Intelligent fastener for urban rail transit

Abstract

The utility model belongs to the technical field of urban rail transit fasteners, and discloses an intelligent fastener for urban rail transit, which comprises a rail fastener and an intelligent elastic base plate, and the intelligent elastic base plate is adhered to the rail fastener and is integrally designed; the rail fastener comprises a top plate and a bottom plate; the intelligent elastic base plate comprises an elastic material and a radio frequency chip RFID; wherein the top plate, the bottom plate and the elastic material are bonded into a whole to form a vibration and noise reduction main body part; the radio frequency chip RFID is adhered to the outer side of the bottom plate, the distance between the radio frequency chip RFID and the bottom surface of the bottom plate is 60-70mm, and a radio frequency antenna is designed outside the radio frequency chip RFID and is used for collecting and wirelessly transmitting information.

Description

Technical Field

[0001] The utility model relates to the technical field of urban rail transit fasteners, and more specifically, to intelligent fasteners for urban rail transit. Background Art

[0002] Rail fasteners mainly consist of elastic pads, bolts, spring clips, washers and other related accessories. Among them, the core component, the elastic pad, is mainly composed of a metal part and an elastic material, and is used to fix and restrain the rail and reduce vibration and noise. Its main types include: integral vulcanized fasteners and split fasteners, and can also be divided into compression-type vibration reduction fasteners and shear-type fasteners. Rail fasteners are one of the important components of the rail system, and have a very important impact on the safety, reliability and comfort of vehicles. In order to provide reliable guarantee for the long-term operation of the rail system, workers need to regularly inspect the fasteners on the rail.

[0003] At present, the following problems exist in the work of fastener inspection:

[0004] 1. After the fasteners are produced, the production date can only be recorded by ink printing or engraving, and permanent identification cannot be achieved.

[0005] 2. At present, the production date, use date and installation date of fasteners cannot be permanently marked by intelligent means, and efficient and accurate acquisition of fastener information in real time cannot be achieved.

[0006] 3. After the rail fasteners are installed on the subway line, the installation position cannot be accurately located. As a result, after the fasteners are damaged, maintenance personnel cannot replace the damaged fasteners in a timely and efficient manner, posing a safety hazard to train operation.

[0007] 4. During the daily rail maintenance process, the inspection of fasteners requires manual entry into the tunnel or elevated line for walking inspection, and the integrity of the fasteners is identified by the naked eye. The identification process is slow and inefficient.

[0008] 5. After identifying damaged or abnormal fasteners, the inspection personnel mark them on the roadbed or tunnel wall. The replacement personnel need to find the corresponding fasteners according to the marks. There may be unclear marks or the marks may be smeared, resulting in the inability to find and replace the fasteners in time.

[0009] Therefore, this application proposes an intelligent fastener for rapid identification, marking and positioning of urban rail transit. Utility Model Content

[0010] To solve the above problems, this application provides a design concept of intelligent fasteners for urban rail fasteners.

[0011] An intelligent fastener for urban rail fasteners, comprising: a rail fastener and an intelligent elastic pad, wherein the intelligent elastic pad is bonded to the rail fastener and is of an integrated design; the rail fastener includes a top plate, a bottom plate, a spring clip and a rail; the intelligent elastic pad includes an elastic material and a radio frequency chip RFID; wherein the top plate and the bottom plate are bonded to the elastic material as a whole, which is the main part for vibration reduction and noise reduction; the radio frequency chip RFID is bonded to the outside of the bottom plate, and the distance from the bottom surface of the bottom plate is 60 mm to 70 mm. A radio frequency antenna is designed outside the radio frequency chip RFID for information collection and wireless transmission.

[0012] Further, the radio frequency antenna is of a symmetric design, and its shape extends symmetrically to both sides in a spiral shape.

[0013] A manufacturing method for an intelligent fastener for urban rail fasteners, based on the above-mentioned intelligent elastic pad for urban rail transit, the manufacturing method includes the following steps:

[0014] Step 1: Place the RFID in its original state on the outside of the bottom plate, 60 mm to 70 mm away from the bottom surface of the bottom plate;

[0015] Step 2: Spray adhesive on the bottom plate and the top plate with the RFID installed in Step 1 together;

[0016] Step 3: Place the bottom plate and the top plate sprayed with adhesive in Step 2 together with the intelligent elastic material body in a vulcanizer for vulcanization and molding.

