A rail bottom eddy current detection system and method

Abstract

The present invention relates to a rail bottom eddy current detection system and method, which includes an inlet encoder device, a sliding slide rail group, a floating frame, a fixed frame, an inlet clamping roller, a real-time follow-up device for the rail bottom eddy current probe, an outlet clamping roller, and an outlet encoder device. The inlet encoder device is arranged at the inlet of the eddy current detection area, and the outlet encoder device is arranged at the outlet of the eddy current detection area. The fixed frame is fixed within the eddy current detection area, and a sliding slide rail group is fixed on the fixed frame. The floating frame is slidably connected to the fixed frame through the sliding slide rail group, enabling the floating frame to slide along a direction perpendicular to the running direction of the rail. The floating frame is sequentially connected with an inlet clamping roller, a real-time follow-up device for the rail bottom eddy current probe, and an outlet clamping roller from the inlet side to the outlet side. The inlet clamping roller and the outlet clamping roller can be clamped against both side surfaces of the rail head. The advantages are as follows: It can realize on-line replacement of manual detection of the rail bottom, and has a high detection accuracy rate.

Description

Technical Field

[0001] The present invention belongs to the field of non-destructive testing of steel rails, and particularly relates to a steel rail bottom eddy current detection system and method. Background Art

[0002] Currently, the quality inspection of the lower surface of the rail bottom in domestic steel rail factories all adopts the method of manual visual inspection. Closed defects on the lower surface of the rail bottom cannot be effectively detected, and at the same time, the situation of missed detection due to manual fatigue is likely to occur. When the steel rail is laid on the railway line, the lower surface of the rail bottom is in contact with the sleeper and the roadbed. If there are defects on the lower surface of the rail bottom, the existing technical means cannot effectively detect the defects and cannot eliminate the safety "hidden dangers" caused by the defects on the lower surface of the rail bottom. When the imported eddy current flaw detectors in domestic steel rail factories detect the defects on the lower surface of the rail bottom, multiple point probes are arranged along the circumferential direction on a high-speed rotating disc, and the point probes are set at specific angles to ensure that each point probe can vertically or approximately vertically scan the corresponding area of the rail bottom, so as to achieve effective detection of longitudinal and oblique defects on the lower surface of the rail bottom. For example: Patent Publication No.: CN113109433A discloses a steel rail on-line eddy current detection device, which uses 9 eddy current detection components. The detection range of this detection device can cover the top and side surfaces of the rail head of the steel rail to be detected, as well as the bottom and side surfaces of the rail bottom. Patent Publication No.: CN112525987A discloses a steel rail eddy current flaw detection device, which uses multiple flaw detection brackets to drive eddy current probes to be distributed on both sides of the rail head, both sides of the rail head tread, both sides of the rail head arc area, both sides of the rail bottom side, and below the rail bottom, so as to achieve multi-directional and comprehensive flaw detection and improve the flaw detection accuracy. However, in the actual use process, due to the fact that the rotating probe system at the rail bottom cannot ensure a constant lift-off gap during the detection process and cannot achieve real-time follow-up of the probe to the rail bottom, false alarms and missed alarms frequently occur during the detection process, losing the guiding significance for actual production. [[ID=X]]Summary of the Invention

[0003] To overcome the deficiencies of the prior art, the purpose of the present invention is to provide a steel rail bottom eddy current detection system and method, which applies multi-directional sensitive eddy current detection technology to realize on-line eddy current flaw detection of the rail bottom. Static eddy current probes are used to detect open and closed surface defects of various directions and types on the lower surface of the rail bottom of the steel rail from 0° to 90°, and on-line replacement of manual detection is realized, greatly improving the detection accuracy and production efficiency.

[0004] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0005] A rail bottom eddy current detection system includes an inlet encoder device, a sliding slide rail group, a floating frame, a fixed frame, an inlet clamping roller, a real-time following device for the rail bottom eddy current probe, an outlet clamping roller, and an outlet encoder device. The inlet encoder device is arranged at the inlet of the eddy current detection area, and the outlet encoder device is arranged at the outlet of the eddy current detection area. The fixed frame is fixed within the eddy current detection area, and the sliding slide rail group is fixed on the fixed frame. The floating frame is slidably connected to the fixed frame through the sliding slide rail group, enabling the floating frame to slide along a direction perpendicular to the running direction of the rail.

[0006] The floating frame is sequentially connected with an inlet clamping roller, a real-time following device for the rail bottom eddy current probe, and an outlet clamping roller from the inlet side to the outlet side. The inlet clamping roller and the outlet clamping roller can be clamped against both side surfaces of the rail head.

[0007] Both the inlet encoder device and the outlet encoder device include an encoder disk, a speed measurement rubber wheel, a lifting cylinder, a swing arm, a return spring, a support frame, a conveying roller path, and roller path bearings. The conveying roller path is installed on the support frame through the roller path bearings. The lifting cylinder is hinged to the support frame, the cylinder rod of the lifting cylinder is hinged to the swing arm, one end of the swing arm is rotatably connected to the support frame, the other end is connected with the speed measurement rubber wheel, the encoder disk is connected with the speed measurement rubber wheel, and one end of the return spring is fixed on the support frame and the other end is fixedly connected with the swing arm.

