Fatigue testing device and method for automobile parts

Abstract

The invention relates to the technical field of reliability testing of automobile parts, in particular to a fatigue testing device and method for automobile parts. The technical problem is that an existing automobile part fatigue testing device only simulates a vertical load and ignores lateral and longitudinal combined stress, so that a testing result is not real; according to the technical scheme, the fatigue testing device for the automobile parts comprises a bottom plate, a support, a top plate, a moving frame, a mounting plate, a controller, a testing assembly, a locking assembly, a clamping assembly and an adjusting assembly, the support is arranged on one side of the bottom plate, the top plate is arranged above the bottom plate, and the moving frame is arranged below the top plate; according to the invention, the dynamic load with multi-directional components is passively and naturally generated by using the vector characteristic of the rotating centrifugal force, and the random change of the amplitude and frequency of the load can be effectively simulated by simply changing a single rotating speed variable, so that the authenticity and test efficiency of the fatigue test are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of automotive component reliability testing technology, and in particular to a fatigue testing device and method for automotive components. Background Technology

[0002] In the field of automotive component reliability testing, fatigue life verification of key load-bearing components such as suspension control arms is a core aspect of ensuring driving safety. Existing automotive component fatigue testing devices mainly use hydraulic servo systems as actuators. Their technical features are: generating vertical sinusoidal loads through hydraulic cylinders to simulate the impact of road bumps on the control arm during vehicle operation; their working principle is: the hydraulic actuator pushes the control arm mounting point to perform periodic vertical displacement, and the load spectrum is reproduced in conjunction with the closed-loop control of the electro-hydraulic servo valve.

[0003] However, the hydraulic servo system of the existing automotive parts fatigue testing device can only achieve unidirectional loading along the Z-axis (vertical direction), while the control arm is subjected to three-dimensional composite stress in actual road conditions. For example, when a vehicle passes through a tortuous road surface, the control arm simultaneously bears the Z-axis bump impact, the Y-axis tilt torque, and the X-axis braking inertial force. Existing equipment cannot reproduce this multi-axis coupled stress state, which may lead to a serious deviation between the test results and the actual service performance, directly threatening the safety performance of road vehicles.

[0004] Therefore, to address the above problems, a fatigue testing device and method for automotive parts is proposed. This device passively and naturally generates dynamic loads with multiple directional components by utilizing the vector characteristics of centrifugal force. By simply changing a single rotational speed variable, it can effectively simulate the random changes in load amplitude and frequency, significantly improving the realism and efficiency of fatigue testing. Summary of the Invention

[0005] To overcome the problem that existing automotive part fatigue testing devices only simulate vertical loads and ignore the combined lateral and longitudinal stresses, resulting in inaccurate test results.

[0006] The technical solution of this invention is as follows: A fatigue testing device for automotive parts, comprising a base plate, a bracket, a top plate, a movable frame, a mounting plate, a controller, a testing component, a locking component, a clamping component, and an adjusting component. A bracket is provided on one side of the base plate, and a top plate is provided above the base plate, with the top plate and bracket connected to each other. A movable frame is provided below the top plate, a mounting plate is provided on one side of the bracket, and a controller is provided on one side of the mounting plate. A testing component is provided below the movable frame, and a locking component is provided at one end of the testing component. A clamping component is provided above the base plate, and an adjusting component is provided on one side of the top plate. The testing component includes a first motor, a first rotating shaft, a connecting plate, a counterweight, a first bearing, a first connecting rod, a first connecting frame, a second connecting frame, a second bearing, a telescopic rod, a third bearing, a third connecting frame, a fourth connecting frame, a second connecting rod, and a fourth bearing. A first motor is provided above the movable frame, and a first motor's output end is provided with a locking component. A rotating shaft has a connecting plate connected to its outer keyway. A counterweight is located at one end of the connecting plate. A first bearing is located below the connecting plate. A first connecting rod is rotatably connected to the inner side of the first bearing. A first connecting frame is located below the first connecting rod. A second connecting frame is rotatably connected to the inner side of the first connecting frame. A second bearing is located below the second connecting frame. A telescopic rod is rotatably connected to the inner side of the second bearing. A third bearing is rotatably connected to one end of the telescopic rod. A third connecting frame is located below the third bearing. A fourth connecting frame is rotatably connected to the outer side of the third connecting frame. A connecting rod is located below the fourth connecting frame. A fourth bearing is located at one end of the connecting rod. The locking assembly includes a fixed frame, a second motor, a lead screw, and a locking plate. A fixed frame is located below the fourth bearing. A second motor is located on one side of the fixed frame. A lead screw is located at the output end of the second motor. The lead screw has two opposite threads. Two sets of locking plates are connected to the outer thread of the lead screw.

