A device and method for measuring whirl vibration of a marine shafting

Abstract

The application provides a ship shafting whirling vibration measuring device and method, which comprises a support and a radial force measuring mechanism. The radial force measuring mechanism is sleeved on a shaft section and fixed on a shafting bottom plate through the support. A power supply unit and a signal acquisition and transmission module are arranged on the support and electrically connected with the radial force measuring mechanism to supply power and interconnect information for the radial force measuring mechanism. The application greatly improves the whirling vibration measuring precision by measuring the change of radial force when the shaft section generates radial displacement in multiple directions.

Description

Technical Field

[0001] This invention relates to the technical field of ship shafting monitoring, and specifically to a ship shafting gyroscopic vibration measuring device and method. Background Technology

[0002] Due to its own weight, the rotation centerline of a ship's propulsion shafting deviates from its geometric centerline, causing precession during rotation. This precession manifests as vibration perpendicular to the shafting's centerline in the longitudinal or vertical direction, known as gyroscopic vibration. If this gyroscopic vibration is not effectively controlled over a long period, it can cause mechanical damage to the shafting and bearings, and in severe cases, may lead to shaft breakage. Therefore, designing measurement methods for shafting gyroscopic vibration is crucial.

[0003] Currently, gyroscopic vibration signals for ship shafting are obtained by placing eddy current sensors on the side of the shaft section under test and measuring the radial displacement generated by the shaft section. This method of measuring gyroscopic vibration has high requirements for the sensor installation location and is limited by the sensor's range. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a device and method for measuring the gyroscopic vibration of a ship shafting system, which measures the strain caused by the radial displacement of the shafting system by a radial force measuring device, and obtains the gyroscopic vibration signal by analysis, no longer limited by the sensor installation process.

[0005] The embodiments of this application are implemented as follows: This application provides a ship shafting gyroscopic vibration measuring device, characterized in that it includes a support and a radial force measuring mechanism. The radial force measuring mechanism is sleeved on the shaft section and fixed to the shafting base plate by the support. The support is provided with a power supply unit and a signal acquisition and transmission module, both of which are electrically connected to the radial force measuring mechanism, providing power and information interconnection for the radial force measuring mechanism, respectively.

[0006] In some alternative implementations, the radial force measuring mechanism includes a slip ring, a fixed sleeve, a preload adjustment mechanism, and a piezoelectric sensor. The fixed sleeve is concentrically arranged with the shaft segment and fixed to the support. The piezoelectric sensors are evenly spaced along the circumference of the fixed sleeve and fixed to the inner wall of the fixed sleeve. One end of the preload adjustment mechanism is fixed to the piezoelectric sensor, and the other end is connected to the outer wall of the slip ring.

[0007] In some alternative implementations, the preload adjustment mechanism includes a micro stepper motor, a lead screw, and an elastic support. The micro stepper motor is fixed to the piezoelectric sensor and connected to the lead screw. The lead screw nut is connected to the elastic support, and the end of the elastic support is connected to the slip ring.

[0008] In some alternative implementations, the elastic support is a miniature spring.

[0009] In some alternative implementations, the slip ring is made of a lightweight, high-strength alloy or a wear-resistant material.

[0010] A method for measuring the gyroscopic vibration of a ship's shafting system, characterized by comprising the following steps: S1, complete the installation and debugging of each component; S2, calibrating the preload of the piezoelectric sensor in its initial state; S3, the signal acquisition and transmission module transmits the pressure fluctuation signal from the piezoelectric sensor to the backend, and obtains the cyclonic vibration signal through analysis; S4, the signal acquisition and transmission module transmits the preload signal to the backend, and obtains the preload adjustment signal through analysis. The backend then issues a control command to adjust the preload of the piezoelectric sensor.

[0011] In some optional implementations, obtaining the piezoelectric sensor pressure fluctuation signal in step S3 specifically involves: The piezoelectric sensor senses the pressure pulsation generated by the vibration of the shaft system under the action of preload and outputs a charge signal. After impedance transformation and amplification by a charge amplifier, the charge signal is converted into a voltage analog signal.

[0012] In some optional implementations, the parsing of the piezoelectric sensor pressure fluctuation signal in step S3 specifically involves: High-frequency noise interference is eliminated by low-pass filtering, while retaining the effective frequency band pressure fluctuation signal that reflects the gyroscopic vibration characteristics of the reaction shaft system.

[0013] In some alternative implementations, the preload of the piezoelectric sensor is greater than the maximum dynamic force generated by the vibration of the shaft system, so that the piezoelectric sensor is always under pressure.

[0014] In some alternative implementations, the preload of the piezoelectric sensor is less than the bearing's support force, so as not to significantly constrain or distort the original trajectory of the shaft system.

