A method for measuring the axle temperature and speed of a motor train unit

Abstract

This invention relates to the field of rail transit vehicle testing technology, specifically a method for measuring axle temperature and speed in high-speed trains. The fixed housing has an internal circuit board mounting groove with an anti-reverse design for installing and fixing the circuit board assembly. The mounting surface of the fixed housing has two threaded mounting holes for fixing and connecting the sensor. Rh is fixed to the air vent side with potting compound, and Rk and Rh are at the same distance from the housing surface in the direction of the mounting gap. This method abandons the gear-dependent measurement principle based on the Hall effect. Instead, it drives the temperature and resistance changes of the platinum resistance thermometer Rh by the change in airflow pressure in the mounting gap caused by the rotation of the measured axle. Combined with a Wheatstone bridge, it completes the axle speed measurement, completely eliminating the sensor's limitations on the installation position and gear module, significantly improving the sensor's installation flexibility in complex spaces under high-speed trains and its adaptability to different train models and axle structures.

Description

Technical Field

[0001] This invention relates to the field of rail transit vehicle testing technology, specifically to a method for measuring axle temperature and speed in high-speed trains. Background Technology

[0002] Axle temperature and speed parameters of rail transit vehicles, especially EMU trains, are core monitoring indicators to ensure train operation safety. Real-time and accurate measurement is of great significance for preventing axle overheating, jamming and other faults and avoiding train operation accidents. In the current technology system, EMU axle speed measurement mainly relies on speed sensors based on the Hall effect principle.

[0003] The working mechanism of this type of Hall effect speed sensor is as follows: When the metal gear of the device under test passes through the sensing end face of the sensor during rotation, it will cause periodic changes in the surrounding magnetic field. Specifically, when the tooth root passes through the sensing end face, the magnetic field lines are more dispersed and the magnetic field strength is weaker; when the tooth tip passes through the sensing end face, the magnetic field lines are relatively concentrated and the magnetic field strength is stronger. The Hall element built into the sensor generates an induced electromotive force by sensing the dynamic changes in the magnetic field line density. After the built-in circuit is further adjusted and amplified, the electromotive force is converted into a rectangular pulse signal corresponding to the gear rotation speed, thereby indirectly realizing the measurement of shaft speed.

[0004] However, existing Hall effect-based axle speed measurement technologies have significant limitations: First, their measurement principle is highly dependent on metal gears, requiring the sensor to be installed at the corresponding position on the gear to meet the magnetic field change sensing requirements. This severely restricts the sensor's installation location, making it difficult to adapt to the complex spatial layout under the EMU (Electric Multiple Unit) train. Second, the speed measurement conversion process of this type of sensor is closely related to the gear module. In practical applications, the spacing of the Hall elements on the circuit board needs to be adjusted individually for gears with different modules, making the sensor essentially a customized product with a lack of versatility. This customization not only increases production, procurement, and maintenance costs but also reduces the interchangeability and adaptation efficiency of the equipment in different train models or axle structures. Therefore, a method for measuring axle temperature and speed in EMU trains is proposed to solve the problems of gear-dependent and position-restricted installation of existing Hall effect-based axle speed sensors, improving installation flexibility; eliminating gear module limitations to enhance sensor versatility, reduce customization and maintenance costs, and ensure the stability and adaptability of EMU axle temperature and speed monitoring. Summary of the Invention

[0005] To address the problems in existing technologies, this invention provides a method for measuring axle temperature and speed in high-speed trains. This method solves the problems of existing Hall effect-based axle speed sensors, which rely on gears for installation and have limited position, thus improving installation flexibility. It also eliminates the limitations of gear module to improve sensor versatility, reduce customization and maintenance costs, and ensure the stability and compatibility of axle temperature and speed monitoring in high-speed trains.

[0006] The technical solution adopted by this invention to solve its technical problem is a method for measuring axle temperature and axle speed of high-speed trains, comprising the following steps:

[0007] Step 1: Arrange the sensor at the axle box position of the EMU. The sensor includes a fixed housing and a circuit board assembly set inside the fixed housing. The bottom of the fixed housing is provided with an air guide hole, and the air guide hole is directly facing the radial surface of the shaft being measured. The sensor installation gap is set to 1-3mm.