[0007] Preferably, the lower end of the part to be tested is fixed above the base plate by the clamping assembly. The second motor is started to drive the lead screw to rotate, which in turn causes the locking plate to move linearly to clamp the part to be tested. The first motor is started to drive the first rotating shaft to rotate, which in turn causes the connecting plate and counterweight to rotate. The eccentric structure formed by the counterweight and connecting plate generates centrifugal force during rotation. The resulting centrifugal force vector rotates at high speed within the water surface. Simultaneously, within the plane of rotation of the counterweight, the radial force is a periodic centrifugal force. The rotating centrifugal force vector directly acts on the force points on the part to be tested, which is fixed by the locking plate, through the multi-directional rotatable and telescopic adjustable connecting structure consisting of the first bearing, first connecting rod, first connecting frame, second connecting frame, second bearing, telescopic rod, third bearing, third connecting frame, fourth connecting frame, second connecting rod, and fourth bearing. The rotating centrifugal force vector directly pulls on the force points on the part to be tested in a rotating manner. In the local coordinate system of the stress point of the test part, alternating radial and tangential load components are generated simultaneously. The speed of the first motor is pseudo-randomly changed by the frequency converter built into the controller. The change in speed causes changes in the magnitude and frequency of the centrifugal force. Changing the speed is equivalent to dynamically changing the impact state of the combination of impact intensity, frequency and direction of action, thereby simulating the random impact load spectrum with varying amplitude and frequency caused by road surface unevenness. Compared with constant amplitude sine wave loading, it is closer to the actual situation. The rotating centrifugal force will continuously pull the tested car parts in the direction containing vertical, lateral and longitudinal components with varying amplitude and frequency, simulating the complex stress state under the working conditions of the vehicle encountering bumps, potholes, and tilting during driving. Thus, the vector characteristics of the rotating centrifugal force are used to passively and naturally generate dynamic loads with multiple directional components. By simply changing a single speed variable, the random changes of load amplitude and frequency can be effectively simulated, significantly improving the realism and efficiency of fatigue testing.

[0008] Preferably, the clamping assembly includes a fixing tube and a worm gear, with the fixing tube located above the base plate and the worm gear rotatably connected to the outside of the fixing tube.

[0009] Preferably, the clamping assembly also includes a worm gear and a third motor, with the worm gear meshing with one side of the worm wheel and the third motor being provided at one end of the worm gear.

[0010] Preferably, the clamping assembly further includes a grooved plate, a first slider, a second slider, and a limiting seat. The grooved plate is provided above the worm gear, and multiple sets of first sliders are provided on the inner side of the grooved plate. The second slider is rotatably connected above the first slider, and a limiting seat is provided on the outer side of the grooved plate. The second slider and the limiting seat are slidably connected.

[0011] Preferably, the adjustment assembly includes a first adjustment frame, a fourth motor, and a first threaded rod. The first adjustment frame is provided on one side of the top plate, the fourth motor is provided on one side of the first adjustment frame, and the first threaded rod is provided at the output end of the fourth motor.

[0012] Preferably, the adjustment assembly also includes a second adjustment bracket and a fifth motor, with the second adjustment bracket threadedly connected to the outer side of the first threaded rod, and the fifth motor disposed on one side of the second adjustment bracket.

[0013] Preferably, the adjustment assembly also includes a second threaded rod and a moving block. The output end of the fifth motor is provided with a second threaded rod, and the moving block is threadedly connected to the outer side of the second threaded rod. The moving block and the moving frame are connected to each other.

[0014] A fatigue testing method for automotive parts includes the following steps:

[0015] S1: The worm gear of the clamping assembly drives the groove plate to rotate, causing multiple sets of first sliders to synchronously contract / expand radially, which in turn drives the second slider to adaptively clamp the lower end of automotive parts of different sizes under the constraint of the limit seat.

[0016] S2: The second motor of the starting locking assembly drives the bidirectional lead screw, causing the two locking plates to move towards each other along the fixed frame and clamp the part to be tested.

[0017] S3: Start the fourth motor of the adjustment component to drive the first threaded rod, which in turn moves the second adjustment frame longitudinally along the first adjustment frame; start the fifth motor to drive the second threaded rod, which causes the moving block to move the moving frame laterally until the rotation axis of the counterweight of the test component coincides with the theoretical force center of the test point.

