Bullet train hollow shaft inner hole integrated nondestructive testing method adaptive to step structure

Abstract

The invention relates to the technical field of nondestructive testing, and discloses a bullet train hollow shaft inner hole integrated nondestructive testing method matched with a step structure. According to the method, a probe assembly integrated with a positioning sensor, an eddy current sensor, a magnetic memory sensor, an ultrasonic sensor and a visual sensor is adopted, and detection is automatically executed based on preset step axial coordinates. The probe firstly moves to the position of a target step, and image recognition and centering verification are carried out through a visual sensor; then a coupling agent supply system is started, and a coupling film layer is formed between the ultrasonic sensor and the hole wall; then controlling the probe to perform forward and reverse rotary scanning, synchronously acquiring ultrasonic, eddy current, magnetic memory and visual data, and binding with the rotation angle; according to the method, fixed-point, stable and synchronous detection is carried out on the known high-risk area, low-efficiency global scanning is replaced, controllability and optimization of the coupling state are achieved, the detection efficiency, reliability and defect detection rate are remarkably improved, and the method is particularly suitable for accurate and efficient comprehensive evaluation of the internal step area of the hollow shaft of the bullet train.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, and in particular to an integrated nondestructive testing method for the inner hole of a hollow axle of a high-speed train that is adapted to a stepped structure. Background Technology

[0002] The internal inspection of hollow axles in high-speed trains is one of the core aspects of ensuring their operational safety. The steps (unloading grooves) within the axle bore, due to abrupt geometric changes, result in high stress concentration and are a primary area for the initiation and propagation of fatigue cracks, making them a crucial focus of internal non-destructive testing. Currently, the mainstream testing technology for this area is ultrasonic testing, often supplemented by eddy current or video testing for surface verification.

[0003] Existing automated internal hole inspection solutions generally employ a uniform scanning mode covering the entire surface. Typically, a detection assembly integrating ultrasonic or eddy current probes is pushed into the axle's internal hole. As the assembly moves forward at a constant speed, the axle itself or the probe assembly rotates at a constant speed, thus achieving a spiral-like, full-coverage scan of the entire internal hole surface. However, this mode has revealed the following significant drawbacks in practice:

[0004] (1) Low inspection efficiency: In order to achieve the coverage required by the inspection standard, the entire inner hole length must be scanned slowly and continuously. The inspection time of a single axle is usually as long as ten minutes or even longer, which cannot meet the needs of large-scale and high-efficiency maintenance.

[0005] (2) Damage to the reliability of detection in critical parts: During continuous movement, the coupling state between the ultrasonic probe and the inner wall of the borehole (usually achieved through a water film or rolling coupler) is prone to fluctuation. In critical step areas, poor coupling may lead to signal loss or misjudgment. At the same time, mechanical couplers wear out severely under long-term friction, resulting in short lifespan and high maintenance costs.

[0006] (3) Complex equipment and motion logic: In order to realize the rotation and forward movement of the probe in the narrow inner hole, a complex propulsion-rotation mechanism and corresponding cable management scheme need to be designed. The mechanism is complex and has a high failure rate.

[0007] Based on the above-mentioned technical problems, this invention proposes a novel detection method. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides an integrated non-destructive testing method for the inner bore of hollow axles in high-speed trains, adapted to stepped structures. This invention is implemented as follows:

[0009] A non-destructive testing method for the inner hole of a hollow axle of a high-speed train with a stepped structure is provided. This method employs a probe assembly integrating a positioning sensor, an eddy current sensor, a magnetic memory sensor, an ultrasonic sensor, and a vision sensor for alignment and verification. The method automatically executes the following steps according to a preset program:

[0010] S0: Based on the drawing data of the hollow shaft under inspection, the axial coordinates of each inner hole step are pre-set into the control system;

[0011] S1: Drive the probe assembly to move from the current position or from the end of the shaft hole to the current target step coordinates; during this movement, activate the positioning sensor for position feedback and path recording, while keeping the ultrasonic coupling system in a non-working state;

[0012] S2: After the probe assembly moves to the axial position corresponding to the target coordinates, it stops and performs image recognition and position verification on the step structure through the vision sensor used for alignment and verification; then, the posture of the probe assembly is adjusted or confirmed to align it with the inner hole axis;

[0013] S3: Start the coupling agent supply system to supply liquid coupling agent to the ultrasonic sensor coupling interface of the probe assembly, so that it forms a continuous coupling film between the ultrasonic sensor and the inner hole wall.