[0008] Step 2: Utilize the pressure change caused by the change in air velocity at the installation gap when the measured shaft rotates, and guide the airflow into the interior of the fixed housing through the air guide hole;

[0009] Step 3: The airflow flows in from the back of the air guide hole, causing the temperature of the platinum resistance thermometer Rh set on the side of the air guide hole to change; Rh, together with the platinum resistance thermometer Rk, resistor Ra, Rb and operational amplifier circuit set on the circuit board assembly, form a Wheatstone bridge. The change in the resistance value of Rh causes the Wheatstone bridge to become unbalanced. The unbalance signal is amplified by the operational amplifier circuit and the shaft speed measurement value is output.

[0010] Step 4: Monitor the temperature using Rh and Rk, where Rh is the hot-end bridge arm resistance and Rk is the cold-end bridge arm resistance, and Rh and Rk are isolated by polytetrafluoroethylene material to avoid heat exchange.

[0011] Specifically, the fixed housing has a circuit board mounting groove with anti-reverse design inside for installing and fixing the circuit board assembly; the mounting surface of the fixed housing has two threaded mounting holes for fixing and connecting the sensor; Rh is fixed to the air vent side by potting compound, and Rk and Rh are at the same distance from the housing surface in the direction of the mounting gap.

[0012] Specifically, the sensor also includes a sheath, a cable assembly, and a connector. The sheath is made of EPDM material and has annular structures at both the front and rear ends for fixed connection with the fixed housing and the connector tail bracket. The sheath adopts a symmetrical structural design.

[0013] Specifically, the outer side of the fixed housing is provided with an adjustment frame, and the outer side of the adjustment frame is provided with a waist-shaped adjustment hole that is wider at the bottom and narrower at the top. The adjustment hole corresponds to the air guide hole, and several sets of fixing bolts are threadedly connected to the outer side of the adjustment frame away from the adjustment hole.

[0014] Specifically, the adjustment frame has a slot on one side, an adjustment plate is provided in the slot, the adjustment plate has a vent hole corresponding to the adjustment hole, and a number of adjustment bolts are threaded to the side of the adjustment plate away from the adjustment frame. One end of the adjustment bolt passes through the adjustment plate and is rotatably connected to the outside of the adjustment frame.

[0015] Specifically, an elastic sleeve is fixedly connected between the vent hole and the adjustment hole.

[0016] Specifically, the lower surface of the fixed housing is provided with a sliding groove, which communicates with the air guide hole. An elastic metal sheet is fixedly connected to the lower surface of the fixed housing. A first spring sheet and a second spring sheet are fixedly connected to the side of the elastic metal sheet near the measured shaft and the side away from the measured shaft, respectively. The first spring sheet and the second spring sheet are respectively located in the corresponding sliding groove and are slidably connected to the sliding groove in a sealed manner. Both the first spring sheet and the second spring sheet are provided with through holes corresponding to the air guide hole. In the initial state, the through holes are staggered with the air guide hole.

[0017] Specifically, the elastic metal sheet is made of spring steel, the thickness of the first and second spring sheets is 0.3-0.5mm, the inner wall of the groove is provided with a rubber sealing layer, and the rubber sealing layer is in contact with the surface of the first and second spring sheets.

[0018] The beneficial effects of this invention are:

[0019] The present invention discloses a method for measuring axle temperature and speed in high-speed trains. This method abandons the gear-dependent measurement principle based on the Hall effect. Instead, it drives the temperature and resistance of a platinum resistance thermometer Rh by the change in airflow pressure in the installation gap caused by the rotation of the measured axle. Combined with a Wheatstone bridge, the axle speed is measured. This completely eliminates the limitations of sensor installation position and gear module constraints on metal gears, and significantly improves the installation flexibility of the sensor in the complex space layout under the high-speed train and the adaptability to different train models and axle structures.

[0020] The present invention discloses a method for measuring axle temperature and speed in high-speed trains. It utilizes the temperature difference between the hot end bridge arm (Rh) and the cold end bridge arm (Rk) of a platinum resistance thermometer, and avoids heat exchange by using polytetrafluoroethylene (PTFE) material for isolation. This allows Rh to accurately reflect the temperature near the axle being measured, while Rk serves as a stable reference. The method achieves synchronous monitoring of axle temperature and speed within the same sensor system, eliminating the need for additional independent measuring devices and simplifying the system architecture for monitoring the axle system of high-speed trains.

[0021] The present invention discloses a method for measuring axle temperature and speed in high-speed trains. By fixing the adjustment frame on the outside of the housing and the waist-shaped adjustment hole (wider at the bottom and narrower at the top), the width of the air inlet channel can be adjusted according to the diameter of the axle being measured, avoiding signal saturation caused by strong airflow or insufficient signal due to weak airflow. With the fine adjustment of the adjustment plate and adjustment bolts, it can accurately adapt to the installation gap requirement of 1-3mm. The elastic sleeve ensures sealing and airflow stability during the adjustment process, significantly improving the sensor's adaptability to different axle diameters and installation gaps, and ensuring the stability and accuracy of the measurement signal.

