Laser detection mechanism for air leakage of railway vehicle pipeline and detection method thereof

Abstract

The invention relates to the technical field of railway vehicle pipeline detection equipment, and discloses a laser detection mechanism for air leakage of a railway vehicle pipeline. The laser detection mechanism comprises a detection gun, a split gun head is installed at the detection end of the detection gun, a laser emission port is formed in the left side of the detection gun, and an infrared receiving window is formed in the right side of the detection gun; a dichroscope is obliquely installed in the middle of the split type gun head, the dichroscope and the split type gun head are inclined by 45 degrees, the dichroscope reflects laser incident from the left side by 90 degrees and emits the laser to a to-be-detected pipeline, and infrared rays radiated by the pipeline penetrate to a window on the right side. According to the detection method of the laser detection mechanism for the air leakage of the railway vehicle pipeline, a detection path is set through the control handle or the control host; the magnetic attraction robot automatically moves along the track, and the multi-axis mechanical arm drives the detection gun to scan according to a preset track; automatically executing infrared scanning and laser detection by the system when delta Tgt is met at the same time; 2 DEG C and gas concentration gt; when the pressure is 100 ppm, the leakage is judged; the detection data is transmitted to the display screen in real time, and a detection report is generated.

Description

Technical Field

[0001] This invention relates to the field of railway vehicle pipeline testing equipment technology, specifically to a laser detection mechanism and method for detecting air leakage in railway vehicle pipelines. Background Technology

[0002] The braking and air suspension systems of rail vehicles rely on high-pressure air pipelines, typically operating at 8-10 bar. During factory testing and long-term exposure to vibration, temperature differences, and aging, minute leaks can easily occur. If these leaks are not detected in time, they can lead to brake failure, increased energy consumption, or even safety accidents.

[0003] Typical leakage scenarios include weld cracks, aging of pipe joint seals, and valve leaks.

[0004] Traditional testing methods include the soap and water bubble method, which involves pressurizing the pipeline to 9.0 bar, manually applying soap and water, observing the location of bubble formation, maintaining the pressure for 30 minutes, and confirming that the pressure drop is ≤0.10 bar. This method requires workers to crawl under the vehicle, brush soap and water at each point, mark the leak point after finding bubbles, and then re-inspect after repair.

[0005] The shortcomings of this method are: low efficiency (it takes 3 hours to inspect a single train and requires 2 skilled workers to cooperate); high false negative rate (the soap water method relies on visual observation of bubbles, which is greatly affected by surface cleanliness and lighting conditions, and cannot detect micro-leaks of <0.5mm); and narrow space under the train, requiring workers to crawl into high-risk areas, which can easily lead to collisions or electric shock accidents.

[0006] There is also ultrasonic leak detection, which uses a microphone to capture high-frequency sound waves (40kHz) of leaks. However, it has a high false alarm rate, such as when detecting noise interference from motors or ventilation systems. The sound source positioning error is >10cm, making it difficult to accurately locate leaks in bolts or welds, resulting in ambiguous positioning.

[0007] Therefore, we propose a laser detection mechanism and method for detecting air leakage in railway vehicle pipelines to address the problems mentioned above. Summary of the Invention

[0008] This invention provides a laser detection mechanism and method for detecting air leaks in railway vehicle pipelines. It can solve the problems of existing technologies that use the soap water bubble method to detect air leaks in railway vehicle pipelines. This method involves manually applying soap water and observing the location of the bubbles. The soap water method relies on visual observation of the bubbles, which leads to a high rate of missed detection and the inability to detect even minor leaks.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A laser detection mechanism for air leakage in pipelines of rail vehicles includes a detection gun, the detection end of which is equipped with a split gun head, with a laser emission port on the left and an infrared receiving window on the right. A dichroic mirror is installed at an angle in the middle of the split-type gun head. The dichroic mirror is tilted at 45° to the split-type gun head. The dichroic mirror reflects the laser incident from the left side at 90° toward the pipe to be tested, while at the same time it transmits the infrared light radiated by the pipe to the window on the right side. It also includes a magnetic robot, which includes a magnetic guide base, on which a multi-axis robotic arm is mounted. The movable end of the multi-axis robotic arm is equipped with a retainer for fixing the detection gun. The back of the detection gun is provided with a quick-release interface that mates with the retainer. The magnetic robot is wirelessly connected to a control handle.