[0014] S4: Under stable coupling conditions, control the probe assembly to rotate and scan around its own axis; the rotation scan includes one forward rotation and one reverse rotation, each rotation covering at least 180 degrees; during the rotation, the detection data of the ultrasonic sensor, eddy current sensor, and magnetic memory sensor are simultaneously triggered and acquired, and the visual image data of the inner hole surface is simultaneously acquired; all acquired data are bound to the real-time acquired rotation angle information;

[0015] S5: After completing the rotational scan, data acquisition is stopped, the coupling agent supply system stops supplying liquid, and the probe assembly returns to its movable state;

[0016] S6: Determine whether all preset step positions in step S0 have been detected; if not, set the next step position to be detected as the current target coordinates and return to step S1.

[0017] Furthermore, in step S1, the positioning sensor records the absolute displacement through a contact-type encoder wheel to achieve axial coarse positioning and stroke feedback of the probe assembly; the probe assembly also integrates a wide-angle camera sensor for environmental recording and auxiliary positioning during movement.

[0018] Furthermore, in step S2, the vision sensor for alignment and verification is a macro vision sensor; the adjustment or confirmation of the probe assembly's posture is achieved by processing the image obtained by the macro vision sensor, determining the relative position of the probe and the inner hole, and providing prompts or automatic fine-tuning accordingly.

[0019] Furthermore, in step S3, the supplied liquid coupling agent is a special ultrasonic coupling oil; the coupling process is achieved by filling a flexible cavity surrounding the ultrasonic sensor with the coupling oil, causing it to expand and adhere to the inner wall of the cavity.

[0020] Furthermore, in step S4:

[0021] The ultrasonic sensor includes a pair of 45° shear wave angle probes with opposite emission directions and a 70° dual-crystal focused shear wave probe.

[0022] The eddy current sensor is a circumferentially arranged eddy current sensor array;

[0023] The magnetic memory sensor is a pair of magnetic memory probes symmetrically distributed at 180°.

[0024] Furthermore, during the rotation synchronization data acquisition process in step S4:

[0025] The pair of 45° shear wave angle probes and the 70° dual-crystal focusing shear wave probe operate at a repetition frequency that matches the rotational scanning speed, ensuring that their sound beams form a continuous rotational scanning coverage of the step root region.

[0026] The eddy current sensor array operates in a multi-channel differential mode to detect discontinuities on and near the surface of the inner hole.

[0027] The pair of magnetic memory probes continuously measure the circumferential distribution of the tangential component of the geomagnetic field.

[0028] Furthermore, in step S4, the scanning speed of forward and reverse rotation is consistent with the data sampling rate, and the data obtained from the two scans are used for mutual comparison and verification.

[0029] Furthermore, in step S6, the judgment logic is based on the comparison between the completed detection location list and the preset list of all coordinates in step S0.

[0030] Furthermore, the method also includes: comparing and correlating ultrasonic, eddy current, and magnetic memory data collected at the same step location with visual image data collected synchronously in step S4 based on their bound angle and position information, and generating a comprehensive detection result accordingly.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) Significantly improve detection efficiency

[0033] Unlike conventional and inefficient full-area continuous scanning modes, this invention uses key area location detection based on preset step coordinates to achieve rapid and focused inspection of known high-risk areas, significantly reducing detection time while ensuring full coverage.

[0034] (2) Solving the problems of unstable coupling state and component wear

[0035] This invention employs an active coupling supply method that "shuts down during movement and starts on demand during detection," establishing a stable and uniform coupling film layer only at the detection point. This fundamentally avoids the problems of coupling medium loss and fluctuation during long-distance movement and the resulting signal unreliability caused by traditional methods, while also significantly reducing the wear and maintenance costs of coupling components.

[0036] (3) Effectively ensure the consistency of probe detection posture

[0037] This invention utilizes a vision sensor integrated into the probe for real-time image recognition and alignment verification, enabling precise alignment of the probe axis and the inner hole axis in a narrow inner hole space, thus ensuring the consistency of sensor posture in each test.