[0008] The support frame includes a frame body, a height adjustment rod, a swing arm base plate, a swing arm back plate, and a positioning block. The swing arm base plate is fixed on the frame body, the swing arm back plate is slidably connected to the swing arm base plate, the positioning block is fixedly connected to the swing arm back plate, the height adjustment rod is threadedly connected to the positioning block, the height adjustment rod is connected to the swing arm base plate through a bearing, one end of the swing arm is rotatably connected to the swing arm back plate through a rotating shaft, the lifting cylinder is hinged to the swing arm back plate, and one end of the return spring is fixed on the swing arm back plate.

[0009] The real-time following device for the rail bottom eddy current probe is at least two.

[0010] The inlet clamping roller and the outlet clamping roller have the same structure, and both include a clamping mechanism rotating shaft, a clamping driving left arm, a clamping driving right arm, a base, a clamping roller, a connecting rod, a hydraulic cylinder, and a clamping roller swing arm. The base is connected to the clamping mechanism rotating shaft through a bearing, and the base is fixedly connected to the floating frame. The clamping driving left arm and the clamping driving right arm are respectively fixedly connected to the clamping mechanism rotating shafts arranged on both sides of the rail. The piston rod of the hydraulic cylinder is hinged to one end of the clamping driving left arm, the other end of the clamping driving left arm is hinged to one end of the connecting rod, and the other end of the connecting rod is hinged to the clamping driving right arm. One end of the clamping roller swing arm is connected to the clamping roller, and the other end is fixedly connected to the clamping mechanism rotating shaft.

[0011] It further includes a supporting roller, and the supporting roller is fixedly connected within the floating frame for supporting the rail.

[0012] The described idler includes an adjusting bolt, a fixing plate, an adjusting back plate, and an idler body. The adjusting back plate is provided with an oblong hole. The adjusting back plate and the fixing plate are fixedly connected by bolts. The fixing plate is threadedly connected with the adjusting bolt. The top end of the adjusting bolt abuts against the adjusting back plate. The idler body is installed on the adjusting back plate through a bearing.

[0013] It further includes a reset cylinder. The reset cylinder is fixedly connected to the top of the fixed frame. The reset cylinders are arranged oppositely and can push the floating frame to move towards the middle of the fixed frame.

[0014] The described real-time follow-up device for the eddy current probe at the rail bottom includes a horizontal follow-up mechanism, a vertical follow-up mechanism, and a group of eddy current probes at the rail bottom. The horizontal follow-up mechanism is connected to the vertical follow-up mechanism. Both the horizontal follow-up mechanism and the vertical follow-up mechanism include a follow-up base plate, a follow-up crossed roller bearing, an action cylinder, a follow-up compression spring, a positioning wheel plate, and a follow-up slide plate. The follow-up base plate is connected to the follow-up slide plate through the follow-up crossed roller bearing. The push rod of the action cylinder is connected to the follow-up slide plate. A follow-up compression spring is sleeved on the push rod of the action cylinder. The positioning wheel plate is installed on the follow-up slide plate. The follow-up slide plate of the horizontal follow-up mechanism is fixedly connected to the follow-up base plate of the vertical follow-up mechanism. A horizontal positioning wheel is connected to the positioning wheel plate of the horizontal follow-up mechanism, and a lift-off gap positioning wheel is connected to the positioning wheel plate of the vertical follow-up mechanism.

[0015] A method for eddy current detection of the rail bottom includes the following steps:

[0016] 1) When the conveying roller table sends the rail into the entrance encoder device, the speed measuring rubber wheel of the entrance encoder device presses onto the tread of the rail head. The rail continues to move forward, driving the speed measuring rubber wheel to rotate, and the encoder code disk starts to count to form the rail length information.

[0017] 2) When the rail runs to the position of the entrance clamping roller, the two clamping rollers press against both side surfaces of the rail head. At the same time, the floating frame follows horizontally, and the rail enters the area of the real-time follow-up device for the eddy current probe at the rail bottom. The horizontal positioning wheel and the lift-off gap positioning wheel of the real-time follow-up device for the eddy current probe at the rail bottom simultaneously press against the side surface of the rail waist and the lower plane of the rail bottom. The gap between the group of eddy current probes at the rail bottom and the lower surface of the rail bottom is 2.5 - 3.0 mm, and the eddy current detection of the lower surface of the rail bottom starts.

[0018] 3) When the rail runs to the exit clamping roller of the eddy current flaw detector, the exit clamping roller of the eddy current flaw detector repeats the action process of the entrance clamping roller, pressing the two clamping rollers against both side surfaces of the rail head; during the eddy current detection process, the rail drives the floating frame to slide relative to the fixed frame on the sliding rail group, and the real-time positioning of the whole real-time follow-up device for the eddy current probe at the rail bottom in the horizontal direction is realized.

[0019] 4) When the rail runs into the area of the exit encoder device, the speed-measuring rubber wheel of the exit encoder device presses onto the tread surface of the rail head. As the rail continues to move forward, it drives the speed-measuring rubber wheel to rotate, and the encoder disk coaxial with the rubber wheel starts to count to form the rail length information. When the tail of the rail leaves the exit encoder device, its speed-measuring rubber wheel rises and disengages from the tread surface of the rail head to complete the measurement of the rail length data.

[0020] 5) When the tail of the rail leaves the entrance clamping rollers, the two clamping rollers move away from both sides of the rail head. When the tail of the rail leaves the real-time follow-up device for the rail bottom eddy current probe, the real-time follow-up device for the rail bottom eddy current probe moves downward, and the rail bottom eddy current probe group quickly descends and disengages from the detection position in the height direction. At the same time, the rail bottom eddy current probe group horizontally moves out of the rail bottom area of the rail. At this time, the lift-off gap positioning wheel of the real-time follow-up device for the rail bottom eddy current probe leaves the lower plane of the rail bottom first, and the horizontal positioning wheel moves away from the side surface of the rail web later. After the above actions are completed, the real-time follow-up device for the rail bottom eddy current probe returns to the original position.