[0010] Preferably, the quick-release interface includes a magnetic positioning ring, which is disposed on the back of the detection gun, and multiple sets of spring pins are disposed on the inner side of the magnetic positioning ring.

[0011] Preferably, the card holder is equipped with a ring electromagnet inside, which magnetically engages with the magnetic positioning ring on the back of the detection gun, and the card holder is equipped with power supply contacts corresponding to the spring pin.

[0012] Preferably, the split-type gun head is equipped with a bracket at its front end, the bracket has an inclined mirror frame, the dichroic mirror is installed in the mirror frame groove of the bracket, and the laser emission port and infrared receiving window are located on both sides of the dichroic mirror.

[0013] Preferably, the magnetic guide base includes a mounting base, with electric push rods fixedly mounted on both sides of the mounting base. A wheel seat is mounted on the telescopic end of the electric push rod, and a magnetic wheel is rotatably connected inside the wheel seat. A stepper motor that drives the magnetic wheel to rotate is fixedly mounted on the wheel seat.

[0014] Preferably, the magnetic wheel includes an outer rubber tire, a middle aluminum alloy hub, and an inner layer of neodymium magnet blocks. The neodymium magnet blocks are arranged in a circumferential array on the inner ring of the aluminum alloy hub, and the neodymium magnet blocks are used for magnetic attraction with the track.

[0015] Preferably, the wheel base is equipped with a control host and an energy storage battery. The control host is used for the drive control and signal processing of the equipment. A display screen is installed on the front of the detection gun. A two-stage trigger is installed on the detection gun. Half-pressing the two-stage trigger on the detection gun activates the infrared detection mode, and the display screen displays the thermal image of the pipe surface in real time. Fully pressing the trigger activates the laser beam emission.

[0016] Preferably, it also includes a detachable reflective prism accessory, which is installed on the front end of the split-type gun head by a snap-fit ​​structure. Its reflective surface forms a 90° angle with the main optical path. Concealed area detection is performed by installing the 90° reflective prism; the probe extends into the back of the pipe.

[0017] A manual detection method based on the laser detection mechanism for air leakage in rail vehicle pipelines according to any one of claims 1-8 includes the following steps: S1. Hold the test gun and aim it at the area of ​​the pipe to be tested; S2. Half-press the dual-stage trigger on the detection gun to activate the infrared detection mode and observe the thermal image of the pipe surface on the display screen; S3. When an abnormal temperature area is detected, press the trigger to emit a laser beam for gas detection; S4. If the detected gas concentration is >100ppm, the detection gun will emit a red light and vibrate as a warning. S5. For concealed areas such as the back of pipes, repeat steps S2-S4 after installing the detachable reflective prism accessory.