[0022] The present invention discloses a method for measuring axle temperature and speed in high-speed trains. An elastic metal sheet on the lower surface of a fixed housing, in conjunction with a first and second spring sheet, and a rubber sealing layer within a sliding groove, achieves initial impurity blocking and airflow-induced sealing opening. This prevents dust and moisture from entering the air vent when there is no or weak airflow, and also prevents airflow leakage, ensuring the purity of the measurement signal. When the measured axle rotates and generates airflow, the airflow pressure drives the elastic metal sheet to deform, causing the first and second spring sheets to slide within the sliding groove, aligning the through hole with the air vent, thus achieving automatic opening of the air vent. This method requires no additional power control and is adaptable to the dynamic operating state of the axle system. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is an isometric view of the present invention;

[0025] Figure 2 This is an isometric view of the present invention from another perspective;

[0026] Figure 3 This is a schematic diagram of the sheath structure of the present invention;

[0027] Figure 4 This is a schematic diagram of the connector structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the fixed housing structure of the present invention;

[0029] Figure 6 This is a schematic diagram of the circuit board fixing groove of the present invention;

[0030] Figure 7 This is a schematic diagram of the adjustment frame structure of the present invention;

[0031] Figure 8 This is a schematic cross-sectional view of the adjustment frame portion of the present invention;

[0032] Figure 9 This is a schematic diagram of the scraping elastic metal sheet structure of the present invention;

[0033] Figure 10 This is a schematic diagram of the first and second springs of the present invention;

[0034] Figure 11 This is a schematic diagram showing the airflow direction at the fixed housing position of the present invention;

[0035] Figure 12 This is a circuit diagram of the Wheatstone bridge of the present invention;

[0036] In the diagram: 1. Fixed housing; 2. Vent hole; 3. Circuit board mounting slot; 4. Threaded mounting hole; 5. Sheath; 6. Cable assembly; 7. Connector; 8. Ring structure; 9. Adjustment frame; 10. Adjustment hole; 11. Fixing bolt; 12. Slot; 13. Adjustment plate; 14. Vent hole; 15. Adjustment bolt; 16. Elastic sleeve; 17. Slide groove; 18. Elastic metal sheet; 19. First spring sheet; 20. Second spring sheet; 21. Through hole. Detailed Implementation

[0037] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0038] To address the limitations of existing Hall effect-based axle speed sensors, which rely on gears for installation and have restricted placement, and to improve installation flexibility; to eliminate gear module limitations to enhance sensor versatility, reduce customization and maintenance costs, and ensure stable and compatible axle temperature and speed monitoring for high-speed trains, as one embodiment of the present invention, such as... Figure 1 , Figure 2 , Figure 5 , Figure 11 , Figure 12 As shown, the method for measuring axle temperature and axle speed of a high-speed train according to the present invention includes the following steps:

[0039] Step 1: Arrange a sensor at the axle box position of the EMU. The sensor includes a fixed housing 1 and a circuit board assembly set inside the fixed housing 1. The bottom of the fixed housing 1 is provided with an air guide hole 2, and the air guide hole 2 is directly facing the radial surface of the shaft being measured. The sensor installation gap is set to 1-3mm.

[0040] Step 2: Utilize the pressure change caused by the change in air velocity at the installation gap when the measured shaft rotates, and guide the airflow into the interior of the fixed housing 1 through the air guide hole 2;

[0041] Step 3: The airflow flows in from the back of the air guide hole 2, causing the temperature of the platinum resistance thermometer Rh set on the side of the air guide hole 2 to change; Rh, together with the platinum resistance thermometer Rk, resistor Ra, Rb and operational amplifier circuit set on the circuit board assembly, form a Wheatstone bridge. The change in the resistance value of Rh causes the Wheatstone bridge to become unbalanced. The unbalance signal is amplified by the operational amplifier circuit and the shaft speed measurement value is output.

[0042] Step 4: Monitor the temperature using Rh and Rk, where Rh is the hot-end bridge arm resistance and Rk is the cold-end bridge arm resistance, and Rh and Rk are isolated by polytetrafluoroethylene material to avoid heat exchange.

