Adaptive clamping high-toughness vehicle body structure fatigue test bench

Abstract

The present application relates to the technical field of fatigue test, in particular to a kind of self-adapting clamping high-strength tough car body structural member fatigue test bench, including fatigue test ontology and self-adapting clamping device, the fatigue test ontology is adapted to install with self-adapting clamping device.The present application is by being provided with cycle test mechanism and other components, by the cooperation between the driving source in cycle test mechanism and transmission column component, the connecting piece can be made to complete bolt tightening action, after being tightened in place, sliding engagement piece automatically switches power path, power is transmitted to gear ring through connecting gear, and the linear displacement trigger state switching of cooperation push ring, the complex load history of multiple disassembly and assembly in actual service can be reproduced, the defect that traditional test bench can only test constant pre-tightening force working condition is made up, the matching degree of test data and engineering practice is improved, and then the effect that the device is through the screw transmission of gear ring and push ring, bolt is carried out tightening and loosening cycle test for high-strength tough car body structural member is achieved.

Description

Technical Field

[0001] This invention relates to the field of fatigue testing technology, specifically to a fatigue testing bench for high-strength and tough vehicle body structural components with adaptive clamping. Background Technology

[0002] In high-strength and tough body structural components, high-strength bolts, nuts, or rivets are used extensively as key connecting fasteners, and their fatigue performance is directly related to the reliability and safety of the entire vehicle frame. In order to accurately evaluate this performance, the fatigue test bench applies cyclic alternating loads to the test components through a loading mechanism, thereby determining their fatigue strength and durability. It is an indispensable core test equipment in structural component verification.

[0003] Traditional fatigue testing benches employ a relatively simple loading mode when conducting fatigue tests on bolts, typically simulating only a single tightening followed by a stable cyclic load under constant preload. However, in actual engineering, the service conditions of bolts are far more complex than the test conditions. Over the long service life of equipment, bolt connections may undergo multiple disassemblies and reassemblies, such as repeated tightening during regular maintenance, or encounter unexpected impacts or overloads, or sudden fluctuations in operating conditions leading to instantaneous load exceeding limits, before being put back into normal use. This multi-stage load history causes repeated redistribution of the residual stress field inside the bolt, resulting in nonlinear cumulative micro-damage. Traditional testing benches cannot reproduce this real-world process involving multiple clamping force abrupt changes and overload memories, leading to a significant disconnect between test data and actual engineering conditions, making it difficult to accurately predict the remaining life of bolts under complex load histories. This limits the scope of test evaluation, significantly reduces the effectiveness of fatigue testing benches, and fails to provide reliable test support for the fatigue resistance design of structural components and the optimization of maintenance cycles. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides an adaptive clamping fatigue testing bench for high-strength and tough vehicle body structural components. This bench effectively solves the problem that existing fatigue testing benches cannot reproduce the residual stress redistribution and damage accumulation process of bolted connections under multiple disassembly and assembly and complex load processes.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a fatigue testing bench for high-strength and tough vehicle body structural components with adaptive clamping, including a fatigue testing body and an adaptive clamping device. The fatigue testing body and the adaptive clamping device are adapted and installed together. It also includes a cyclic testing mechanism for tightening and loosening cycles. The cyclic testing mechanism includes a drive source, with a transmission column fixedly connected to the output end of the drive source. A sliding groove is formed at the top of the transmission column, and a connecting rod is slidably connected inside the sliding groove. A connecting member is provided at the top of the connecting rod, and a sliding engagement member is provided at the bottom of the connecting rod. A connecting gear is provided on one side of the top of the sliding engagement member, and a gear ring meshes with one side of the connecting gear. A push ring is threadedly connected to the outer side of the gear ring, and a telescopic movable rod is rotatably connected to the inner side of the push ring. The telescopic movable rod is slidably connected to the inside of the gear ring, and the top of the telescopic movable rod is inserted into the connecting rod.

[0006] Furthermore, the drive source is fixedly connected to the bottom surface inside the fatigue test body, the bottom of the toothed ring is rotatably connected to the inside of the fatigue test body, and the push ring is slidably connected to the fatigue test body.

[0007] Furthermore, the connecting component includes a connecting ring, a connecting block, a pushing block, a separating rod, and a mounting base. The connecting ring is slidably connected to the mounting base, and the surface of the connecting ring is fixedly connected to the connecting block. The connecting ring and the mounting base are elastically connected through an elastic element. The connecting ring is rotatably connected to the fatigue test body. Several sets of connecting blocks are provided, and the bottom of the connecting block is abutted against the pushing block. The pushing block is slidably connected to the mounting base, and the bottom of the pushing block is slidably connected to the separating rod. The pushing block is elastically connected to the mounting base through an elastic reset element. The separating rod is slidably connected to the mounting base, and the bottom pushing end of the separating rod is annular, with the bottom of the separating rod located at the top of the telescopic movable rod.

[0008] Furthermore, a fixed post is fixedly connected to the bottom of the connecting ring, a sliding rod is slidably connected to the bottom of the fixed post, and the sliding rod is fixedly connected to the connecting rod. An elastic compression member is elastically connected inside the fixed post, and the other end of the elastic compression member is elastically connected to the sliding rod.