[0018] An automatic detection method based on the laser detection mechanism for air leakage in rail vehicle pipelines according to any one of claims 1-8 includes the following steps: S1. Set the detection path via the control handle or control host; S2. The magnetic robot moves automatically along the track, and the multi-axis robotic arm drives the detection gun to scan along the preset trajectory; S3. The system automatically performs infrared scanning and laser detection. When both ΔT>2℃ and gas concentration>100ppm are met, a leak is determined. S4. The test data is transmitted to the display screen in real time, and a test report is generated; S5. For concealed areas, the system prompts you to install the detachable reflective prism accessory and then automatically adjusts the detection parameters.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are: The detection mechanism of this invention adopts a split-type gun head design. The 3.3μm laser beam emitted from the left laser emission port is reflected by a dichroic mirror installed at a 45° angle and then deflected at 90° to precisely target the surface of the pipe to be tested. This wavelength of laser is specifically optimized for the absorption peak of oil vapor in compressed air. At the same time, the 8-14μm infrared radiation radiated from the pipe surface can directly penetrate the dichroic mirror and be captured by the infrared receiving window on the right. Through the dual-optical-path synchronous detection mechanism, the simultaneous verification of laser detection of gas composition and infrared monitoring of temperature changes is achieved, which greatly improves the reliability of detection. The six-axis robotic arm of the magnetic robot has a quick-release interface at its end, which can quickly install the detection gun and facilitate the connection, removal and separation of the detection gun. The magnetic robot uses a magnetic guide base to adhere to the track under the vehicle and moves autonomously. The robotic arm has position compensation capability and can automatically adapt to the curved surface of the pipe. The control system enables human-machine interaction via a wireless handle. The operator only needs to set the detection path, and the system can automatically complete the full vehicle scan. Manual fixed-point operation detection is also possible, which can ensure efficiency and improve detection accuracy. Non-contact detection avoids the risk of manual entry under the vehicle. When detecting hidden areas, a 90° reflecting prism accessory can be quickly installed to rotate the laser by 90°. The detection gun can be quickly installed and removed via the magnetic positioning ring of the quick-release interface and the ring electromagnet of the holding seat. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall external structure of the present invention; Figure 2 This is a schematic diagram of the separation structure of the detection gun and the holder of the present invention; Figure 3 For the present invention Figure 2 A partially enlarged structural diagram; Figure 4 This is a schematic diagram of the split-type gun head structure of the present invention; Figure 5 This is a cross-sectional view of the detection gun of the present invention.

[0021] The components include: 1. Detection gun; 2. Split gun head; 3. Laser emission port; 4. Infrared receiving window; 5. Dichroic mirror; 7. Magnetic guide base; 8. Multi-axis robotic arm; 9. Holder; 11. Control handle; 12. Magnetic positioning ring; 13. Spring pin; 14. Ring electromagnet; 15. Power supply contact; 16. Bracket; 17. Frame; 20. Mounting base; 21. Electric push rod; 22. Wheel seat; 23. Magnetic wheel; 24. Stepper motor; 30. Display screen; 31. Two-stage trigger. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0023] Example 1: Please see Figure 1-5 The present invention provides a technical solution: A laser detection mechanism for air leakage in pipelines of rail vehicles includes a detection gun 1, a split gun head 2 installed at the detection end of the detection gun 1, a laser emission port 3 on the left side and an infrared receiving window 4 on the right side. A dichroic mirror 5 is installed at an angle in the middle of the split-type gun head 2. The dichroic mirror 5 is tilted at 45° to the split-type gun head 2. The dichroic mirror 5 reflects the laser incident from the left side at 90° and directs it toward the pipe to be tested, while at the same time it transmits the infrared radiation radiated by the pipe to the window on the right side. It also includes a magnetic robot, which includes a magnetic guide base 7 for moving along the vehicle guide rail. A multi-axis robotic arm 8 is mounted on the magnetic guide base 7, and a retaining seat 9 is mounted on the movable end of the multi-axis robotic arm 8 for fixing the detection gun 1. The back of the detection gun 1 is provided with a quick-release interface that cooperates with the retaining seat 9. The magnetic robot is wirelessly connected to a control handle 11, which can be remotely controlled without the need for operators to enter under the vehicle.

[0024] The testing mechanism employs a split-type laser head design. A 3.3μm laser beam emitted from the left laser emission port 3 is reflected by a dichroic mirror 5 installed at a 45° angle and then precisely directed at the surface of the pipe under test at a 90° angle. This laser wavelength is specifically optimized for the absorption peak of oil vapor in compressed air. Simultaneously, the 8-14μm infrared radiation radiated from the pipe surface can directly penetrate the dichroic mirror 5 and be captured by the infrared receiving window 4 on the right. Through this dual-optical-path synchronous detection mechanism, simultaneous verification of laser detection of gas composition and infrared monitoring of temperature changes is achieved, significantly improving detection reliability. The six-axis robotic arm mounted on the magnetic robot has a quick-release interface at its end for rapid installation of the testing gun 1, facilitating connection, removal, and separation of the testing gun 1. The magnetic robot uses a magnetic guide base 7 to adhere to the track under the vehicle and moves autonomously. The robotic arm has position compensation capabilities and can automatically adapt to the curved surface of the pipe. The control system enables human-machine interaction via a wireless handle. The operator only needs to set the detection path, and the system can automatically complete a full vehicle scan. Manual spot-checking is also possible, ensuring both efficiency and improved accuracy. Non-contact detection eliminates the risk of manual entry under the vehicle. Dual-sensor collaboration enhances micro-leak detection capabilities, and automated scanning significantly improves detection efficiency. The entire system is easy to operate, requiring only a single person for remote control to complete a full vehicle inspection, achieving safe, accurate, and efficient pipeline leak detection.