[0017] Further, in Step 1, the RFID and the bottom plate are fixed with structural glue.

[0018] Further, the elastic material in Step 3 includes but is not limited to rubber.

[0019] Further, the vulcanization pressure of the vulcanizer in Step 3 is 180 kg, the vulcanization temperature is 150 degrees, and the vulcanization time is 16 minutes.

[0020] Through the above manufacturing steps, it is ensured that the RFID is firmly connected to the elastic pad, avoiding loosening or falling off during use. In addition, the structural glue also has good properties such as high temperature resistance, low temperature resistance, and corrosion resistance, and can adapt to different environmental conditions.

[0021] The elastic material can be selected according to actual needs, including but not limited to rubber. Rubber has good elasticity and buffering and absorption capabilities, and can effectively reduce and absorb vibrations and noises generated during the operation of rail transit, improving the stability and comfort of passengers.

[0022] The vulcanization process of the elastic material in the above steps is a key process in the integral molding of the elastic cushion plate, which has an important impact on the molding, stiffness and durability of the elastic cushion plate. Its process parameters such as the vulcanization pressure, vulcanization temperature and vulcanization time of the vulcanizer need to be adjusted according to the characteristics of different elastic materials to obtain the best quality and performance of the elastic cushion plate. To ensure the stability of product performance, the entire vulcanization process adopts an automated control system to precisely and automatically control the vulcanization pressure, vulcanization temperature and vulcanization time, ensuring that the quality of each intelligent elastic cushion plate meets the standards.

[0023] In summary, the technical solution of installing RFID in the intelligent elastic cushion plate adopted in this application at least includes the following beneficial technical effects:

[0024] (1) Rapidly scan and collect the information and status of track fasteners, and achieve wireless rapid transmission, quickly and accurately positioning the fasteners installed on the track; it can also be used as a reference for accurately positioning other components on the track.

[0025] (2) RFID has a small volume, simple structure, low cost, low failure rate, and its service life is 15 - 20 years, achieving the same service life as the fasteners.

[0026] (3) While having the basic functions of restraining and fixing the rail with traditional fasteners and providing vibration reduction and noise reduction, a new type of intelligent elastic cushion plate is adopted.

[0027] (4) The technical solution of installing RFID in the track fasteners adopted in this application can effectively reduce the frequency of manual inspections, greatly improve the efficiency of inspections; accurately position the fasteners and improve the efficiency of daily maintenance; can accurately collect the effective information of the fasteners, accumulate data, and help the subway company analyze the operation cost, so as to further control and save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of the intelligent fastener of this application;

[0029] Figure 2 is a cross-sectional view of the intelligent elastic cushion plate;

[0030] Figure 3 is a schematic structural diagram of RFID;

[0031] Figure 4 is a structural diagram of the interaction mode of this application;

[0032] Figure 5 is the load application position;

[0033] Figure 6 is a schematic diagram of the test device;

[0034] Figure 7 is a schematic diagram of vertical tensile cyclic loading;

[0035] Figure 8 is a schematic diagram of push-pull cyclic loading;

[0036] Figure 9 is a schematic diagram of vertical bearing;

[0037] Figure 10 is a schematic diagram of vertical tension;

[0038] Figure 11 is a schematic diagram of longitudinal resistance test;

[0039] Figure 12 is a load-displacement diagram.

[0040] Description of reference numerals in the figure: 1. Intelligent elastic pad; 2. Top plate; 3. Bottom plate; 4. Elastic material; 5. RF chip RFID; 6. RF antenna; 7. Spring clip; 8. Rail. Specific implementation manners

[0041] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application; obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0042] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "top / bottom end", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0043] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "provided with", "sheathed / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0044] Embodiment:

[0045] The following combines the attached Figure 1-4 and Table 1 are used to further elaborate on this application in detail.