[0009] Furthermore, a constant force spring box is fixedly connected to the bottom of the toothed ring, and the constant force spring box is fixedly connected to the fatigue test body.

[0010] Furthermore, the sliding engagement component includes a rotating ring, an ejector ring, a sliding gear, and a guide block. The top of the rotating ring is rotatably connected to the bottom of the connecting rod, and the surface of the rotating ring is fixedly connected to the ejector ring. The outer side of the rotating ring is fixedly connected to the sliding gear. The top of the ejector ring is slidably connected to the bottom of the connecting rod. The sliding gear is slidably connected to the transmission column and meshes with the connecting gear. The top of the sliding gear is fixedly connected to the bottom of the guide block, and the top of the guide block is inclined.

[0011] Furthermore, an elastic support plate is fixedly connected inside the sliding groove, and the elastic support plate is elastically connected to the connecting rod.

[0012] Furthermore, a locking block is fixedly connected to the extended end of the telescopic movable rod, and an electromagnetic block is magnetically connected to the outside of the locking block. The electromagnetic block is fixedly connected to the fixed end of the telescopic movable rod, and the electromagnetic block is electrically connected to a micro switch via a wire. The micro switch is fixedly connected to the telescopic movable rod.

[0013] Furthermore, a strong magnetic block is magnetically connected to the top of the sliding gear, and the strong magnetic block is fixedly connected to the transmission column.

[0014] Furthermore, a movable block is rotatably connected to the bottom of the sliding gear, and the movable block is slidably connected to the telescopic movable rod.

[0015] Beneficial effects: The technical solution provided by this invention has the following advantages compared with the known prior art: I. This invention, by setting up components such as a cyclic testing mechanism, enables the connecting parts to complete the bolt tightening action through the mutual cooperation between the drive source and transmission column components inside the cyclic testing mechanism. After tightening to the correct position, the sliding meshing parts automatically switch the power path, transmitting the power to the gear ring via the connecting gear. In conjunction with the linear displacement trigger state switching of the push ring, it can reproduce the complex load process of multiple disassemblies and reassemblies in actual service, making up for the deficiency of traditional test benches that can only test constant preload conditions, improving the matching degree between test data and engineering reality, and thus achieving the effect of this device performing cyclic tightening and loosening tests on bolts of high-strength and tough body structural components through the helical transmission of the gear ring and the push ring.

[0016] II. This invention, through the setting of components such as connectors, fixed columns, and sliding rods, forms a releasable limiting structure by the mutual abutment between the connecting blocks and pushing blocks inside the connectors. This allows the mounting seat to automatically float upwards with the thread feed during bolt tightening. Simultaneously, the connecting ring provides axial displacement compensation space through the relative sliding of the fixed column and the sliding rod. When the telescopic movable rod pushes the separating rod upwards, the separating rod simultaneously pushes multiple sets of pushing blocks to release the limiting of the connecting blocks. The mounting seat can then continue to move upwards to release the preload when the bolt is loosened. Thus, this device achieves the effect of automatically adapting to the axial displacement of the bolt during tightening and loosening cycles through the adaptive floating clamping function of the connectors, ensuring the continuity of power transmission and smooth transition of working conditions.

[0017] Third, this invention, by setting up components such as a sliding engagement element, a strong magnetic block, an elastic support plate, an electromagnetic block, and a constant force spring box, achieves the following: when the connecting rod is obstructed, the ejector ring in the sliding engagement element converts the rotational motion into axial thrust, causing the connecting rod to disengage from the sliding groove. Simultaneously, the guide block and the strong magnetic block cooperate to assist the sliding gear in smoothly rising and engaging with the connecting gear, realizing automatic switching of the power path. After being triggered by a micro switch, the electromagnetic block drives the locking block to move, causing the sliding gear to disengage from the connecting gear. The constant force spring box drives the toothed ring to reset and rotate. The elastic support plate provides a buffer displacement margin for the end of the connecting rod. Thus, this device can achieve automatic switching and reliable reset of the transmission state at each stage of the tightening and loosening cycle through the coordinated cooperation of various components, and can operate continuously without external timing control. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is an overall schematic diagram of the present invention; Figure 2 This is a schematic diagram of the internal structure of the fatigue test body of the present invention; Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the connector of the present invention; Figure 5 This is a schematic diagram of the sliding engagement component of the present invention; Figure 6 For the present invention Figure 5 Enlarged view of point B in the middle; Figure 7This is a schematic cross-sectional view of the transmission column of the present invention; Figure 8 This is a schematic diagram of the driving ring of the present invention; Figure 9 For the present invention Figure 8 Enlarged diagram of point C in the middle.

[0020] Reference numerals: 1. Fatigue test body; 2. Adaptive clamping device; 3. Cyclic test mechanism; 31. Transmission column; 32. Sliding groove; 33. Connecting rod; 34. Connecting part; 341. Connecting ring; 342. Connecting block; 343. Pushing block; 344. Separating rod; 345. Mounting base; 35. Sliding meshing part; 351. Rotating ring; 352. Pushing ring; 353. Sliding gear; 354. Guide block; 36. Connecting gear; 37. Gear ring; 38. Pushing ring; 39. Telescopic movable rod; 4. Fixed column; 5. Sliding rod; 6. Elastic compression part; 7. Constant force spring box; 8. Elastic support plate; 9. Locking block; 10. Electromagnetic block; 11. Micro switch; 12. Strong magnetic block; 13. Movable block. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] The present invention will be further described below with reference to embodiments.