[0025] In another embodiment, during actual operation, the inspector first holds the inspection gun 1 at a distance of 30cm from the pipe and half-presses the trigger to activate the infrared scanning mode. Based on the principle of adiabatic expansion and cooling during gas leakage, the detection gun's display screen shows a real-time thermal image of the pipe surface. The system automatically marks areas with abnormal temperatures, which are defined as areas with ΔT > 2℃ and highlighted with a blue box. The infrared receiver window receives light, and the infrared camera identifies all "low-temperature anomaly points" with a temperature difference greater than 2 degrees. These points may be leaks or false signals caused by other factors, such as shadows or different surface materials. The operator aims the equipment at each "low temperature anomaly point" and emits a laser to detect it. Only when the point meets both the conditions of "abnormal temperature" and "excessive oil vapor concentration" is it finally determined to be a leak point.

[0026] At the same time, the system triggers a red light and vibration to complete the confirmation; When a suspected leak is detected (the system automatically marks areas of abnormal temperature), the operator aligns the crosshair with the marked area and fully presses the trigger. At this point, a 3.3μm laser beam is emitted and the gas absorption spectrum is analyzed. The leak was identified through two methods: (1) Leakage can be determined by detecting the characteristic absorption spectrum of CH bonds in oil vapor using a 3.3μm band laser. This relies on the naturally occurring lubricating oil vapor in compressed air as a tracer. Since the air compressor uses lubricating oil for lubrication and cooling during operation, some of the oil will atomize or evaporate and enter the pipeline system with the compressed air. The compressed air inside the pipeline contains trace amounts of oil vapor, while the external ambient air contains almost none.

[0027] (2) To achieve higher reliability, universality and accuracy of detection, an active injection of environmentally friendly specific tracer gas is adopted to ensure the accuracy of detection. Environmentally friendly specific tracer gas such as hexafluoroisobutylene (HFIB) is used.

[0028] This gas possesses environmentally friendly characteristics such as being non-toxic, non-flammable, and having extremely low global warming potential. During detection, the laser wavelength is precisely tuned to the strong infrared absorption peak of HFIB molecules, enabling sensitive detection of extremely low concentrations of the gas at the ppb level at leak points. This method is applicable to all types of compressed air systems and is environmentally friendly.

[0029] For hidden areas such as the back of pipes that are difficult to cover with conventional inspections, a 90° reflecting prism accessory can be quickly installed to rotate the laser beam 90° for inspection. The entire process does not require equipment replacement or complex adjustments.

[0030] By employing a coaxial dual-sensor system—where laser and infrared share the same optical axis—the spatial positions of the two detection methods are completely consistent, avoiding the positioning deviation problems of traditional multi-sensor systems. Secondly, an intelligent hierarchical leak detection strategy is adopted: infrared rapid screening first narrows down the detection range, followed by precise laser verification of suspicious areas, ensuring both detection speed and improved accuracy. Finally, a modular reflective prism design enables seamless switching between routine and concealed area detection. This design reduces the inspection time for a single train to 1 / 10 of traditional methods, while increasing the micro-leak detection rate from less than 50% to over 98%, providing an innovative solution for rail vehicle pipeline maintenance.