[0015] The beneficial effects of this application are as follows: The ship shafting gyratory vibration measuring device and method provided in this application reduce the measurement error caused by preload changes during the operation of the measuring device by setting a dynamic preload adjustment device, realize online automatic preload calibration, and improve the sensitivity and linearity of the piezoelectric sensor. No matter how the working conditions change, the piezoelectric sensor always operates in the preload range with the highest sensitivity and best linearity. At the same time, by measuring the change of radial force when the shaft segment generates radial displacement in multiple directions, the gyratory vibration measurement accuracy is greatly improved. This measuring device has a simple structure and is easy to manufacture. In addition, it can be processed for a series of shaft segments in the initial stage of manufacturing, and has good adaptability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front view of the ship shafting gyratory vibration measuring device according to an embodiment of this application; Figure 2 This is a side view of the ship shafting gyratory vibration measuring device according to an embodiment of this application; Figure 3 This is a flowchart illustrating the measurement of gyroscopic vibration of a ship shafting system according to an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0022] like Figure 1 , Figure 2 As shown, the present invention provides a ship shafting gyroscopic vibration measuring device, including a support 1 and a radial force measuring mechanism 2. The radial force measuring mechanism is sleeved on the shaft section 3 and fixed to the shafting base plate 4 by the support. The support is provided with a power supply unit 5 and a signal acquisition and transmission module 6, both of which are electrically connected to the radial force measuring mechanism, providing power and information interconnection for the radial force measuring mechanism, respectively.

[0023] Furthermore, the radial force measuring mechanism includes a slip ring 21, a fixed sleeve 22, a preload adjustment mechanism 23, and a piezoelectric sensor 24. The fixed sleeve is concentrically arranged with the shaft segment and fixed on the support. The piezoelectric sensors are evenly spaced along the circumference of the fixed sleeve and fixed on the inner wall of the fixed sleeve. One end of the preload adjustment mechanism is fixed to the piezoelectric sensor, and the other end is connected to the outer wall of the slip ring.

[0024] A piezoelectric sensor and a preload adjustment mechanism are installed between the slip ring and the fixed sleeve. When the shaft section generates gyratory vibration, the piezoelectric sensor can sense the axial strain signal and obtain the gyratory vibration signal through analysis.

[0025] Furthermore, the preload adjustment mechanism includes a miniature stepper motor, a lead screw, and an elastic support. The miniature stepper motor is fixed to the piezoelectric sensor and connected to the lead screw. The lead screw nut is connected to the elastic support, and the end of the elastic support is connected to a slip ring. The stepper motor drives the lead screw to rotate, causing the lead screw nut to move radially, and a small preload is applied through the slip ring connected to the elastic support.

[0026] A piezoelectric sensor is mounted on the inner wall of the fixed sleeve, arranged radially, to sense the radial force generated by the shaft segment. A preload adjustment mechanism is located outside the piezoelectric sensor and connected to a slip ring. It applies a small radial preload to ensure the stability of force transmission between the slip ring and the shaft segment. The slip ring is fitted onto the outside of the shaft segment and remains stationary. Its surface is connected to the preload adjustment mechanism, but it allows for slight elastic displacement, enabling the shaft segment to move freely during gyratory vibrations or minor radial axial movement. The force signal measured by the piezoelectric sensor is fed back to the backend via a signal acquisition and transmission module. The backend can dynamically adjust the preload based on the measured signal to ensure measurement accuracy and signal integrity.

[0027] The force on the piezoelectric sensor is indirectly transmitted through the elastic support. During the measurement process, the piezoelectric sensor feeds back the force signal to the signal acquisition module. The backend controls the stepper motor to rotate according to the deviation, and the lead screw drives the elastic support to finely adjust the displacement, so as to realize dynamic compensation of preload and ensure measurement accuracy and axis freedom.

[0028] When the piezoelectric sensor is in close contact with the preload adjustment mechanism and reaches the preset initial pressure value, a stable mechanical coupling circuit is formed. When the preload deviates from the initial calibration value during the measurement process, the preload adjustment mechanism can adjust it to avoid errors.

[0029] The gyroscopic vibration of the shaft system is bidirectional (it involves both pressure towards the sensor and movement away from the sensor). By applying a preload greater than the maximum dynamic force generated by the vibration, the backward movement of the shaft manifests as a reduction in pressure on the sensor. This ensures that the sensor remains under pressure throughout the entire vibration cycle, thus enabling a complete and accurate reconstruction of the shaft system's vibration waveform.

[0030] Furthermore, the elastic support can be a miniature spring, with the cross-sectional diameter (wire diameter) of the spring material being less than 0.5 mm. The elastic support allows the shaft segment to slide or elastically deform during gyratory vibration or minor radial movement, thus not restricting the shaft's degrees of freedom.

