A method and apparatus for testing the bending resistance of cables

Abstract

This application relates to a method and apparatus for testing the bending resistance of cables, belonging to the field of cable performance testing. The apparatus includes a frame, a placement mechanism, and a force-applying mechanism. The placement mechanism includes at least two support points, which abut against the same side of the cable and apply a supporting force in the same direction. The force-applying mechanism applies a force to the cable in the opposite direction to the supporting force, and the force application point is located between two adjacent support points. The force-applying mechanism also includes a detection element for detecting the magnitude of the force applied to the cable by the force-applying mechanism. Based on the lowest or highest ambient temperature during cable laying and the cable's bending radius requirements, this application causes the cable to bend under the combined action of the placement mechanism and the force-applying mechanism, facilitating a direct and intuitive test of the cable's bending resistance.

Description

Technical Field

[0001] This application relates to the field of cable performance testing, and in particular to a method and apparatus for testing cable bending resistance. Background Technology

[0002] In recent years, with the widespread use of low-smoke halogen-free flame-retardant power cables in railway construction, airports, high-rise buildings and other projects with high requirements for flame retardant performance, they have played a certain role in protecting national and people's property and public safety. However, low-smoke halogen-free flame-retardant cables are prone to sheath cracking during installation, laying and use due to cable bending stress. This problem has attracted the attention of cable manufacturers and even the cable industry.

[0003] According to GB / T2951.31-2008, the crack resistance test method was used. After multiple tests on samples of cables that showed cracks, the test results were still qualified. Therefore, passing the crack resistance test does not guarantee that the sheath will not crack during construction, laying or use. How to find a suitable test method to verify the sheath crack resistance performance of low smoke halogen-free flame retardant cables in actual use is an urgent problem to be solved in this industry. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a method and apparatus for testing the bending resistance of cables.

[0005] The cable bending resistance test method and test apparatus provided in this application adopt the following technical solution:

[0006] A method for testing the bending resistance of cables includes the following steps:

[0007] S1: Perform environmental simulation treatment on the cable, including extreme temperature;

[0008] S2: Place the cable after environmental simulation treatment on the cable bending resistance test device to cause the cable to bend and deform, and observe the changes in the surface quality of the cable.

[0009] S3: Adjust the circumferential angle of the cable in the same bending deformation direction and conduct multiple tests.

[0010] Through environmental simulation, the cable's own structure undergoes corresponding changes in physical and chemical properties, making it closer to actual practical conditions. Then, by using a cable bending resistance test device to induce bending deformation in the cable, the reliability of the test results is improved.

[0011] A cable bending resistance testing device is applied in S2 of the above-mentioned cable bending resistance testing method. It includes a frame, a placement mechanism, and a force application mechanism. The placement mechanism includes at least two support points, which abut against the same side of the cable and apply a support force in the same direction to the cable. The force application mechanism is used to apply a force to the cable. The direction of the force is opposite to the direction of the support force, and the point of application of the force is located between two adjacent support points. The force application mechanism also includes a detection element, which is used to detect the magnitude of the force applied to the cable by the force application mechanism.

[0012] By adopting the above technical solution, the placement mechanism and the force application mechanism work together to cause the cable to bend and deform, which makes it easy to intuitively detect the crack resistance of the cable under actual bending deformation.

[0013] Preferably, the force-applying mechanism includes a traction rope, a connector, and a drive source. One end of the traction rope is fixed to the connector, the connector is movably connected to a cable, the drive source is used to apply tension to the traction rope, and the detection element is fixed to the middle section of the traction rope. The detection element is a tension detector.

[0014] By adopting the above technical solution, the traction rope is connected to the cable through the connector, and the movement of the traction rope generates tension on the cable.

[0015] Preferably, the placement mechanism includes a placement roller that rotates relative to the frame, the rotation axis of the placement roller is perpendicular to the length direction of the cable, and the roller surface of the placement roller abuts against the side wall of the cable.

[0016] By adopting the above technical solution, the placement roller abuts against the bottom of the cable to provide support, and when the cable bends and deforms, the rotation of the placement roller can adapt to the movement trend of the cable, so that the cable maintains high placement stability.