[0046] Table 1 is an RFID parameter diagram:

[0047]

[0048] The embodiment of this application discloses an intelligent fastener 1 for urban rail fasteners, including: a rail fastener and an intelligent elastic pad 1. The intelligent elastic pad 1 is bonded to the rail fastener and is of an integrated design; the rail fastener includes a top plate 2, a bottom plate 3, a spring clip 7 and a rail 2; the intelligent elastic pad 1 includes an elastic material 4 and a radio frequency chip RFID5; among them, the top plate 2 and the bottom plate 3 are bonded to the elastic material 4 as a whole, which is the main part for vibration reduction and noise reduction; the radio frequency chip RFID5 is bonded to the outside of the bottom plate 3, and the distance from the bottom surface of the bottom plate 3 is 60mm to 70mm. A radio frequency antenna 6 is designed outside the radio frequency chip RFID5 for collecting and wirelessly transmitting information.

[0049] See Figure 3 , the radio frequency antenna 6 is of a symmetric design, and its shape extends to both sides in a spiral shape; this design can improve the gain and directivity of the antenna 6, enhance the signal transmission effect, and ensure the accurate and timely transmission of data.

[0050] A manufacturing method for an intelligent fastener for urban rail transit, based on the above-mentioned intelligent fastener for urban rail transit, the method includes the following steps:

[0051] Step 1: Place the RFID5 in its original state on the outside of the bottom plate 3 at a distance of 60mm to 70mm from the bottom surface of the bottom plate 3;

[0052] Step 2: Spray adhesive on both the bottom plate 3 with the RFID5 installed in Step 1 and the top plate 2 together;

[0053] Step 3: Place the bottom plate 3 and the top plate 2 sprayed with adhesive in Step 2 together with the intelligent elastic material 4 in a vulcanizer for vulcanization and molding.

[0054] See Figure 2 , in Step 1, a structural glue is used to fix the radio frequency chip RFID5 to the bottom plate 3; to ensure a firm connection between the radio frequency chip RFID5 and the bottom plate 3 and avoid loosening or falling off during use. In addition, the structural glue also has good properties such as high temperature resistance, low temperature resistance, and corrosion resistance, and can adapt to different environmental conditions.

[0055] See Figure 2, the elastic material 4 in step 3 includes but is not limited to rubber; the elastic material 4 can be selected according to actual needs, such as rubber. Rubber has good elasticity and buffering ability, which can reduce vibrations and noises during the operation of rail transit and improve the comfort of passengers. In addition, rubber also has good wear resistance and corrosion resistance, which can extend the service life of the fasteners.

[0056] See Figure 2 , the vulcanization pressure of the vulcanizer in step 3 is 180 kg, the vulcanization temperature is 150 degrees, and the vulcanization time is 16 minutes; the vulcanization pressure, vulcanization temperature and vulcanization time of the vulcanizer can be adjusted according to the characteristics of the elastic material 4 to ensure the quality and performance of the fasteners. During the vulcanization process, an automated control system can be used to precisely control the vulcanization pressure, vulcanization temperature and vulcanization time to ensure that the quality of each fastener meets the standards.

[0057] It should be noted that there are various types of rail transit fasteners, mainly the integral vulcanized type fasteners and the split assembled type fasteners mentioned in this application. The technical solution of this application is also applicable to the split assembled type fasteners. The RFID 5 can be fixed on the outer side of the upper tie plate of the split assembled type fasteners using a structural glue bracket.

[0058] The implementation principle of the intelligent fasteners for urban rail transit in the embodiments of this application is as follows:

[0059] Install the RFID 5 storing relevant information inside the rail fasteners. When reading is required, place the reader close to the position where the RFID 5 is installed. The reader realizes wireless interaction with the RFID chip RFID 5 through the RF antenna 6 to obtain relevant information, and then the reader transmits the obtained information to the terminal device through the cloud server.

[0060] As an important vibration and noise reduction component of the rail transit system, the core component of the rail fastener is the elastic pad. The traditional elastic pad is composed of a top plate 2, a bottom plate 3 and an elastic material 4, mainly providing functions of fixing and restraining the rail 8 and reducing vibrations and noises of the rail system. The intelligent elastic pad 1 in this application adds an RFID chip RFID 5 on the basis of the traditional elastic pad. Through the RFID chip RFID 5, information is collected and wirelessly transmitted. Therefore, the elastic intelligent pad not only has the basic functions of the traditional elastic pad, but also provides functions of information collection, wireless information transmission and fast and accurate positioning, which makes the later maintenance and management of the rail fasteners more efficient, convenient and effectively reduces the maintenance cost.