[0023] See attached document Figure 1-9 A fatigue testing bench for high-strength and tough vehicle body structural components with adaptive clamping is disclosed, comprising: a fatigue testing body 1 and an adaptive clamping device 2. The fatigue testing body 1 and the adaptive clamping device 2 are adapted and installed together. The fatigue testing body 1 and the adaptive clamping device 2 are existing technologies. The fatigue testing body 1 serves as a basic load-bearing and loading platform, applying cyclic alternating loads to the test component through mature methods such as electro-hydraulic servo and electromagnetic resonance to determine its fatigue strength and durability. The adaptive clamping device 2 is used to fix the test component and adopts a mature component with adaptive capabilities from the existing technology. The two are adapted and installed together to form a conventional testing platform. The system also includes a cycle test mechanism 3 for tightening and loosening cycles. The cycle test mechanism 3 includes a drive source, which is a motor commonly used in the prior art. The specific model can be selected by those skilled in the art according to the specific use environment and load requirements. This is a conventional technical means and will not be described in detail. The output end of the drive source is fixedly connected to a transmission column 31. A sliding groove 32 is provided on the top of the transmission column 31. A connecting rod 33 is slidably connected inside the sliding groove 32. A connecting piece 34 is provided on the top of the connecting rod 33. A sliding engagement piece 35 is provided at the bottom of the connecting rod 33. A connecting gear 36 is provided on one side of the top of the sliding engagement piece 35. A toothed ring 37 is engaged on one side of the connecting gear 36. A push ring 38 is threadedly connected to the outside of the toothed ring 37. A telescopic movable rod 39 is rotatably connected to the inside of the push ring 38. The telescopic end and the fixed end inside the telescopic movable rod 39 are elastically connected through an elastic abutment. The telescopic movable rod 39 is slidably connected to the inside of the toothed ring 37. The top of the telescopic movable rod 39 is inserted into the connecting rod 33. The drive source provides rotational power as the power input for the cyclic test mechanism 3; the transmission column 31 transmits the rotational power from the drive source, and its internal sliding groove 32 provides axial sliding space and circumferential transmission for the connecting rod 33; the connecting rod 33 transmits rotational power and can slide axially within the transmission column 31 after being stressed to adapt to the displacement requirements of different working stages; the connecting piece 34 is driven by the connecting rod 33 and completes a threaded connection with the bolt to be tested, realizing the tightening and loosening of the bolt; the sliding engagement piece 35 is used to switch the power transmission path, in The connecting rod 33 performs state transitions between transmission and gear transmission; the connecting gear 36 transmits power from the sliding meshing part 35 to the gear ring 37, realizing the conversion of power path; the gear ring 37 receives power from the connecting gear 36 and rotates, and its outer thread and the push ring 38 form a helical transmission pair; the push ring 38 converts the rotational motion of the gear ring 37 into axial linear motion, driving the telescopic movable rod 39 to perform axial displacement; the telescopic movable rod 39 realizes power docking and state switching, can complete plug-in transmission with the connecting rod 33, and trigger subsequent actions at the same time; The drive source and transmission column 31 together constitute the primary power input mechanism, which stably outputs rotational power. The transmission column 31 and the connecting rod 33 form a slidable transmission connection through the sliding groove 32, which takes into account both power transmission and axial displacement. The sliding meshing part 35 and the connecting gear 36 together constitute the power switching mechanism, which realizes the smooth transition between the two transmission paths. The connecting gear 36 and the gear ring 37 mesh with each other and realize the conversion of transmission direction. The gear ring 37 and the push ring 38 form a spiral lifting mechanism through threaded engagement, which converts rotational motion into linear displacement. The push ring 38 and the telescopic movable rod 39 move synchronously to complete the switching trigger of the transmission state. The whole can realize the automatic cycle test of bolt tightening and loosening, simulate the fatigue characteristics of bolts under multiple disassembly and assembly conditions, make up for the shortcomings of traditional test benches that can only test constant preload conditions, improve the matching degree between test data and engineering reality, and provide more reliable test basis for fatigue performance evaluation of high strength and toughness body structural components. The drive source is fixedly connected to the bottom surface inside the fatigue test body 1, the bottom of the gear ring 37 is rotatably connected to the inside of the fatigue test body 1, and the push ring 38 is slidably connected to the fatigue test body 1. The drive source is fixed to the bottom surface inside the fatigue test body 1 to ensure the stability of the power output and avoid displacement during operation. The gear ring 37 is rotatably connected to the inside of the fatigue test body 1 to provide stable rotational support for the gear ring 37 and ensure the accuracy of meshing transmission. The push ring 38 is slidably connected to the fatigue test body 1 to limit the circumferential rotation of the push ring 38, so that it can only move linearly along the axial direction. The drive source, gear ring 37, and push ring 38 are all installed with the fatigue test body 1 as the mounting reference, and their spatial positions are relatively fixed. The power provided by the drive source is finally transmitted to the gear ring 37 through the transmission path. The rotation of the gear ring 37 drives the push ring 38 to move axially along the body guide. The whole system ensures the positional accuracy and motion reliability of each moving part of the cyclic test mechanism 3, avoids off-center loading or jamming during transmission, and improves the overall stability and service life of the device. The bottom of the toothed ring 37 is fixedly connected to a constant force spring box 7, which is also fixedly connected to the fatigue test body 1. The constant force spring box 7 provides a constant reset force for the toothed ring 37, and drives the toothed ring 37 to rotate and reset when the power is lost. The constant force spring box 7 is fixedly connected to the toothed ring 37 and can accumulate elastic potential energy as the toothed ring 37 rotates. After the power is disconnected, the potential energy is released to drive the toothed ring 37 back to the initial position. The whole system realizes the automatic reset function of the toothed ring 37, ensuring that the transmission mechanism can return to the ready state after each cycle, and prepare for the next cycle test. There is no need to set up an additional reset drive device, which simplifies the overall structure. The sliding groove 32 is internally fixedly connected to an elastic support plate 8, which is elastically connected to the connecting rod 33. The elastic support plate 8 provides elastic support for the connecting rod 33 and provides buffer and displacement margin when the connecting rod 33 moves axially. The elastic support plate 8 is fixed inside the sliding groove 32, elastically contacts the connecting rod 33, and can absorb the impact load when the connecting rod 33 moves downward. The whole avoids rigid collision between the connecting rod 33 and the bottom of the transmission groove during the reset process, preventing the components from being damaged by impact. At the same time, after the mounting base 345 is connected to the bolt, when the connecting rod 33 cannot