A pulse fatigue testing device and method for steel wires and cords

Abstract

This invention discloses a pulse fatigue testing device and method for steel wires and cords, comprising: a roller bracket slidably mounted on the top center of a machine base, with a bending roller assembly mounted on its front; and a drive mechanism mounted on one side of the top of the machine base for driving the roller bracket to move horizontally reciprocally. In this pulse fatigue testing device and method for steel wires and cords, when the roller bracket is driven to reciprocate on the machine base by the drive mechanism, a connecting rod can drive a lever bracket to move synchronously on the machine base. As the lever bracket moves, the relative position of the lever guide wheel and the lever changes periodically. A counterweight applies a periodic tensile force, i.e., pulse pressure, to the sample under test through the lever. Simultaneously, the bending roller assembly causes the sample under test to undergo bending deformation, simulating the bending stress of the hose steel wire. Using the lever theorem, and through a simple mechanical structure, the pulse fatigue performance of the hose steel wire can be tested based on the wire material.

Description

Technical Field

[0001] This invention relates to a pulse fatigue testing device and method for steel wires and cords, belonging to the technical field of wire testing instruments. Background Technology

[0002] A rubber hose is a tubular rubber product used to transport gases, liquids, slurries, or granular materials, such as hydraulic hoses and high-pressure hoses. The structure of a rubber hose mainly consists of rubber and a reinforcing material. The steel wire used as the reinforcing material is called hose wire. When single layers of steel wire are interwoven into a mesh, it is called a braided hose; when single layers of steel wire are wound into a cylinder in the same direction, it is called a spiral wound hose.

[0003] During use, rubber hoses primarily withstand periodic fluctuations in hydraulic loads, also known as pulse pressure. Therefore, the pulse fatigue performance of the hose's reinforcing material, the steel wire, is crucial. Current methods for testing the pulse fatigue of hose steel wires involve fabricating the steel wire into a finished hose, placing it in a pulse fatigue testing machine, filling it with hydraulic oil, and then applying pulsed hydraulic pressure. This method is not only complex and time-consuming, but also inefficient and costly.

[0004] Therefore, in order to solve the above-mentioned technical problems, there is an urgent need for a pulse fatigue testing device and method for steel wires and cords. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pulse fatigue testing device and method for steel wires and cords. When the roller support is driven to reciprocate on the machine platform by the drive mechanism, the connecting rod can drive the lever support to move synchronously on the machine platform. As the lever support moves, the relative position of the lever guide wheel and the lever changes periodically. The counterweight applies a periodic tensile force, i.e., pulse pressure, to the sample under test through the lever. At the same time, the bending roller group can cause the sample under test to bend and deform, simulating the bending stress of the hose steel wire. By applying the lever theorem and through a simple mechanical structure, the pulse fatigue performance of the hose steel wire can be tested on the basis of the wire material.

[0006] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution:

[0007] In a first aspect, the present invention provides a pulse fatigue testing device for steel wires and cords, comprising:

[0008] The roller bracket is slidably installed at the top center of the machine base, and a set of bending rollers is installed on the front.

[0009] The drive mechanism is installed on one side of the top of the machine tool and is used to drive the roller support to move horizontally back and forth.

[0010] A lever bracket is slidably mounted on the other side of the top of the machine tool to support the lever.

[0011] A lever is slidably mounted on the top of a lever bracket. The end of the lever away from the roller bracket is connected to a counterweight, and the other end is slidably connected to a fixed pulley bracket. A lever fixing point is provided at the end of the lever close to the fixed pulley bracket.

[0012] A fixed pulley bracket is disposed between the lever bracket and the roller bracket to limit the lever's up-and-down movement within a set range. A fixed pulley is mounted on the fixed pulley bracket.

[0013] The connecting rod has a scale on its surface. One end is fixed to the lever bracket, and the other end is adjustablely connected to the roller bracket. It is used to adjust the distance between the lever bracket and the roller bracket before testing.

[0014] The roller fixing point is located between the drive mechanism and the roller support and is fixed to the machine base. During testing, one end of the sample to be tested is fixed to the roller fixing point, and the other end passes around the curved roller group and the fixed pulley and is fixed to the lever fixing point.

