Direct type bearing load measuring system and method

Abstract

According to the direct type bearing load measuring system and method, the strain gauges and the displacement sensors are directly arranged on the shaft section close to the bearing, the mechanical state parameters of the shaft section are obtained in real time, the bearing supporting counter-force is directly calculated in combination with the three-bending-moment theory, the direct measuring mode is adopted, errors caused by model hypothesis are avoided, and the measuring accuracy is improved. The system can adapt to various complex working conditions, and high-precision, real-time and stable monitoring of the dynamic load of the bearing is realized by adopting a high-speed synchronous sampling technology and a wireless transmission scheme.

Description

Technical Field

[0001] This invention relates to the technical field of ship shafting monitoring, and specifically to a direct bearing load measurement system and method. Background Technology

[0002] Accurate measurement of bearing load is crucial for equipment operation monitoring, fault prediction, and maintenance. Currently, bearing load measurement methods are mainly divided into two categories: static measurement and dynamic measurement. Static measurement is typically performed after equipment shutdown, failing to reflect the dynamic load under actual operating conditions. Dynamic measurement methods, on the other hand, often rely on indirect measurements or empirical formulas, resulting in low accuracy, poor real-time performance, and insufficient adaptability. Traditional methods use finite element simulation or simplified mechanical models to infer bearing load, but these are limited by model assumptions and the complexity of operating conditions, making it difficult to accurately capture the true stress state under high-speed rotation or impact loads. Furthermore, existing dynamic measurement schemes also have significant shortcomings in data synchronization, anti-interference capabilities, and ease of installation. Specific problems are as follows: 1) Insufficient measurement accuracy: Traditional indirect measurement methods rely on finite element models or simplified mechanical assumptions, which significantly increase errors under complex working conditions such as high-speed rotation and impact loads, making it difficult to meet the stringent requirements for measurement accuracy in industrial settings; 2) Poor dynamic synchronization: Multi-sensor signals have microsecond-level time base deviations, which lead to the accumulation of phase errors and seriously affect the accuracy of bearing load calculation; 3) Complex installation and maintenance: Traditional wired measurement solutions are difficult to wire on rotating parts, and it is difficult to solve the problems of stable power supply and data transmission between rotating and stationary parts.

[0003] Therefore, there is an urgent need for a new method that can directly and accurately measure the dynamic load of bearings. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a direct bearing load measurement system and method to address the above-mentioned problems, which can acquire the mechanical state parameters of the shaft segment in real time and directly calculate the bearing support reaction force by combining the three bending moment theory.

[0005] The embodiments of this application are implemented as follows: This application provides a direct bearing load measurement system, characterized in that it includes a bearing unit and a measurement unit. The bearing unit includes a bearing to be measured, a shaft, and a shaft base for support. The measurement unit includes strain gauges, a wireless signal transmitter, and a displacement sensor. The strain gauges are mounted on the shaft surfaces on both sides of the bearing to be measured and are electrically connected to the wireless signal transmitter. The displacement sensor is mounted corresponding to the strain gauges.

[0006] In some alternative implementations, the strain gauges are connected in a full-bridge configuration and bonded to the axial surface.

[0007] In some alternative implementations, the displacement sensor is mounted directly below the strain gauge and aligned with the center of the strain gauge.

[0008] In some alternative implementations, the displacement sensor is held in place by a clamp on the top of a universal joint located on the shaft base.

[0009] In some alternative implementations, the bottom of the gimbal is magnetically connected to the shaft base via an electromagnet.

[0010] A method for a direct bearing load measurement system, characterized by comprising the following steps: Step S1: Simplify the shaft system and perform force analysis on the shaft segment of the bearing under test. Based on the principle of force balance, perform theoretical calculations by measuring the strain signal of the shaft segment to obtain the bending moment of the shaft segment. Step S2: Based on the bending moment of the shaft segment and the measured bearing displacement, calculate the bearing support reaction force according to the three bending moment equations.