[0061] The above radio frequency chip RFID5 has a symmetrically designed radio frequency antenna 6 that extends spirally to both sides to improve the gain and directivity of the antenna 6, enhance the transmission intensity of the signal, and ensure the accurate, stable, and timely transmission of data. In addition, the radio frequency chip RFID5 is designed to be placed outside the bottom plate 3, at a distance of 60 mm to 70 mm from the bottom surface of the bottom plate 3, to avoid signal shielding and attenuation and make its receiving and transmitting capabilities stable and reliable.

[0062] It should be noted that the reader, cloud server, and terminal device can be selected according to actual needs in terms of model, quantity, etc. Moreover, the above-mentioned reader, cloud server, and related devices of the terminal device are extremely mature existing technologies in this field and are also technical solutions that can be easily thought of by those skilled in the art. Therefore, they will not be elaborated too much in this application document.

[0063] The following are the technical specifications and test standards of this application:

[0064] 1.1 During the service life of the intelligent fastener, at vibration-sensitive buildings in the vibration isolation section required, the Z vibration level transmitted from the train passing to the tunnel wall or bridge deck should be reduced by 5 dB or more compared to the ordinary monolithic track bed. The measurement and evaluation methods of the vibration reduction effect shall be implemented in accordance with the provisions of the "Technical Specification for Floating Slab Track" (CJJ / T 191-2012).

[0065] 1.2 Vertical stiffness

[0066] The static stiffness of the intelligent fastener within the load range of 10 - 50 kN is 18 ± 3 kN / mm.

[0067] 2) Lateral stiffness

[0068] According to the lateral static stiffness test method, the lateral stiffness should not be less than 20 kN / mm, and there should be no phenomena such as slipping, yielding, cracking, and bonding failure during the test. After unloading for 3 minutes, the specimen should return to within 1.5 mm of the initial position.

[0069] 3) Dynamic-static stiffness ratio

[0070] The dynamic-static stiffness ratio measured by the low-frequency dynamic stiffness test should not be greater than 1.4.

[0071] 4) Dynamic lateral displacement of the rail head

[0072] When conducting the fatigue test according to 7.3, the dynamic lateral displacement of the rail head of a single-track rail should not be greater than 3 mm.

[0073] 1.3 Anti-fatigue performance

[0074] 1) Ability to resist vertical cyclic load

[0075] When tested according to the specified test methods, after 3 million cycles, no component shall be damaged or severely deformed, and no yielding, cracking or rubber debonding shall occur in the shock absorber. The widening of the gauge of a single-track rail shall not be more than 3 mm, and the change rate of the static stiffness shall not be more than 15%.

[0076] 2) Ability to resist vertical tensile cyclic load

[0077] When tested according to the specified test methods, after 1.5 million cycles, no deformation, cracking or debonding shall occur in the shock absorber.

[0078] 3) Ability to resist push / pull cyclic load

[0079] According to the specified test methods, after 2,000 cycles of load with an amplitude of 12 mm and 1 million cycles of load with an amplitude of 3 mm in sequence, there shall be no failure, and no deformation, cracking or debonding shall occur in the shock absorber.

[0080] 1.4 Vertical load-bearing capacity

[0081] When tested according to the specified test methods, the ratio of the deformation measured under the load condition of 70 kN / fastener to the average thickness of the fastener rubber shall not be more than 25%. During and after the test, no slipping, wear, cracking or rubber debonding shall occur in the shock absorber.

[0082] 1.5 Vertical tensile performance

[0083] When tested according to the specified test methods, the ratio of the tensile deformation to the compressive deformation corresponding to 9 kN / fastener shall not be more than 235%, and no slipping, cracking or rubber debonding shall occur in the shock absorber.

[0084] 1.6 Longitudinal rail resistance

[0085] The longitudinal resistance of each smart fastener for the underground line shall not be less than 9 kN. The longitudinal resistance of each smart fastener for the general section of the elevated line shall not be less than 7 kN, and the longitudinal resistance of each fastener for the section with small resistance on the elevated line shall preferably be 4 ± 1 kN.