[0031] Furthermore, the slip ring is made of lightweight, high-strength alloy or wear-resistant material. Its mass is much smaller than that of the shaft rotor, and it will not change the critical speed or natural frequency of the shaft. At the same time, the radial force provided by the preload adjustment mechanism is only used to maintain the contact of the piezoelectric sensor, and is much smaller than the bearing support force, so it will not significantly constrain or distort the original trajectory of the shaft, thus ensuring the accuracy of the measurement results.

[0032] To resolve the conflict between signal transmission and friction and wear, the slip ring contact pair adopts a design with high radial strength and low tangential friction. Specifically, the radial side eliminates gaps through preload to ensure rigid contact and ensure that the vibration signal is transmitted without attenuation. The tangential side uses self-lubricating and wear-resistant materials to ensure an extremely low coefficient of friction, avoiding the impact of frictional heat or wear on shaft operation.

[0033] In a static state, the piezoelectric end of the piezoelectric sensor is connected to the slip ring via a preload adjustment mechanism, generating an initial preload. The piezoelectric sensors should be evenly distributed circumferentially, and their number can be selected, including but not limited to four. During use, the number can be increased or decreased as needed according to the measurement accuracy requirements. That is, when the shaft system generates gyroscopic vibration, the slip ring will undergo radial displacement with the shaft, generating pressure on the piezoelectric sensors arranged at different positions. This allows for the integration of measurement signals from various piezoelectric sensors, and the acquisition of the shaft system's gyroscopic vibration signal through signal analysis technology. However, during the measurement process, the preload between the piezoelectric sensor and the slip ring is prone to change. Therefore, the initial preload needs to be calibrated during initial installation, and adjusted during operation using the preload adjustment mechanism.

[0034] Furthermore, the power supply unit is fixed on the support and is used to supply power to the preload adjustment mechanism, piezoelectric sensor and signal acquisition and transmission module. The power supply unit itself can obtain power by charging or direct connection, so that it can also ensure that it can continuously supply power to the electrical device for a period of time in the event of a power outage. In other words, the power supply unit has the functions of charging and discharging and direct power supply through external power source. Under normal circumstances, the power supply unit supplies power to the electrical device by direct power supply. In the event of an occasional power outage, it can also use the stored electrical energy to supply power to the electrical device for a period of time.

[0035] like Figure 3 As shown, the above-mentioned ship shafting gyratory vibration measuring device includes the following steps when in use: 1. Complete the installation and debugging of each component.

[0036] 2. Calibrate the preload of the piezoelectric sensor in its initial state.

[0037] 3. The signal acquisition and transmission module transmits the pressure fluctuation signal from the piezoelectric sensor to the backend (the piezoelectric sensor senses the pressure pulsation generated by the vibration of the shaft system under the action of preload, and outputs a charge signal. After impedance transformation and amplification by the charge amplifier, the charge signal is converted into a voltage analog signal). The gyroscopic vibration signal is obtained through analysis (high-frequency noise interference is eliminated by low-pass filtering, and the effective frequency band signal that reflects the gyroscopic vibration characteristics of the shaft system is retained).

[0038] 4. The signal acquisition and transmission module transmits the preload signal to the backend, and obtains the preload adjustment signal through analysis. The backend then issues a control command to adjust the preload of the piezoelectric sensor.

[0039] Example 1 In this embodiment, a section of shaft with a diameter of 200 mm and a length of 3 m is selected on the shafting system of a long-wheelbase ship for gyroscopic vibration measurement. The radial force measuring mechanism is installed as follows: 1. Fixed sleeve: made of aluminum alloy, 5 mm thick, arranged concentrically along the shaft section, and fixed to the base plate of the shaft system by a support, providing a stable mounting base for the piezoelectric sensor and the preload adjustment mechanism. 2. Piezoelectric sensors: Four are evenly arranged along the circumference of the fixed sleeve, with the base fixed to the inner wall of the fixed sleeve, used to sense the radial force signal generated by the shaft segment. 3. Preload Adjustment Mechanism: This includes a miniature stepper motor (0.9° / step), a 4 mm diameter lead screw, a slider, and a miniature spring (0.3 mm wire diameter, initial preload set to 15 N). The stepper motor drives the slider to move radially via the lead screw. The slider is connected to a slip ring via an elastic support, applying a small preload to maintain stable contact with the piezoelectric sensor. The elastic support allows for slight displacement of the shaft segment during gyroscopic vibration or minor radial movement, without restricting the shaft's degrees of freedom. 4. Slip ring: Sleeved on the outside of the shaft section, made of lightweight high-strength alloy, with a total weight of less than 0.5 kg, fixed in place, its surface is in contact with the preload adjustment mechanism, allowing slight elastic displacement, bearing the preload and ensuring stable force transmission. 5. Signal acquisition and transmission module: Fixed on the support, electrically connected to the piezoelectric sensor and charge amplifier, used to transmit the measured pressure fluctuation signal and preload signal to the background analysis. 6. Power supply unit: Fixed on the support, it supplies power to the preload adjustment mechanism, piezoelectric sensor and signal acquisition module. It can be powered by an external power source or internal energy storage to ensure normal operation for a short time in the event of a power outage.