[0011] In some optional implementations, the calculation process for the shaft segment bending moment in step S1 is as follows: Step S 11 The shaft system is simplified. The bearing to be tested is located at point B on the shaft segment, and the adjacent bearings are located at points A and B on the shaft segment, respectively. The equivalent forces of the uniformly distributed load on the shaft segment are F1 and F2, respectively. The strain gauges are installed at points O and P on the shaft segment. The distances of points F1, O, B, P, F2, and C from point A are X1, X2, X3, X4, X5, and X6, respectively. The simplified shaft segment is subjected to force analysis according to the principle of force balance, resulting in the following equation:

[0012] In the formula, R A R is the supporting force of the bearing at point A. B R represents the support reaction force of the bearing under test. C Let Q be the support reaction force of the bearing at point C. m For the self-weight of the shaft segment; Step S 12 Since the bending moment of the shaft segment cannot be directly measured and needs to be measured indirectly through strain, strain gauges are selected to measure the strain and stress σ of the shaft segment. 测 With strain ε 测 The relationship between them can be represented as:

[0013] In the formula, E is the elastic modulus of the material; ε 测 The strain was measured using strain gauges; For a circular cross-section shaft segment, the bending moment M on the cross-section is calculated using the following formula:

[0014]

[0015] In the formula, d is the diameter of the shaft segment.

[0016] In some optional implementations, the calculation process of the bearing support reaction force in step S2 is as follows: Step S 21 When the shaft section bears a load, the bearings at points A, B, and C will experience bearing displacements of y, respectively. A y B y C The included angles caused by bearing displacement are θ A θ B The moment equilibrium equations are obtained as follows;

[0017] In the formula, M B M is the bending moment experienced by the bearing under test. O M P The bending moments at strain gauges O and P; Taking point A as the analysis point, based on the bending moment equilibrium... have:

[0018]

[0019] Taking point B as the analysis point, based on the bending moment equilibrium... have:

[0020]

[0021] The equilibrium equation matrix can be obtained:

[0022] Let the equilibrium matrix equation be AR=B, where A, R, and B represent the first, second, and third matrices, respectively. Based on the matrix inverse, we can obtain:

[0023]

[0024]

[0025] By combining the strain, shaft diameter, and spacing parameters obtained from actual measurements, the theoretical support force R of the bearing under test can be directly calculated.B .

[0026] The beneficial effects of this application are as follows: The direct bearing load measurement system and method provided by this application directly deploys strain and displacement sensors on the shaft section close to the bearing to obtain the mechanical state parameters of the shaft section in real time. Combined with the three bending moment theory, the bearing support reaction force is directly calculated, which not only avoids the errors caused by model assumptions, but also can adapt to various complex working conditions. At the same time, the system adopts high-speed synchronous sampling technology and wireless transmission scheme, which effectively solves the problems of multi-sensor synchronization and data transmission, and realizes high-precision, real-time and stable monitoring of bearing dynamic load. Attached Figure Description

[0027] 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.

[0028] Figure 1 This is a schematic diagram of the bearing load measurement system according to an embodiment of this application; Figure 2 This is a simplified force analysis diagram of the shaft segment according to an embodiment of this application; Figure 3 This is a schematic diagram of the three-moment equation for the shaft segment according to an embodiment of this application. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0033] like Figure 1 As shown, the present invention provides a direct bearing load measurement system, including a bearing unit and a measurement unit. The bearing unit includes a bearing to be measured 1, a shaft 2, and a shaft base 3 for support. The measurement unit includes a strain gauge 4, a wireless signal transmitter 5, and a displacement sensor 6. The strain gauge is installed on the shaft surface on both sides of the bearing to be measured and is electrically connected to the wireless signal transmitter. The displacement sensor is installed corresponding to the strain gauge.

