A bolt vibration resistance testing device and testing method

Abstract

This invention discloses a testing device and method for testing the vibration resistance of bolts, including a vibration table and a pressure sensor. A torque sensor is fixedly mounted on the vibration table, and a bolt mounting component is fixedly mounted on the torque sensor. The pressure sensor is mounted on the bolt mounting component, and a torque adjusting rod is fixedly mounted on the bolt mounting component. An inertia disk is movably connected to the torque adjusting rod, and the inertia disk is axially adjustable to the torque adjusting rod. This invention allows for better study of bolt loosening patterns, significantly improving testing efficiency; it provides a direct and real-time understanding of bolt tightness and torque through sensor data transmission; the test results more closely match the actual service life of bolts; the small-volume loading mechanism simulates a large load; it achieves fine-tuning of load torque; and it avoids deviations in experimental data caused by changes in loading torque under vibration.

Description

Technical Field

[0001] The present invention relates to the technical field of bolt testing, and in particular to a device and method for testing the vibration resistance of a bolt. Background Art

[0002] Due to its special manufacturing factors and operating conditions, industrial forklifts are affected by their own weight. When operating, they will be subjected to different degrees of vibration impact from the road surface. Therefore, higher requirements are placed on the mechanical fastening performance of the forklift. The fastening method of the bolts, the thread type of the bolts, the material of the bolts, the preload force, etc. will all affect the fastening performance of the bolts. Which connection method should be adopted according to the application and installation location is more reliable? This requires a special bolt vibration test device to verify the fastening of the bolts.

[0003] At present, the commonly used bolt vibration test device on the market uses a vibration table to load a certain vibration load, and then monitors the corresponding relationship between the clamping force and the vibration time. Through long-term loading, the relationship between the clamping force attenuation and the vibration load size and time is finally obtained. Although the existing bolt vibration test device can eventually obtain the changing law of bolt attenuation, it takes a long time to test to find the change of the bolt clamping force. Characterizing the bolt clamping force by failure time is not a good reference result. Moreover, the forklift has a large deadweight, and the bolt is loaded with a large load during actual use. The existing bolt vibration test device is difficult to simulate a large load condition, and it is difficult to adjust the load according to the actual situation. Therefore, the time of bolt vibration failure is difficult to correspond to the actual service life, and the experimental results are far from the actual situation, so it is difficult to give a qualitative result.

[0004] For example, a "bolt connection assembly anti-loosening and anti-fatigue comprehensive performance test device" disclosed in Chinese patent documents, with publication number CN111721490A, includes a test unit, a bracket unit and a drive unit. The bracket unit is used to install the test unit and the drive unit; the test unit includes a vibration mold, a fixed mold, a ball, a heating furnace, a pressure sensor and a stop plate with center holes on the coaxial center line, a movable gap is provided between the center hole of the vibration mold and the screw rod, the center hole of the stop plate has a circumferential limiting structure corresponding to the screw rod, which is used to install the bolt to be tested, and two vertical support ears are radially provided on the outer periphery of the vibration mold; the drive unit is connected to the two support ears through two sets of crank-connecting rod mechanisms, and the vibration mold is driven by the drive shaft to perform gyroscopic vibration. Its disadvantage is that the failure time of the bolt vibration tested by the pressure sensor is long, and it is difficult to correspond to the actual service life. Summary of the invention

[0005] The present invention aims to overcome the problems of long testing time and difficulty in matching failure time with actual service life in the prior art, and to provide a bolt vibration resistance testing device and testing method, which has high testing efficiency and the reliability of bolt tightening represented by the test is closer to the actual service life.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for testing the vibration resistance of bolts comprises a vibration table and a pressure sensor, wherein a torque sensor is fixedly provided on the vibration table, a bolt mounting piece is fixedly provided on the torque sensor, the pressure sensor is arranged on the bolt mounting piece, a torque adjustment rod is fixed on the bolt mounting piece, an inertia disk is movably connected to the torque adjustment rod, and the inertia disk is adjustably connected to the torque adjustment rod along the axial direction.

