Visual detection tool and method for inspection and repair of ac-dc socket of motor train unit

Abstract

The application discloses a kind of visual detection tool and method for EMU AC-DC socket maintenance, belongs to the technical field of EMU AC-DC socket maintenance, including insulating shell, AC detection unit, DC detection unit, switch, display unit and detection plug-in assembly, AC, DC detection unit and switch are arranged in the inside of insulating shell, display unit is arranged on the outer surface of shell, the operating part of switch is exposed to shell, the common end of switch is connected with the first power terminal of detection plug-in assembly, and the input positive terminal of two types of detection units is branched from two output ends;The input negative terminal of two types of detection units, the common end of display unit are connected with the second power terminal, the signal output end is connected with the input end of display unit, detection plug-in assembly is connected with shell through connecting part, and plug-in end can be plugged with the socket to be measured.

Description

Technical Field

[0001] This invention belongs to the field of AC / DC socket maintenance technology for high-speed trains, specifically relating to a visual inspection tooling and method for AC / DC socket maintenance of high-speed trains. Background Technology

[0002] The power outlets in the passenger compartment of high-speed trains provide power interfaces for passengers and onboard equipment, and are a key item in the daily maintenance of high-speed trains. Currently, both AC and DC power outlets are installed in the interiors of Type 2 high-speed trains, and the existing maintenance methods generally have the following problems: 1. Existing testing tools are separate and lack versatility. AC sockets and DC sockets need to be tested with AC voltmeters and DC voltmeters respectively. This requires carrying many tools and switching frequently, which is not conducive to rapid inspection. 2. Currently, measuring the voltage of sockets on high-speed trains requires opening the distribution cabinet to locate the socket circuit and using a multimeter to measure the total voltage of the socket circuit in the entire carriage. This method can only determine the circuit status and cannot accurately locate the faulty socket. For a single socket fault, the circuit needs to be checked section by section, which is time-consuming and difficult.

[0003] 3. Existing multimeters are large, benchtop devices, lacking lightweight and drop-resistant structural designs for the confined spaces of high-speed train carriages, making them inconvenient to carry and use. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of existing testing tools for AC / DC sockets of high-speed trains being separate, having poor versatility, being time-consuming to operate, being difficult to operate, and being inconvenient to carry and use. This invention proposes a visual testing fixture and method for the maintenance of AC / DC sockets of high-speed trains.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a visual inspection fixture for the maintenance of AC / DC sockets in high-speed trains, including an insulating shell, an AC detection unit, a DC detection unit, a switching switch, a display unit, and a detection plug-in assembly; The AC detection unit, DC detection unit, and changeover switch are all housed inside an insulating housing. The display unit is disposed on the outer surface of the insulating housing; The switch is equipped with an operating part, which is exposed outside the insulating housing; The detection plug-in assembly is provided with a first power terminal and a second power terminal. The detection plug-in assembly is connected to the insulating shell through a connecting part. The plug-in terminal of the detection plug-in assembly is plugged into the socket under test. The common terminal of the switch is electrically connected to the first power terminal of the detection plug-in assembly, and the two output terminals of the switch are electrically connected to the positive input terminal of the AC detection unit and the positive input terminal of the DC detection unit, respectively. The negative input terminal of the AC detection unit and the negative input terminal of the DC detection unit are both electrically connected to the second power terminal of the detection plug-in assembly; the signal output terminal of the AC detection unit and the signal output terminal of the DC detection unit are both electrically connected to the signal input terminal of the display unit. The common terminal of the display unit is electrically connected to the second terminal of the detection plug-in assembly.

[0006] Furthermore, the switching switch is a single-pole double-throw switch.

[0007] Furthermore, the display unit includes a first display screen and a second display screen. The signal input terminal of the first display screen is electrically connected to the signal output terminal of the AC detection unit, and the signal input terminal of the second display screen is electrically connected to the signal output terminal of the DC detection unit.

[0008] Furthermore, the connecting part is a flexible connecting part, and the plug-in end of the detection plug-in assembly is provided with a plug-in plate structure, which is plugged into and cooperates with two-hole sockets and three-hole sockets.

[0009] Furthermore, the insulating housing includes a housing body and a cover plate. The cover plate has multiple fixing holes at its corners, and the cover plate is fixedly connected to the housing body by fasteners passing through the fixing holes.