rotate and is still in the sliding groove 32 and is pushed out by the push-out ring 352, it provides a certain end displacement compensation, prevents the transmission mechanism from jamming, and improves the smoothness of the device operation. The telescopic rod 39 has a locking block 9 fixedly connected to its extended end, and an electromagnetic block 10 is magnetically connected to the outside of the locking block 9. The electromagnetic block 10 is existing technology and is fixedly connected to the fixed end of the telescopic rod 39. The electromagnetic block 10 is electrically connected to a micro switch 11 via a wire. The micro switch 11 is existing technology and is fixedly connected to the telescopic rod 39. The power supply, installation, and wiring methods of the electromagnetic block 10 and the micro switch 11 are all implemented using existing technology. The locking block 9 is used for fixed connection to the telescopic rod 39. The telescopic end; the electromagnetic block 10 is used to generate magnetic attraction, which drives the locking block 9 to move outward when energized, and drives the telescopic end of the telescopic rod 39 to move; the micro switch 11 is used to trigger the energization of the electromagnetic block 10, and is pressed to trigger when the connecting rod 33 moves down to the set position; the locking block 9 and the electromagnetic block 10 together constitute an electromagnetic locking control mechanism to realize the locking and releasing of the telescopic position of the telescopic rod 39; the micro switch 11 and the electromagnetic block 10 are electrically connected by wires to form a position-triggered electrical control circuit, which is directly triggered by mechanical displacement to open and close the circuit; the overall implementation The automatic trigger release of the limit state of the telescopic movable rod 39 is realized. When the release action is completed and the set position is reached, the transmission state is automatically switched, so that the connecting rod 33 resumes the power connection with the transmission column 31, ensuring the automatic connection of the cycle process without the need for external timing control, thus improving the automation level of the cycle test. It is worth noting that during the downward movement of the connecting rod 33, its bottom end face first contacts the contact of the micro switch 11. At this time, the micro switch 11 is not yet turned on, and its contact generates a certain resistance to the connecting rod 33 under the action of the spring, which plays a limiting role, so that the connecting rod... The connecting rod 33 pauses briefly at this position to ensure the accuracy of the triggering action. When the connecting rod 33 continues to apply pressure and fully presses the contact in, the micro switch 11 is turned on, sending a positioning signal to trigger the electromagnetic block 10 to move. At the same time, after the contact is pressed to the limit position, it no longer provides additional obstruction to the connecting rod 33, and the connecting rod 33 continues to move down to complete the reset. In other words, the micro switch 11 does play a limiting role before being turned on, but this limit is not stuck. Instead, it releases itself after the signal is triggered by the elastic stroke of the contact, and the connecting rod 33 will not be blocked and unable to move. See attached document Figure 2-4 The connector 34 includes a connecting ring 341, a connecting block 342, a pushing block 343, a separating rod 344, and a mounting base 345. The connecting ring 341 is slidably connected to the mounting base 345, and the surface of the connecting ring 341 is fixedly connected to the connecting block 342. The connecting ring 341 and the mounting base 345 are elastically connected through an elastic element. The connecting ring 341 is rotatably connected to the fatigue test body 1. Several sets of connecting blocks 342 are provided, and the bottom of the connecting block 342 is abutted against the pushing block 343. The pushing block 343 is slidably connected to the mounting base 345, and the bottom of the pushing block 343 is slidably connected to the separating rod 344. The pushing block 343 is elastically connected to the mounting base 345 through an elastic reset element. The separating rod 344 is slidably connected to the mounting base 345, and the bottom pushing end of the separating rod 344 is annular. The part is located at the top of the telescopic movable rod 39; the connecting ring 341 and the fatigue test body 1 are rotatably connected, and the connection is a double-sided rotatable structure. The specific implementation method belongs to the prior art. For example, bearings can be set at the double-sided connection points, and relative rotation can be achieved through the connecting parts between the bearings; when the telescopic movable rod 39 rises to push the separating rod 344, although the telescopic movable rod 39 has its own rotational motion during the pushing process, since the connecting ring 341 has an independent degree of rotational freedom, motion decoupling can be achieved in this motion transmission path, effectively blocking the transmission of the rotational motion of the telescopic movable rod 39 to the connecting ring 341, avoiding the connecting ring 341 being driven to produce unexpected rotation, thereby ensuring that the pushing action of the separating rod 344 and the rotational state of the connecting ring 341 are independent of each other and do not interfere with each other, ensuring the accuracy and reliability of the mechanism action; The connecting ring 341 transmits rotational power, driving the mounting base 345 to rotate synchronously, and simultaneously provides a mounting carrier for the connecting block 342. The connecting block 342 cooperates with the pushing block 343 to form a limiting pushing structure, facilitating the movement of the connecting ring 341 by pushing the connecting block 342 through the pushing block 343 when the mounting base 345 is under force. The pushing block 343 can be released from its pushing state under the action of the separating rod 344. The separating rod 344 is used to trigger the limiting release action, and its bottom annular pushing end can be easily driven by the telescopic movable rod 39. The mounting base 345 is used to directly connect to the threaded bolt to be tested, serving as the execution end for tightening and loosening actions. The elastic element provides elastic restoring force to the connecting ring 341, maintaining the initial relative position of the connecting ring 341 and the mounting base 345. The elastic restoring element provides restoring elastic force to the pushing block 343, ensuring the push block 343... The device maintains a limited position when no external force is applied. The connecting ring 341 and the mounting base 345 are elastically connected through an elastic element, which can pull the mounting base 345 downward to reset. The connecting block 342 and the pushing block 343 abut against each other to form a releasable limited pushing mechanism, which maintains the synchronous movement of the connecting ring 341 and the mounting base 345 under normal conditions. The separating rod 344 and multiple sets of pushing blocks 343 together form a synchronous release mechanism to achieve unified trigger release of the limited pushing state. The elastic element and the elastic reset element provide reset elastic force for the corresponding components, ensuring that each component can return to its initial working position. The whole device realizes the adaptive floating clamping function of the mounting base 345, which can automatically adapt to axial displacement during bolt tightening. At the same time, the limit can be released by triggering the separating rod 344 to realize the switching of the bolt pre-tightening state, which meets the working conditions of different stages of tightening and loosening in cyclic testing. The connecting ring 341 is fixedly connected to a fixed post 4 at its bottom, and a sliding rod 5 is slidably connected to the bottom of the fixed post 4. The sliding rod 5 is fixedly connected to the connecting rod 33. An elastic