[0038] (4) Achieve accurate fusion and comprehensive evaluation of multi-physics information

[0039] This invention overcomes the problems of signal asynchrony and positioning deviation in step-by-step detection by synchronously triggering and acquiring ultrasonic, eddy current, magnetic memory, and visual data at fixed points, and ensuring that all data are strictly bound to spatial location. The deep fusion of multi-source data makes defect identification and stress state assessment more comprehensive and accurate, providing strong quantitative evidence for the safety assessment and predictive maintenance of axle inner bores. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the present invention or the prior art, or to provide a simple description of the drawings used in the prior art, it is obvious that those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0041] Figure 1 This is a flowchart of the detection method in this embodiment.

[0042] Figure 2 This is a schematic diagram of the planar structure of a detection device according to this embodiment.

[0043] Figure 3 This embodiment presents a three-dimensional structural diagram of a detection device. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0045] This embodiment, in conjunction with the accompanying drawings, will provide a detailed description of the integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as proposed in this invention. The core of this method lies in: for the known high-risk area of ​​the inner hole step, a strategy of "key point positioning - visual alignment - on-demand coupling - fixed-point rotation scanning" is adopted to replace the conventional continuous full-area scanning, thereby systematically solving problems such as low efficiency, unstable coupling, and easy wear of components.

[0046] like Figure 1 As shown in the flowchart of the detection method, the automatic execution of the method of the present invention includes the following core steps:

[0047] Step S0: Detection planning and parameter preset.

[0048] Before the inspection begins, the operator or the system pre-sets the precise axial coordinates of each inner hole step into the central control system based on the engineering drawings of the hollow shaft being inspected. The system then generates an ordered queue of inspection points and loads the corresponding sensor parameters and motion control parameters, creating a task map for automated inspection.

[0049] Step S1: Axial movement and coarse positioning.

[0050] According to the path planned in step S0, the control system drives the probe assembly to move from the end of the shaft hole or its current position towards the coordinates of the first target step. During this process, the axial positioning unit integrated with the probe (preferably a contact-type encoder wheel) is activated for real-time position feedback and travel recording to ensure the linearity of movement and the reliability of positioning. Simultaneously, to ensure movement safety and efficiency, the ultrasonic coupling system is in a non-operating state during this stage (i.e., no coupling agent is supplied). Optionally, the wide-angle camera unit integrated with the probe operates synchronously, providing continuous images of the internal environment for auxiliary navigation and macroscopic condition monitoring.

[0051] Step S2: Precise positioning and attitude alignment.

[0052] Once the probe assembly moves to near the axial coordinates of the target step and stops, the alignment and verification vision unit is activated. This unit images the inner wall of the bore and the edge of the step, and the control system runs an image processing algorithm. By identifying step features, it verifies the deviation between the actual position and the preset coordinates, and accurately calculates the offset and tilt angle between the probe axis and the inner hole axis. Based on the calculation results, the detection system can guide the manual or automatic fine-tuning mechanism to adjust the probe assembly's posture, achieving precise alignment with the inner hole axis and ensuring spatial consistency of subsequent detection signals.

[0053] Step S3: Establishment of the ultrasonic coupling interface.

[0054] After alignment is completed, the control system activates the couplant supply system. The system pumps a dedicated liquid ultrasonic couplant (such as coupling oil) through the delivery pipeline into the flexible coupling cavity in front of the ultrasonic testing unit at the probe head. The continuous filling of the couplant causes the flexible cavity to expand until its outer surface adheres tightly and evenly to the inner wall of the cavity. This forms a continuous, stable, and bubble-free coupling film between the ultrasonic sensor wafer and the testing surface, creating the necessary conditions for high-quality ultrasonic testing.

[0055] Step S4: Rotational scanning and simultaneous acquisition of multimodal data.

[0056] After confirming that the coupling state is stable, the control system commands the probe assembly to perform a rotational scan around its own axis. This scan typically includes one forward rotation and one reverse rotation, with each rotation covering at least 180 degrees of the circumference to ensure complete coverage of the step circumference.

[0057] During the rotational scan:

[0058] The system uses a unified clock source to synchronously trigger the ultrasonic testing unit, eddy current testing unit, and magnetic memory testing unit to acquire data, and simultaneously records the inner hole surface image of the alignment and verification vision unit.