[0010] Furthermore, a sealing element is provided between the main body of the housing and the cover plate, and the sealing element is arranged circumferentially along the cover plate.

[0011] Furthermore, the insulating housing is provided with a first mounting cavity and a second mounting cavity that are isolated from each other. The AC detection unit is housed in the first mounting cavity, and the DC detection unit is housed in the second mounting cavity.

[0012] Furthermore, the connecting part is provided with a universal joint, the detection plug-in assembly is connected to the universal joint, and the detection plug-in assembly is rotatably connected to the insulating shell through the universal joint.

[0013] Furthermore, all edges and corners of the insulating shell are rounded.

[0014] Secondly, the present invention provides a visual inspection method for the maintenance of AC / DC sockets in high-speed trains, which uses a visual inspection fixture for the maintenance of AC / DC sockets in high-speed trains for inspection, and includes the following steps: The operating unit of the switch selects the circuit between the AC detection unit and the detection plug-in assembly, or selects the circuit between the DC detection unit and the detection plug-in assembly. Connect the connector of the test connector to the socket under test; The selected AC or DC detection unit acquires the voltage signal of the socket under test; The display unit receives voltage signals and outputs them for display.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This invention proposes a visual testing fixture for the maintenance of AC and DC sockets in high-speed trains. It integrates an AC testing unit, a DC testing unit, a switch, and a display unit within an insulating housing. The switch allows for selective conduction of the AC and DC testing circuits. One fixture can cover the testing needs of both AC and DC sockets in high-speed trains, eliminating the need to carry separate testing instruments, effectively reducing the amount of tools required and simplifying on-site operations. The fixture uses a direct-plug design for the testing socket, enabling direct voltage testing of individual sockets without disassembling the distribution cabinet to check the circuits of the entire carriage. This allows for quick and accurate location of faulty sockets, significantly shortening the troubleshooting cycle. The integrated handheld design is compact and easy to operate with one hand, adapting to the confined working space of high-speed train carriages. The display unit outputs test results in real time, providing clear and intuitive readings, reducing the difficulty of manual judgment, and effectively improving the efficiency and accuracy of high-speed train socket maintenance. This meets the standardized operation requirements of various scenarios such as depot inspection and patrol inspection. Attached Figure Description

[0016] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0017] Figure 1 This is a schematic diagram of the external structure of a visual inspection fixture for the maintenance of AC / DC sockets in high-speed trains according to the present invention.

[0018] Figure 2 This is a schematic diagram of the internal structure of a visual inspection fixture for the maintenance of AC / DC sockets in high-speed trains, according to the present invention.

[0019] Figure 3 This is a schematic diagram of the cover plate structure of a visual inspection fixture for the maintenance of AC / DC sockets in high-speed trains according to the present invention.

[0020] Figure 4 This is a schematic diagram of a visual inspection fixture for the maintenance of AC / DC sockets in high-speed trains, according to the present invention.

[0021] Among them, 11-first display screen; 12-second display screen; 13-insulating housing; 14-detection input terminal interface; 15-operation unit; 21-AC detection unit; 22-visual display module mounting cavity; 23-DC detection unit; 24-changeover switch; 25-bolt hole; 31-fixing hole; 32-cover plate. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] Example 1 A visual inspection fixture for AC / DC socket maintenance on high-speed trains includes an insulating housing 13, an AC detection unit 21, a DC detection unit 23, a switch 24, a display unit, and a detection plug-in assembly. The AC detection unit 21, DC detection unit 23, and switch 24 are all housed inside the insulating housing 13. The display unit is located on the outer surface of the insulating housing 13. The switch 24 has an operating part 15, which is exposed outside the insulating housing 13. The detection plug-in assembly has a first electrical terminal and a second electrical terminal, and is connected to the insulating housing 13 via a connecting part. The insertion of the detection plug-in assembly is monitored. The test unit connects to the socket under test. The common terminal of the switch 24 is electrically connected to the first power terminal of the test connection assembly. The two output terminals of the switch 24 are electrically connected to the positive input terminals of the AC test unit 21 and the DC test unit 23, respectively. The negative input terminals of both the AC test unit 21 and the DC test unit 23 are electrically connected to the second power terminal of the test connection assembly. The signal output terminals of both the AC test unit 21 and the DC test unit 23 are electrically connected to the signal input terminal of the display unit. The common terminal of the display unit is electrically connected to the second power terminal of the test connection assembly. The AC test unit, DC test unit, and switch are all integrated into an insulating housing, forming a handheld integrated tool, reducing the overall size and making it suitable for operation in the confined space of a high-speed train carriage. At the same time, the insulating housing ensures the electrical safety of live-line testing operations.