[0021] 6) When the tail of the rail leaves the exit clamping rollers of the eddy current flaw detector, the two clamping rollers move away from both sides of the rail head. At this time, the floating frame remains at the horizontal position at the moment when the tail of the rail leaves. The cylinder rods of the four floating frame reset cylinders at the four top corners of the fixed frame simultaneously extend an equal length to push the floating frame back to the initial position.

[0022] When the tail of the rail leaves the eddy current flaw detection exit encoder device, its speed-measuring rubber wheel rises and disengages from the tread surface of the rail head, completing the quality detection of the entire lower surface of one rail.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. During the detection process, the floating frame is realized to move horizontally in real time along with the rail. At the same time, the real-time follow-up device for the rail bottom eddy current probe is used to realize the horizontal and vertical follow-up of the rail bottom eddy current probe group, achieving real-time tracking of the rail position.

[0025] 2. The gap between the detection surface of the rail bottom eddy current probe group and the rail bottom plane of the detected rail can be arbitrarily set within the range of 2.0 - 3.0 mm, realizing a constant gap between the rail bottom eddy current probe group and the lower surface of the detected rail. Whether the rail moves horizontally and vertically or suddenly jumps, the rail bottom eddy current probe group can rely on the horizontal and vertical real-time follow-up devices of the probe to achieve real-time tracking of the rail position.

[0026] 3. For the rail bottom eddy current detection system, in 30 dynamic tests of the sample rail, the false alarm rate of all longitudinal and transverse artificial defects on the sample rail is zero, and the false alarm rate ≤ 3%, which can effectively detect various types of defects in all directions on the lower surface of the rail bottom.

[0027] 4. It solves the problems such as probe lift-off interference during the eddy current testing of rail and the sensitivity balance of static probe for detecting open and closed defects in all directions from 0° to 90°.

[0028] 5. The detection sensitivity meets the requirements of European standard EN 13674 and Chinese railway standard TB / T 2344.

[0029] 6. It realizes on-line replacement of manual inspection with high detection accuracy. Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of the eddy current detection system for the rail bottom.

[0031] Figure 2 It is a front view of the real-time follow-up device for the rail bottom eddy current probe.

[0032] Figure 3 It is a side view of the real-time follow-up device for the rail bottom eddy current probe.

[0033] Figure 4 It is a schematic structural diagram of the outlet encoder device.

[0034] Figure 5 It is a schematic structure of the outlet clamping roller Figure 1 。

[0035] Figure 6 It is a schematic structure of the outlet clamping roller Figure 2 。

[0036] Figure 7 It is a front view of the idler roller.

[0037] Figure 8 It is a side view of the idler roller.

[0038] Figure 9 Group diagram of the rail bottom eddy current probe.

[0039] In the figure: 1 - rail; 2 - inlet encoder device; 3 - sliding rail group; 4 - floating frame; 5 - fixed frame; 6 - reset cylinder; 7 - inlet clamping roller; 8 - idler roller; 9 - No.1 real-time follow-up device for the rail bottom eddy current probe; 10 - No.2 real-time follow-up device for the rail bottom eddy current probe; 11 - outlet clamping roller; 12 - outlet encoder device; 13 - conveying roller table;

[0040] 201 - height adjusting rod; 202 - swing arm base plate; 203 - swing arm back plate; 204 - rotating shaft; 205 - reset spring; 206 - connecting shaft; 207 - swing arm; 208 - code disk; 209 - roller bearing; 210 - base; 211 - height adjusting handwheel; 212 - positioning block; 213 - cylinder rod; 214 - lifting cylinder; 215 - speed measuring rubber wheel; 216 - conveying roller table; 217 - foot;

[0041] 701 - Clamping roller 702 - Hydraulic cylinder 703 - Bearing 704 - Clamping roller swing arm 705 - Rotation shaft of clamping mechanism 706 - Left arm of clamping drive 707 - Adjusting rod for clamping roller opening 708 - Right arm of clamping drive 709 - Hydraulic cylinder position adjusting rod 710 - Cross beam of floating frame 4 711 - Hydraulic cylinder mounting base 712 - Hydraulic cylinder stroke adjusting rod 713 - Fastening nut for hydraulic cylinder position adjusting rod;

[0042] 801 - Idler roller body 802 - Idler roller bearing 803 - Installation platform 804 - Adjusting back plate 805 - Fixed plate 806 - Adjusting bolt 807 - Base;

[0043] 901 - Horizontal action cylinder 902 - Horizontal follow-up compression spring 903 - Horizontal follow-up slide plate 904 - Horizontal follow-up base plate 905 - Horizontal follow-up cross roller bearing 906 - Horizontal positioning wheel plate 907 - Probe horizontal position positioning wheel 909 - Eddy current probe group for rail bottom 910 - Vertical follow-up slide plate 911 - Vertical follow-up base plate 912 - Vertical follow-up compression spring 913 - Vertical action cylinder 915 - Probe group connection plate 916 - Base 917 - Lift-off gap positioning wheel 918 - Vertical follow-up cross roller bearing;

[0044] 001 - Eddy current probes for multi-directionally sensitive rail bottom of No. 1, 2, 3, 4, 5, 6, 7, 8 002 - Shielding strip for mutual inductance signal between probe rows 003 - Probe group housing. Detailed implementation mode