[0008] The characteristics of the present invention are that, on the one hand, a torque sensor is provided to detect the static load torque of the bolt, and at the same time, the changes of the bolt clamping force and the load torque are monitored. Since the change of the bolt load torque usually precedes the change of the clamping force, the law of bolt loosening can be better studied, and the test efficiency will be greatly improved; on the other hand, a torque adjustment rod and an inertia disk are provided to simulate the actual load of the bolt. Since the torque adjustment rod is provided to form a force arm, only a smaller and lighter inertia disk is needed to simulate a larger torque to fit the actual load, thereby reducing the space occupied by the simulated load. At the same time, by adjusting the position of the inertia disk, that is, adjusting the length of the force arm, the load can be adjusted to meet the requirements of different load torques.

[0009] Preferably, the inertia disk is threadedly connected to the torque adjustment rod.

[0010] The load torque can be fine-tuned by adjusting the axial position of the rotating inertia disk on the torque adjustment rod, with high adjustment accuracy.

[0011] Preferably, the bolt mounting member includes a transition plate and a loading member, the pressure sensor is pressed between the transition plate and the loading member through the bolt to be tested, the transition plate is fixed on the torque sensor, and one end of the torque adjustment rod is fixedly connected to the loading member.

[0012] On the one hand, the transition plate is used to transitionally connect the torque sensor and the pressure sensor, and on the other hand, the transition plate and the loading part are respectively arranged on the two layers of the pressure sensor. The pressure sensor is pressed from both sides by tightening the bolt to be tested. The pressure sensor is used to detect the tightening force of the bolt after tightening, and the loading part is used to load the torque formed by the inertia plate and the torque adjustment rod onto the bolt to be tested.

[0013] Preferably, a computer is further included, and the pressure sensor and the torque sensor are both connected to the computer.

[0014] Monitor and record the changes of clamping force and loading torque in real time.

[0015] Preferably, the vibration table provides lateral vibration and / or axial vibration.

[0016] By changing the direction of the vibration table, the device can not only achieve the purpose of lateral loading, but also axial loading to test the tightening performance of the bolts when subjected to axial force.

[0017] Preferably, a positioning groove is axially provided on the outer side of the torque adjustment rod, and a screw hole connected to the positioning groove is radially provided on the inertia disk. A positioning bolt is threadedly connected in the screw hole, and the positioning bolt is plug-fitted with the positioning groove.

[0018] In order to prevent the inertia disk from loosening and changing its position during the vibration process, causing changes in the loading torque and affecting the actual measurement results, the positioning bolts are radially screwed into the screw holes and positioning grooves. The ends of the positioning bolts are limited by the walls of the positioning grooves, and the inertia disk cannot rotate and loosen, thereby ensuring the consistency of the loading torque during the vibration process.

[0019] Preferably, a plurality of the screw holes are evenly spaced along the circumferential direction.

[0020] The inertia disk is adjusted in steps. By increasing the number of screw holes, the rotation angle required for the inertia disk to move to the next fixable point, that is, when the screw holes correspond to the positioning slots, is reduced, thereby improving the adjustment accuracy. For example, 6 screw holes are evenly arranged along the circumference, and a screw hole is aligned with the positioning slot every time the inertia disk rotates 60°. The bolts are inserted to fix it. The number of screw holes can be set according to actual adjustment requirements.

[0021] A method for testing the vibration resistance of a bolt comprises the following steps:

[0022] a. Tighten the bolt to be tested onto the bolt mounting part and control the pre-tightening force with a torque wrench;

[0023] b. Adjust the position of the inertia disc on the torque adjustment rod until the preset torque value or pressure value is reached;

[0024] c. Start the vibration table to perform lateral or axial vibration, and record the changes in torque and pressure values ​​in real time.

[0025] Preferably, step b further comprises adjusting the axial position of the inertia disc by rotating the inertia disc until the screw hole is aligned with the positioning groove, and screwing the positioning bolt into the screw hole until the positioning bolt is inserted into the positioning groove.

[0026] Therefore, the present invention has the following beneficial effects: (1) The change of bolt load torque usually precedes the change of clamping force, which can better study the law of bolt loosening and greatly improve the test efficiency; (2) The real-time monitoring method of the bolt vibration test can intuitively and real-time understand the bolt tightening condition and torque size through the data transmitted by the sensor; (3) The actual load condition of the bolt is simulated, and the test result is more in line with the actual service life of the bolt. The loading mechanism simulates a large load with a small volume; (4) The purpose of load torque fine-tuning can be achieved by adjusting the position of the inertia disk on the torque adjustment rod; (5) By setting the positioning groove and the corresponding screw hole, the inertia disk can be fixed after the position is adjusted to avoid deviations in the experimental data caused by changes in the loading torque under vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Figure 2 It is a cross-sectional view of the inertia disk of the present invention.