[0027] The changeover switch 24 is a single-pole double-throw switch. This single-pole double-throw switch controls the on / off state of the two detection circuits, ensuring that only one detection unit is connected to the circuit under test at any given time, thus avoiding interference between AC and DC signals. A single circuit architecture is compatible with both AC and DC socket detection, replacing multiple discrete detection instruments. The display unit includes a first display screen 11 and a second display screen 12. The signal input terminal of the first display screen 11 is electrically connected to the signal output terminal of the AC detection unit 21, and the signal input terminal of the second display screen 12 is electrically connected to the signal output terminal of the DC detection unit 23. By connecting the first and second display screens to the output terminals of the AC and DC detection units respectively, the two types of detection results are displayed independently without the need to switch display interfaces. The detection results are read directly and clearly, avoiding confusion.

[0028] The connecting part is a flexible connecting part, and the plug-in end of the detection plug-in assembly is equipped with a plug-in plate structure, which is compatible with two-hole and three-hole sockets. The detection plug-in assembly is connected to the housing through the flexible connecting part, and the plug-in angle can be flexibly adjusted; the plug-in end adopts a plug-in plate structure adapted to two-hole and three-hole sockets, which can be adapted to different specifications of passenger compartment sockets of EMU without changing the connector, thus improving the versatility of the detection.

[0029] The insulating housing 13 includes a housing body and a cover plate 32. Multiple fixing holes 31 are provided at the corners of the cover plate 32. The cover plate 32 is fixedly connected to the housing body by fasteners passing through the fixing holes 31. A sealing element is provided between the housing body and the cover plate 32, and the sealing element is arranged circumferentially along the cover plate 32. The insulating housing adopts a split structure of a housing body and a cover plate, which is locked through the fixing holes by fasteners, facilitating the assembly and maintenance of internal modules. The circumferential sealing element between the cover plate and the housing body improves the dustproof and moisture-proof performance of the tooling, adapting to the complex onboard environment of high-speed trains.

[0030] The insulating housing 13 has two mutually isolated mounting cavities: a first mounting cavity and a second mounting cavity. The AC detection unit 21 is housed in the first mounting cavity, and the DC detection unit 23 is housed in the second mounting cavity. The two mutually isolated mounting cavities inside the housing, which respectively house the AC and DC detection units, reduce electromagnetic interference between the two types of circuits through physical isolation, thereby improving the stability and accuracy of voltage detection.

[0031] The connecting part is equipped with a universal joint, and the detection plug-in component is connected to the universal joint. The detection plug-in component is rotatably connected to the insulating housing 13 through the universal joint. The universal joint in the connecting part allows the detection plug-in component to rotate at multiple angles relative to the insulating housing. In scenarios where the carriage is narrow and the socket position is limited, the plug-in posture can be flexibly adjusted, reducing the difficulty of socket plug-in operation.

[0032] All edges and corners of the insulating housing 13 are rounded. The rounded corners of all edges and corners of the insulating housing prevent scratches to the interior of the vehicle from bumps and collisions, while reducing stress concentration at the edges and corners during drops, improving the housing's impact and drop resistance, and extending the service life of the tooling.

[0033] Specifically, this fixture is an integrated handheld device, mainly composed of an insulating shell, a visual display module, an AC / DC switching switch, an AC detection unit V1 (AC), a DC detection unit V2 (DC), and a universal joint detection socket. All circuit modules are integrated within the handheld insulating shell, and the universal joint is linearly connected to the main body of the fixture, forming an integrated portable testing fixture with a compact structure, suitable for operation in the confined spaces of high-speed train carriages. The overall structure of this fixture is as follows: Figure 1 , Figure 2 , Figure 3 As shown, the design of each part is as follows: See Figure 1 The overall design of the insulating shell is a rectangular handheld insulating shell. The shell is made of engineering plastic and has the characteristics of insulation, drop resistance and anti-electromagnetic interference. The size is suitable for one-handed grip and easy to move and work in the carriage. The corners of the shell are rounded to avoid bumps, damage or scratches to the interior of the carriage.