[0034] During testing, strain gauges measure axial strain signals, displacement sensors measure longitudinal displacement of the strain gauge cross-section, and then the measured relevant parameter signals are transmitted to the calculation module 7 via a wireless signal transmitter for calculation.

[0035] Furthermore, the strain gauges are connected by a full bridge and bonded to the axial surface, which can effectively reduce the impact of axial bending and has bending resistance characteristics. They are connected to a wireless signal transmitter via wires.

[0036] The displacement sensor is clamped and fixed at the top of the gimbal 8, perpendicular to the cross-section where the strain gauge is bonded. The bottom of the gimbal has a passable electromagnet, which magnetically attaches the sensor to the shaft base, effectively keeping the displacement sensor in the same position. This facilitates efficient measurement of bearing load using the three-moment method.

[0037] Because the structure of a ship's propulsion shafting system is relatively simple, it is easy to simplify the shafting and perform force analysis using relevant structural mechanics knowledge. Then, by establishing the relationship between relevant parameters through force balance and bending moment balance, the bearing load that needs to be solved can be obtained. The three-moment equations, by considering the displacement condition that the relative rotation angle between the left and right sides at each intermediate support on the basic structure should be zero, can establish typical equations with the same number of redundant unknown forces. Each of these typical equations contains at most three redundant unknown forces, and thus, the bending moments at all intermediate supports can be obtained by solving these equations.

[0038] The specific process is as follows: like Figure 2 The diagram shows a simplified force diagram of a shaft segment in a shaft system. The bearing under test is located at point B on the shaft segment, and the adjacent bearings are located at points A and B on the shaft segment, respectively. The equivalent forces of the uniformly distributed loads on the shaft segment are F1 and F2, respectively. The strain gauges are installed at points O and P on the shaft segment. The distances from points F1, O, B, P, F2, and C to point A are X1, X2, X3, X4, X5, and X6, respectively. The simplified force analysis of the shaft segment according to the principle of force balance yields the following equation:

[0039] In the formula, RA R is the supporting force of the bearing at point A. B R represents the support reaction force of the bearing under test. C Let Q be the support reaction force of the bearing at point C. m This is the weight of the shaft segment itself.

[0040] Since the bending moment of the shaft segment cannot be directly measured and needs to be measured indirectly through strain, strain gauges are selected to measure the strain and stress σ of the shaft segment. 测 With strain ε 测 The relationship between them can be represented as:

[0041] In the formula, E is the elastic modulus of the material; ε 测 The strain was measured using a strain gauge.

[0042] At a certain cross-section of the shaft, due to the non-uniform stress distribution caused by strain, the total moment on the cross-section can be calculated by integration. For a circular cross-section shaft segment, the bending moment M on its cross-section is calculated using the following formula:

[0043]

[0044] In the formula, d is the diameter of the shaft segment.

[0045] The above describes the bending moment of the shaft segment obtained through theoretical calculation by measuring the strain signal of the shaft segment.

[0046] like Figure 3 As shown, this represents the bearing displacement under load on the shaft segment. The bearing displacements at points A, B, and C are respectively y A y B y C The included angles caused by bearing displacement are θ A θ B The moment equilibrium equations are obtained as follows;

[0047] In the formula, M B M is the bending moment experienced by the bearing under test. O M P The bending moments are at strain gauges O and P.

[0048] Taking point A as the analysis point, based on the bending moment equilibrium... have:

[0049]

[0050] Taking point B as the analysis point, based on the bending moment equilibrium... have:

[0051]

[0052] The equilibrium equation matrix can be obtained:

[0053] F1 and F2 are the applied concentrated force loads, which can be directly obtained during the experiment. M A M B M C The results are determined by the material properties and can be calculated. Q m This is the self-weight of the shaft segment, which can be directly obtained before the experiment. Therefore, this system of equations consists of three unknowns and three equations. By solving the system of equations, R can be obtained. B Let the equilibrium matrix equation be AR=B, where A, R, and B represent the first, second, and third matrices, respectively. Based on the matrix inverse, we can obtain:

[0054]

[0055]

[0056] By combining the strain, shaft diameter, and spacing parameters obtained from actual measurements, the theoretical support force R of the bearing under test can be directly calculated. B .