[0029] In the figure: 1. vibration table, 2. pressure sensor, 3. torque sensor, 4. transition plate, 5. loading part, 6. torque adjustment rod, 61. positioning groove, 7. inertia plate, 71. screw hole, 72. positioning bolt, 8. computer, 9. bolt to be tested. Specific implementation method 3

[0031] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] like Figure 1As shown, a bolt vibration resistance test device includes a vibration table 1, a pressure sensor 2, a torque sensor 3, a transition plate 4, a loading piece 5, a torque adjustment rod 6 and a plurality of inertia plates 7. The pressure sensor 2, the torque sensor 3, the transition plate 4, the loading piece 5 and the bolt 9 to be tested are coaxially arranged. The vibration table 1 is a prior art that can provide lateral vibration and axial vibration. For its specific structure, please refer to the "Bolt Connection Vibration Test System and Method" with the publication number CN112161770A. The torque sensor 3 is a double-flange static torque sensor. The bottom of the torque sensor 3 is fixed on the vibration table 1, and the wire of the torque sensor 3 is connected to the computer 8. The top of the torque sensor 3 is fixed with a transition plate 4 by bolts. The center of the transition plate 4 is provided with a screw hole adapted to the bolt 9 to be tested. The transition plate 4 is provided with an annular groove for installing the pressure sensor 2, and one side of the annular groove is provided with a wire groove connected to the outside. The pressure sensor 2 is an annular pressure sensor, fixed in the annular groove, and the wire of the pressure sensor 2 is connected to the computer 8 through the wire groove. The pressure sensor 2 is provided with a cylindrical loading member 5, and the loading member 5 is provided with a countersunk hole adapted to the bolt 9 to be tested. A torque adjustment rod 6 is fixed to one side of the loading member 5, and the extension direction of the torque adjustment rod 6 is perpendicular to the axial direction of the bolt 9 to be tested. The end of the torque adjustment rod 6 away from the loading member 5 is provided with a thread, and the part with the thread is provided with an inertia disk 7 through a threaded connection sleeve, such as Figure 2 As shown, two positioning grooves 61 are provided in the axial direction on the outer side of the torque adjustment rod 6, and the two positioning grooves 61 are symmetrically arranged with respect to the central axis of the adjustment rod. A screw hole 71 is provided in the radial direction on the inertia disk 7 to communicate with the positioning groove 61, and the screw hole 71 is a countersunk hole. There are 6 screw holes 71 in total, which are evenly spaced in the circumferential direction. A positioning bolt 72 is threadedly connected in the screw hole 71, and the end of the positioning bolt 72 is plugged into the positioning groove 61. A protective plug can be inserted into the outer end of the screw hole 71 to further fix the positioning bolt.

[0034] The computer is used to display in real time the load torque and the clamping force of the bolt to be tested when it is excited by the vibration table. The flange static torque sensor is used to measure the real-time load torque of the bolt and generate a real-time curve on the computer. The annular pressure sensor is used to measure the clamping force of the bolt and generate a real-time curve on the computer. The bolt to be tested and the torque adjustment rod can be designed with a variety of mounting hole sizes according to bolts of different specifications to meet the test requirements of different bolt inner diameters. The end of the positioning bolt 72 is matched with the positioning groove 61 to prevent the inertia disk 7 from rotating and loosening under vibration. Every time the inertia disk rotates 60°, the corresponding screw hole is aligned with the positioning groove. The load torque on the bolt is adjusted by adjusting the left and right positions of the inertia disk. According to the test needs, various sizes of inertia disks are designed to meet the requirements of different load torques.

[0035] Example 2

[0036] A method for testing the vibration resistance of a bolt comprises the following steps:

[0037] a. Pass the bolt to be tested through the countersunk hole of the loader 5, the center hole of the pressure sensor 2 and the screw hole of the transition plate 4 in sequence and tighten them, and control the preload force by a torque wrench;

[0038] b. Adjust the axial position of the inertia disc 7 by rotating it until the screw hole 71 is aligned with the positioning groove 61, screw the positioning bolt 72 into the screw hole until the positioning bolt is inserted into the positioning groove, and determine the position and number of the inertia disc 7 and the number and position of the positioning bolt 72 corresponding to the required torque through multiple tests through the real-time display of static torque on the computer, and perform vibration test after fixing;

[0039] c. Start the vibration table to perform lateral or axial vibration, and record the changes in torque and pressure values ​​under different loading torques in real time to help analyze the relationship between the changes in torque and pressure values ​​and the actual failure time of the bolt.