[0040] Take measurements: 1. Complete the installation and debugging of each component to ensure that the fixed sleeve, piezoelectric sensor, preload adjustment mechanism and slip ring are in the correct position. 2. The initial preload of the calibrated piezoelectric sensor is 15 N. 3. The signal acquisition and transmission module sends the pressure fluctuation signal from the piezoelectric sensor to the backend for analysis after low-pass filtering, and obtains the shaft segment rotational vibration signal. 4. The back-end determines the deviation based on the preload signal and controls the stepper motor to fine-tune the slider displacement to achieve dynamic preload compensation and ensure measurement accuracy. During the measurement process, the elastic support allows for slight displacement of the shaft segment, ensuring that the shaft's degrees of freedom are unrestricted.

[0041] Measurement results show that the radial amplitude of the shaft section is within the range of 0 to 0.8 mm, the measurement signal is stable, and the preload fluctuation is less than ±0.5 N.

Claims

1. A device for measuring the gyroscopic vibration of a ship's shafting, characterized in that, It includes a support and a radial force measuring mechanism. The radial force measuring mechanism is sleeved on the shaft segment and fixed to the shaft system base plate by the support. The support is equipped with a power supply unit and a signal acquisition and transmission module, both of which are electrically connected to the radial force measuring mechanism, providing power and information interconnection for the radial force measuring mechanism, respectively.

2. The ship shafting gyratory vibration measuring device according to claim 1, characterized in that, The radial force measuring mechanism includes a slip ring, a fixed sleeve, a preload adjustment mechanism, and a piezoelectric sensor. The fixed sleeve is concentrically arranged with the shaft segment and fixed to the support. The piezoelectric sensors are evenly spaced along the circumference of the fixed sleeve and fixed to the inner wall of the fixed sleeve. One end of the preload adjustment mechanism is fixed to the piezoelectric sensor, and the other end is connected to the outer wall of the slip ring.

3. The ship shafting gyratory vibration measuring device according to claim 2, characterized in that, The preload adjustment mechanism includes a micro stepper motor, a transmission screw, and an elastic support. The micro stepper motor is fixed to the piezoelectric sensor and connected to the transmission screw. The screw nut is connected to the elastic support, and the end of the elastic support is connected to the slip ring.

4. The ship shafting gyratory vibration measuring device according to claim 3, characterized in that, The elastic support is a miniature spring.

5. A ship shafting gyratory vibration measuring device according to claim 2, 3, or 4, characterized in that, The slip ring is made of lightweight, high-strength alloy or wear-resistant material.

6. A method for measuring the gyratory vibration of a ship shafting system using the device described in claim 3, 4, or 5, characterized in that, The steps include the following: S1, complete the installation and debugging of each component; S2, calibrating the preload of the piezoelectric sensor in its initial state; S3, the signal acquisition and transmission module transmits the pressure fluctuation signal from the piezoelectric sensor to the backend, and obtains the cyclonic vibration signal through analysis; S4, the signal acquisition and transmission module transmits the preload signal to the backend, and obtains the preload adjustment signal through analysis. The backend then issues a control command to adjust the preload of the piezoelectric sensor.

7. The method for measuring the gyroscopic vibration of a ship shafting system according to claim 6, characterized in that, The specific steps for obtaining the piezoelectric sensor pressure fluctuation signal in step S3 are as follows: The piezoelectric sensor senses the pressure pulsation generated by the vibration of the shaft system under the action of preload and outputs a charge signal. After impedance transformation and amplification by a charge amplifier, the charge signal is converted into a voltage analog signal.

8. The method for measuring the gyroscopic vibration of a ship shafting system according to claim 7, characterized in that, The analysis of the piezoelectric sensor pressure fluctuation signal in step S3 is specifically as follows: High-frequency noise interference is eliminated by low-pass filtering, while retaining the effective frequency band pressure fluctuation signal that reflects the gyroscopic vibration characteristics of the reaction shaft system.

9. A method for measuring the gyroscopic vibration of a ship shafting system according to claim 6 or 8, characterized in that, The preload of the piezoelectric sensor is greater than the maximum dynamic force generated by the vibration of the shaft system, so that the piezoelectric sensor is always under pressure.

10. The method for measuring the gyroscopic vibration of a ship shafting system according to claim 9, characterized in that, The preload of the piezoelectric sensor is less than the bearing's supporting force, so it does not significantly constrain or distort the original trajectory of the shaft system.

Images