[0017] Preferably, the frame has a plurality of positioning holes arranged along the length of the cable, and the end of the placement roller is rotatably connected to a positioning block. A positioning bolt is inserted through the positioning block, and the positioning bolt passes through the positioning hole and is threadedly connected to a nut.

[0018] By adopting the above technical solution, multiple positioning holes provide multiple positions on the frame for mounting positioning blocks and placement rollers, thereby changing the distance between the two placement rollers and enabling the placement mechanism to adapt to the placement of cables with different test bending radii.

[0019] Preferably, a detection scale is fixedly connected to the frame. The detection scale includes a horizontal scale and a vertical scale. The length direction of the horizontal scale is perpendicular to the length direction of the vertical scale. The length direction of the horizontal scale is consistent with the length direction of the cable. The length direction of the vertical scale is consistent with the direction of the force exerted by the force application mechanism on the cable.

[0020] By adopting the above technical solution, the horizontal ruler can provide a reference for the installation position of the positioning block, and the vertical ruler can provide a reference for the movement of one end of the cable suspended by the traction rope; the distance between the two placement rollers is twice the test bending radius, and then the middle of the cable is pulled down to test the bending radius length, at which point the cable reaches the expected bending deformation.

[0021] Preferably, the placement mechanism further includes protective angle irons, which are connected to the frame, and there are two protective angle irons located on opposite sides of the cable.

[0022] By adopting the above technical solution, when the radial dimension of the cable being tested is large, the protective angle iron can be installed on the frame to reduce the probability of the cable accidentally slipping off the frame.

[0023] Preferably, the placement mechanism further includes an angle assembly, which includes a mounting frame and an adjusting wheel. The adjusting wheel rotates relative to the mounting frame, and the rotation axis of the adjusting wheel is parallel to the length direction of the cable. The circumferential surface of the adjusting wheel abuts against the side wall of the cable. The angle assembly also includes an adjusting power source for controlling the rotation of the adjusting wheel. Each placement roller includes two separate and coaxial split rollers with a gap between them. Placement balls are embedded at the ends of the two split rollers that are close to each other, and the placement balls abut against the side wall of the cable.

[0024] By adopting the above technical solution, after a single cable bending test is completed, the adjusting wheel abuts against the side wall of the cable and rotates, so that the cable also rotates at a certain angle under the action of friction. Then, the bending test is carried out again, thus achieving the purpose of changing the cable test angle.

[0025] Preferably, the mounting bracket includes a lever cylinder, the cylinder body of which is connected to the mounting bracket, the adjusting wheel is rotatably connected to the lever of the lever cylinder, and the lever rotation plane of the lever cylinder is perpendicular to the length direction of the cable.

[0026] By adopting the above technical solution, the lever of the lever cylinder can be raised or lowered to change the spatial position of the adjusting wheel. When the cable is bent and deformed and the end is raised, the lever of the lever cylinder is raised to reduce its spatial obstruction to the cable deformation.

[0027] Preferably, the regulating power source includes a regulating motor and a regulating rope. A power ring groove is coaxially formed on the circumferential surface of the regulating wheel. One end of the regulating rope is wound around the drive shaft of the regulating motor, and the other end is fixedly connected to the regulating wheel and located in the power ring groove. A torsion spring is provided on the rotating shaft of the regulating wheel.

[0028] By adopting the above technical solution, the motor transmits torque to the adjusting wheel through the adjusting rope to make it rotate.

[0029] Preferably, the mounting bracket is slidably connected to the frame, and the sliding direction is consistent with the length direction of the cable. The angle assembly includes an adjusting cylinder, which is fixedly connected to the frame, and the piston rod of the adjusting cylinder is fixedly connected to the mounting bracket.

[0030] By adopting the above technical solution, after a single bending and tensile test is completed, the adjusting cylinder controls the mounting bracket to move to the side of the placement roller facing the belt ring. Then, the lever cylinder controls the lever to descend, and the wheel surface of the adjusting wheel abuts against the upper side wall of the cable near the support point. Subsequently, the piston rod of the adjusting cylinder retracts, and the adjusting wheel moves to the mounting bracket, which can apply friction to the cable and straighten it.