compression member 6 is elastically connected inside the fixed post 4, and the other end of the elastic compression member 6 is elastically connected to the sliding rod 5. The fixed post 4 is fixedly connected to the bottom of the connecting ring 341 and rotates and moves axially synchronously with the connecting ring 341. The sliding rod 5 is fixedly connected to the top of the connecting rod 33 and moves synchronously with the connecting rod 33. Its top can slide inside the fixed post 4 and can be pulled and moved by the fixed post 4. The fixed post 4 and the sliding rod 5 together constitute a telescopic transmission rod mechanism, which can transmit circumferential rotational power and adapt to the axial relative displacement between the connecting ring 341 and the connecting rod 33. The whole mechanism ensures the continuity of power transmission between the connecting rod 33 and the connecting ring 341, and provides compensation space for axial displacement during the tightening process. See attached document Figure 2-9The sliding engagement member 35 includes a rotating ring 351, an ejection ring 352, a sliding gear 353, and a guide block 354. The top of the rotating ring 351 is rotatably connected to the bottom of the connecting rod 33, and the surface of the rotating ring 351 is fixedly connected to the ejection ring 352. The outer side of the rotating ring 351 is fixedly connected to the sliding gear 353. The top of the ejection ring 352 is slidably connected to the bottom of the connecting rod 33. The sliding gear 353 is slidably connected to the transmission column 31, and the sliding gear 353 meshes with the connecting gear 36. The top of the sliding gear 353 is fixedly connected to the bottom of the guide block 354, and the top of the guide block 354 is inclined. The rotating ring 351 connects to the bottom of the connecting rod 33 and moves axially synchronously with the connecting rod 33. It also provides a mounting carrier for the ejector ring 352 and the sliding gear 353. The ejector ring 352 converts the rotational force into an axial thrust on the connecting rod 33 when it is obstructed, pushing the connecting rod 33 upwards out of the sliding groove 32. The sliding gear 353 transmits rotational power and can engage or disengage with the connecting gear 36 to switch the power path. The guide block 354 guides the engagement of the sliding gear 353 and the connecting gear 36; its inclined top surface provides guidance and correction during engagement to ensure smooth completion of the engagement. The rotating ring 351 and the connecting gear 352... The bottom of the connecting rod 33 is rotatably connected, allowing it to continue rotating relative to the rod after it stops rotating. The push-out ring 352 and the rotating ring 351 are fixedly connected, together forming a rotary lifting mechanism that converts rotational motion into axial displacement. The sliding gear 353 and the guide block 354 are fixedly connected, together forming a liftable meshing mechanism that enables the connection and disconnection of the transmission path. The whole system realizes the automatic switching function of the power transmission path. After the bolts are tightened in place, the power is automatically switched from the path of the connecting rod 33 to the gear transmission path, triggering the subsequent loosening cycle action. The switching process does not require additional control elements and is completed automatically by the mechanical structure, improving the automation level and operational reliability of the device. The sliding gear 353 is magnetically connected to a strong magnetic block 12 at its top, and the strong magnetic block 12 is fixedly connected to the transmission column 31. The strong magnetic block 12 is used to generate a magnetic attraction to the sliding gear 353, assisting the sliding gear 353 to move upward and complete the meshing with the connecting gear 36. This avoids the situation where the sliding gear 353 cannot continue to move upward and complete the effective meshing with the connecting gear 36 after the connecting rod 33 moves upward. The strong magnetic block 12 is fixed to the transmission column 31 and corresponds to the top position of the sliding gear 353. When the sliding gear 353 rises to the near position, it generates a magnetic attraction force. The whole provides auxiliary power for the upward meshing of the sliding gear 353, ensuring that the sliding gear 353 can smoothly reach the meshing position, avoiding the situation where the meshing is not complete due to mechanical resistance, and improving the success rate of power switching and the reliability of device operation. Among them, the bottom of the sliding gear 353 is rotatably connected to the movable block 13, and the movable block 13 is slidably connected to the telescopic movable rod 39; the movable block 13 is rotatably connected to the bottom of the sliding gear 353 and slidably connected to the telescopic movable rod 39. Its function is to convert the telescopic movement of the telescopic movable rod 39 into the axial downward displacement of the sliding gear 353 during the power path switching process, so as to ensure the stability of the sliding gear 353 during the downward process. It is worth noting that all the elastic elements involved in this technical solution, including the elastic component between the connecting ring 341 and the mounting base 345, the elastic reset component of the push block 343, the elastic compression component 6 inside the fixed column 4, the elastic clamping component inside the telescopic movable rod 39, and the elastic support plate 8, can be selected from existing elastic components such as helical springs or rubber springs. The specific selection and parameter settings (such as stiffness coefficient, pre-compression amount, fatigue limit and working stroke, etc.) should be adapted and tested according to the actual working conditions (including test environment temperature, operating frequency, load size and creep characteristics after long-term operation, etc.) to ensure that each elastic element maintains stable mechanical properties and sufficient fatigue life in frequent linkage cycles. Operators can also reasonably replace or adjust the material (such as spring steel, stainless steel or high temperature resistant alloy), structural form (such as helical spring, disc spring or gas spring) or installation pre-tightening method of the above elastic elements according to specific usage requirements, and are not limited to the specific forms listed in the embodiments. This is prior art and will not be elaborated here. Furthermore, all moving parts in this device involving relative sliding or rotation include the sliding engagement between the connecting ring 341 and the mounting base 345, the sliding engagement between the connecting rod 33 and the sliding groove 32, the relative sliding between the fixed column 4 and the sliding rod 5, the sliding connection between the separating rod 344 and the mounting base 345, the sliding connection between the pushing block 343 and the mounting base 345, the sliding connection between the sliding gear 353 and the transmission column 31, the meshing guidance between the guide block 354 and the connecting gear 36, the internal sliding connection between the telescopic movable rod 39 and the gear ring 37, and the sliding connection between the movable block 13 and the telescopic movable rod 39. The connection between the telescopic movable rod 39 and the connecting rod 33 can be achieved using existing mature technologies such as guide rails, limit grooves, linear bearings, hinge seats, or pin connection structures. The attached drawings do not show all the details to ensure that the actions of each mechanism are precise, the fit clearance is reasonable, and the operation is stable and reliable. Depending on the different installation space and maintenance requirements, dustproof seals, self-lubricating bushings, or wear compensation devices can be added to key moving parts to further improve the durability and smoothness of the equipment under long-term cyclic testing and complex working conditions. This is existing technology and will not be described in detail here.

