accuracy of the sound velocity calibration. If the distance is too small, it will weaken the structural strength of the bearing wall and bring safety hazards. The 1 mm design can ensure the mechanical strength of the bearing while allowing the first temperature sensor to be as close as possible to the oil film, so as to obtain the measurement value that is closest to the true oil film temperature.

[0022] 3. It ensures that the temperature sensor and the ultrasonic sensor are sufficiently close in space. Since there is a temperature gradient along the bearing axis, if the two are too far apart, the temperature measured by the temperature sensor cannot represent the temperature at the location of the ultrasonic sensor, thus causing the temperature compensation to fail. This limitation ensures the locality and representativeness of the temperature measurement, which is a prerequisite for the effectiveness of temperature compensation.

[0023] 4. AB glue has good acoustic damping characteristics. Under high temperature and high pressure conditions, it provides physical protection and regulates damping characteristics. It can absorb and attenuate ultrasonic waves emitted from the back of the ultrasonic sensor, effectively suppress multiple reflection noise from the sensor housing or other structures, and purify the received echo signal, making the reflection signal at the oil film interface clearer, thereby improving the accuracy of subsequent signal processing and oil film thickness inversion.

[0024] 5. Aviation-grade sockets and plugs possess excellent sealing and vibration resistance. Even in an environment filled with high-pressure refrigerant and lubricating oil inside the compressor, this connection method ensures the reliability and safety of the electrical connection, prevents oil leakage and short circuits, and guarantees the long-term stable operation of the measurement system.

[0025] 6. Compared with existing technologies, the 1 / b coefficient at the time level has been removed. On the one hand, this can reduce transmission errors. On the other hand, since the rotary compressor is a closed, high-pressure, and long-term operating scenario, reducing a physical quantity to be measured eliminates the reliance on real-time monitoring of the initial wave, making the system more robust.

[0026] 7. When the oil film is thin, stiffness dominates, and the spring model inversion is more accurate. When the oil film is thick, stiffness and mass effects need to be considered simultaneously, and a composite model is more accurate. This adaptive strategy avoids the errors that may occur when using a single model across the entire range, enabling the measuring device to adapt to a wide range of working conditions from extremely thin oil films to thicker oil films, greatly enhancing the robustness and practicality of the system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the blind hole arrangement in the bearing of the present invention; Figure 2 This is a diagram showing the arrangement of sensors on the main bearing of the rotor compressor pump body of the present invention; Figure 3 This is a diagram showing the arrangement of sensors in the auxiliary bearing of the rotor compressor pump body of the present invention; Figure 4 The following is a comparison of the evolution of the reference signal at a single ultrasonic measuring point of the main bearing in a wide temperature range. (a) is a comparison of the reference time domain signal, and (b) is a graph showing the relationship between the amplitude variation factor and the time shift factor obtained from the fitting and the temperature. Figure 5This is a temperature distribution diagram of two temperature measuring points on the main bearing of an embodiment of the present invention after the rotor compressor has stabilized. Figure 6 The following is a diagram showing the sound velocity of the lubricating oil after refrigerant dissolution, synchronously calibrated under stable operating conditions according to an embodiment of the present invention. (a) is a comparison diagram of the frequency domain amplitude signals of the reference and oil film reflection; (b) is a diagram of the amplitude and phase signals of the reflection coefficient. Figure 7 The following is a distribution diagram of the ultrasonic signal of the oil film at a single ultrasonic measuring point of the main bearing under a set target working condition, in accordance with the present invention. (a) is a distribution diagram of the time domain signal of the continuously acquired ultrasonic reflection of the oil film, (b) is a distribution diagram of the amplitude and phase of the reflection coefficient at the center frequency, and (c) is a distribution diagram of the oil film thickness obtained by inversion through an adaptive acoustic model. Among them: 1. blind hole, 2. first temperature sensor, 3. second temperature sensor, 4. ultrasonic sensor, 5. sound velocity calibration device. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0029] An ultrasonic continuous measurement device for oil film in rotor compressor bearings, such as Figure 2 As shown, it includes: Two ultrasonic sensors are symmetrically arranged along the circumference near the end of the bearing. Two primary temperature sensors are respectively arranged axially on one side of the two ultrasonic sensors near the bearing ends, as shown below. Figure 1 As shown, it is located in a blind hole, which is set from the outer side wall of the bearing towards the inner side wall, and the blind hole does not penetrate the inner side wall on one side. Two second temperature sensors are respectively arranged axially on one side of the two ultrasonic sensors near the bearing root and attached to the outer wall of the bearing; The sound velocity calibration device is connected to the compressor pump body through a high-pressure pipeline, forming an oil circulation loop and a gas phase balance loop. It includes a temperature control unit for adjusting the lubrication temperature inside the sound velocity calibration device, and a signal output unit for outputting the sound velocity calibration value. The control device, connected to the ultrasonic sensor, the first temperature sensor, the second temperature sensor, the temperature control unit, and the signal output unit respectively, is configured as follows: The system acquires the first temperature collected by the first temperature sensor, sends it to the temperature control unit as the temperature control target, and receives the sound velocity of the lubricating oil corresponding to the first temperature value output by the signal output unit. The second temperature is acquired by the second temperature sensor and the measurement signal is acquired by the continuous or ultrasonic sensor. The reference signal is temperature compensated based on the second temperature, and the oil film thickness is obtained by inversion calculation combined with the measurement signal.