[0045] The present invention will be described in detail below in conjunction with the accompanying drawings of the specification, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0046] See Figures 1 - 8 , a rail bottom eddy current detection system for a rail 1, comprising an inlet encoder device 2, a sliding rail group 3, a floating frame 4, a fixed frame 5, an inlet clamping roller 7, a real-time follow-up device for rail bottom eddy current probes, an outlet clamping roller 11, and an outlet encoder device 12. The inlet encoder device 2 is arranged at the inlet of the eddy current detection area, the outlet encoder device 12 is arranged at the outlet of the eddy current detection area, the fixed frame 5 is fixed in the eddy current detection area, the sliding rail group 3 is fixed on the fixed frame 5, and the floating frame 4 is slidably connected to the fixed frame 5 through the sliding rail group 3, so that the floating frame 4 can slide along a direction perpendicular to the running direction of the rail 1.

[0047] The floating frame 4 is sequentially connected with an inlet clamping roller 7, a real-time follow-up device for eddy current probes at the rail bottom, and an outlet clamping roller 11 from the inlet side to the outlet side. When the rail passes through the inlet and outlet sides by means of the clamping rollers 7 and 11, the two clamping rollers of the clamping rollers 7 and 11 clamp both sides of the rail head. The large instantaneous horizontal displacement during the operation of the rail at a speed of 1.5 m / s will drive the overall horizontal real-time follow-up of the floating frame 4. The two sets of real-time follow-up devices for eddy current probes at the rail bottom on the floating frame 4 also achieve real-time follow-up of the large displacement of the horizontal position of the rail. The real-time follow-up device for eddy current probes at the rail bottom is at least two sets. Figure 1 Two sets are used, one for normal operation and one as a standby. Once the real-time follow-up device for eddy current probes at the rail bottom in the working state shuts down, the other can be started within a short time (5 minutes) to ensure continuous production.

[0048] See Figure 4 , the inlet encoder device 2 and the outlet encoder device 12 have the same structure. Taking the outlet encoder device 12 as an example, this device includes a code disk 208, a speed measurement rubber wheel 215, a lifting cylinder 214, a swing arm 207, a return spring 205, a support frame, a conveying roller path 216, and a roller path bearing 209. The conveying roller path 216 is installed on the support frame through the roller path bearing 209. The lifting cylinder 214 is hinged to the support frame. The cylinder rod 213 of the lifting cylinder 214 is hinged to the swing arm 207. One end of the swing arm 207 is rotatably connected to the support frame, and the other end is connected with the speed measurement rubber wheel 215. The code disk 208 is connected with the speed measurement rubber wheel 215. One end of the return spring 205 is fixed on the support frame, and the other end is fixedly connected with the swing arm 207.

[0049] The support frame includes a frame body, a height adjustment rod 201, a swing arm base plate 202, a swing arm back plate 203, and a positioning block 212. The bottom of the frame body is connected to a base 210, and the bottom of the base 210 is connected to a foot 217. The swing arm base plate 202 is fixed to the frame body, the swing arm back plate 203 is slidably connected to the swing arm base plate 202, the positioning block 212 is fixedly connected to the swing arm back plate 203, the height adjustment rod 201 is threadedly connected to the positioning block 212, the height adjustment rod 201 is connected to the swing arm base plate 202 through a bearing, one end of the swing arm 207 is rotatably connected to the swing arm back plate 203 through a rotating shaft 204, the lifting cylinder 214 is hinged to the swing arm back plate 203, and one end of the return spring 205 is fixed to the swing arm back plate 203. A height adjustment handwheel 211 is fixedly connected to the height adjustment rod 201. The height of the swing arm back plate 203 is adjusted by rotating the height adjustment handwheel 211 to move the height adjustment rod 201 up or down. The height adjustment rod 201 drives the swing arm back plate 203 to move up or down, thereby realizing the up or down movement of the swing arm 207. A speed measurement rubber wheel 215 is installed on the swing arm 207. The support frame can adapt to the detection of rails 1 with various heights. The height of the rail is generally between 140 and 200 mm. When detecting a rail with a low height, the height of the speed measurement rubber wheel 215 can be reduced by rotating the height adjustment handwheel 211 to ensure good contact between the speed measurement rubber wheel 215 and the tread of the rail head of the rail 1. Conversely, the height of the speed measurement rubber wheel 215 can also be increased by rotating the height adjustment handwheel 211 to ensure good contact between the speed measurement rubber wheel 215 and the tread of the rail head of the rail 1 with a high height. During the detection process, ensuring good contact between the speed measurement rubber wheel 215 and the tread of the rail head of the rail 1 ensures that the speed measurement rubber wheel 215 does not lose "revolutions" during the high-speed movement of the rail 1, thereby ensuring that the encoder disk 208 does not lose "revolutions", ensuring accurate measurement of the rail length, and facilitating the accurate positioning of "defects" in the length direction of the rail.