[0031] Furthermore, the quick-release interface includes a magnetic positioning ring 12, which is disposed on the back of the detection gun 1, and multiple sets of spring pins 13 are disposed on the inner side of the magnetic positioning ring 12.

[0032] The card holder 9 is equipped with a ring electromagnet 14, which magnetically engages with the magnetic positioning ring 12 on the back of the detection gun 1. The card holder 9 is also equipped with a power supply contact 15 corresponding to the spring pin 13.

[0033] The magnetic positioning ring 12 on the back of the detection gun 1 and the annular electromagnet 14 inside the holder 9 form a magnetic connection mechanism. When the detection gun 1 approaches the holder 9, the magnetic positioning ring 12 and the electromagnet automatically align and attract each other, achieving rapid positioning. At the same time, multiple sets of spring pins 13 on the inner side of the positioning ring form elastic contact with the power supply contacts 15 on the holder 9, establishing an electrical connection path while completing the fixation, realizing power transmission and data communication between the detection gun 1 and the robot. This design ensures the reliability of the connection and achieves convenient plug-and-play operation. When the annular electromagnet 14 inside the holder 9 is energized, it generates a strong magnetic field, which forms a firm attraction with the magnetic positioning ring 12 on the back of the detection gun 1, ensuring that it will not fall off in the vehicle vibration environment. When disassembly is required, simply cut off the power supply to the electromagnet, and the attraction force will immediately disappear. At this time, the detection gun 1 can be separated with a little force. The whole process does not require tool assistance, which greatly improves the efficiency of equipment maintenance and detection mode switching.

[0034] The split-type gun head 2 is equipped with a bracket 16 at its front end. The bracket 16 is provided with an inclined mirror frame 17. The dichroic mirror 5 is installed in the groove of the mirror frame 17 of the bracket 16. The laser emission port 3 and the infrared receiving window 4 are located on both sides of the dichroic mirror 5.

[0035] The bracket 16 at the front end of the split-type gun head 2 is provided with a slanted groove. The dichroic mirror 5 is fixed in the groove by an elastic pressure plate to ensure that the mirror surface and the optical axis form a precise 45° angle. The laser emission port 3 and the infrared receiving window 4 are located on both sides of the mirror surface, with the distance controlled at 27±0.1mm. This layout makes the laser beam spatially orthogonal to the infrared light path after reflection, which not only achieves optical path separation but also ensures the consistency of the detection position. The anti-vibration silicone pad in the groove of the frame 17 can also effectively absorb the influence of mechanical vibration on the optical system.

[0036] In another embodiment, a detachable reflective prism accessory is also included. This accessory is attached to the front end of the split-type gun head 2 via a snap-fit ​​structure. Its reflective surface forms a 90° angle with the main optical path. For concealed area detection, the 90° reflective prism is installed; the probe extends into the back of the pipe. This detachable reflective prism accessory is quickly installed at the front end of the detection gun head via a snap-fit ​​structure. Its reflective surface forms a precise 90° angle with the main optical path. When concealed area detection is required, the operator simply snaps the prism accessory into the gun head. At this time, the laser beam is deflected 90° and directed towards areas difficult to cover by conventional detection, such as the back of the pipe. The principle is similar to a periscope, where the laser beam undergoes two total internal reflections through the prism before being deflected 90°.

[0037] Example 4: Please see Figure 1-2 Furthermore, in conjunction with Embodiment 1, it is further obtained that the magnetic guide base 7 includes a mounting base 20, electric push rods 21 are fixedly mounted on both sides of the mounting base 20, wheel seats 22 are mounted on the telescopic ends of the electric push rods 21, magnetic wheels 23 are rotatably connected inside the wheel seats 22, and a stepper motor 24 for driving the magnetic wheels 23 to rotate is fixedly mounted on the wheel seats 22.

[0038] The magnetic guide base 7 can dynamically adapt to different widths of the vehicle track by extending and retracting the electric push rods 21 on both sides. When a change in track spacing is detected, the main control unit drives the electric push rods 21 to extend and retract synchronously, so that the magnetic wheel 23 always maintains the best adsorption state. The electric push rods 21 on both sides can also be extended and retracted to adjust the lateral position of the multi-axis robotic arm 8 under the vehicle for obstacle avoidance.