[0030] like Figure 1 As shown, the distance between the blind hole and the inner wall of the bearing is 1 mm.

[0031] Furthermore, the projected lengths of the distance between the first temperature sensor and the corresponding ultrasonic sensor along the bearing axis, as well as the projected lengths of the distance between the second temperature sensor and the corresponding ultrasonic sensor along the bearing axis, are both less than a first set threshold length. This ensures that the temperature sensors and ultrasonic sensors are sufficiently close in space. Since there is a temperature gradient along the bearing axis, if the distance between them is too great, the temperature measured by the temperature sensor will not represent the temperature at the location of the ultrasonic sensor, leading to temperature compensation failure. This limitation ensures the locality and representativeness of temperature measurement, which is a prerequisite for the effectiveness of temperature compensation.

[0032] It is particularly important to note that, since wear generally occurs at the bearing ends, the relative positions of the first and second sensors along the bearing axial direction cannot be changed.

[0033] The back of the ultrasonic sensor is coated with a damping protective layer made of AB glue to provide physical protection and regulate damping characteristics under high temperature and high pressure conditions.

[0034] The control device achieves a sealed connection with the ultrasonic sensor, the first temperature sensor, and the second temperature sensor via an aviation socket and plug.

[0035] In this application, for each ultrasonic sensor, a first temperature sensor for monitoring the temperature of the friction interface and a second temperature sensor for monitoring the temperature of the bearing body are provided in the axial direction of the bearing. On the one hand, the differentiated design of the dual temperature sensors can solve the core contradiction. By setting the first temperature sensor embedded in a blind hole near the oil film and the second temperature sensor attached to the outer wall near the ultrasonic sensor, the temperature required for sound velocity calibration and the temperature required for temperature compensation are clearly distinguished for the first time. This design directly solves the fundamental problem that using a single temperature value to serve two systems simultaneously is ineffective, and significantly improves the measurement accuracy. On the other hand, the sound velocity calibration device is integrated and connected to the compressor pump body through a high-pressure pipeline, realizing online and continuous calibration of the sound velocity of lubricating oil affected by refrigerant dissolution. Compared with the offline calibration scheme, this method can track the changes in oil state in real time, without the need for pre-calibration for all operating condition combinations, making it more practical and universal.

[0036] For details on the sound velocity calibration device, please refer to the design of Chinese patent application CN 122217235 A, which will not be repeated in this application.

[0037] In addition, this application also provides a measurement method based on an ultrasonic continuous measurement device for rotor compressor bearing oil film, including: Step S1: Construct a temperature correction model that includes an amplitude variation factor and a time shift factor; The temperature correction model is as follows: in: For temperature T Lower time-domain reference signal, t For a moment, a The amplitude variation factor, room temperature T Time-domain compensated signal at 0, This is the time shift factor.

[0038] Step S2: After starting the rotor compressor and making it reach a stable operating state under each target working condition, acquire the measurement signal collected by the ultrasonic sensor, the first temperature collected by the first temperature sensor, and the second temperature collected by the second temperature sensor. Step S3: Send the first temperature to the temperature control unit as the temperature control target, and receive the sound velocity of the lubricating oil corresponding to the first temperature value output by the signal output unit as the calibration sound velocity. Step S4: Extract the first oil film interface reflection pulse as the oil film reflection signal based on the measurement signal acquired by the ultrasonic sensor; The amplitude and phase of the compensated reference signal are as follows: Where: T2 is the second temperature. The frequency domain amplitude spectrum of the reference signal at the second temperature. room temperature T The frequency domain amplitude spectrum of the reference signal at 0. The frequency domain phase spectrum of the reference signal at the second temperature. This is the amplitude variation factor corresponding to the second temperature. room temperature T The frequency domain phase spectrum of the reference signal at 0. For signal frequency, This is the time shift factor corresponding to the second temperature.

[0039] Step S5: Compensate the temperature correction model based on the second temperature to obtain the compensated reference signal; Step S6: Determine the amplitude spectrum and phase spectrum of the reflection coefficient based on the oil film reflection signal and the compensated reference signal; The amplitude spectrum and phase spectrum of the reflection coefficient are as follows: in: The amplitude spectrum of the reflection coefficient, The amplitude spectrum of the oil film reflection signal. The phase spectrum of the reflection coefficient. This represents the phase spectrum of the oil film reflection signal.