[0031] In summary, this application includes at least one of the following beneficial technical effects:

[0032] 1. Through environmental simulation, the cable's own structure undergoes corresponding changes in physical and chemical properties, making it closer to actual practical conditions. Then, the cable is subjected to bending deformation using a cable bending resistance test device. Under the joint indication of the test scale and tensile tester, the test personnel can intuitively detect the bending deformation and actual crack resistance of the tested cable.

[0033] 2. During the test, the distance between two adjacent placement rollers is the bending radius of the cable. By setting up positioning holes, positioning blocks and positioning bolts, the distance between multiple placement rollers can be adjusted, so that the equipment has the ability to test cables with different bending radius requirements. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the cable bending resistance test method in the embodiments of this application.

[0035] Figure 2 This is a schematic diagram of the structure of the cable bending resistance test device in Embodiment 1 of this application.

[0036] Figure 3 This is a schematic diagram of the cable bending resistance test device used in Embodiment 2 of this application.

[0037] Figure 4 This is a schematic diagram illustrating the working principle of the angle component in Embodiment 2 of this application.

[0038] Explanation of reference numerals in the attached drawings: 1. Frame; 11. Positioning hole; 12. Detection scale; 121. Horizontal ruler; 122. Vertical ruler; 13. Protective angle iron; 2. Placement mechanism; 21. Placement roller; 211. Split roller; 212. Placement ball; 22. Positioning block; 23. Positioning bolt; 3. Force application mechanism; 31. Drive source; 32. Traction rope; 33. Connector; 34. Detection component; 35. Directional wheel; 4. Angle assembly; 41. Adjusting wheel; 411. Power ring groove; 42. Adjusting rope; 43. Adjusting motor; 44. Mounting bracket; 441. Horizontal plate; 442. Lever cylinder; 443. Guide wheel; 45. Adjusting cylinder; 5. Cable. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0040] Firstly, embodiments of this application disclose a method for testing the bending resistance of cables, such as... Figure 1 As shown, it includes the following steps in sequence:

[0041] S1: Perform environmental simulation processing on the cable, including but not limited to environmental conditions such as extreme temperature, humidity, airflow speed, and air quality;

[0042] S2: The cable, after environmental simulation treatment, is placed on the cable bending resistance test device, and a force perpendicular to its length direction is applied to the cable to cause bending deformation. The operator observes the changes in the surface quality of the cable.

[0043] S3: Adjust the circumferential angle of the cable in the same bending deformation direction and conduct multiple tests.

[0044] Through environmental simulation, the cable's own structure undergoes corresponding changes in physical and chemical properties, making the test sample closer to actual practical conditions. Then, the cable bending test device causes the cable to bend and deform, allowing the operator to intuitively observe the changes in the surface quality of the tested cable. The test results are then closer to the actual usage conditions.

[0045] On the other hand, this application also discloses a cable bending resistance test device applied to the above-mentioned cable bending resistance test method S2.

[0046] Example 1:

[0047] like Figure 2As shown, the cable bending resistance test device includes a frame 1, on which a placement mechanism 2 and a force application mechanism 3 are provided. The placement mechanism 2 is used to place the cable 5 to be tested and to apply a supporting force to the cable 5. The force application mechanism 3 is used to apply a force opposite to the aforementioned supporting force to the cable 5. The two mechanisms work together to cause the cable 5 to bend and deform.

[0048] like Figure 2 As shown, the placement mechanism 2 includes a positioning block 22 and a placement roller 21. The positioning block 22 is detachably connected to the frame 1, and the placement roller 21 is rotatably connected to the positioning block 22. In this embodiment, there are two placement rollers 21, and the axes of the two placement rollers 21 are parallel to each other. The cable 5 rests on the two placement rollers 21, and the length direction of the cable 5 is perpendicular to the axis of the placement roller 21. The two placement rollers 21 form two support points that abut against the lower sidewall of the cable 5, generating an upward supporting force on the cable 5. The placement mechanism 2 also includes a positioning bolt 23, which passes through the positioning block 22. Several positioning holes 11 are provided on the frame 1 along the length direction of the cable 5, and the positioning holes 11 allow the positioning bolt 23 to selectively pass through. After passing through the positioning holes 11, the positioning bolt 23 is threadedly connected to a nut, thereby realizing the installation of the positioning block 22 and the placement roller 21. Different positioning holes 11 allow the positioning block 22 to be installed in different positions on the frame 1, thereby changing the distance between the two placement rollers 21.