[0015] Furthermore, the drive mechanism includes a motor, a transmission wheel, and a rocker arm, wherein,

[0016] The motor is used to drive the transmission wheel to rotate, and the rocker arm is used to connect the transmission wheel and the roller bracket;

[0017] One end of the rocker arm is hinged to the front side of the transmission wheel, and the other end is hinged to the roller bracket. The hinge point between the roller bracket and the rocker arm is on the same horizontal line as the center of the transmission wheel.

[0018] Furthermore, the motor has a rotational speed of 30–90 r / min, the transmission wheel has a diameter of 300–800 mm, and the rocker arm has a length of not less than 0.7 times the diameter of the transmission wheel.

[0019] Furthermore, it also includes roller guide rails and lever guide rails, with the roller bracket slidably connected to the machine base via the roller guide rails and the lever bracket slidably connected to the machine base via the lever guide rails.

[0020] Furthermore, when the lever is in a horizontal position, the sample to be tested, located between the fixed pulley and the lever, is perpendicular to the lever.

[0021] Furthermore, it also includes limiting hole one, limiting hole two, limiting pin one, limiting pin two, and a spring, among which,

[0022] The top of the fixed pulley bracket is provided with an open groove to accommodate the lever, and the first limiting hole and the second limiting hole are both vertical slots opened on the side wall of the open groove.

[0023] The first limiting pin and the second limiting pin are respectively adapted to the first limiting hole and the second limiting hole, and are respectively fixed to the surface of the lever;

[0024] One end of the spring is fixed to the bottom side of the lever away from the counterweight, and the other end is fixed to the open groove.

[0025] Furthermore, it also includes a limiting bolt, through which the connecting rod is adjustablely connected to the roller bracket;

[0026] The bending roller assembly comprises at least three rollers.

[0027] Furthermore, it also includes a lever guide wheel, which is rotatably mounted on the top of the lever bracket, and has a groove on its outer surface for placing the lever.

[0028] Secondly, the present invention provides a detection method for the pulse fatigue testing device for steel wires and cords described in the first aspect, comprising the following steps:

[0029] Select appropriate motor speed, lever, and counterweight, and record them;

[0030] The distance between the lever bracket and the roller bracket is adjusted according to the lever length using the limiting bolts;

[0031] Apply oil to the sample to be tested, or cover the surface of the bending roller with a layer of rubber sheet;

[0032] One end of the sample to be tested is fixed at the roller fixing point, and the other end is passed around the curved roller group and the fixed pulley and fixed at the lever fixing point;

[0033] Start the motor and record the number of cycles until the sample breaks.

[0034] Furthermore, the value of scale 16 corresponding to the connection point between connecting rod 8 and roller bracket 5 is determined by the following formula:

[0035]

[0036] The range of pulsed force experienced by the sample under test is:

[0037]

[0038] The relationship between the pulse force on the sample under test and time is as follows:

[0039]

[0040] In the formula, P is the scale value of the connecting rod corresponding to the connection point between the connecting rod 8 and the roller bracket 5; a is the length of the lever; b is the movable range of the lever bracket; M is the weight of the counterweight; F is the pulse force on the sample to be tested; and k is the fixed parameter of the machine tool.

[0041] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0042] The pulse fatigue testing device for steel wires and cords provided by this invention, when the roller support is driven to reciprocate on the machine platform by the drive mechanism, the connecting rod can drive the lever support to move synchronously on the machine platform. As the lever support moves, the relative position of the lever guide wheel and the lever changes periodically. The counterweight applies a periodic tensile force, i.e., pulse pressure, to the sample under test through the lever. At the same time, the bending roller group can cause the sample under test to bend and deform, simulating the bending stress of the hose steel wire. By applying the lever theorem and through a simple mechanical structure, the pulse fatigue performance of the hose steel wire can be tested on the basis of the wire material. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of a pulse fatigue testing device for steel wire and cord provided in Embodiment 1;

[0044] Figure 2 for Figure 1 Front view of the connection status between the middle lever and the fixed pulley bracket;

[0045] Figure 3 for Figure 1 Top view of the connection status between the middle lever and the fixed pulley bracket;

[0046] Figure 4 for Figure 1 A diagram illustrating the forces acting on the lever.

[0047] Figure 5 This is a schematic diagram of a pulse waveform.