[0050] See Figure 5 , Figure 6, the inlet clamping roller 7 and the outlet clamping roller 11 have the same structure, both including a clamping mechanism rotating shaft 705, a clamping drive left arm 706, a clamping drive right arm 708, a base 710, a clamping roller 701, a connecting rod 707, a hydraulic cylinder 702, and a clamping roller swing arm 704. The base 710 is connected to the clamping mechanism rotating shaft 705 through a bearing 703, and the base 710 is fixedly connected to the floating frame 4. The clamping drive left arm 706 and the clamping drive right arm 708 are respectively fixedly connected to the clamping mechanism rotating shafts 705 arranged on both sides of the rail 1. The piston rod of the hydraulic cylinder 702 is hinged to one end of the clamping drive left arm 706, the other end of the clamping drive left arm 706 is hinged to one end of the connecting rod 707, and the other end of the connecting rod 707 is hinged to the clamping drive right arm 708. One end of the clamping roller swing arm 704 is connected to the clamping roller 701, and the other end is fixedly connected to the clamping mechanism rotating shaft 705. The connecting rod 707 can adopt a structure with adjustable length. For example, the connecting rod adopts a connection method of a screw sleeve and a screw rod. The two ends of the screw sleeve are connected by a screw rod in the middle. The two ends of the screw rod are respectively processed with left-handed threads and right-handed threads, and nuts can be fixed on the screw rod to facilitate the on-line adjustment of the length of the connecting rod 707. It can also adopt a structure with a screw sleeve with left-handed internal threads and right-handed internal threads in the middle and screw rods at both ends, and the length is adjusted by rotating the screw sleeve.

[0051] A hydraulic cylinder position adjusting rod 709 is installed at the rear of the hydraulic cylinder 702. The hydraulic cylinder position adjusting rod 709 is connected to the hydraulic cylinder mounting base 711 and is fastened to the hydraulic cylinder mounting base 711 through a hydraulic cylinder position adjusting rod fastening nut 713. The hydraulic cylinder mounting base 711 is welded to the cross beam 710 of the floating frame 4. Loosen the hydraulic cylinder position adjusting rod fastening nut 713, move the hydraulic cylinder mounting base 711 horizontally, so as to change the position of the hydraulic cylinder 702 in the horizontal direction. At the same time, by cooperating with the adjustment of the hydraulic cylinder stroke adjusting rod 712, rough positioning and precise positioning of the two clamping rollers 701 in the horizontal position can be realized, so as to realize the adaptive adjustment of the actual horizontal position of the rail operation. The hydraulic cylinder stroke adjusting rod 712 can adopt the same structure as the connecting rod 707 to realize the length adjustment.

[0052] Figure 7 , Figure 8, the eddy current detection system for the rail base of the rail 1 further includes a roller 8. The roller 8 is fixedly connected within the floating frame 4 and can be arranged on the left and right sides of the real-time follow-up device for the rail base eddy current probe, and is used to support the rail 1. The roller 8 includes an adjusting bolt 806, a fixing plate 805, an adjusting back plate 804, and a roller body 801. The adjusting back plate 804 is provided with an oblong hole. The adjusting back plate 804 and the fixing plate 805 are fixedly connected by bolts, and the relative height between the fixing plate 805 and the adjusting back plate 804 can be adjusted. The fixing plate 805 is threadedly connected with the adjusting bolt 806. The top end of the adjusting bolt 806 abuts against the adjusting back plate 804. The adjusting back plate 804 is fixedly connected with the mounting platform 803. The mounting platform 803 is horizontally arranged, and the roller body 801 is mounted thereon through bearings. The roller body 801 is made of shock-absorbing and wear-resistant polyimide material; the bottom of the fixing plate 805 is fixedly connected with the base 807. By screwing the adjusting bolt 806 and the bolt, the height of the adjusting back plate 804 is adjusted, and thus the height of the roller body 801 is adjusted smoothly.

[0053] See Figure 1 , a reset cylinder 6 is fixedly connected to the top of the fixed frame 5. It can be arranged at the four corners of the fixed frame 5. The reset cylinders 6 are arranged oppositely and can push the floating frame 4 to move towards the middle of the fixed frame 5. When starting to detect the bottom surface of the rail 1, the cylinder rod 213 of the reset cylinder 6 retracts, and the floating frame 4 can move along the sliding rail group 3.

[0054] See Figure 2 , Figure 3 , the real-time follow-up device for the rail base eddy current probe includes a horizontal follow-up mechanism, a vertical follow-up mechanism, and a rail base eddy current probe group 909. The horizontal follow-up mechanism is connected to the vertical follow-up mechanism, and the two respectively drive the horizontal direction and the vertical direction of the rail base eddy current probe group 909. The horizontal follow-up mechanism drives the rail base eddy current probe group 909 to move horizontally along with the rail waist of the rail 8, and the vertical follow-up mechanism drives the rail base eddy current probe group 909 to move vertically along with the bottom surface of the rail 8.

[0055] For the horizontal follow-up mechanism and the vertical follow-up mechanism, taking the horizontal follow-up mechanism as an example, the horizontal follow-up mechanism includes a horizontal follow-up base plate 904, a horizontal follow-up crossed roller bearing 905, a horizontal action cylinder 901, a horizontal follow-up compression spring 902, a horizontal positioning wheel plate 906, and a horizontal follow-up sliding plate 903.