[0040] Step S7: Use the amplitude spectrum and phase spectrum of the reflection coefficient to calibrate the sound velocity and obtain the oil film thickness.

[0041] If the amplitude spectrum of the reflection coefficient is less than 0.95, the oil film thickness is calculated by inversion using the spring model; otherwise, the oil film thickness is calculated using the composite model. The oil film thickness calculated based on the spring model is: in: h 1 represents the oil film thickness. For the density of lubricating oil, c 2 represents the calibrated speed of sound. For the acoustic impedance of the bearing medium, The acoustic impedance of the crankshaft medium; The oil film thickness calculated based on the composite model is: in: The oil film thickness is calculated based on the composite model. V 12 The interface reflectance coefficient, z 2 represents the acoustic velocity impedance of the lubricating oil film layer.

[0042] Before assembly, this application refers to... Figure 2 and Figure 3 As shown, an ultrasonic sensor, a first temperature sensor, and a second temperature sensor need to be pre-installed in the sensor mounting areas of the main and auxiliary bearings. Then, the bearings are placed in a constant temperature chamber, and ultrasonic reference time-domain signals at different temperatures are acquired according to step S1, specifically as follows... Figure 4 As shown in the figure; the analysis indicates that with increasing temperature, the time-domain signal exhibits amplitude attenuation and overall lag, while the frequency-domain signal shows amplitude reduction and phase shift. Based on this, a fast Fourier transform was applied to the signal, and phase and amplitude information near the center frequency domain were compared. A temperature correction model incorporating amplitude variation and time shift factors was constructed, as detailed in the attached figure. Figure 4 As shown in (b).

[0043] Next, the main and auxiliary bearings with pre-installed sensors were assembled into a twin-cylinder rotor compressor, and the compressor was connected to the sound velocity measuring device via a high-pressure pipeline to achieve air and oil circuit connectivity. After starting the compressor and waiting for operating parameters such as speed, intake and exhaust pressure, and temperature to fully stabilize, a high-precision oscilloscope was used to continuously acquire the oil film reflection signal at one of the ultrasonic measuring points on the main bearing. The continuously acquired oil film ultrasonic reflection time-domain signal... Figure 7 As shown in (a), data from two temperature sensors located near the ultrasonic measuring point were simultaneously acquired, and the acquired temperature values ​​are shown in the attached figure. Figure 5 As shown.

[0044] Then, after the rotary compressor has stabilized, the sound velocity of the VG74 lubricating oil after the refrigerant R410A has dissolved is simultaneously calibrated at the current operating pressure, with the film thickness set at 50 μm. The calibrated sound velocity is as follows: Figure 6 As shown.

[0045] The continuously acquired bearing oil film reflection time-domain signal is truncated and the effective signal is extracted.

[0046] Based on the real-time collected bearing surface temperature data, the fitted temperature compensation model is invoked to perform frequency domain compensation on the reference signal.

[0047] The extracted effective oil film signal sequence was compared with the temperature-compensated reference signal after undergoing a Fast Fourier Transform, and the amplitude and phase spectra of the reflection coefficients were calculated. The amplitude and phase distributions of the reflection coefficients near the center frequency are shown in the attached figure. Figure 7 As shown in (b).

[0048] Based on the synchronously calibrated acoustic model considering the sound velocity of VG74 lubricating oil after refrigerant R410A dissolution, and the adaptive switching acoustic model, the dynamic change curve of the oil film thickness at the selected ultrasonic measuring points of the main bearing under the test conditions was obtained through inversion calculation. Specifically, as shown... Figure 7 As shown in (c).

[0049] The oil film thickness measured under the test conditions is affected by the combined effects of the centrifugal force of the rotor counterweight and the periodic fluctuations of the cylinder pressure, exhibiting a periodic change that is strictly synchronized with the rotational speed; and after the operation stabilizes, the distribution characteristics of the oil film thickness remain stable within a single cycle.