[0048] In the diagram: 1. Motor; 2. Transmission wheel; 3. Rocker arm; 4. Bending roller assembly; 5. Roller bracket; 6. Roller guide rail; 7. Roller fixing point; 8. Connecting rod; 9. Lever guide rail; 10. Fixed pulley; 11. Lever; 12. Lever bracket; 13. Lever guide wheel; 14. Counterweight; 15. Limiting bolt; 16. Scale; 17. Sample to be tested; 18. Fixed pulley bracket; 19. Lever fixing point; 20. Spring; 101. Limiting hole one; 102. Limiting hole two; 201. Limiting pin one; 202. Limiting pin two. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0050] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] Example 1:

[0053] like Figures 1-5 As shown, this embodiment provides a pulse fatigue testing device for steel wires and cords, including:

[0054] Roller bracket 5 is slidably installed at the top center of the machine base, and a bending roller group 4 is installed on the front.

[0055] The drive mechanism is installed on one side of the top of the machine tool and is used to drive the roller support 5 to move horizontally back and forth.

[0056] Lever bracket 12 is slidably mounted on the other side of the top of the machine tool to support lever 11;

[0057] Lever 11 is slidably mounted on the top of lever bracket 12. One end of lever 11 away from roller bracket 5 is connected to counterweight 14, and the other end is slidably connected to fixed pulley bracket 18. Lever fixing point 19 is provided at the end of lever 11 close to fixed pulley bracket 18.

[0058] A fixed pulley bracket 18 is disposed between the lever bracket 12 and the roller bracket 5 to limit the lever 11 from moving up and down within a set range. A fixed pulley 10 is mounted on the fixed pulley bracket 18.

[0059] The connecting rod 8 has a scale 16 on its surface. One end is fixed to the lever bracket 12, and the other end is adjustablely connected to the roller bracket 5. It is used to adjust the distance between the lever bracket 12 and the roller bracket 5 before the test so that the lever bracket 12 is at the center of the lever 11.

[0060] Roller fixing point 7 is set between the drive mechanism and the roller bracket 5 and fixed to the machine base. During testing, one end of the sample to be tested 17 is fixed at roller fixing point 7, and the other end passes around the curved roller group 4 and the fixed pulley 10 and is fixed at lever fixing point 19.

[0061] In the above technical solution, the diameter of the sample to be tested 17 is in the range of 0.25 to 1.5 mm, the weight of the counterweight 14 is 5 to 50 N, and the length of the lever 11 is 550 to 1000 mm.

[0062] When the roller support 5 is driven to reciprocate on the machine platform by the drive mechanism, the connecting rod 8 can drive the lever support 12 to move synchronously on the machine platform. As the lever support 12 moves, the relative position of the lever guide wheel 13 and the lever 11 changes periodically. The counterweight 14 applies a periodic tension, i.e., pulse pressure, to the sample 17 to be tested through the lever 11. At the same time, the bending roller group 4 can cause the sample 17 to be tested to bend and deform, simulating the bending stress of the hose wire. By applying the lever theorem and through a simple mechanical structure, the pulse fatigue performance of the hose wire can be tested on the basis of the wire.

[0063] The value of scale 16 gradually increases from left to right on the connecting rod 8. The reading point of scale 16 is the connection point between the connecting rod 8 and the roller bracket 5. The zero mark of scale 16 is defined as follows: when the movable range of lever bracket 12 is the same as the length of lever 11, both lever bracket 12 and roller bracket 5 are placed in the middle of the movable range, and the value read by scale 16 at this time is the zero mark.

[0064] To achieve the horizontal reciprocating movement of the roller support 5 under the drive mechanism, the drive mechanism includes a motor 1, a transmission wheel 2, and a rocker arm 3, wherein...

[0065] The motor 1 is used to drive the transmission wheel 2 to rotate, and the rocker arm 3 is used to connect the transmission wheel 2 and the roller bracket 5;

[0066] One end of the rocker arm 3 is hinged to one side of the front of the transmission wheel 2, and the other end is rotatably hinged to the roller bracket 5. The hinge point between the roller bracket 5 and the rocker arm 3 is on the same horizontal line as the center of the transmission wheel 2.

[0067] To ensure the stable movement of the roller support 5, the speed of the motor 1 is 30-90 r / min, the diameter of the transmission wheel 2 is 300-800 mm, and the length of the rocker arm 3 is not less than 0.7 times the diameter of the transmission wheel 2.