[0049] like Figure 2 As shown, the force application mechanism 3 includes a traction rope 32, a connector 33, a drive source 31, and a detection element 34. The drive source 31 is a drive motor, which is fixedly mounted on the frame 1. A reversing wheel 35 is rotatably connected to the frame 1 directly below the cable 5. In this embodiment, the connector 33 is a belt ring, which is sleeved on the cable 5 and positioned between the two placement rollers 21. One end of the traction rope 32 is fixedly connected to the connector 33, and the other end passes around the reversing wheel 35 and is fixedly connected to the output shaft of the drive motor. When the drive motor starts, the output shaft rotates, causing the traction rope 32 to move. The traction rope 32 applies tension to the cable 5 through the belt ring, with the tension direction downward, thereby causing the cable 5 to bend and deform. The detection element 34 is a tension detector, which is fixed to the middle section of the traction rope 32. It can transmit the magnitude of the tension generated on the traction rope 32 to the control console and display it in real time.

[0050] like Figure 2As shown, a detection scale 12 is fixedly connected to the frame 1. The detection scale 12 includes a horizontal scale 121 and a vertical scale 122, which are arranged in a T-shape. The length direction of the horizontal scale 121 is perpendicular to the length direction of the vertical scale 122, and the length direction of the horizontal scale 121 is consistent with the length direction of the cable 5. The length direction of the vertical scale 122 is vertical and consistent with the direction of the tension applied to the cable 5 by the traction rope 32. The horizontal scale 121 provides a reference for the installation position of the positioning block 22, and the vertical scale 122 provides a reference for the amount of movement of one end of the cable 5 suspended by the traction rope 32. The distance between the two placement rollers 21 is twice the test bending radius. Then, the middle part of the cable 5 is pulled downward by the length of the test bending radius. At this time, the cable 5 reaches the expected bending deformation. The placement mechanism 2 also includes protective angle irons 13. There are two protective angle irons 13, which are located on opposite sides of the cable 5. The length direction of the protective angle irons 13 is consistent with the length direction of the cable 5. The protective angle irons 13 are detachably connected to the frame 1 by bolts. When the radial dimension of the cable 5 being tested is large, the protective angle irons 13 can be installed on the frame 1 to reduce the probability of the cable 5 accidentally slipping off the frame 1.

[0051] The implementation principle of the cable bending resistance testing device in this application embodiment is as follows:

[0052] Before the test, the cable 5 is subjected to environmental condition simulation treatment based on the extreme environmental conditions under actual use. Then, the belt loop is put around the cable 5 and the cable 5 is placed horizontally on the placement roller 21. The force application component applies tension to the cable 5. According to the indication of the test scale 12, when the cable 5 reaches the predetermined bending radius, the cracking and damage condition of the cable 5 surface is observed. If there are no defects such as cracks on the circuit surface, it means that it has passed the bending performance test.

[0053] Example 2:

[0054] like Figure 2 , 3 As shown in Figure 4, the difference from Embodiment 1 is that: a single placement roller 21 is composed of two separate and coaxial split rollers 211, with a gap between the two split rollers 211. Placement balls 212 are embedded at the ends of the two split rollers 211 that are close to each other. The placement balls 212 rotate omnidirectionally on the split rollers 211. When the cable 5 is placed on the placement roller 21, the placement balls 212 abut against the side wall of the cable 5. The positioning hole 11 on the frame 1 is a threaded hole. The positioning bolt 23 passes through the positioning block 22 and directly enters the positioning hole 11, and is threadedly connected to the frame 1. The placement mechanism 2 also includes an angle assembly 4, which is used to control the cable 5 to rotate on the frame 1 about its own axial direction.