[0059] Sensor operating modes:

[0060] Ultrasonic unit: Preferably configured with a pair of 45° shear wave angle probes with opposite emission directions and a 70° dual-crystal focused shear wave probe. They operate at a pulse repetition frequency matched to the rotation speed, and the sound beam achieves rotating scanning coverage of the root of the step.

[0061] Eddy current unit: Employs a circumferentially arranged array of sensors, operating in multi-channel differential mode, to sensitively capture discontinuous defect signals on and near the surface.

[0062] Magnetic memory unit: It consists of a pair of magnetically sensitive probes symmetrically distributed at 180°, which continuously measure the distribution changes of the tangential component of the geomagnetic field and locate stress concentration areas.

[0063] Data binding: All collected sensor data and image data are strictly bound to the rotation angle information fed back in real time by the rotary encoder to ensure that each data point corresponds to a specific spatial orientation.

[0064] Step S5: End of single-point detection and reset.

[0065] After completing forward and reverse rotation scanning of a step position, the control system stops all data acquisition tasks. Subsequently, the control coupling agent supply system stops supplying fluid and can selectively recycle the coupling agent in the flexible cavity, causing the cavity to shrink and the probe assembly to return to a freely movable state, preparing it for movement to the next detection point.

[0066] Step S6: Loop judgment and task management.

[0067] The control system compares the currently completed detection positions with the list of all step coordinates preset in step S0. If there are undetected steps, the system automatically sets the next target coordinate as the current task and returns to step S1 to start a new round of positioning-alignment-coupling-scanning process. This cycle continues until all preset step positions have been detected.

[0068] Step S7: Data fusion and comprehensive evaluation.

[0069] After all points have been inspected, the control system runs a data fusion algorithm. This algorithm spatially correlates and compares ultrasonic, eddy current, and magnetic memory data collected at the same step location with simultaneously acquired visual image data, based on their associated angle and axial position information. By comprehensively analyzing the characteristics and correlations of different physical field signals, the system can generate more comprehensive and reliable inspection results, such as the type, size, orientation of defects, and their stress environment, ultimately forming a structured comprehensive inspection report.

[0070] Reference Appendix Figure 2-3 The present invention also discloses a detection device for implementing the detection method of the present invention. The detection device 10 mainly consists of four parts: an integrated probe assembly 11, a drive and motion mechanism 12, a coupling agent supply system, and a central control system. The components are interconnected by mechanical, fluid, and electrical means to form a coordinated organic whole.

[0071] The integrated probe assembly 11 serves as the core detection unit, and its housing is a slender cylindrical rod-shaped structure. The rear end of the housing is connected to the external drive control unit and the coupling agent supply system via a composite cable bundle containing power and signal lines, as well as a fluid delivery pipeline. The housing surface integrates axial positioning units (such as contact-type encoder wheels), while the front detection head integrates, in a specific layout, an alignment and verification vision unit, an ultrasonic detection unit, an eddy current detection unit, and a magnetic memory detection unit.

[0072] The drive and motion mechanism 12 is mechanically fixed to the rear end of the probe assembly housing via the support arm on its axial feed unit, and is responsible for providing power for the axial movement and rotational scanning of the probe.

[0073] Specifically:

[0074] The axial feed unit drives the entire probe assembly to move linearly along the axis of axle 20.

[0075] The rotary scanning unit directly drives the transmission shaft connected to the probe housing, causing the probe to rotate around its own axis.

[0076] Each servo motor and encoder in the device is connected to the central control system via cables to receive motion commands and provide position information.

[0077] The coupling agent supply system is directly connected to a flexible coupling cavity inside the probe assembly via its delivery conduit. This cavity surrounds the front of the probe wafer of the ultrasonic testing unit. The system's pump valve actuators, controlled by a central control system, precisely supply or recover coupling agent into the cavity according to the testing sequence.

[0078] The central control system, as the core of the overall control, coordinates all components through electrical connections:

[0079] Its motion control module is connected to each motor of the drive and motion mechanism via a driver.

[0080] Its data acquisition module is connected to each detection unit (visual, ultrasonic, eddy current, magnetic memory) and encoder in the probe assembly via a high-speed bus to realize synchronous acquisition of excitation transmission and signal.

[0081] Its logic control module is connected to the pumps and valves of the coupling agent supply system via I / O interfaces.