[0043] When in use, the sensor, including the fixed housing 1 and the internal circuit board assembly, is installed in the axle box of the EMU. Ensure that the air guide hole 2 at the bottom of the fixed housing 1 is facing the radial surface of the shaft being measured, and strictly control the installation gap between the sensor and the shaft being measured to be 1-3mm to ensure that subsequent airflow changes can be effectively captured.

[0044] When the shaft under test rotates, the air velocity at the mounting gap changes with the rotation of the shaft, which in turn causes a change in pressure. This airflow is guided into the interior of the fixed housing 1 through the air guide hole 2 at the bottom of the fixed housing 1, providing a physical signal source for subsequent measurements. The airflow flowing into the interior of the fixed housing 1 acts on the platinum resistance thermometer Rh on the side of the air guide hole 2 from the back, causing the temperature of Rh to change, which in turn causes its resistance value to fluctuate. Since Rh, together with the platinum resistance thermometer Rk, resistor Ra, Rb and the operational amplifier circuit on the circuit board assembly, form a Wheatstone bridge, the change in the resistance value of Rh will disrupt the balance of the bridge. The imbalance signal is amplified by the operational amplifier circuit and converted into a recognizable electrical signal, and finally outputs the shaft speed measurement value corresponding to the rotational speed of the shaft under test.

[0045] The temperature is monitored by using platinum resistance thermometer Rh as the hot end bridge arm resistance and Rk as the cold end bridge arm resistance. Rh and Rk are isolated by polytetrafluoroethylene material to prevent heat exchange between them, ensuring that Rh can accurately reflect the temperature near the shaft being measured (hot end temperature) and Rk can stably serve as a reference (cold end temperature), thereby achieving effective monitoring of shaft temperature.

[0046] It breaks away from the dependence of traditional Hall effect sensors on metal gears, is not limited by gear position, and is adaptable to the complex space layout under high-speed trains. At the same time, the measurement principle does not depend on specific parameters such as gear module, eliminating the need to customize sensors for different gears, thus improving the sensor's versatility and reducing customization costs in production, procurement, and maintenance. It utilizes the change in airflow pressure caused by the rotation of the measured shaft to drive the change in the Rh resistance value, converts the physical signal into an electrical signal through a Wheatstone bridge, and outputs the shaft speed value after amplification by an operational amplifier circuit. This realizes non-contact shaft speed measurement based on airflow characteristics, and the signal conversion process is stable and reliable.

[0047] For example, such as Figure 4 , Figure 5 As shown, the present invention also includes a circuit board fixing groove 3 with anti-reverse design inside the fixed housing 1 for installing and fixing the circuit board assembly; the mounting surface of the fixed housing 1 is provided with two threaded mounting holes 4 for fixing and connecting the sensor; Rh is fixed to the side of the air vent 2 by potting compound, and Rk and Rh are at the same distance from the housing surface in the direction of the mounting gap.

[0048] During use, the circuit board assembly is installed in the circuit board fixing slot 3 with anti-reverse design inside the fixed housing 1. The anti-reverse design of the fixing slot ensures that the circuit board assembly is installed in the correct direction and achieves a stable fixation of the circuit board assembly, ensuring the correctness of the circuit connection and preventing it from loosening during the vibration of the EMU during operation.

[0049] By utilizing the two threaded mounting holes 4 provided on the mounting surface of the fixed housing 1, the sensor is fixed as a whole and connected to the corresponding mounting position of the EMU axle box through a threaded connection, ensuring the installation stability of the sensor under complex working conditions;

[0050] Use potting compound to fix the platinum resistance thermometer Rh to the two sides of the air vent to ensure that the installation position of Rh is stable and to avoid the position displacement caused by vibration and other factors affecting the measurement.

[0051] Simultaneously controlling the installation position of the platinum resistance thermometer Rk ensures that the distances between Rk and Rh to the housing surface in the direction of the installation gap are the same. This reduces inconsistencies in environmental thermal interference caused by distance differences, laying the foundation for the accuracy of subsequent temperature measurements.

[0052] For example, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, the present invention also includes a sheath 5, a cable assembly 6 and a connector 7. The sheath 5 is made of EPDM material and has annular structures 8 at both the front and rear ends for fixed connection with the fixed housing 1 and the tail bracket of the connector 7. The sheath 5 adopts a symmetrical structural design.

[0053] When in use, the sheath 5 is made of EPDM material. The properties of this material can provide good protection for the sensor-related components and adapt to the complex environment in the operation of the EMU, so as to adapt to the under-vehicle operating environment of -40℃ to 125℃.