[0039] The stepper motor 24 drives the magnetic wheel 23 to rotate through the reduction mechanism, and with the help of encoder feedback, it achieves precise position control to ensure that the detection gun 1 can move smoothly along the track.

[0040] The magnetic wheel 23 includes an outer rubber tire, a middle aluminum alloy hub, and an inner layer of neodymium magnet blocks. The neodymium magnet blocks are arranged in a circumferential array on the inner ring of the aluminum alloy hub and are used for magnetic attraction with the track.

[0041] The magnetic wheel 23 adopts a three-layer composite structure. The outer rubber tire provides friction and grip, the middle aluminum alloy hub ensures structural strength, and the inner ring forms a continuous magnetic field through 8 neodymium magnets arranged at 45° intervals. When the magnetic wheel 23 rotates, it always ensures that at least 2 magnets simultaneously attract the track, generating a total attraction force of ≥200N, which can resist vibration and impact of 10m / s².

[0042] The wheel base 22 houses the control host and energy storage battery. The control host is used for the drive control and signal processing of the equipment. The wheel base 22 integrates the control host and a 48V / 20Ah lithium battery energy storage system. The control host is designed based on the STM32H743 chip. The control host receives handle commands through the CAN bus and coordinates the operation of the stepper motor 24, electric push rod 21 and detection gun 1 in real time.

[0043] The working principle of the laser leak detection mechanism for railway vehicle pipelines is as follows: The split-type gun head 2 of the detection gun 1 emits a 3.3μm laser beam through the laser emission port 3 on the left side. After being reflected by the dichroic mirror 5 installed at a 45° angle, the beam is directed perpendicularly towards the surface of the pipeline. At the same time, the 8-14μm infrared radiation emitted by the pipeline penetrates the dichroic mirror 5 and is captured by the infrared receiving window 4 on the right side, realizing the simultaneous verification of laser gas detection and infrared temperature monitoring. The magnetic guide base 7 of the magnetic robot adjusts the distance between the magnetic wheels 23 through the electric push rods 21 on both sides, so that the circumferential array Neodymium magnets distributed in a specific pattern are firmly attached to the track under the vehicle. Stepper motor 24 drives magnetic wheel 23 to move along the track. At the same time, multi-axis robotic arm 8 drives the detection gun 1 fixed by the holder 9 to perform three-dimensional scanning. When detecting hidden areas, a 90° reflecting prism accessory can be quickly installed to refract the laser by 90°. The detection gun 1 can be quickly installed and removed from the holder 9 via the magnetic positioning ring 12 of the quick-release interface and the annular electromagnet 14. The control host coordinates the work of each module. The operator can complete the non-contact and precise detection of the entire vehicle pipeline through a wireless handle.

[0044] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A laser detection mechanism for air leakage in railway vehicle pipelines, characterized in that, The device includes a detection gun (1), the detection end of which is equipped with a split gun head (2), a laser emission port (3) on the left side and an infrared receiving window (4) on the right side. A dichroic mirror (5) is installed at an angle in the middle of the split-type gun head (2). The dichroic mirror (5) is tilted at 45° to the split-type gun head (2). The dichroic mirror (5) reflects the laser incident from the left side at 90° toward the pipe to be tested, and at the same time, it transmits the infrared radiation radiated by the pipe to the right window. It also includes a magnetic robot, which includes a magnetic guide base (7), a multi-axis robotic arm (8) is mounted on the magnetic guide base (7), and a retainer (9) is mounted on the movable end of the multi-axis robotic arm (8). The retainer (9) is used to fix the detection gun (1). The back of the detection gun (1) is provided with a quick-release interface that cooperates with the retainer (9). The magnetic robot is wirelessly connected to a control handle (11).

2. The laser detection mechanism for pipeline leakage in rail vehicles according to claim 1, characterized in that: The quick-release interface includes a magnetic positioning ring (12), which is located on the back of the detection gun (1). Multiple sets of spring pins (13) are provided inside the magnetic positioning ring (12).