[0057] Compared with existing technologies, the measurement system and method described herein have the following advantages: 1. High-precision dynamic measurement: This invention directly measures the strain and displacement of the shaft segment and calculates the bearing support reaction force using an improved three-moment equation, avoiding model errors inherent in traditional indirect measurement methods and significantly improving measurement accuracy. The system employs multi-sensor data fusion technology, effectively eliminating the effects of temperature drift and assembly tolerances, ensuring measurement stability in ambient temperatures ranging from -20℃ to 80℃.

[0058] 2. Superior Real-Time Performance: Thanks to high-speed synchronous sampling and optimized edge computing algorithms, the system's entire process latency from data acquisition to load calculation is controlled within 50ms, meeting the real-time monitoring needs of most industrial scenarios. For sudden impact loads, the system features a specially designed fast response mode. Through pre-triggered caching and a dedicated impact detection algorithm, the latency for capturing and uploading critical events can be reduced to 10ms, providing timely early warnings for safe equipment operation.

[0059] 3. Strong Environmental Adaptability: The system adopts a modular design, with all key components achieving IP67 protection rating, enabling stable operation in harsh environments such as humidity, oil contamination, and high electromagnetic interference. The wireless transmission module supports automatic frequency hopping and adaptive power adjustment, ensuring communication reliability in complex industrial environments, with a measured packet loss rate of <0.01%. It can be equipped with magnetic resonance wireless power supply technology to solve the power supply problem for rotating components, and with supercapacitor energy storage, it can support continuous operation for more than 30 minutes after an external power outage.

[0060] 4. Intelligent Operation and Maintenance Support: The system not only provides real-time load data, but also integrates advanced fault diagnosis functions: the deep learning-based anomaly detection algorithm can automatically identify typical faults such as bearing wear and shaft misalignment, with a diagnostic accuracy of >95%; the digital twin platform realizes three-dimensional visualization monitoring, supports historical load data backtracking and trend prediction; it supports OTA remote upgrades, which can update algorithm models and functional modules at any time, significantly extending the equipment's technical life cycle.

[0061] 5. Significant economic benefits: Compared with traditional measurement solutions, this invention can reduce installation and maintenance costs by about 40%: the wireless design saves more than 90% of cabling costs; the modular structure shortens on-site installation time to less than 2 hours; and the predictive maintenance function can reduce unplanned downtime losses by more than 30%.

[0062] Example 1 In this embodiment, the bearings are asymmetrically arranged, subjected to dual loads, with a shaft diameter d = 120 mm and an elastic modulus E = 2.06 × 10⁻⁶. 11 Pa, F1=8kN, F2=6kN, X1=0.4m, X3=1.2m, X5=2.5m, X6=3.0m, axle self-weight Q m =3kN, strain at point A was measured. =85 .

[0063] The calculated section modulus of the shaft segment is W = 1.70 × 10⁻⁶. -4 m 3 Bending moment M of section A ≈2970 N·m.

[0064] Based on the known parameters, the reaction force R of bearing B is calculated. B ≈-25.2KN.

[0065] Example 2 In this embodiment, the bearings are symmetrically arranged, subjected to a single load, with a shaft diameter d = 100 mm and an elastic modulus E = 2.1 × 10⁻⁶. 11 Pa, F1=10kN, X1=0.5m, X3=1.0m, X6 X3 = 1.0m, the strain at point A is measured. =120 .

[0066] The calculated section modulus of the shaft segment is W = 9.82 × 10⁻⁶. -5 m 3 Bending moment M of section A ≈2470 N·m.