[0054] The annular structures 8 at the front and rear ends are respectively fixed to the fixed housing 1 and the tail bracket of the connector 7 to ensure that the sheath 5 is firmly connected under the vibration of the EMU during operation, and to prevent it from loosening or falling off.

[0055] For example, such as Figure 7 , Figure 8 As shown, the present invention also includes an adjustment frame 9 on the outer side of the fixed housing 1, and an oblong adjustment hole 10 with a wider bottom and narrower top that is provided on the outer side of the adjustment frame 9. The adjustment hole 10 corresponds to the air guide hole 2, and a number of sets of fixing bolts 11 are threadedly connected to the outer side of the adjustment frame 9 away from the adjustment hole 10.

[0056] When using it, depending on the actual diameter of the shaft being measured, such as a large-diameter shaft or a small-diameter shaft, first loosen several sets of fixing bolts 11 on the outer side of the adjusting frame 9 away from the adjusting hole 10, so that the adjusting frame 9 is in an adjustable state.

[0057] If the shaft being measured is a large-diameter shaft, the airflow intensity generated when the large-diameter shaft rotates is relatively large. In this case, move the adjustment frame 9 so that the narrower part of the waist-shaped adjustment hole 10 on the adjustment ring coincides with the air guide hole 2 of the fixed housing 1, reducing the air intake channel of the air guide hole 2 and reducing the air intake volume. This can prevent excessive air intake of the air guide hole 2 due to the strong airflow generated by the rotation of the large shaft, prevent the temperature of the platinum resistance thermometer Rh from changing too much due to excessive airflow impact, avoid saturation or distortion of the Wheatstone bridge signal, and ensure the stability of the shaft speed measurement signal.

[0058] Similarly, if the shaft being measured is a small-diameter shaft, the airflow intensity driven by the rotation of the small-diameter shaft is relatively weak. At this time, the adjustment frame 9 is moved so that the wider part of the waist-shaped adjustment hole 10 on the adjustment ring coincides with the air guide hole 2 of the fixed housing 1, thereby expanding the air intake channel of the air guide hole 2 and increasing the air intake volume. This can compensate for the insufficient airflow generated by the rotation of the small shaft, ensuring that enough airflow enters the fixed housing 1 and acts on Rh, so that Rh can sense obvious temperature changes, ensuring the strength of the Wheatstone bridge imbalance signal and improving the accuracy of shaft speed measurement.

[0059] For example, such as Figure 7 , Figure 8 As shown, the present invention also includes a slot 12 on one side of the adjustment frame 9, an adjustment plate 13 in the slot 12, a vent hole 14 corresponding to the adjustment hole 10 on the adjustment plate 13, and a plurality of adjustment bolts 15 threadedly connected to the side of the adjustment plate 13 away from the adjustment frame 9, one end of the adjustment bolt 15 passing through the adjustment plate 13 and rotatably connected to the outside of the adjustment frame 9.

[0060] During use, the sensor needs to be fitted to a standard range of 1-3mm according to the actual installation gap of the sensor. The position of the adjusting plate 13 in the slot 12 is adjusted by rotating the adjusting bolt 15. When the adjusting bolt 15 is rotated, the adjusting plate 13 will move closer to or further away from the adjusting frame 9 along the direction of the slot 12. At this time, the relative position of the vent hole 14 on the adjusting plate 13 and the adjusting hole 10 of the adjusting frame 9 will change accordingly. By moving the adjusting plate 13 in the slot 12 and fixing the adjusting bolt 15, the sensor's installation gap requirement of 1-3mm can be accurately matched, ensuring the accuracy and reliability of shaft temperature and shaft speed measurement within the 1-3mm installation gap range.

[0061] For example, such as Figure 8 As shown, the present invention also includes an elastic sleeve 16 fixedly connected between the vent hole 14 and the adjustment hole 10.

[0062] When in use, the adjusting plate 13 is moved within the slot 12 by adjusting the adjusting bolt 15. The relative position of the vent hole 14 and the adjusting hole 10 will change slightly. The elastic sleeve 16 can adapt to the relative movement of the two holes by its own elasticity, and always maintain the sealing coverage of the connection part, so as to avoid the sealing failure caused by the movement of the adjusting plate 13 and ensure the stability of the air intake adjustment process.

[0063] During the operation of the EMU, there is continuous vibration. The elastic sleeve 16 can absorb the vibration impact between the adjustment plate 13 and the adjustment frame 9, reduce the wear of rigid collision on the vent hole 14, adjustment hole 10 and connection structure, extend the service life of the components, and at the same time avoid the connection loosening caused by vibration, ensuring the reliability of the sealing performance in long-term use.