[0082] Its data processing module runs dedicated software, which is responsible for receiving visual images, performing centering analysis, and fusing multimodal detection data to finally generate a detection report.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, characterized in that, A probe assembly integrating a positioning sensor, an eddy current sensor, a magnetic memory sensor, an ultrasonic sensor, and a vision sensor for alignment and verification is used to automatically execute the following steps according to a preset program: S0: Based on the drawing data of the hollow shaft under inspection, the axial coordinates of each inner hole step are pre-set into the control system; S1: Drive the probe assembly to move from the current position or from the end of the shaft hole to the current target step coordinates; during this movement, activate the positioning sensor for position feedback and path recording, while keeping the ultrasonic coupling system in a non-working state; S2: After the probe assembly moves to the axial position corresponding to the target coordinates, it stops and performs image recognition and position verification on the step structure through the vision sensor used for alignment and verification; then, the posture of the probe assembly is adjusted or confirmed to align it with the inner hole axis; S3: Start the coupling agent supply system to supply liquid coupling agent to the ultrasonic sensor coupling interface of the probe assembly, so that it forms a continuous coupling film between the ultrasonic sensor and the inner hole wall. S4: Under stable coupling conditions, control the probe assembly to rotate and scan around its own axis; the rotation scan includes one forward rotation and one reverse rotation, each rotation covering at least 180 degrees; during the rotation, the detection data of the ultrasonic sensor, eddy current sensor, and magnetic memory sensor are simultaneously triggered and acquired, and the visual image data of the inner hole surface is simultaneously acquired; all acquired data are bound to the real-time acquired rotation angle information; S5: After completing the rotational scan, data acquisition is stopped, the coupling agent supply system stops supplying liquid, and the probe assembly returns to its movable state; S6: Determine whether all preset step positions in step S0 have been detected; if not, set the next step position to be detected as the current target coordinates and return to step S1.

2. The integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in claim 1, is characterized in that... In step S1, the positioning sensor records the absolute displacement through a contact encoder wheel to achieve axial coarse positioning and stroke feedback of the probe assembly; the probe assembly also integrates a wide-angle camera sensor for environmental recording and auxiliary positioning during movement.

3. The integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in claim 1, is characterized in that... In step S2, the alignment and verification visual sensor is a macro vision sensor; the adjustment or confirmation of the probe assembly's posture is achieved by processing the image obtained by the macro vision sensor, determining the relative position of the probe and the inner hole, and providing prompts or automatic fine-tuning accordingly.

4. The integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in claim 1, is characterized in that... In step S3, the supplied liquid coupling agent is a special ultrasonic coupling oil; the coupling process is achieved by filling a flexible cavity surrounding the ultrasonic sensor with the coupling oil, causing it to expand and adhere to the inner wall of the cavity.

5. The integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in claim 1, is characterized in that... In step S4: The ultrasonic sensor includes a pair of 45° shear wave angle probes with opposite emission directions and a 70° dual-crystal focused shear wave probe. The eddy current sensor is a circumferentially arranged eddy current sensor array; The magnetic memory sensor is a pair of magnetic memory probes symmetrically distributed at 180°.

6. The integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in claim 5, is characterized in that... During the rotation synchronization data acquisition process in step S4: The pair of 45° shear wave angle probes and the 70° dual-crystal focusing shear wave probe operate at a repetition frequency that matches the rotational scanning speed, ensuring that their sound beams form a continuous rotational scanning coverage of the step root region. The eddy current sensor array operates in a multi-channel differential mode to detect discontinuities on and near the surface of the inner hole. The pair of magnetic memory probes continuously measure the circumferential distribution of the tangential component of the geomagnetic field.

7. The integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in claim 1, is characterized in that... In step S4, the scanning speed of forward and reverse rotation is consistent with the data sampling rate, and the data obtained from the two scans are used for mutual comparison and verification.

8. The integrated non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in claim 1, is characterized in that... In step S6, the judgment logic is based on the comparison between the completed detection location list and the preset list of all coordinates in step S0.

9. A non-destructive testing method for the inner hole of a hollow axle of a high-speed train adapted to a stepped structure, as described in any one of claims 1-8, characterized in that... The method further includes: comparing and correlating ultrasonic, eddy current, and magnetic memory data collected at the same step location with visual image data collected synchronously in step S4 based on their bound angle and position information, and generating a comprehensive detection result accordingly.

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