[0056] The horizontal follower substrate 904 is connected to the horizontal follower slide plate 903 through a horizontal follower crossed roller bearing 905. The push rod of the horizontal action cylinder 901 is connected to the horizontal follower slide plate 903. A horizontal follower compression spring 902 is sleeved on the push rod of the horizontal action cylinder 901. The horizontal positioning wheel plate 906 is installed on the horizontal follower slide plate 903. The horizontal follower slide plate 903 of the horizontal follower mechanism is fixedly connected to the vertical follower substrate 911 of the vertical follower mechanism. A horizontal position positioning wheel 907 is connected to the horizontal positioning wheel plate 906, and a lift-off clearance positioning wheel 917 is connected to the positioning wheel plate of the vertical follower mechanism. When the positioning wheel 907 and the lift-off clearance positioning wheel 917 are pressed against the surface of the rail 1, the follower compression springs 902 and 912 are in a contracted state. Two sets of horizontal follower crossed roller bearings 905 are provided on the horizontal follower substrate 904 to balance the sliding friction force exerted by the probe horizontal position positioning wheel 907 on the two sets of bearings during flaw detection, ensuring that the horizontal follower slide plate 903 runs smoothly without shaking and improving the detection accuracy. Two sets of vertical follower crossed roller bearings 918 are provided on the vertical follower substrate 911, and their functions are the same as those of the horizontal follower crossed roller bearings 905 on the horizontal follower substrate 904. The structure and working process of the real-time follower device for the rail bottom eddy current probe are the same as those of an eddy current probe real-time follower device for steel surface flaw detection disclosed in the application number: 202110290333.2.

[0057] Adjust the height of the lift-off clearance positioning wheel 917 to achieve clearance setting. When the height of the lift-off clearance positioning wheel 917 increases, the clearance between the detection surface of the rail bottom eddy current probe group and the bottom plane of the detected rail increases, and vice versa. The adjustment process is to loosen the upper and lower fastening nuts of the lift-off clearance positioning wheel 917, and then adjust the lower nut to make the nut rise along the bolt, and the clearance becomes smaller. Adjust the lower nut to make the nut descend along the bolt, and the clearance becomes larger. After the clearance is adjusted appropriately, lock the upper and lower nuts, and the clearance is set. It is realized that the clearance between the detection surface of the rail bottom eddy current probe group and the bottom plane of the detected rail can be arbitrarily set within the range of 2.0 - 3.0 mm.

[0058] During the detection process, the lift-off clearance positioning wheel 917 is in direct contact with the lower surface of the detected rail bottom. At this time, the clearance between the rail bottom eddy current probe group 909 and the lower surface of the detected rail bottom is a known set value, and the clearance is ensured to be constant during the detection process. When the rail moves horizontally and vertically or suddenly jumps, the rail bottom eddy current probe group 909 can rely on the horizontal and vertical real-time follower mechanisms of the probe to achieve real-time tracking of the rail position.

[0059] At least two (2 to N) eddy current probes 001 are installed on the rail bottom eddy current probe group. The eddy current probes are fixed in the probe group housing 003. The eddy current probes 001 are arranged in rows, with shielding strips 002 provided between rows. The eddy current probes 001 between rows are arranged staggeredly to form an array eddy current composite probe. Driven by the rail bottom eddy current probe real-time follow-up device, it is placed on the rail bottom. The detection range of the array eddy current composite probe fully covers the rail bottom transversely.

[0060] The array eddy current composite probe generates eddy currents and electromagnetic fields with multi-directional complex transformations on the surface and near-surface of the rail bottom. When defects in all directions from "0 to 90°" on the rail bottom surface pass through the detection area of the array eddy current composite probe, the resulting eddy current changes cause changes in the spatial electromagnetic field. The electromagnetic field change signal is detected as the maximum change signal by a certain detection coil among the n groups of detection coils of 2 to N eddy current probes. The detected maximum change signal is transmitted to the multi-frequency analysis eddy current flaw detector, which detects and displays the defect feedback maximum signal, achieving accurate detection of defects on the rail bottom surface.

[0061] Rail 1 rail bottom eddy current detection method:

[0062] 1) When the conveying roller table 216 sends the rail 1 into the entrance encoder device 2, its speed measurement rubber wheel 215 presses onto the tread of the rail head of the rail 1, and the rail 1 continues to move forward, driving the speed measurement rubber wheel 215 to rotate (see Figure 1 、 Figure 4 ), and the encoder code disk 208 coaxial with the speed measurement rubber wheel starts to count to form the rail 1 length information;

[0063] 2) See Figure 1 、 Figure 5 、 Figure 6 , when the rail 1 runs to the position of the entrance clamping roller 7, the piston rod of the hydraulic cylinder 702 extends, driving the clamping drive left arm 706, connecting rod 707 and clamping drive right arm 708 to move, driving the clamping roller swing arm 704 and clamping roller 701 to move towards each other, and pressing the two clamping rollers 701 against both side surfaces of the rail head of the rail 11.

[0064] 3) The rail 1 continues to move forward through the supporting roller 8 and enters the area of the 1# rail bottom eddy current probe real-time follow-up device 9 and the 2# rail bottom eddy current probe real-time follow-up device 10. See Figure 2 、 Figure 3 , the horizontal action cylinder 901 and the vertical action cylinder drive the horizontal follow-up slide plate and the vertical follow-up slide plate to move simultaneously, pressing the probe horizontal position positioning wheel and the lift-off gap positioning wheel against the side surface of the rail waist and the lower plane of the rail bottom of the rail 1 at the same time. At this time, the gap between the rail bottom eddy current probe group 909 and the lower plane of the rail bottom of the rail 1 is 2.5 to 3.0 mm, and the eddy current detection of the lower surface of the rail bottom of the rail 1 starts.