[0064] By using the sealing and deformation adaptation of the elastic sleeve 16, the airflow path between the vent hole 14 and the adjustment hole 10 can be kept stable, reducing airflow turbulence or pressure loss, ensuring that the airflow intensity entering the air guide hole 2 is consistent with the adjusted air intake design value, providing a stable physical signal basis for the platinum resistance thermometer Rh to sense temperature changes, and indirectly improving the accuracy of shaft temperature and shaft speed measurement.

[0065] For example, such as Figure 9 , Figure 10 As shown, the present invention further includes a groove 17 on the lower surface of the fixed housing 1, the groove 17 communicating with the air guide hole 2, an elastic metal sheet 18 fixedly connected to the lower surface of the fixed housing 1, a first spring sheet 19 and a second spring sheet 20 fixedly connected to the side of the elastic metal sheet 18 near the measured shaft and the side away from the measured shaft, respectively, the first spring sheet 19 and the second spring sheet 20 are respectively located in the corresponding groove 17 and are slidably connected to the groove 17 in a sealed manner, and each of the first spring sheet 19 and the second spring sheet 20 is provided with a through hole 21 corresponding to the air guide hole 2, the through hole 21 initially intersecting with the air guide hole 2.

[0066] During use, when the shaft being measured rotates, the airflow generated at the installation gap acts on the surface of the elastic metal sheet 18. The airflow pressure causes the elastic metal sheet 18 to deform. When the elastic metal sheet 18 deforms, it pulls the second spring sheet 20, causing the second spring sheet 20 to slide in the sliding groove 17 along the sealing direction. Its lower end gradually moves out of the sliding groove 17, and the through hole 21 on the second spring sheet 20 gradually aligns with the air guide hole 2 as it slides. Simultaneously, the side of the elastic metal sheet 18 closest to the shaft being measured presses the first spring sheet 19 inward and pushes the first spring sheet 19 to slide upward in the sliding groove 17, so that the through hole 21 on the first spring sheet 19 gradually aligns with the air guide hole 2 as it moves upward. Finally, under the continuous action of the airflow pressure, the through holes 21 of both the second spring sheet 20 and the first spring sheet 19 are completely aligned with the air guide hole 2. The air guide hole 2 is opened, and the airflow enters the interior of the fixed housing 1 through the through hole 21 and the air guide hole 2, providing a stable temperature change signal for the platinum resistance thermometer Rh.

[0067] In the initial state, the through holes 21 of the first spring 19 and the second spring 20 are staggered with the air guide hole 2, which can block dust, water vapor and other impurities from entering the air guide hole 2 when there is no airflow or weak airflow. During the opening process, the first spring 19 and the second spring 20 are always sealed and slidably connected with the slide groove 17 to prevent airflow from leaking from the gap, ensure the purity of the airflow entering the air guide hole 2, and reduce the influence of external interference on the measurement.

[0068] For example, such as Figure 10 As shown, the present invention also includes that the elastic metal sheet 18 is made of spring steel, the thickness of the first spring sheet 19 and the second spring sheet 20 is 0.3-0.5mm, the inner wall of the slide groove 17 is provided with a rubber sealing layer, and the rubber sealing layer is in contact with the surface of the first spring sheet 19 and the second spring sheet 20.

[0069] When in use, when the measured shaft rotates and generates airflow, the airflow pressure acts on the elastic metal sheet 18 made of spring steel, causing it to undergo adaptive deformation; during the deformation of the elastic metal sheet 18, the first spring sheet 19 and the second spring sheet 20 are simultaneously driven to slide in the slide groove 17. Because the thickness of the spring sheet is appropriate and the surface is in contact with the rubber sealing layer, the sliding process always maintains a sealed state, preventing airflow from leaking from the gaps.

[0070] The elastic metal sheet 18 is made of spring steel, which has high strength and excellent elastic recovery performance. It can be stably deformed under airflow pressure and is not easily fatigued after long-term repeated deformation, ensuring continuous response to airflow changes and extending the service life of the component.

[0071] In use, the present invention utilizes two threaded mounting holes 4 provided on the mounting surface of the fixed housing 1 to fix the sensor as a whole and connect it to the corresponding mounting position of the EMU axle box through a threaded connection.