[0018] S4: The controller outputs a pseudo-random frequency conversion signal to the first motor, driving the first rotating shaft to rotate at a variable speed, causing the eccentric mechanism formed by the connecting plate and the counterweight to generate a centrifugal force F=mω with dynamically changing amplitude / frequency. 2 r, where ω is the instantaneous angular velocity, m is the mass of the counterweight, and r is the radius of rotation;

[0019] S5: Centrifugal force is transmitted via a multi-degree-of-freedom transmission chain, specifically as follows:

[0020] The centrifugal force vector is decomposed to the first connecting rod through the first bearing;

[0021] The direction is changed via the hinge point between the first connecting frame and the second connecting frame;

[0022] The telescopic rod adapts to the deformation of the parts;

[0023] Finally, the fourth bearing applies the rotational pulling force to the locking plate clamping point;

[0024] S6: Place strain gauges at preset positions on the part and record the data via the controller.

[0025] Real-time load spectrum, including vertical, lateral and longitudinal components;

[0026] Location of crack initiation and propagation rate in parts;

[0027] Number of failure cycles.

[0028] Preferably, the worm gear drive in step S1 specifically includes:

[0029] The third motor is started to drive the worm gear to rotate, and the wedge-shaped groove of the groove plate guides the first slider to slide radially, so that the second slider always presses the part mounting surface perpendicularly.

[0030] As a preferred embodiment, the pseudo-random frequency conversion method in step S4 is as follows:

[0031] A road load spectrum database is pre-set in the controller, and typical road conditions are transformed into the speed control function ω(t)=ω0+Δω·rand(t). Typical road conditions include gravel roads, Belgian roads, and angular step inputs, where:

[0032] ω0 is the base rotational speed;

[0033] Δω represents the amplitude disturbance;

[0034] rand(t) is a random function that follows a Weibull distribution with a shape parameter β = 1.2. This simulates the statistical characteristics of impact loads.

[0035] The beneficial effects of this invention are:

[0036] This invention uses a clamping assembly to fix the lower end of the part to be tested above a base plate. A second motor drives a lead screw to rotate, which in turn causes a locking plate to move linearly, clamping the part to be tested. A first motor drives a first rotating shaft to rotate, which in turn causes a connecting plate and a counterweight to rotate. The eccentric structure formed by the counterweight and connecting plate generates centrifugal force during rotation. This centrifugal force vector rotates at high speed within the water surface. Simultaneously, within the plane of rotation of the counterweight, a periodic centrifugal force is generated in the radial direction. This rotating centrifugal force vector directly acts on the force points on the part to be tested, which are fixed by the locking plate, through a multi-directional rotating and telescopic adjustable connecting structure consisting of a first bearing, a first connecting rod, a first connecting frame, a second connecting frame, a second bearing, a telescopic rod, a third bearing, a third connecting frame, a fourth connecting frame, a second connecting rod, and a fourth bearing. The rotating centrifugal force vector directly pulls on the force points on the part to be tested in a rotating manner. In the local coordinate system of the stress point of the part, alternating radial and tangential load components are generated simultaneously. The speed of the first motor is pseudo-randomly changed by the frequency converter built into the controller. The change in speed causes the magnitude and frequency of the centrifugal force to change. Changing the speed is equivalent to dynamically changing the impact state of the combination of impact intensity, frequency and direction of action, thereby simulating the random impact load spectrum with varying amplitude and frequency caused by road surface unevenness. Compared with constant amplitude sine wave loading, it is closer to the actual situation. The rotating centrifugal force will continuously pull the tested car parts in the direction containing vertical, lateral and longitudinal components with varying amplitude and frequency, simulating the complex stress state under the working conditions of the vehicle encountering bumps, potholes and tilting during driving. Thus, the vector characteristics of the rotating centrifugal force are used to passively and naturally generate dynamic loads with multiple directional components. By simply changing a single speed variable, the random changes of load amplitude and frequency can be effectively simulated, significantly improving the realism and efficiency of fatigue testing. Attached Figure Description

[0037] Figure 1 The diagram shown is a first three-dimensional structural schematic of the fatigue testing device for automotive parts according to the present invention.

[0038] Figure 2 The diagram shown is a second three-dimensional structural schematic of the fatigue testing device for automotive parts according to the present invention.

[0039] Figure 3 The diagram shown is a three-dimensional cross-sectional view of the fatigue testing device for automotive parts according to the present invention.

[0040] Figure 4 The diagram shown is a first partial cross-sectional view of the fatigue testing device for automotive parts according to the present invention.