[0065] 4) SeeFigure 1 , Figure 4 , Figure 5 When the rail 1 runs to the area of the outlet clamping roller 11, the outlet clamping roller 11 repeats the action process of the inlet clamping roller 7, and presses the two clamping rollers 701 against both side surfaces of the rail head of the rail 1. At this time, the floating frame 4 is positioned by the real-time horizontal position of the rail 1, that is, during the detection process, the rail 1 drives the floating frame 4 to make real-time relative sliding on the sliding rail group 3, realizing the real-time horizontal positioning of the entire 1# bottom-rail eddy current probe real-time follower device 9 and the 2# bottom-rail eddy current probe real-time follower device 10. When the rail 1 runs to the area of the outlet encoder device 12, it repeats the action process of the inlet encoder device 2, and its encoder disk 208 starts to count to form the length information of the rail 1.

[0066] 5) See Figures 1 - 8 , when the tail of the rail 1 leaves the inlet encoder device 2, the speed-measuring rubber wheel 215 rises and disengages from the tread surface of the rail head of the rail 1. When the tail of the rail 1 leaves the inlet clamping roller 7, the two clamping rollers 701 move away from both side surfaces of the rail head of the rail 1. When the tail of the rail 1 leaves the 1# bottom-rail eddy current probe real-time follower device 9 and the 2# bottom-rail eddy current probe real-time follower device 10, the bottom-rail eddy current probe group 909 quickly moves out of the bottom-rail area of the rail 1 and at the same time the bottom-rail eddy current probe group 909 quickly descends, and the probe horizontal position positioning wheel and the lift-off gap positioning wheel move away from the side surface of the rail waist and the bottom plane of the rail bottom of the rail 1 at the same time, and return to the original position of the detection device.

[0067] 6) See Figure 1 , when the tail of the rail 1 leaves the outlet clamping roller 11, the two clamping rollers 701 move away from both side surfaces of the rail head of the rail 1. At this time, the position of the floating frame 4 remains at the horizontal position at the moment when the tail of the rail 1 leaves. The piston rods 213 of the four reset cylinders 6 at the four corners of the fixed frame 5 extend the same length at the same time, and push the floating frame 4 back to the initial position. When the tail of the rail 1 leaves the outlet encoder device 12, its speed-measuring rubber wheel 215 rises and disengages from the tread surface of the rail head of the rail 1, completing the quality detection of the entire lower surface of the rail bottom of one rail 1.

Claims

1. A rail bottom eddy current detection system, characterized in that, It includes an entrance encoder device, a sliding rail group, a floating frame, a fixed frame, entrance clamping rollers, a real-time following device for the eddy current probe at the rail bottom, exit clamping rollers, and an exit encoder device. The entrance encoder device is arranged at the entrance of the eddy current detection area, and the exit encoder device is arranged at the exit of the eddy current detection area. The fixed frame is fixed within the eddy current detection area, and a sliding rail group is fixed on the fixed frame. The floating frame is slidably connected to the fixed frame through the sliding rail group, enabling the floating frame to slide perpendicular to the running direction of the rail. The floating frame is sequentially connected with an entrance clamping roller, a real-time following device for the eddy current probe at the rail bottom, and an exit clamping roller from the entrance side to the exit side. The entrance clamping roller and the exit clamping roller can be clamped against both side surfaces of the rail head. At least two of the real-time following devices for the eddy current probe at the rail bottom are provided. The rail bottom eddy current detection system for the rail also includes a reset cylinder. The reset cylinder is fixedly connected to the top of the fixed frame and is arranged oppositely, capable of pushing the floating frame to move towards the middle of the fixed frame. A rail bottom eddy current detection method implemented by using the system includes the following steps: 1) When the conveying roller table sends the rail into the entrance encoder device, the speed measuring rubber wheel of the entrance encoder device presses onto the tread surface of the rail head. As the rail continues to move forward, it drives the speed measuring rubber wheel to rotate, and the encoder code disk starts to count to form the rail length information. 2) When the rail runs to the position of the entrance clamping rollers, the two clamping rollers press against both side surfaces of the rail head. At the same time, the floating frame follows horizontally. The rail enters the area of the real-time following device for the eddy current probe at the rail bottom. The horizontal positioning wheel and the lift-off gap positioning wheel of the real-time following device for the eddy current probe at the rail bottom simultaneously press against the side surface of the rail web and the lower plane of the rail bottom. The gap between the eddy current probe group at the rail bottom and the lower surface of the rail bottom is 2.5 - 3.0 mm, and the eddy current detection of the lower surface of the rail bottom starts. 3) When the rail runs to the exit clamping rollers of the eddy current flaw detector, the exit clamping rollers of the eddy current flaw detector repeat the action process of the entrance clamping rollers, pressing the two clamping rollers against both side surfaces of the rail head. During the eddy current detection process, the rail drives the floating frame to slide relative to the fixed frame on the sliding rail group, and the real-time positioning of the whole real-time following device for the eddy current probe at the rail bottom is carried out in the horizontal direction. 4) When the rail runs to the area of the exit encoder device, the speed measuring rubber wheel of the exit encoder device presses onto the tread surface of the rail head. As the rail continues to move forward, it drives the speed measuring rubber wheel to rotate, and the encoder code disk coaxial with the rubber wheel starts to count to form the rail length information. When the tail of the rail leaves the exit encoder device, its speed measuring rubber wheel rises and disengages from the tread surface of the rail head to complete the measurement of the rail length data. 5) When the tail of the rail leaves the inlet clamping rollers, the two clamping rollers move away from both sides of the rail head; when the tail of the rail leaves the real-time follow-up device of the rail bottom eddy current probe, the real-time follow-up device of the rail bottom eddy current probe moves downward, and the rail bottom eddy current probe group quickly descends, getting out of the detection position in the height direction; at the same time, the rail bottom eddy current probe group horizontally moves out of the rail bottom area of the rail. At this time, the lift-off gap positioning wheel of the real-time follow-up device of the rail bottom eddy current probe leaves the lower plane of the rail bottom first, and the horizontal positioning wheel moves away from the side of the rail web later. After the above actions are completed, the real-time follow-up device of the rail bottom eddy current probe returns to the original position; 6) When the tail of the rail leaves the outlet clamping rollers of the eddy current flaw detector, the two clamping rollers move away from both sides of the rail head; at this time, the floating frame position remains at the horizontal position at the moment when the tail of the rail leaves. The cylinder rods of the four floating frame reset cylinders at the four top corners of the fixed frame extend the same length at the same time, pushing the floating frame back to the initial position; When the tail of the rail leaves the eddy current flaw detection outlet encoder device, its speed measuring rubber wheel rises, getting out of the tread of the rail head, and the quality detection of the entire length of the lower surface of one rail is completed; For 30 dynamic tests of the sample rail, the missed alarm rate of all longitudinal and transverse artificial defects on the sample rail is zero, and the false alarm rate ≤ 3%; the gap between the detection surface of the rail bottom eddy current probe group and the lower plane of the detected rail can be arbitrarily set within the range of 2.0 - 3.0 mm, realizing a constant gap between the rail bottom eddy current probe group and the lower surface of the detected rail.