[0068] To achieve a sliding connection between the roller support 5, the lever support 12 and the machine base, a roller guide rail 6 and a lever guide rail 9 are also included. The roller support 5 is slidably connected to the machine base through the roller guide rail 6, and the lever support 12 is slidably connected to the machine base through the lever guide rail 9.

[0069] When lever 11 is in a horizontal state, the sample to be tested, located between fixed pulley 10 and lever 11, is perpendicular to lever 11.

[0070] To restrict lever 11 to move only up and down within a set range, and to restrict the rotation of lever 11, such as... Figure 2 and Figure 3 As shown, it also includes a limiting hole 101, a limiting hole 102, a limiting pin 201, a limiting pin 202, and a spring 20, wherein,

[0071] The top of the fixed pulley bracket 18 is provided with an open groove to accommodate the lever 11, and the limiting hole 101 and the limiting hole 102 are both vertical slots opened on the side wall of the open groove.

[0072] The limiting pin 1 201 and the limiting pin 202 are respectively adapted to the limiting hole 101 and the limiting hole 2 102, and are respectively fixed to the surface of the lever 11;

[0073] One end of the spring 20 is fixed to the bottom side of the lever 11 away from the counterweight 14, and the other end is fixed to the open groove. The function of the spring 20 is to compensate for the tension and pressure generated by the lever 11 on the sample 17 to be tested due to its own weight.

[0074] To achieve an adjustable connection between the connecting rod 8 and the roller bracket 5, a limiting bolt 15 is also included, through which the connecting rod 8 is adjustablely connected to the roller bracket 5;

[0075] In order to induce bending deformation in the sample 17 to simulate the bending stress of the hose wire, the bending roller group 4 includes at least three rollers.

[0076] To achieve a sliding connection between lever 11 and lever support 12, a lever guide wheel 13 is also included. The lever guide wheel 13 is rotatably mounted on the top of lever support 12, and its outer surface has a groove for placing lever 11.

[0077] In summary, the pulse fatigue testing device for steel wire and cord provided in this embodiment, when the roller support 5 is driven to reciprocate on the machine platform by the drive mechanism, the connecting rod 8 can drive the lever support 12 to move synchronously on the machine platform. As the lever support 12 moves, the relative position of the lever guide wheel 13 and the lever 11 changes periodically. The counterweight 14 applies a periodic tension, i.e., pulse pressure, to the sample 17 to be tested through the lever 11. At the same time, the bending roller group 4 can cause the sample 17 to be tested to bend and deform, simulating the bending stress of the hose steel wire. By applying the lever theorem and through a simple mechanical structure, the pulse fatigue performance of the hose steel wire can be tested on the basis of the wire material.

[0078] Example 2:

[0079] This embodiment provides a detection method for the pulse fatigue testing device for steel wires and cords described in Embodiment 1, including the following steps:

[0080] Select appropriate motor speed, lever 11, and counterweight 14, and record them;

[0081] The distance between the lever bracket 12 and the roller bracket 5 is adjusted according to the length of the lever 11 by using the limiting bolt 15;

[0082] The sample 17 to be tested is coated with oil, or a layer of rubber sheet is wrapped around the surface of the bending roller;

[0083] One end of the sample 17 to be tested is fixed at roller fixing point 7, and the other end is passed around the curved roller group 4 and the fixed pulley 10 and fixed at lever fixing point 19.

[0084] Start motor 1 and record the number of cycles until the sample breaks.

[0085] Based on the recorded information, the value of scale 16 corresponding to the connection point between connecting rod 8 and roller bracket 5 is determined by the following formula:

[0086]

[0087] The range of pulse force experienced by the sample 17 under test is:

[0088]

[0089] The relationship between the pulse force and time experienced by the sample 17 under test is as follows:

[0090]

[0091] In the formula, P is the scale value of scale 16 on the connecting rod 8 corresponding to the connection point between the connecting rod 8 and the roller bracket 5; a is the length of the lever 11; b is the movable range of the lever bracket 12; M is the weight of the counterweight 14; F is the pulse force on the sample 17 to be tested; and k is the fixed parameter of the machine tool.

[0092] The effectiveness of the detection method provided in this specific implementation method is explained below with reference to experimental data:

[0093] Experiment 1

[0094] The sample to be tested was a Φ0.25mm rubber hose wire, the bending roller diameter was 30mm, the movable range of lever bracket 12 was 500mm, the length of lever 11 was 600mm, the weight of counterweight 14 was 5N, the speed of motor 1 was 30r / min, the pulse force range was 0.5~55N according to formula (2), and the scale was adjusted to 50 according to formula (1). The sample did not break after 10,000 cycles.