[0034] Visualization module: Located on the upper front of the casing, it is an LCD / OLED digital display screen that directly displays the voltage value, making the reading intuitive and eliminating the need for conversion.

[0035] Functional module area: The lower front of the casing has a reserved mounting position for an AC / DC switching switch with clear positions, anti-accidental touch design, and easy one-handed operation for switching.

[0036] Universal connector for socket testing: It adopts a flexible universal connector and multi-specification socket compatible probe design, and is connected to the main body of the tooling through an insulated wire. The connector can be rotated and adjusted at multiple angles. The probe integrates two-hole and three-hole compatible plugs, which can be directly inserted into any AC or DC socket in the passenger compartment of the EMU, realizing direct testing of a single socket.

[0037] See Figure 2 The internal circuit integrated cavity is a modular integrated cavity. The AC detection unit and DC detection unit are set in independent chambers. The electrical isolation structure realizes anti-interference between circuits. The chamber is equipped with positioning buckles to facilitate assembly and maintenance.

[0038] See Figure 3 The outer shell is a split design, consisting of a shell and a sealing cover. The cover is fixed to the shell with screws, which facilitates the installation and maintenance of the internal modules. At the same time, a sealing strip is set between the cover and the shell to improve dustproof and moisture-proof performance, making it suitable for the complex operating environment of EMU trains.

[0039] See Figure 4 , Figure 4 This is a schematic diagram of a visual testing fixture for inspecting AC / DC sockets on high-speed trains. Uin(+): Positive / live wire terminal; Uin(-): Negative / neutral wire terminal; S: AC / DC detection mode switch (single-pole double-throw); V1(AC): AC voltage detection unit; V2(DC): DC voltage detection unit. The circuit connections are as follows: The tooling is set with a positive input terminal Uin(+) and a negative input terminal Uin(-) for connecting to the output terminal of the socket under test; The AC detection unit V1 and the DC detection unit V2 are connected in parallel to the input circuit; The switching switch S is a single-pole double-throw switch, which enables selective conduction of the AC detection circuit and the DC detection circuit. The common terminal of the switch S is connected to the input circuit, and the two outputs are respectively connected to the sampling terminals of V1 (AC) and V2 (DC); The signal output terminals of both the AC detection unit V1 (AC) and the DC detection unit V2 (DC) are connected to the visualization display module to realize real-time display of voltage values.

[0040] The specific working principle is as follows: Mode switching: Select AC detection or DC detection by switching switch S. Only one detection unit works at a time to avoid mutual interference between AC and DC signals.

[0041] Signal acquisition: AC mode: V1(AC) samples, steps down, rectifies, and converts the measured AC voltage to RMS value, outputting a stable analog signal; DC mode: V2 (DC) performs voltage division, filtering, and voltage regulation on the measured DC voltage, and outputs a linear analog signal.

[0042] This invention aims to provide a dedicated maintenance tool for EMU (Electric Multiple Unit) sockets that integrates AC / DC power supply, is visual, handheld and portable, and can independently test single sockets while adapting to two-hole and three-hole sockets of various specifications. It enables rapid, accurate and intuitive testing of AC220V and DC110V sockets, improves maintenance efficiency and fault identification rate, and meets the standardized operation requirements of EMU depot inspection and patrol.

[0043] It has the following advantages: AC / DC integrated, one machine for all: one tooling can simultaneously meet the testing of AC220V AC sockets and DC110V DC sockets, replacing multiple instruments, greatly reducing the amount of tools to carry and simplifying the work process.

[0044] Independent testing of individual sockets for precise fault location: The voltage of a single socket can be directly tested through the universal plug, eliminating the need to check the circuit segment by segment. This allows for quick identification of the faulty socket, significantly reducing troubleshooting time and improving repair accuracy. Multi-spec socket compatibility and strong adaptability: The universal head probe is compatible with two-hole and three-hole sockets, eliminating the need to change the test connector. It is compatible with various passenger compartment sockets in EMU trains, further simplifying operation and improving operational versatility.

[0045] Portable and efficient, improving maintenance efficiency: The handheld lightweight design is simple to operate and quick to switch, enabling rapid inspection of sockets in the carriage, shortening the downtime for maintenance and improving preparation efficiency; the compact shell structure makes it easy to move and operate in the small space of the EMU carriage.