[0050] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. An ultrasonic continuous measuring device for oil film in a rotor compressor bearing, characterized in that, include: Two ultrasonic sensors are symmetrically arranged along the circumference near the end of the bearing. Two first temperature sensors are respectively arranged axially on one side of the two ultrasonic sensors near the bearing end, and are located in blind holes. The blind holes are set from the outer side wall of the bearing towards the inner side wall, and the blind holes do not penetrate the inner side wall. Two second temperature sensors are respectively arranged axially on one side of the two ultrasonic sensors near the bearing root and attached to the outer wall of the bearing; The sound velocity calibration device is connected to the compressor pump body through a high-pressure pipeline, forming an oil circulation loop and a gas phase balance loop. It includes a temperature control unit for adjusting the lubrication temperature inside the sound velocity calibration device, and a signal output unit for outputting the sound velocity calibration value. The control device, connected to the ultrasonic sensor, the first temperature sensor, the second temperature sensor, the temperature control unit, and the signal output unit respectively, is configured as follows: The system acquires the first temperature collected by the first temperature sensor, sends it to the temperature control unit as the temperature control target, and receives the sound velocity of the lubricating oil corresponding to the first temperature value output by the signal output unit. The second temperature is acquired by the second temperature sensor and the measurement signal is acquired by the continuous or ultrasonic sensor. The reference signal is temperature compensated based on the second temperature, and the oil film thickness is obtained by inversion calculation combined with the measurement signal.

2. The ultrasonic continuous measuring device for rotor compressor bearing oil film according to claim 1, characterized in that, The distance between the blind hole and the inner wall of the bearing is 1 mm.

3. The ultrasonic continuous measuring device for oil film of a rotor compressor bearing according to claim 1, characterized in that, The projected length of the distance between the first temperature sensor and the corresponding ultrasonic sensor in the bearing axis direction, and the projected length of the distance between the second temperature sensor and the corresponding ultrasonic sensor in the bearing axis direction, are both less than the first set threshold length.

4. The ultrasonic continuous measuring device for rotor compressor bearing oil film according to claim 1, characterized in that, The back of the ultrasonic sensor is coated with a damping protective layer made of AB glue.

5. The ultrasonic continuous measuring device for oil film of a rotor compressor bearing according to claim 1, characterized in that, The control device achieves a sealed connection with the ultrasonic sensor, the first temperature sensor, and the second temperature sensor via an aviation socket and plug.

6. A measurement method based on the ultrasonic continuous measuring device for rotor compressor bearing oil film according to any one of claims 1-5, characterized in that, The measurement method includes: Step S1: Construct a temperature correction model that includes an amplitude variation factor and a time shift factor; Step S2: After starting the rotor compressor and making it reach a stable operating state under each target working condition, acquire the measurement signal collected by the ultrasonic sensor, the first temperature collected by the first temperature sensor, and the second temperature collected by the second temperature sensor. Step S3: Send the first temperature to the temperature control unit as the temperature control target, and receive the sound velocity of the lubricating oil corresponding to the first temperature value output by the signal output unit as the calibration sound velocity. Step S4: Extract the first oil film interface reflection pulse as the oil film reflection signal based on the measurement signal acquired by the ultrasonic sensor; Step S5: Compensate the temperature correction model based on the second temperature to obtain the compensated reference signal; Step S6: Determine the amplitude spectrum and phase spectrum of the reflection coefficient based on the oil film reflection signal and the compensated reference signal; Step S7: Use the amplitude spectrum and phase spectrum of the reflection coefficient to calibrate the sound velocity and obtain the oil film thickness.

7. The measurement method according to claim 6, characterized in that, The temperature correction model is as follows: in: For temperature T Lower time-domain reference signal, t For a moment, a The amplitude variation factor, room temperature T Time-domain compensated signal at 0, This is the time shift factor.

8. The measurement method according to claim 7, characterized in that, The amplitude and phase of the compensated reference signal are as follows: Where: T2 is the second temperature. The frequency domain amplitude spectrum of the reference signal at the second temperature. room temperature T The frequency domain amplitude spectrum of the reference signal at 0. The frequency domain phase spectrum of the reference signal at the second temperature. This is the amplitude variation factor corresponding to the second temperature. room temperature T The frequency domain phase spectrum of the reference signal at 0. For signal frequency, This is the time shift factor corresponding to the second temperature.

9. The measurement method according to claim 8, characterized in that, The amplitude spectrum and phase spectrum of the reflection coefficient are as follows: in: The amplitude spectrum of the reflection coefficient, The amplitude spectrum of the oil film reflection signal. The phase spectrum of the reflection coefficient. This represents the phase spectrum of the oil film reflection signal.

10. The measurement method according to claim 8, characterized in that, In step S7, if the amplitude spectrum of the reflection coefficient is less than 0.95, the oil film thickness is calculated by inversion using the spring model; otherwise, the oil film thickness is calculated using the composite model. The oil film thickness calculated based on the spring model is: in: h 1 represents the oil film thickness. For the density of lubricating oil, c 2 represents the calibrated speed of sound. For the acoustic impedance of the bearing medium, The acoustic impedance of the crankshaft medium; The oil film thickness calculated based on the composite model is: in: The oil film thickness is calculated based on the composite model. V 12 The interface reflectance coefficient, z 2 represents the acoustic velocity impedance of the lubricating oil film layer.

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