[0095] Experiment 2

[0096] The sample to be tested was a Φ0.25mm rubber hose wire, the bending roller diameter was 30mm, the movable range of the transmission wheel 2 was 500mm, the length of the lever 11 was 600mm, the weight of the counterweight 14 was 5N, the speed of the motor 1 was 90r / min, the pulse force range was 0.5~55N according to formula (2), and the scale was adjusted to 50 according to formula (1). After 5339 cycles, the sample broke, and the fracture surface was a fatigue fracture surface.

[0097] Experiment 3

[0098] The sample to be tested was a Φ0.25mm rubber hose wire, the bending roller diameter was 30mm, the movable range of lever bracket 12 was 500mm, the length of lever 11 was 600mm, the weight of counterweight 14 was 8N, the speed of motor 1 was 90r / min, the pulse force range was 0.7~88N according to formula (2), and the scale was adjusted to 50 according to formula (1). After 3731 cycles, the sample broke, and the fracture surface was a fatigue fracture surface.

[0099] Experiment 4

[0100] The sample to be tested was a Φ0.25mm rubber hose wire, the bending roller diameter was 30mm, the movable range of lever bracket 12 was 500mm, the length of lever 11 was 1000mm, the speed of motor 1 was 90r / min, the weight of counterweight 14 was 25N, the pulse force range was 8.3~75N according to formula (2), and the scale was adjusted to 250 according to formula (1). The sample broke after 4917 cycles, and the fracture surface was a fatigue fracture surface.

[0101] Experiment 5

[0102] The sample to be tested was a Φ0.70mm rubber hose wire, the bending roller diameter was 30mm, the movable range of lever bracket 12 was 500mm, the length of lever 11 was 600mm, the weight of counterweight 14 was 50N, the speed of motor 1 was 30r / min, the pulse force range was 4.5~550N according to formula (2), and the scale was adjusted to 50 according to formula (1). The sample did not break after 10,000 cycles.

[0103] Experiment 6

[0104] The sample to be tested was a Φ0.70mm rubber hose wire, the bending roller diameter was 30mm, the movable range of lever bracket 12 was 500mm, the length of lever 11 was 550mm, the weight of counterweight 14 was 40N, the speed of motor 1 was 30r / min, the pulse force range was 1.9~840N according to formula (2), and the scale was adjusted to 25 according to formula (1). After 2049 cycles, the sample broke, and the fracture surface was a fatigue fracture surface.

[0105] Experiment 7

[0106] The sample to be tested was Φ0.99mm steel cord, the diameter of the bending roller was 30mm, the movable range of the lever bracket 12 was 500mm, the length of the lever 11 was 550mm, the weight of the counterweight 14 was 50N, the speed of the motor 1 was 30r / min, the range of the pulse force according to formula (2) was 2.4~1020N, ​​and the scale was adjusted to 25 according to formula (1). After 7325 cycles, the steel cord showed broken strands.

[0107] Experiment 8

[0108] The sample to be tested was Φ0.99mm steel cord, the diameter of the bending roller was 150mm, the movable range of the lever bracket 12 was 500mm, the length of the lever 11 was 550mm, the weight of the counterweight 14 was 50N, the speed of the motor 1 was 30r / min, the pulse force range was 2.4~1020N according to formula (2), and the scale was adjusted to 25 according to formula (1). After 10,000 cycles, there were no broken strands in the steel cord.