[0086] 1.7 Corrosion resistance

[0087] After the shock absorber undergoes a 1,000-hour neutral salt spray test, the protection rating of the test piece shall be carried out in accordance with the provisions of GB / T 6461, and the protection rating of the shock absorber shall not be lower than Grade 9.

[0088] 1.8 Insulation resistance

[0089] When tested according to the specified test methods, the dry-state insulation resistance of the smart fastener shall not be less than 108 Ω, and the wet-state insulation resistance shall not be less than 5,000 Ω.

[0090] For the above intelligent elastic pads for urban rail transit, their performance needs to be tested during the manufacturing process. The specific test methods are as follows:

[0091] 2. Test Methods

[0092] 2.1 Vibration Damping Performance

[0093] Provide on-site test reports of similar projects.

[0094] 2.2 Stiffness Test

[0095] 1) Vertical Stiffness Test

[0096] Refer to the relevant regulations of TB / T 3396.3-2015 and conduct the static stiffness test of the intelligent fastener through a static testing machine (test load greater than 110 kN). During the test process, no disassembly and adjustment should be carried out in any way. When using the sensors of the testing machine itself to measure displacement, the systematic error caused by the self-deformation of the testing machine during loading should be eliminated.

[0097] First, preload the specimen, vertically load it at a speed of 1 - 2 kN / s until the load reaches 60 kN, unload, and statically stop for 30 s. After loading 2 times in this way, conduct the formal static stiffness test and record the loading force and displacement.

[0098] And calculate the static stiffness through the displacement value corresponding to the effective wheel load.

[0099]

[0100] The label explanations in the formula: P1, 10 kN; P2, 50 kN; S1, the displacement corresponding to P1; S2, the displacement corresponding to P2.

[0101] 2) Lateral Stiffness Test

[0102] Apply vertical and lateral loads simultaneously. The vertical load is 0 - 40 kN, and the lateral load is 0.5 times the vertical load. The lateral load acts horizontally, perpendicular to the inner side of the rail head and at 14 mm below the rail top. Continuously load / unload 3 cycles at a lateral speed of 2.5 kN / min, record the load-deformation data for every 2.5 kN increase in the lateral direction during the 3rd cycle, plot the load-displacement curve and calculate the lateral static stiffness. The applied vertical and lateral loads are accurate to 0.1 kN, the measured lateral displacement is accurate to 0.01 mm, and at least 3 tests are conducted and the average value is taken.

[0103] 3) Static-Dynamic Stiffness Ratio Test

[0104] The dynamic stiffness test of the intelligent fastener is carried out by a dynamic testing machine that can generate a load of up to 80 kN at a frequency of 10 Hz. During the test, no disassembly and adjustment should be carried out in any way. When using the sensors of the testing machine itself to measure the displacement, the systematic error caused by the self-deformation of the testing machine during loading should be eliminated.

[0105] Apply a cyclic load of 10 kN to 50 kN to the test piece, with a loading frequency of 10 Hz and 1300 cycles. Record the displacement values corresponding to 10 kN and 50 kN at the 1201st to 1204th times (TB / T 3395.1 requires 1000 load cycles, record the last 100 load cycles and select the actually applied load and displacement in 10 consecutive cycles), and then calculate the corresponding dynamic stiffness value with reference to the static stiffness calculation formula. Take the average value as the dynamic stiffness Kd of the test piece, and then calculate the static-dynamic stiffness ratio according to the following formula.

[0106]

[0107] In the formula: K s — The static stiffness of the shock absorber; K d — The dynamic stiffness of the shock absorber.

[0108] 2.3 Anti-fatigue performance test

[0109] 1) Ability to resist vertical cyclic load

[0110] (1) Refer to the provisions of TB / T 3396.4-2015 to conduct the test on the ability of the intelligent fastener to resist vertical cyclic load. Apply cyclic load to the rail head at the loading position and direction as shown, and equivalent loading can be used. Determine the anti-vertical cyclic load performance of the fastener through the changes in the static stiffness of the fastener and the position of the rail during the test, as well as the state of the fastener components after fatigue. Figure 6 As shown in the following figure, the label description: 1 represents the load action line; 2 represents the center of the inner corner arc of the rail head.