[0046] Example 2 A visual inspection method for the maintenance of AC / DC sockets in high-speed trains, using the visual inspection fixture for AC / DC socket maintenance in Example 1, includes the following steps: The operation section 15 of the operation switch 24 can select the circuit between the AC detection unit 21 and the detection plug-in assembly, or select the circuit between the DC detection unit 23 and the detection plug-in assembly. Connect the connector of the test connector to the socket under test; The selected AC detection unit 21 or DC detection unit 23 acquires the voltage signal of the socket under test; The display unit receives voltage signals and outputs them for display.

[0047] Specifically, the following steps are included: S1. Detection Mode Switching: The maintenance personnel hold the insulating housing 13 and rotate the exposed operating part 15 to drive the internal switch 24. When testing an AC socket, connect the common terminal of the switch 24 to the positive input terminal of the AC detection unit 21 to complete the AC detection mode setting; when testing a DC socket, connect the common terminal of the switch 24 to the positive input terminal of the DC detection unit 23 to complete the DC detection mode setting.

[0048] S2. Socket insertion under test: Hold the test insertion component and, with the help of the flexible structure of the connecting part and the rotation adjustment function of the universal joint, adjust the insertion angle and posture of the insertion end, align the insertion plate structure with the socket of the passenger compartment of the EMU under test, and insert it so that the first and second electrical terminals of the test insertion component are connected to the two poles of the socket under test.

[0049] S3. Voltage Signal Acquisition and Processing: The power supply voltage of the socket under test is connected to the internal circuit of the fixture via the detection plug-in assembly. Under the selection action of the switch 24, the voltage signal is only input to the selected detection unit. In AC mode, the AC voltage signal enters the AC detection unit 21, and after sampling, rectification, and RMS conversion, a detection signal is output. In DC mode, the DC voltage signal enters the DC detection unit 23, and after voltage division, filtering, and voltage regulation, a detection signal is output.

[0050] S4. Visualized output of test results: The test signal output by the AC test unit 21 is transmitted to the first display screen 11, which displays the voltage value of the AC socket under test in real time; the test signal output by the DC test unit 23 is transmitted to the second display screen 12, which displays the voltage value of the DC socket under test in real time; maintenance personnel can directly read the values ​​presented by the display unit to complete the voltage status determination of a single socket.

[0051] S5. Inspection flow and completion: After the single socket test is completed, unplug the plug end of the test plug assembly, and repeat the above steps S1 to S4 along the inspection path of the carriage to complete the test of all AC and DC sockets in the entire carriage in turn; after all the test work is completed, reset the operation unit 15 and put away the tooling.

[0052] The following example, taking the maintenance of an AC220V socket in the passenger compartment of a CRH2 high-speed train, further explains the present invention: 1.1 Set the selector switch S to the AC position; 1.2. Use the handheld universal head to test the socket, insert it into the two-hole or three-hole socket to be measured, and the display module will output the voltage value in real time; 1.3. Quickly determine the power supply status of the socket based on the display results, without the need for additional instrument calibration, and directly carry out subsequent maintenance or recording.

[0053] The following example, taking the maintenance of a DC110V socket in the passenger compartment of a CRH2 high-speed train, further explains the present invention: 2.1 The switch S is set to the DC position; 2.2 The DC voltage value is displayed after connecting to the socket under test; 2.3 Visually assess whether there are any abnormalities in the DC power supply module, wiring, or socket itself.

[0054] This invention employs an integrated detection circuit architecture combining AC / DC parallel connection and single-pole double-throw switch switching, enabling a single tooling unit to be compatible with both AC and DC socket testing. It proposes an independent single-socket testing structure, using a universal probe to directly connect to individual sockets, abandoning traditional circuit testing methods and achieving precise fault socket location without disassembling the distribution cabinet or troubleshooting the wiring. It also offers multi-spec socket compatibility, with the universal probe compatible with two-prong and three-prong sockets, allowing one probe to adapt to all specifications of AC / DC sockets in the passenger compartments of high-speed trains, improving testing versatility and convenience. The invention provides real-time digital visualization of test results, enabling intuitive judgment of socket status and eliminating reliance on manual experience. Furthermore, the invention features an integrated handheld insulating shell design adapted to the confined space of high-speed train carriages, combined with a split-type sealed structure, achieving portability, drop resistance, dust and moisture protection, and improving onboard operation adaptability.