[0109] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A pulse fatigue testing method for steel wires and cords, characterized in that, The following device is used: Roller bracket (5) is slidably installed at the top center of the machine base, and a bending roller group (4) is installed on the front. A drive mechanism is installed on one side of the top of the machine base and is used to drive the roller support (5) to move horizontally back and forth. The drive mechanism includes a motor (1), a transmission wheel (2) and a rocker arm (3). The motor (1) is used to drive the transmission wheel (2) to rotate, and the rocker arm (3) is used to connect the transmission wheel (2) and the roller support (5). One end of the rocker arm (3) is hinged to one side of the front of the transmission wheel (2), and the other end is hinged to the roller support (5). The hinge point between the roller support (5) and the rocker arm (3) is on the same horizontal line as the center of the transmission wheel (2). A lever bracket (12) is slidably mounted on the other side of the top of the machine tool to support the lever (11); A lever (11) is slidably mounted on the top of a lever bracket (12). One end of the lever (11) away from the roller bracket (5) is connected to a counterweight (14), and the other end is slidably connected to a fixed pulley bracket (18). A lever fixing point (19) is provided at the end of the lever (11) close to the fixed pulley bracket (18). A fixed pulley bracket (18) is disposed between the lever bracket (12) and the roller bracket (5) to restrict the lever (11) from moving up and down within a set range and to restrict its rotation. A fixed pulley (10) is mounted on the fixed pulley bracket (18). The connecting rod (8) has a scale (16) on its surface. One end is fixed to the lever bracket (12), and the other end is adjustablely connected to the roller bracket (5). It is used to adjust the distance between the lever bracket (12) and the roller bracket (5) before testing so that the lever bracket (12) is at the center of the lever (11). The roller fixing point (7) is set between the drive mechanism and the roller bracket (5) and fixed to the machine base. During the test, one end of the sample to be tested (17) is fixed at the roller fixing point (7), and the other end passes around the curved roller group (4) and the fixed pulley (10) and is fixed at the lever fixing point (19). The top of the fixed pulley bracket (18) is provided with an open groove to accommodate the lever (11), and the first limiting hole (101) and the second limiting hole (102) are vertical slots opened on the side wall of the open groove. Limiting pin one (201) and limiting pin two (202) are respectively adapted to limiting hole one (101) and limiting hole two (102), and are respectively fixed to the surface of lever (11); One end of the spring (20) is fixed to the bottom side of the lever (11) away from the counterweight (14), and the other end is fixed to the open slot. The method includes: Select appropriate motor (1) speed, lever (11) and counterweight (14), and record them; The distance between the lever bracket (12) and the roller bracket (5) is adjusted according to the length of the lever (11) by means of the limiting bolt (15); The sample to be tested (17) is coated with oil or a layer of rubber sheet is wrapped around the surface of the bending roller; One end of the sample to be tested (17) is fixed at the roller fixing point (7), and the other end is passed around the curved roller group (4) and the fixed pulley (10) and fixed at the lever fixing point (19); Start the motor (1) and record the number of cycles until the sample (17) breaks; The value of the scale (16) corresponding to the connection point between the connecting rod (8) and the roller support (5) is determined by the following formula: ； The range of pulse force experienced by the sample (17) to be tested is: ； The relationship between the pulse force and time on the sample (17) to be tested is as follows: ； In the formula, P is the scale value of the scale (16) on the connecting rod (8) corresponding to the connection point between the connecting rod (8) and the roller bracket (5); a is the length of the lever (11); b is the movable range of the lever bracket (12); M is the weight of the counterweight (14); F is the pulse force on the sample (17) to be tested; and k is the fixed parameter of the machine tool.

2. The pulse fatigue testing method for steel wires and cords according to claim 1, characterized in that, The motor (1) has a rotational speed of 30 to 90 r / min, the transmission wheel (2) has a diameter of 300 to 800 mm, and the rocker arm (3) has a length of not less than 0.7 times the diameter of the transmission wheel (2).

3. The pulse fatigue testing method for steel wires and cords according to claim 1, characterized in that, It also includes a roller guide rail (6) and a lever guide rail (9). The roller bracket (5) is slidably connected to the machine base through the roller guide rail (6), and the lever bracket (12) is slidably connected to the machine base through the lever guide rail (9).

4. The pulse fatigue testing method for steel wires and cords according to claim 1, characterized in that, When the lever (11) is in a horizontal state, the sample to be tested located between the fixed pulley (10) and the lever (11) is perpendicular to the lever (11).

5. The pulse fatigue testing method for steel wires and cords according to claim 1, characterized in that, It also includes a limiting bolt (15), and the connecting rod (8) is adjustablely connected to the roller bracket (5) through the limiting bolt (15); The bending roller assembly (4) comprises at least three rollers.

6. The pulse fatigue testing method for steel wires and cords according to claim 1, characterized in that, It also includes a lever guide wheel (13), which is rotatably mounted on the top of the lever bracket (12), and has a groove on its outer surface for placing the lever (11).

Images