[0111] Figure 6

[0112] (2) Test parameters

[0113] The maximum load P of the cyclic load v / cosα = 70 kN P V / cosα = 70 kN; the loading angle α of the cyclic load = 26°.

[0114] (3) Test steps

[0115] Figure 7 Assemble the intelligent fastener and its corresponding supporting components into a fastener system, and use Figure 7The test device shown is used for fatigue testing. An alternative test method with an inclined base surface can also be adopted with reference to TB / T 3396.4-2015. The sleeper should be supported and fixed on a rigid foundation. A pressure block or other similar material cushion should be placed between the sleeper and the rigid foundation to ensure close contact between the sleeper and the rigid foundation.

[0116] Figure 6 The label descriptions in [reference document] are as follows: 1. Sleeper; 2. Rail; 3. Fastening system; 4. Loading device; 5. Pivot; 6. Cushion on the rigid foundation; 7. Loading frame; 8. Maximum applied load, 2PV.

[0117] Slowly load the test assembly system to the maximum load, and the loading rate for a single sleeper should not exceed 200 kN / min. Repeat the loading 10 times. In the last 3 loadings, the error of the angle α between the maximum load action line and the perpendicular line of the rail bottom surface should be within the range of ±0.5°.

[0118] Apply cyclic load to the test assembly system, from the minimum load of 9 kN to the maximum load of 2PV, with a loading frequency of 3 Hz to 5 Hz. Record the dynamic displacements of the rail relative to the sleeper for 10 cycles within the last 100 cycles of the first 1000 cycles, and take the average value as the dynamic displacement.

[0119] After completing 1000 load cycles, unload, measure the gauge (measure separately on both sides of the fastener and take the average value as the test value), and record it as the initial gauge G1. After 3×10 6 load cycles, measure the gauge again 4 hours after unloading, and record it as the gauge after fatigue

[0120] G2, and the gauge expansion ΔG = G2 - G1 ΔG = G2 - G1.

[0121] During the fatigue test, when the highest surface temperature of the component reaches 50 °C, measures such as using a fan for cooling, or reducing the loading frequency within the range of 3 Hz to 5 Hz, or temporarily stopping the loading should be adopted.

[0122] After the fatigue test, according to the test method in 7.2, measure the static stiffness of the specimen again and calculate the change rate of the static stiffness of the specimen.

[0123] 2) Ability to resist vertical tensile cyclic load

[0124] Refer to Figures 7 - 10 , apply a vertical downward pressure of 100 kN (50 kN per fastener) in the middle of the rail and alternate it to an upward tensile force of 18 kN (9 kN per fastener). The number of test cycles is 1.5×10 6 times, and the test frequency is 2 Hz. During the test, it is not allowed to re-tighten the bolts and move the position of the elastic rail clip.

[0125] 3) Ability to resist push-pull cyclic load

[0126] See Figures 7 - 10 , a cyclic longitudinal load is applied at the centroid of the rail, causing the rail to slide back and forth with an amplitude of 12 mm relative to its initial position for 2000 cycles. Subsequently, the longitudinal load is reduced and the rail slides back and forth with an amplitude of 3 mm relative to its initial position to complete 1×10 6 cycles. The loading frequency is selected on the principle that the temperature of the parts does not exceed 50 °C.

[0127] 2.4 Vertical load-bearing capacity test

[0128] See Figures 7 - 10 , a vertical force of 140 kN is applied to the middle of the rail (i.e., 70 kN per fastener) and maintained for 1 minute. Then unload and zero the displacement sensor. Then, load in steps of 10 kN (5 kN per fastener) at a loading speed of 20 kN per minute (10 kN per fastener) up to 140 kN (70 kN per fastener). When each step value is reached, keep the corresponding load constant for about 3 seconds to facilitate recording of deformation data and record the test data.

[0129] 2.5 Vertical tensile property test

[0130] See Figures 7 - 10 , a vertical load is applied to the middle of the rail, continuously varying from vertical compression of 24 kN (i.e., 12 kN per fastener) to vertical tension of 24 kN (i.e., 9 kN per fastener), for a total of 8 cycles, and the time to complete each cycle is 2 minutes. (The first 6 cycles are preloads, and the average value of the last 2 cycles is calculated.) Record the load at 18 kN and its corresponding deformation.