[0055] like Figure 3 and 4As shown, the angle assembly 4 includes a mounting frame 44, which consists of a horizontal plate 441 and a lever cylinder 442 fixedly connected to each other. The number of mounting frames 44 is the same as the number of placement rollers 21. The horizontal plate 441 is slidably connected to the frame 1, and the sliding direction is the length direction of the cable 5 when it is placed horizontally. An adjusting cylinder 45 is fixedly connected to the frame 1. The piston rod of the adjusting cylinder 45 is fixedly connected to the horizontal plate 441, which provides power for the sliding of the mounting frame 44. There are two lever cylinders 442, which are arranged in a mirror image on both sides of the cable 5. The lever of the lever cylinder 442 is located above the cable 5 and the plane of rotation is perpendicular to the length direction of the cable 5.

[0056] like Figure 3 and 4 As shown, the angle assembly 4 also includes adjusting wheels 41. The number of adjusting wheels 41 is the same as the number of lever cylinders 442, and they correspond one-to-one. The adjusting wheels 41 are rotatably connected to the side of the lever of the lever cylinder 442 facing the cable 5, and the axis of rotation is parallel to the length direction of the cable 5 when it is placed horizontally. When the lever of the lever cylinder 442 can swing downwards, the circumference of the adjusting wheel 41 abuts against the upper side wall of the cable 5. The angle assembly 4 also includes an adjustment power source for controlling the rotation of the adjustment wheel 41. The adjustment power source includes an adjustment motor 43 and an adjustment rope 42. The adjustment motor 43 is fixedly mounted on the mounting bracket 44. A power ring groove 411 is coaxially formed on the circumference of one of the adjustment wheels 41, and a torsion spring (not shown in the figure) is provided on the rotating shaft between this adjustment wheel 41 and the lever cylinder 442. One end of the adjustment rope 42 is wound around the drive shaft of the adjustment motor 43. A hole for the adjustment lift to pass through is formed on the lever of the lever cylinder 442, and a guide wheel 443 for tensioning and guiding the adjustment rope 42 is rotatably set on the lever. The other end of the adjustment rope 42 passes around each guide wheel 443 in sequence and passes through the lever and is then fixedly connected to the adjustment wheel 41, with the connection point located in the power ring groove 411. When the adjustment motor 43 is started, the torque it exerts on the adjustment wheel 41 through the adjustment rope 42 is opposite in direction to the torque applied to the adjustment wheel 41 by the torsion spring.

[0057] The implementation principle of the cable bending resistance testing device in this application embodiment is as follows:

[0058] After a single bending and tensile test is completed, the adjusting cylinder 45 controls the mounting bracket 44 to move to the side of the placement roller 21 facing the belt ring. Then, the lever cylinder 442 controls the lever to descend, and the wheel surface of the adjusting wheel 41 abuts against the upper side wall of the cable 5 near the support point. Subsequently, the piston rod of the adjusting cylinder 45 retracts, and the adjusting wheel 41 moves towards the mounting bracket 44, thus applying friction to the cable 5 and straightening it. Then, the adjusting motor 43 starts and drives the adjusting wheel 41 to rotate through the adjusting rope 42. At this time, the adjusting wheel 41 applies friction to the cable 5 again, causing the cable 5 to rotate, thereby changing the test angle of the cable 5. After the cable 5 changes to the next test angle, the force application mechanism 3 starts again to repeat the test. When the end of the cable 5 is raised, the lever of the lever cylinder 442 is raised, reducing its obstruction of space during the deformation of the cable 5. The setting of the angle component 4 realizes the automatic adjustment of the angle of the cable 5 for multi-angle testing.