2. The eddy current detection system for the rail bottom of a rail according to claim 1, wherein The described inlet encoder device and outlet encoder device both include an encoder code disk, a speed measuring rubber wheel, a lifting cylinder, a swing arm, a return spring, a support frame, a conveying roller path, and roller path bearings. The conveying roller path is installed on the support frame through the roller path bearings. The lifting cylinder is hinged to the support frame. The cylinder rod of the lifting cylinder is hinged to the swing arm. One end of the swing arm is rotatably connected to the support frame, and the other end is connected with a speed measuring rubber wheel. The encoder code disk is connected with the speed measuring rubber wheel. One end of the return spring is fixed on the support frame, and the other end is fixedly connected with the swing arm.

3. The eddy current detection system for the rail bottom of a rail according to claim 2, wherein, The described support frame includes a frame body, a height adjusting rod, a swing arm base plate, a swing arm back plate, and a positioning block. The swing arm base plate is fixed on the frame body. The swing arm back plate is slidably connected with the swing arm base plate. The positioning block is fixedly connected to the swing arm back plate. The height adjusting rod is threadedly connected with the positioning block. The height adjusting rod is connected to the swing arm base plate through a bearing. One end of the swing arm is rotatably connected to the swing arm back plate through a rotating shaft. The lifting cylinder is hinged to the swing arm back plate. One end of the return spring is fixed on the swing arm back plate.

4. A rail bottom eddy current detection system according to claim 1, characterized in that The described inlet clamping rollers and outlet clamping rollers have the same structure, and both include a clamping mechanism rotating shaft, a clamping driving left arm, a clamping driving right arm, a base, a clamping roller, a connecting rod, a hydraulic cylinder, and a clamping roller swing arm. The base is connected to the clamping mechanism rotating shaft through a bearing. The base is fixedly connected to the floating frame. The clamping driving left arm and the clamping driving right arm are respectively fixedly connected to the clamping mechanism rotating shafts arranged on both sides of the rail. The piston rod of the hydraulic cylinder is hinged to one end of the clamping driving left arm. The other end of the clamping driving left arm is hinged to one end of the connecting rod. The other end of the connecting rod is hinged to the clamping driving right arm. One end of the clamping roller swing arm is connected with the clamping roller, and the other end is fixedly connected to the clamping mechanism rotating shaft.

5. The eddy current detection system for the rail bottom of a rail according to claim 1, wherein, It further includes idler rollers which are fixedly connected within the floating frame and used for supporting the rail.

6. The eddy current detection system for the rail bottom of a rail according to claim 5, wherein The idler roller includes an adjusting bolt, a fixing plate, an adjusting back plate and an idler roller body. A long circular hole is provided on the adjusting back plate. The adjusting back plate is fixedly connected with the fixing plate through bolts. The fixing plate is in threaded connection with the adjusting bolt. The top end of the adjusting bolt abuts against the adjusting back plate. The idler roller body is installed on the adjusting back plate through a bearing.

7. The eddy current detection system for the rail bottom of a rail according to claim 1, wherein, The real-time follow-up device for the rail bottom eddy current probe includes a horizontal follow-up mechanism, a vertical follow-up mechanism and a rail bottom eddy current probe group. The horizontal follow-up mechanism is connected with the vertical follow-up mechanism. Both the horizontal follow-up mechanism and the vertical follow-up mechanism include a follow-up substrate, a follow-up crossed roller bearing, an action cylinder, a follow-up compression spring, a positioning wheel plate and a follow-up sliding plate. The follow-up substrate is connected with the follow-up sliding plate through the follow-up crossed roller bearing. The push rod of the action cylinder is connected with the follow-up sliding plate. A follow-up compression spring is sleeved on the push rod of the action cylinder. The positioning wheel plate is installed on the follow-up sliding plate. The follow-up sliding plate of the horizontal follow-up mechanism is fixedly connected with the follow-up substrate of the vertical follow-up mechanism. A horizontal positioning wheel is connected to the positioning wheel plate of the horizontal follow-up mechanism, and a lift-off clearance positioning wheel is connected to the positioning wheel plate of the vertical follow-up mechanism.

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