[0067] Based on the known parameters, the reaction force R of bearing B is calculated. B =-X6 / (2X3 2 )·(2F2X3+ Q m X3 + 2F1X1) = -12KN.

Claims

1. A direct bearing load measurement system, characterized in that, The device includes a bearing unit and a measuring unit. The bearing unit includes a bearing to be tested, a shaft, and a shaft base for support. The measuring unit includes a strain gauge, a wireless signal transmitter, and a displacement sensor. The strain gauge is mounted on the shaft surface on both sides of the bearing to be tested and is electrically connected to the wireless signal transmitter. The displacement sensor is mounted corresponding to the strain gauge.

2. The direct bearing load measurement system according to claim 1, characterized in that, The strain gauges are connected by a full bridge and bonded to the axial surface.

3. The direct bearing load measurement system according to claim 2, characterized in that, The displacement sensor is installed directly below the strain gauge and aligned with the center of the strain gauge.

4. The direct bearing load measurement system according to claim 3, characterized in that, The displacement sensor is held and fixed by a clamp on the top of the universal joint located on the shaft base.

5. The direct bearing load measurement system according to claim 4, characterized in that, The bottom of the gimbal is magnetically connected to the shaft base via an electromagnet.

6. A method using the direct bearing load measurement system described in claim 3, 4, or 5, characterized in that, Includes the following steps: Step S1: Simplify the shaft system and perform force analysis on the shaft segment of the bearing under test. Based on the principle of force balance, perform theoretical calculations by measuring the strain signal of the shaft segment to obtain the bending moment of the shaft segment. Step S2: Based on the bending moment of the shaft segment and the measured bearing displacement, calculate the bearing support reaction force according to the three bending moment equations.

7. The method for a direct bearing load measurement system according to claim 6, characterized in that, The calculation process for the bending moment of the shaft segment described in step S1 is as follows: Step S 11 The shaft system is simplified. The bearing to be tested is located at point B on the shaft segment, and the adjacent bearings are located at points A and B on the shaft segment, respectively. The equivalent forces of the uniformly distributed load on the shaft segment are F1 and F2, respectively. The strain gauges are installed at points O and P on the shaft segment. The distances of points F1, O, B, P, F2, and C from point A are X1, X2, X3, X4, X5, and X6, respectively. The simplified shaft segment is subjected to force analysis according to the principle of force balance, resulting in the following equation: In the formula, R A R is the supporting force of the bearing at point A. B R represents the support reaction force of the bearing under test. C Let Q be the support reaction force of the bearing at point C. m For the self-weight of the shaft segment; Step S 12 Since the bending moment of the shaft segment cannot be directly measured and needs to be measured indirectly through strain, strain gauges are selected to measure the strain and stress σ of the shaft segment. 测 With strain ε 测 The relationship between them can be represented as: In the formula, E is the elastic modulus of the material; ε 测 The strain was measured using strain gauges; For a circular cross-section shaft segment, the bending moment M on the cross-section is calculated using the following formula: In the formula, d is the diameter of the shaft segment.

8. The method for a direct bearing load measurement system according to claim 7, characterized in that the calculation process of the bearing support reaction force in step S2 is as follows: Step S 21 When the shaft section bears a load, the bearings at points A, B, and C will experience bearing displacements of y, respectively. A y B y C The included angles caused by bearing displacement are θ A θ B The moment equilibrium equations are obtained as follows; In the formula, M B M is the bending moment experienced by the bearing under test. O M P The bending moments at strain gauges O and P; Taking point A as the analysis point, based on the bending moment equilibrium... have: Taking point B as the analysis point, based on the bending moment equilibrium... have: The equilibrium equation matrix can be obtained: Let the equilibrium matrix equation be AR=B, where A, R, and B represent the first, second, and third matrices, respectively. Based on the matrix inverse, we can obtain: By combining the strain, shaft diameter, and spacing parameters obtained from actual measurements, the theoretical support force R of the bearing under test can be directly calculated. B .

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