[0131] 2.6 Longitudinal resistance test

[0132] See Figure 11 , the longitudinal resistance test of the rail is carried out in accordance with the provisions of TB / T 3396.1-2015. Such as Figure 12 Install the component on the test bench. The load acts on the center position of the rail bottom cross-section. The dial gauge records the displacement at one end cross-section position of the rail. Ensure that it has sufficient range before the test.

[0133] Figure 11 Explanation of the labels in : 1. Rail; 2. Fastener assembly (including under-rail pad, elastic clip, T-bolt, shock absorber, bolt, gasket, etc.); 3. Dial gauge; 4. Sleeper; 5. Sleeper positioning device.

[0134] Apply the load at a speed of (0.5 - 1) kN / min in increments of 1 kN. Pause for 30 s when each increment is reached, and wait for the displacement to stabilize before applying the next increment. Record the longitudinal displacement of the rail at each increment. When slip occurs between the fastener and the rail, quickly remove the longitudinal load, and record the final position of the rail after 3 min. Plot the recorded values according to Figure 12 Draw a load-displacement graph, with the displacement on the X-axis and the load on the Y-axis.

[0135] Figure 12 The label descriptions in

[0136] D1—the maximum longitudinal displacement of the rail, mm;

[0137] D2—the residual longitudinal displacement of the rail after unloading, mm;

[0138] D3—the elastic longitudinal displacement of the rail before slip, mm

[0139] F4—the maximum axial force borne by the rail before inelastic longitudinal displacement occurs, kN.

[0140] Determine D3 and D1 from each load-displacement graph, and then calculate D2 according to the following formula:

[0141] D3 = D1 - D2

[0142] Find the position value close to D3 on the load-displacement graph curve and read the corresponding load F on the Y-axis.

[0143] 2.7 Corrosion resistance test

[0144] After the intelligent fastener has undergone a 1000-hour neutral salt spray test, the protection rating of the test piece shall not be less than 9 levels in accordance with the provisions of GB / T 6461.

[0145] In accordance with the provisions of TB / T3396.6 - 2015, place the assembled intelligent fastener system in a neutral salt spray environment that meets the requirements of GB / T10125 for a 480-hour salt spray test. After the salt spray test, check whether the fastener system can be disassembled with hand tools, and check the rust condition of the test piece after disassembly.

[0146] 2.8 Insulation resistance

[0147] 1) Dry-state insulation resistance test method

[0148] Conduct the dry-state insulation resistance test in accordance with the provisions of Appendix A "Test Method for the Working Resistance of the Base Plate" of GB / T 21527. Apply 500 V DC between the rail-bearing plate and the base of the test piece and measure the insulation resistance.

[0149] 2) Wet-state insulation resistance test method

[0150] According to TBT 3396.5-2015 Test Methods for High-Speed Railway Fastening Systems - Part 5: Determination of Insulation Resistance, the wet resistance test is carried out. The sleepers used in the test are uniformly prestressed reinforced concrete long sleepers for underground lines.

[0151] The above are all preferred embodiments of this application, and the protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. An intelligent fastener for urban rail transit, characterized in that, Comprising: Track fasteners and an intelligent elastic pad (1), the intelligent elastic pad (1) being bonded to the track fasteners and having an integrated design; the track fasteners comprising a top plate (2), a bottom plate (3), a spring clip (7) and a rail (8); the intelligent elastic pad (1) comprising an elastic material (4) and a radio frequency chip RFID (5); wherein the top plate (2) and the bottom plate (3) are bonded to the elastic material (4) as a whole; the radio frequency chip RFID (5) is bonded to the outside of the bottom plate (3), and the distance from the bottom surface of the bottom plate (3) is 60 mm to 70 mm, and a radio frequency antenna (6) is designed outside the radio frequency chip RFID (5) for collecting and wirelessly transmitting information.

2. The intelligent fastener for urban rail transit according to claim 1, wherein: The radio frequency antenna (6) has a symmetrical design and is shaped like a helix extending to both sides.

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