[0059] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A cable bending resistance testing device, applied to a cable bending resistance testing method, the cable bending resistance testing method comprising the following steps in sequence: S1: Perform environmental simulation treatment on the cable (5), including extreme temperature; S2: Place the cable (5) after environmental simulation treatment on the cable bending test device to make the cable (5) bend and deform, and observe the change in the surface quality of the cable (5); S3: Adjust the circumferential angle of the cable in the same bending deformation direction and test multiple times; The cable bending resistance testing device includes a frame, characterized in that: The cable bending resistance test device is used in S2 of the cable bending resistance test method. It includes a placement mechanism (2) and a force application mechanism (3). The placement mechanism (2) includes two placement rollers (21) and two angle components (4). The two placement rollers (21) form two support points. The two support points abut against the same side of the cable (5) and apply a support force in the same direction to the cable (5). The force application mechanism (3) is used to apply a force to the cable (5). The direction of the force is opposite to the direction of the support force, and the point of application of the force is located between the two support points. The force application mechanism (3) includes a detection element (34). The detection element (34) is used to detect the magnitude of the force applied by the force application mechanism (3) to the cable (5). The placement roller (21) rotates relative to the frame (1), the rotation axis of the placement roller (21) is perpendicular to the length direction of the cable (5), and the roller surface of the placement roller (21) abuts against the side wall of the cable (5). The angle assembly (4) includes a mounting bracket (44) and an adjusting wheel (41). The adjusting wheel (41) rotates relative to the mounting bracket (44). The angle assembly (4) is used to control the cable (5) to rotate on the frame (1) about its own axis. The rotation axis of the adjusting wheel (41) is parallel to the length direction of the cable (5). The circumferential surface of the adjusting wheel (41) abuts against the side wall of the cable (5). The angle assembly (4) also includes an adjusting power source for controlling the rotation of the adjusting wheel (41). Each placement roller (21) comprises two separate and coaxial split rollers (211), with a gap between the two split rollers (211). Placement balls (212) are embedded at the ends of the two split rollers (211) that are close to each other, and the placement balls (212) abut against the side wall of the cable (5). The mounting bracket (44) includes two lever cylinders (442), which are arranged in a mirror image on both sides of the cable (5). The lever of the lever cylinder (442) is located above the cable (5) and its rotation plane is perpendicular to the length direction of the cable (5). The cylinder body of the lever cylinder (442) is connected to the mounting bracket (44). The adjusting wheel (41) is rotatably connected to the lever of the lever cylinder (442). The rotation plane of the lever of the lever cylinder (442) is perpendicular to the length direction of the cable (5). The number of adjusting wheels (41) is the same as the number of lever cylinders (442) and they correspond one-to-one. The adjusting wheel (41) is rotatably connected to the side of the lever of the lever cylinder (442) facing the cable (5). The mounting bracket (44) is slidably connected to the frame (1), and the sliding direction is consistent with the length direction of the cable (5). The angle component (4) includes an adjusting cylinder (45), which is fixedly connected to the frame (1), and the piston rod of the adjusting cylinder (45) is fixedly connected to the mounting bracket (44).

2. The cable bending resistance testing device according to claim 1, characterized in that: The force-applying mechanism (3) includes a traction rope (32), a connector (33), and a drive source (31). One end of the traction rope (32) is fixed to the connector (33), and the connector (33) is movably connected to the cable (5). The drive source (31) is used to apply tension to the traction rope (32). The detection element (34) is fixed to the middle section of the traction rope (32) and is a tension detector.

3. The cable bending resistance testing device according to claim 1, characterized in that: The frame (1) is provided with a plurality of positioning holes (11), which are arranged along the length of the cable (5). The end of the placement roller (21) is rotatably connected to a positioning block (22), and a positioning bolt (23) is provided on the positioning block (22). The positioning bolt (23) passes through the positioning hole (11) and is threadedly connected to a nut.

4. The cable bending resistance testing device according to claim 3, characterized in that: A detection scale (12) is fixedly connected to the frame (1). The detection scale (12) includes a horizontal scale (121) and a vertical scale (122). The length direction of the horizontal scale (121) is perpendicular to the length direction of the vertical scale (122). The length direction of the horizontal scale (121) is consistent with the length direction of the cable (5). The length direction of the vertical scale (122) is consistent with the direction of the force exerted by the force application mechanism (3) on the cable (5).

5. The cable bending resistance testing device according to claim 1, characterized in that: The placement mechanism (2) also includes protective angle irons (13), which are connected to the frame (1). There are two protective angle irons (13) located on opposite sides of the cable (5).

6. The cable bending resistance testing device according to claim 1, characterized in that: The regulating power source includes a regulating motor (43) and a regulating rope (42). A power ring groove (411) is coaxially provided on the circumferential surface of the regulating wheel (41). One end of the regulating rope (42) is wound around the drive shaft of the regulating motor (43), and the other end is fixedly connected to the regulating wheel (41) and located in the power ring groove (411). A torsion spring is provided on the rotating shaft of the regulating wheel (41).

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