[0072] Depending on the actual diameter of the shaft being measured, such as a large-diameter shaft or a small-diameter shaft, first loosen several sets of fixing bolts 11 on the outside of the adjusting frame 9 away from the adjusting hole 10, so that the adjusting frame 9 is in an adjustable state. If the shaft being measured is a large-diameter shaft, the airflow intensity driven by the large-diameter shaft when rotating is relatively large. At this time, move the adjusting frame 9 so that the narrower part of the waist-shaped adjusting hole 10 on the adjusting ring coincides with the air guide hole 2 of the fixed housing 1, reducing the air intake channel of the air guide hole 2 and reducing the air intake volume. This can avoid excessive air intake of the air guide hole 2 due to the strong airflow generated by the rotation of the large shaft, prevent the temperature change amplitude of the platinum resistance thermometer Rh from being too large due to the impact of the airflow, avoid the saturation or distortion of the Wheatstone bridge signal, and ensure the stability of the shaft speed measurement signal.

[0073] Similarly, if the shaft being measured is a small-diameter shaft, the airflow intensity driven by the rotation of the small-diameter shaft is relatively weak. At this time, the adjustment frame 9 is moved so that the wider part of the waist-shaped adjustment hole 10 on the adjustment ring coincides with the air guide hole 2 of the fixed housing 1, thereby expanding the air intake channel of the air guide hole 2 and increasing the air intake volume. This can compensate for the insufficient airflow generated by the rotation of the small shaft, ensuring that enough airflow enters the fixed housing 1 and acts on Rh, so that Rh can sense obvious temperature changes, ensuring the strength of the Wheatstone bridge imbalance signal and improving the accuracy of shaft speed measurement.

[0074] Depending on the actual installation gap of the sensor, a standard range of 1-3mm needs to be adapted. The position of the adjusting plate 13 in the slot 12 is adjusted by rotating the adjusting bolt 15. When the adjusting bolt 15 is rotated, the adjusting plate 13 will move closer to or further away from the adjusting frame 9 along the direction of the slot 12. At this time, the relative position of the vent hole 14 on the adjusting plate 13 and the adjusting hole 10 of the adjusting frame 9 will change accordingly. The elastic sleeve 16 can adapt to the relative movement of the two holes by its own elasticity, and always maintain the sealing coverage of the connection part. By moving the adjusting plate 13 in the slot 12 and fixing the adjusting bolt 15, the installation gap requirement of 1-3mm of the sensor can be accurately adapted, ensuring the accuracy and reliability of shaft temperature and shaft speed measurement within the installation gap range of 1-3mm.

[0075] When the shaft being measured rotates, the air velocity at the mounting gap changes with the rotation of the shaft, which in turn causes a pressure change. The airflow generated at the mounting gap acts on the surface of the elastic metal sheet 18, and the airflow pressure causes the elastic metal sheet 18 to deform. When the elastic metal sheet 18 deforms, it pulls the second spring sheet 20, causing the second spring sheet 20 to slide in the sliding groove 17 along the sealing direction. Its lower end gradually moves out of the sliding groove 17, and the through hole 21 on the second spring sheet 20 gradually aligns with the air guide hole 2 as it slides. Simultaneously, the elastic... The metal sheet 18 presses the first spring sheet 19 inward from the side closest to the shaft being measured, and pushes the first spring sheet 19 to slide upward in the groove 17, so that the through hole 21 on the first spring sheet 19 gradually aligns with the air guide hole 2 as it moves upward; finally, under the continuous action of airflow pressure, the through holes 21 of the second spring sheet 20 and the first spring sheet 19 are completely aligned with the air guide hole 2, the air guide hole 2 is opened, and the airflow enters the interior of the fixed housing 1 through the through hole 21 and the air guide hole 2, providing a stable temperature change signal for the platinum resistance thermometer Rh;

[0076] When the shaft under test rotates, the airflow is guided into the interior of the fixed housing 1 through the air guide hole 2 at the bottom of the fixed housing 1. The airflow flowing into the fixed housing 1 acts on the platinum resistance thermometer Rh on the side of the air guide hole 2 from the back, causing the temperature of Rh to change, which in turn causes its resistance value to fluctuate. Since Rh, together with the platinum resistance thermometer Rk, resistor Ra, Rb and operational amplifier circuit on the circuit board assembly, form a Wheatstone bridge, the change in the resistance value of Rh will disrupt the balance of the bridge. After the imbalance signal is amplified by the operational amplifier circuit, it is converted into a recognizable electrical signal, and finally outputs the shaft speed measurement value corresponding to the rotational speed of the shaft under test.