[0055] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered as falling within the protection scope of the present invention as determined by the submitted content.

Claims

1. A visual inspection fixture for the maintenance of AC / DC sockets on high-speed trains, characterized in that, It includes an insulating housing (13), an AC detection unit (21), a DC detection unit (23), a switch (24), a display unit, and a detection plug-in assembly; The AC detection unit (21), the DC detection unit (23), and the switching switch (24) are all located inside the insulating housing (13); The display unit is disposed on the outer surface of the insulating housing (13); The switching switch (24) is provided with an operating part (15), which is exposed outside the insulating housing (13). The detection plug-in assembly is provided with a first power terminal and a second power terminal. The detection plug-in assembly is connected to the insulating shell (13) through a connecting part. The plug-in terminal of the detection plug-in assembly is plugged into the socket under test. The common terminal of the switching switch (24) is electrically connected to the first power terminal of the detection plug-in assembly, and the two output terminals of the switching switch (24) are electrically connected to the positive input terminal of the AC detection unit (21) and the positive input terminal of the DC detection unit (23), respectively. The negative input terminal of the AC detection unit (21) and the negative input terminal of the DC detection unit (23) are both electrically connected to the second power terminal of the detection plug-in assembly; the signal output terminal of the AC detection unit (21) and the signal output terminal of the DC detection unit (23) are both electrically connected to the signal input terminal of the display unit. The common terminal of the display unit is electrically connected to the second power terminal of the detection plug-in assembly.

2. The visual inspection fixture for AC / DC socket maintenance of high-speed trains according to claim 1, characterized in that, The switching switch (24) is a single-pole double-throw switch.

3. The visual inspection fixture for AC / DC socket maintenance of high-speed trains according to claim 1, characterized in that, The display unit includes a first display screen (11) and a second display screen (12). The signal input terminal of the first display screen (11) is electrically connected to the signal output terminal of the AC detection unit (21), and the signal input terminal of the second display screen (12) is electrically connected to the signal output terminal of the DC detection unit (23).

4. The visual inspection fixture for AC / DC socket maintenance of high-speed trains according to claim 1, characterized in that, The connecting part is a flexible connecting part, and the plug end of the detection plug assembly is provided with a plug-in plate structure, which is plugged into and cooperates with two-hole sockets and three-hole sockets.

5. The visual inspection fixture for inspecting AC / DC sockets of high-speed trains according to claim 1, characterized in that, The insulating housing (13) includes a housing body and a cover plate (32). The cover plate (32) has multiple fixing holes (31) at its corners. The cover plate (32) is fixedly connected to the housing body by fasteners passing through the fixing holes (31).

6. The visual inspection fixture for AC / DC socket maintenance of high-speed trains according to claim 5, characterized in that, A sealing element is provided between the housing body and the cover plate (32), and the sealing element is arranged circumferentially along the cover plate (32).

7. The visual inspection fixture for AC / DC socket maintenance of high-speed trains according to claim 1, characterized in that, The insulating housing (13) has a first mounting cavity and a second mounting cavity that are isolated from each other. The AC detection unit (21) is housed in the first mounting cavity, and the DC detection unit (23) is housed in the second mounting cavity.

8. The visual inspection fixture for AC / DC socket maintenance of high-speed trains according to claim 1, characterized in that, The connecting part is provided with a universal joint, the detection plug-in assembly is connected to the universal joint, and the detection plug-in assembly is rotatably connected to the insulating shell (13) through the universal joint.

9. A visual inspection fixture for inspecting AC / DC sockets on high-speed trains according to claim 1, characterized in that, All corners of the insulating shell (13) are rounded.

10. A visual inspection method for the maintenance of AC / DC sockets in high-speed trains, characterized in that, The inspection is performed using the visual inspection fixture for AC / DC socket maintenance of high-speed trains as described in any one of claims 1-9, including the following steps: Operate the operation section (15) of the switch (24) to select the circuit between the AC detection unit (21) and the detection plug-in assembly, or select the circuit between the DC detection unit (23) and the detection plug-in assembly; Connect the plug end of the detection plug assembly to the socket under test; The selected AC detection unit (21) or DC detection unit (23) acquires the voltage signal of the socket under test; The display unit receives the voltage signal and outputs a display.

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