[0024] Working principle: In use, the adaptive clamping device 2 first clamps the bolt head, and then the fatigue test body 1 is started, which drives the adaptive clamping device 2 and the bolt to move to the top of the mounting base 345 and aligns with the connecting slot at the top of the mounting base 345; then the drive source is started to drive the transmission column 31 to rotate, and the transmission column 31 drives the connecting rod 33 to rotate synchronously through the internal sliding groove 32. The connecting rod 33 transmits power through the sliding rod 5 and the fixed column 4, driving the connecting ring 341 to rotate. The connecting ring 341 then drives the mounting base 345 to rotate, so that the mounting base 345 and the test end of the bolt to be tested are connected by threads and gradually tightened. Because the bolt position is fixed, the mounting base 345 will move upward along the thread during tightening, simultaneously driving the connecting block 342 and the connecting ring 341 to move upward through the pushing block 343. The connecting ring 341 can drive the fixed column 4 to move upward, and the interior of the fixed column 4 and the sliding rod 5 will move away from each other, leaving space for subsequent displacement. The sliding rod 5 will then continue to move driven by the fixed column 4, which can pull the connecting rod 33 to move. At this time, the connecting rod 33 is still under force and maintains transmission with the sliding groove 32 after the sliding rod 5 rises to the preset position. When the mounting base 345 and the bolt are tightened to the limit position, the mounting base 345 can no longer rotate, and the rotation of the connecting rod 33 is also simultaneously blocked. After the connecting rod 33 is obstructed, the transmission column 31 pushes the rotating ring 351, so that the push-out ring 352 on the outside of the rotating ring 351 is fixed in position relative to the connecting rod 33 and continues to rotate. The push-out ring 352 is slidably connected to the connecting rod 33. When the connecting rod 33 cannot rotate, the push-out ring 352 rotates and pushes the connecting rod 33 out of the sliding groove 32. The elastic support plate 8 can provide displacement margin for the connecting rod 33 to avoid the transmission column 31 from jamming due to the inability of the connecting rod 33 to rotate. At this time, the connecting ring 341 also moves up to the limit position, which limits the push block 343 through the connecting block 342, thereby limiting the position of the mounting seat 345 and fixing the position of the mounting seat 345. Then the fatigue test body 1 can drive the adaptive clamping device 2 to pull and carry out the bolt fatigue test. Meanwhile, the rotating ring 351 moves upward synchronously with the connecting rod 33. When the connecting rod 33 is pushed out of the sliding groove 32 by the push-out ring 352, the rotating ring 351 will drive the sliding gear 353 to move upward and insert into the tooth gap of the connecting gear 36 through the guide block 354 at the top of the sliding gear 353. At the same time, the strong magnetic block 12 will generate magnetic attraction to the sliding gear 353. When the sliding gear 353 rises, it can push the connecting rod 33 to continue to move upward through the rotating ring 351, so that the sliding gear 353 and the connecting gear 36 can be smoothly meshed. The power of the transmission column 31 is then transmitted to the connecting gear 36 through the sliding gear 353. The connecting gear 36 drives the toothed ring 37 to rotate. The toothed ring 37 drives the push ring 38 to move upward through the threaded engagement. The push ring 38 drives the telescopic movable rod 39 to move upward synchronously. After the telescopic movable rod 39 pushes the separating rod 344 upward to the set position, it will push the pushing block 343 to move, releasing the limiting effect of the pushing block 343 on the connecting block 342. At this time, because the mounting base 345 can continue to move upward under force, the bolt is no longer in a tight state. Then, the top of the telescopic movable rod 39 is inserted into the bottom of the connecting rod 33 to complete the transmission docking. It is worth noting that at this time, the transmission column 31 drives the sliding gear 353 to rotate forward, the sliding gear 353 drives the connecting gear 36 to rotate in reverse, the connecting gear 36 drives the gear ring 37 to rotate in reverse, and the gear ring 37 drives the telescopic movable rod 39 and the connecting rod 33 to rotate in reverse synchronously, thereby driving the connecting ring 341 and the mounting base 345 to rotate in reverse. Since the bolt position is fixed, the mounting base 345 will move downward along the thread after reversing, and the connecting rod 33 will also move downward simultaneously. During the downward movement of the connecting rod 33, it will be blocked by the micro switch 11 and cannot be completely reset. The fixed column 4 will continue to apply downward pressure, compressing the internal elastic compression member 6. When the pushing force reaches the preset position, the micro switch 11 is triggered, the electromagnetic block 10 is energized and started, driving the locking block 9 to move outward and driving the telescopic end of the telescopic movable rod 39 to move outward. During the telescopic movement of the telescopic rod 39, the movable block 13 connected to the bottom of the sliding gear 353 is pushed, causing the sliding gear 353 to move downwards and disengage from the connecting gear 36. The rotating ring 351 drives the connecting rod 33 to move downwards synchronously. Under the thrust of the elastic compression member 6 and the transmission action of the transmission column 31, the connecting rod 33 is re-engaged into the sliding groove 32. At this time, since the gear ring 37 has no power transmission, the constant force spring box 7 drives the gear ring 37 to reset and rotate, completing the overall return. The micro switch 11 has a built-in timing module, which automatically shuts off after the telescopic rod 39 has fully reset after activation. After the connecting rod 33 is reset, it resumes forward rotation, which drives the mounting base 345 to rotate forward again, and re-tightens the bolt threads, thus realizing the automatic cycle of tightening and loosening. This cycle can simulate the real working conditions of bolt disassembly and assembly and load fluctuation, restore the process of bolt residual stress redistribution and damage accumulation, improve the matching degree between fatigue test results and engineering reality, and make up for the shortcomings of traditional test benches that can only test constant preload working conditions. The detection method is carried out through the fatigue test body 1. If a complete reset of the device is required, manually pushing the separating rod 344 will allow the mounting base 345 and its connected connecting block 342 to be fully reset under the action of gravity. Alternatively, existing electrical components such as electric push rods can be used to replace manual operation and achieve automatic reset by connecting them to the separating rod 344.