3. The laser detection mechanism for air leakage in rail vehicle pipelines according to claim 2, characterized in that: The card holder (9) is equipped with a ring electromagnet (14), which magnetically engages with the magnetic positioning ring (12) on the back of the detection gun (1), and the card holder (9) is equipped with a power supply contact (15) corresponding to the spring pin (13).

4. The laser detection mechanism for pipeline leakage in rail vehicles according to claim 1, characterized in that: The split-type gun head (2) is equipped with a bracket (16) at the front end. The bracket (16) is provided with an inclined mirror frame (17). The dichroic mirror (5) is installed in the groove of the mirror frame (17) of the bracket (16). The laser emission port (3) and the infrared receiving window (4) are located on both sides of the dichroic mirror (5).

5. The laser detection mechanism for pipeline leakage in rail vehicles according to claim 1, characterized in that: The magnetic guide base (7) includes a mounting base (20), electric push rods (21) are fixedly installed on both sides of the mounting base (20), a wheel seat (22) is installed at the telescopic end of the electric push rod (21), a magnetic wheel (23) is rotatably connected inside the wheel seat (22), and a stepper motor (24) for driving the magnetic wheel (23) to rotate is fixedly installed on the wheel seat (22).

6. The laser detection mechanism for pipeline leakage in rail vehicles according to claim 5, characterized in that: The magnetic wheel (23) includes an outer rubber tire and a middle aluminum alloy hub, as well as an inner layer of neodymium magnet blocks. The neodymium magnet blocks are arranged in a circumferential array on the inner ring of the aluminum alloy hub. The neodymium magnet blocks are used for magnetic attraction with the track.

7. The laser detection mechanism for pipeline leakage in rail vehicles according to claim 6, characterized in that: The wheel seat (22) is equipped with a control host and an energy storage battery. The control host is used for the drive control and signal processing of the equipment. The front of the detection gun (1) is equipped with a display screen (30). The detection gun (1) is equipped with a two-stage trigger (31). Half-pressing the two-stage trigger (31) on the detection gun (1) activates the infrared detection mode. The display screen (30) displays the thermal image of the pipe surface in real time. Full-pressing the trigger activates the laser beam emission.

8. The laser detection mechanism for pipeline leakage in rail vehicles according to claim 5, characterized in that: It also includes a detachable reflective prism accessory, which is installed on the front end of the split gun head (2) by a snap-fit ​​structure. Its reflective surface forms a 90° angle with the main optical path. For concealed area detection, a 90° reflective prism is installed; the probe extends into the back of the pipe.

9. A manual detection method based on the laser detection mechanism for pipeline leakage in rail vehicles according to any one of claims 1-8, characterized in that... Includes the following steps: S1. Hold the test gun (1) and aim it at the pipe area to be tested; S2. Press the dual-stage trigger (31) on the detection gun (1) halfway to start the infrared detection mode and observe the thermal image of the pipe surface through the display screen (30); S3. When an abnormal temperature area is detected, press the trigger to emit a laser beam for gas detection; S4. If the detected gas concentration is >100ppm, the detection gun (1) will emit a red light and vibrate to indicate that the gas concentration is >100ppm. S5. For concealed areas such as the back of pipes, repeat steps S2-S4 after installing the detachable reflective prism accessory.

10. An automatic detection method based on the laser detection mechanism for pipeline leakage in rail vehicles according to any one of claims 1-8, characterized in that... Includes the following steps: S1. Set the detection path via the control handle (11) or the control host; S2. The magnetic robot moves automatically along the track, and the multi-axis robotic arm (8) drives the detection gun (1) to scan along the preset trajectory; S3. The system automatically performs infrared scanning and laser detection. When both ΔT>2℃ and gas concentration>100ppm are met, a leak is identified. S4. The detection data is transmitted to the display screen (30) in real time, and a detection report is generated; S5. For concealed areas, the system prompts you to install the detachable reflective prism accessory and automatically adjusts the detection parameters.

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