[0040] The change of bolt load torque usually precedes the change of clamping force, which can better study the law of bolt loosening and greatly improve the test efficiency. The real-time monitoring method of bolt vibration test can intuitively and real-timely understand the bolt tightening condition and torque size through sensor transmission data. The torque formed by the inertia disk and the torque adjustment rod simulates the actual load condition of the bolt. The test result is more in line with the actual service life of the bolt, and the loading mechanism simulates a large load with a small volume. The purpose of load torque fine-tuning can be achieved by adjusting the position of the inertia disk on the torque adjustment rod, that is, the size of the force arm. The positioning groove and the corresponding screw hole are set to facilitate the adjustment of the position and then fix the inertia disk to avoid deviations in the experimental data caused by changes in the loading torque under vibration.

Claims

1. A bolt vibration resistance testing device, comprising a vibration table (1) and a pressure sensor (2), characterized in that: The vibration table (1) is fixedly provided with a torque sensor (3), the torque sensor (3) being a double-flange static torque sensor, the torque sensor (3) being fixedly provided with a bolt mounting member, the pressure sensor (2) being arranged on the bolt mounting member, the bolt mounting member being fixed with a torque adjustment rod (6), the torque adjustment rod (6) being movably connected with an inertia disk (7), the inertia disk (7) being adjustably connected to the torque adjustment rod (6) along the axial direction; the bolt mounting member comprising a transition disk (4) and a loading member (5), the transition disk (4) being fixed on the torque sensor (3), the pressure sensor (2) being pressed between the transition disk (4) and the loading member (5) via a bolt to be tested, the transition disk being used for transitionally connecting the torque sensor and the pressure sensor, and the loading member being used for loading the torque formed by the inertia disk and the torque adjustment rod onto the bolt to be tested; One end of the torque adjustment rod (6) is fixedly connected to the loading member (5); The inertia disk (7) is threadedly connected to the torque adjustment rod (6); The torque adjustment rod (6) is provided with a positioning groove (61) in the axial direction on the outer side, the inertia disc (7) is provided with a screw hole (71) in the radial direction which is connected to the positioning groove (61), a positioning bolt (72) is threadedly connected in the screw hole (71), and the positioning bolt (72) is plug-fitted into the positioning groove (61); Two positioning grooves (61) are axially arranged on the outer side of the torque adjustment rod (6), and the two positioning grooves (61) are symmetrically arranged about the center axis of the torque adjustment rod (6); The positioning bolt (72) is screwed into the screw hole (71) and the positioning groove (61) in the radial direction. The end of the positioning bolt (72) is limited by the groove wall of the positioning groove (61), and the inertia disk (7) cannot be rotated and loosened.

2. A bolt vibration resistance testing device according to claim 1, characterized in that: It also includes a computer (8), and the pressure sensor (2) and the torque sensor (3) are both connected to the computer (8).

3. A bolt vibration resistance testing device according to claim 1, characterized in that: The vibration table (1) provides lateral vibration and / or axial vibration.

4. A bolt vibration resistance testing device according to claim 1, characterized in that: A plurality of screw holes (71) are evenly spaced along the circumferential direction.

5. A testing method using the bolt vibration resistance testing device according to any one of claims 1 to 4, characterized in that: The steps include: a. Tighten the bolt to be tested onto the bolt mounting part and control the pre-tightening force with a torque wrench; b. Adjust the position of the inertia disk (7) on the torque adjustment rod (6) until the preset torque value or pressure value is reached; through the static torque displayed in real time on the computer, determine the position and number of the inertia disks and the number and position of the positioning bolts corresponding to the required torque through multiple tests, and perform a vibration test after fixing; c. Start the vibration table (1) to perform lateral or axial vibration, record the changes in torque and pressure values ​​in real time, and analyze the relationship between the changes in torque and pressure values ​​and the actual failure time of the bolt.

6. A method for testing the vibration resistance of bolts according to claim 5, characterized in that: The step b further comprises adjusting the axial position of the inertia disc (7) by rotating the inertia disc (7) until the screw hole (71) is aligned with the positioning groove (61), and screwing the positioning bolt (72) into the screw hole (71) until the positioning bolt (72) is inserted into the positioning groove (61).

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