[0025] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fatigue testing bench for high-strength and tough vehicle body structural components with adaptive clamping, comprising a fatigue testing body (1) and an adaptive clamping device (2), wherein the fatigue testing body (1) and the adaptive clamping device (2) are adapted to each other and installed, characterized in that: It also includes a cycle test mechanism (3) for tightening and loosening cycles. The cycle test mechanism (3) includes a drive source. The output end of the drive source is fixedly connected to a transmission column (31). A sliding groove (32) is provided on the top of the transmission column (31). A connecting rod (33) is slidably connected inside the sliding groove (32). A connecting piece (34) is provided on the top of the connecting rod (33). A sliding engagement piece (35) is provided on the bottom of the connecting rod (33). A connecting gear (36) is provided on one side of the top of the sliding engagement piece (35). A toothed ring (37) is engaged on one side of the connecting gear (36). A push ring (38) is threadedly connected to the outside of the toothed ring (37). A telescopic movable rod (39) is rotatably connected to the inside of the push ring (38). The telescopic movable rod (39) is slidably connected to the inside of the toothed ring (37). The top of the telescopic movable rod (39) is inserted into the connecting rod (33).

2. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 1, characterized in that, The drive source is fixedly connected to the bottom surface inside the fatigue test body (1), the bottom of the toothed ring (37) is rotatably connected to the inside of the fatigue test body (1), and the push ring (38) is slidably connected to the fatigue test body (1).

3. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 1, characterized in that, The bottom of the toothed ring (37) is fixedly connected to a constant force spring box (7), and the constant force spring box (7) is fixedly connected to the fatigue test body (1).

4. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 1, characterized in that, The sliding groove (32) is internally fixedly connected to an elastic support plate (8), and the elastic support plate (8) is elastically connected to the connecting rod (33).

5. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 1, characterized in that, The extended end of the telescopic movable rod (39) is fixedly connected to a locking block (9), and an electromagnetic block (10) is magnetically connected to the outside of the locking block (9). The electromagnetic block (10) is fixedly connected to the fixed end of the telescopic movable rod (39). The electromagnetic block (10) is electrically connected to a micro switch (11) through a wire, and the micro switch (11) is fixedly connected to the telescopic movable rod (39).

6. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 3, characterized in that, The connector (34) includes a connecting ring (341), a connecting block (342), a pushing block (343), a separating rod (344), and a mounting base (345). The connecting ring (341) is slidably connected to the mounting base (345), and the surface of the connecting ring (341) is fixedly connected to the connecting block (342). The connecting ring (341) and the mounting base (345) are elastically connected by an elastic element. The connecting ring (341) is rotatably connected to the fatigue test body (1). The connecting block (342) is provided with several sets of The bottom of the connecting block (342) is in close contact with the pushing block (343), the pushing block (343) is slidably connected to the mounting base (345), the bottom of the pushing block (343) is slidably connected to the separating rod (344), and the pushing block (343) is elastically connected to the mounting base (345) through an elastic reset member. The separating rod (344) is slidably connected to the mounting base (345), the bottom pushing end of the separating rod (344) is annular, and the bottom of the separating rod (344) is located at the top of the telescopic movable rod (39).

7. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 6, characterized in that, The bottom of the connecting ring (341) is fixedly connected to a fixed post (4), and the bottom of the fixed post (4) is slidably connected to a sliding rod (5), and the sliding rod (5) is fixedly connected to the connecting rod (33). The inside of the fixed post (4) is elastically connected to an elastic compression member (6), and the other end of the elastic compression member (6) is elastically connected to the sliding rod (5).

8. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 1, characterized in that, The sliding engagement component (35) includes a rotating ring (351), an ejector ring (352), a sliding gear (353), and a guide block (354). The top of the rotating ring (351) is rotatably connected to the bottom of the connecting rod (33), and the surface of the rotating ring (351) is fixedly connected to the ejector ring (352). The outer side of the rotating ring (351) is fixedly connected to the sliding gear (353). The top of the ejector ring (352) is slidably connected to the bottom of the connecting rod (33). The sliding gear (353) is slidably connected to the transmission column (31), and the sliding gear (353) meshes with the connecting gear (36). The top of the sliding gear (353) is fixedly connected to the bottom of the guide block (354), and the top of the guide block (354) is inclined.

9. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 8, characterized in that, The top of the sliding gear (353) is magnetically connected to a strong magnetic block (12), and the strong magnetic block (12) is fixedly connected to the transmission column (31).

10. The fatigue testing rig for high-strength and high-toughness vehicle body structural components with adaptive clamping as described in claim 8, characterized in that, The bottom of the sliding gear (353) is rotatably connected to a movable block (13), and the movable block (13) is slidably connected to the telescopic movable rod (39).

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