[0077] The temperature is monitored by using platinum resistance thermometer Rh as the hot end bridge arm resistance and Rk as the cold end bridge arm resistance. Rh and Rk are isolated by polytetrafluoroethylene material to prevent heat exchange between them, ensuring that Rh can accurately reflect the temperature near the shaft being measured (hot end temperature) and Rk can stably serve as a reference (cold end temperature), thereby achieving effective monitoring of shaft temperature.

[0078] Ensure that shaft temperature and speed measurements are independent of gears, adapt to complex working conditions, and guarantee data accuracy.

[0079] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for measuring axle temperature and axle speed in high-speed trains, characterized in that, Includes the following steps: Step 1: Arrange a sensor at the axle box position of the EMU. The sensor includes a fixed housing (1) and a circuit board assembly set inside the fixed housing (1). The bottom of the fixed housing (1) is provided with an air guide hole (2), and the air guide hole (2) is directly facing the radial surface of the shaft being measured. The sensor installation gap is set to 1-3mm. Step 2: Utilize the pressure change caused by the change in air velocity at the installation gap when the measured shaft rotates, guide the airflow into the interior of the fixed housing (1) through the air guide hole (2); Step 3: The airflow flows in from the back of the air guide hole (2), causing the temperature of the platinum resistance thermometer Rh set on the side of the air guide hole (2) to change; Rh, together with the platinum resistance thermometer Rk, resistor Ra, Rb and operational amplifier circuit set on the circuit board assembly, form a Wheatstone bridge. The change in the resistance value of Rh causes the Wheatstone bridge to become unbalanced. The unbalanced signal is amplified by the operational amplifier circuit and the shaft speed measurement value is output. Step 4: Monitor the temperature using Rh and Rk, where Rh is the hot-end bridge arm resistance and Rk is the cold-end bridge arm resistance, and Rh and Rk are isolated by polytetrafluoroethylene material to avoid heat exchange. The fixed housing (1) has a circuit board fixing groove (3) with anti-reverse design inside, which is used to install and fix the circuit board assembly; the mounting surface of the fixed housing (1) has two threaded mounting holes (4) for fixing and connecting the sensor; Rh is fixed to the air vent (2) side by potting compound, and Rk and Rh are the same distance from the housing surface in the direction of the mounting gap; An adjustment frame (9) is provided on the outside of the fixed housing (1). An oblong adjustment hole (10) with a wider bottom and narrower top is provided on the outside of the adjustment frame (9). The adjustment hole (10) corresponds to the air guide hole (2). Several sets of fixing bolts (11) are threadedly connected to the outside of the adjustment frame (9) away from the adjustment hole (10). The adjustment frame (9) has a slot (12) on one side, and an adjustment plate (13) is provided in the slot (12). The adjustment plate (13) has a vent hole (14) corresponding to the adjustment hole (10). The side of the adjustment plate (13) away from the adjustment frame (9) is threaded with several sets of adjustment bolts (15). One end of the adjustment bolt (15) passes through the adjustment plate (13) and is rotatably connected to the outside of the adjustment frame (9). An elastic sleeve (16) is fixedly connected between the vent hole (14) and the adjustment hole (10). The lower surface of the fixed housing (1) is provided with a sliding groove (17), which is connected to the air guide hole (2). An elastic metal sheet (18) is fixedly connected to the lower surface of the fixed housing (1). The elastic metal sheet (18) is fixedly connected to a first spring sheet (19) and a second spring sheet (20) on the side of the elastic metal sheet (18) close to the measured shaft and the side away from the measured shaft, respectively. The first spring sheet (19) and the second spring sheet (20) are respectively located in the corresponding sliding groove (17) and are slidably connected to the sliding groove (17). The first spring sheet (19) and the second spring sheet (20) are each provided with a through hole (21) corresponding to the air guide hole (2). The through hole (21) is initially staggered with the air guide hole (2). The inner wall of the sliding groove (17) is provided with a rubber sealing layer, which is in contact with the surface of the first spring sheet (19) and the second spring sheet (20).

2. The method for measuring axle temperature and axle speed of a high-speed train according to claim 1, characterized in that, The sensor also includes a sheath (5), a cable assembly (6) and a connector (7). The sheath (5) is made of EPDM material and has an annular structure (8) at both the front and rear ends for fixed connection with the fixed housing (1) and the tail bracket of the connector (7). The sheath (5) adopts a symmetrical structure design.

3. The method for measuring axle temperature and axle speed of a high-speed train according to claim 2, characterized in that, The elastic metal sheet (18) is made of spring steel, and the thickness of the first elastic sheet (19) and the second elastic sheet (20) is 0.3-0.5mm.

Images