[0041] Figure 5The diagram shown is a second partial cross-sectional view of the fatigue testing device for automotive parts according to the present invention.

[0042] Figure 6 The diagram shown is a third partial cross-sectional view of the fatigue testing device for automotive parts according to the present invention.

[0043] Figure 7 The diagram shown is a partial three-dimensional structural schematic of the fatigue testing device for automotive parts according to the present invention.

[0044] Explanation of reference numerals in the attached drawings: 1. Base plate; 2. Bracket; 3. Top plate; 4. Movable frame; 5. Mounting plate; 6. Controller; 101. First motor; 102. First rotating shaft; 103. Connecting plate; 104. Counterweight; 105. First bearing; 106. First connecting rod; 107. First connecting frame; 108. Second connecting frame; 109. Second bearing; 110. Telescopic rod; 111. Third bearing; 112. Third connecting frame; 113. Fourth connecting frame; 114. Second connecting rod; 15. Fourth bearing; 201. Fixing frame; 202. Second motor; 203. Lead screw; 204. Locking plate; 301. Fixing tube; 302. Worm gear; 303. Worm; 304. Third motor; 305. Groove plate; 306. First slider; 307. Second slider; 308. Limiting seat; 401. First adjusting frame; 402. Fourth motor; 403. First threaded rod; 404. Second adjusting frame; 405. Fifth motor; 406. Second threaded rod; 407. Moving block. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Please see Figure 1 and Figure 2This invention provides an embodiment of a fatigue testing device for automotive parts, comprising a base plate 1, a bracket 2, a top plate 3, a movable frame 4, a mounting plate 5, a controller 6, a testing component, a locking component, a clamping component, and an adjusting component. The bracket 2 is disposed on one side of the base plate 1, and the top plate 3 is disposed above the base plate 1, with the top plate 3 and bracket 2 connected to each other. The movable frame 4 is disposed below the top plate 3. The mounting plate 5 is disposed on one side of the bracket 2, and the controller 6 is disposed on one side of the mounting plate 5. The testing component is disposed below the movable frame 4, and a locking component is disposed at one end of the testing component. The clamping component is disposed above the base plate 1, and an adjusting component is disposed on one side of the top plate 3. The testing component includes a first motor 101, a first rotating shaft 102, a connecting plate 103, and a counterweight. The moving frame 4 includes a block 104, a first bearing 105, a first connecting rod 106, a first connecting frame 107, a second connecting frame 108, a second bearing 109, a telescopic rod 110, a third bearing 111, a third connecting frame 112, a fourth connecting frame 113, a second connecting rod 114, and a fourth bearing 115. A first motor 101 is mounted above the moving frame 4. A first rotating shaft 102 is mounted at the output end of the first motor 101. A connecting plate 103 is connected to the outer keyway of the first rotating shaft 102. A counterweight block 104 is mounted at one end of the connecting plate 103. A first bearing 105 is mounted below the connecting plate 103. A first connecting rod 106 is rotatably connected to the inner side of the first bearing 105. A first connecting frame 107 is mounted below the first connecting rod 106. A second connecting frame 108 is rotatably connected to the inner side of the connecting frame 107. A second bearing 109 is provided below the second connecting frame 108. A telescopic rod 110 is rotatably connected to the inner side of the second bearing 109. A third bearing 111 is rotatably connected to one end of the telescopic rod 110. A third connecting frame 112 is provided below the third bearing 111. A fourth connecting frame 113 is rotatably connected to the outer side of the third connecting frame 112. A connecting rod is provided below the fourth connecting frame 113. A fourth bearing 115 is provided at one end of the connecting rod. The locking assembly includes a fixing frame 201, a second motor 202, a lead screw 203, and a locking plate 204. The fixing frame 201 is provided below the fourth bearing 115. The second motor 202 is provided on one side of the fixing frame 201. The output end of motor 202 is equipped with a lead screw 203, which has two opposite threads. Two sets of locking plates 204 are connected to the outer threads of the lead screw 203. The lower end of the part to be tested is fixed above the base plate 1 by the clamping assembly. Starting the second motor 202 drives the lead screw 203 to rotate, which in turn causes the locking plates 204 to move linearly to clamp the part to be tested. Starting the first motor 101 drives the first rotating shaft 102 to rotate, which in turn causes the connecting plate 103 and the counterweight 104 to rotate. The eccentric structure formed by the counterweight 104 and the connecting plate 103 generates centrifugal force during rotation. The resulting centrifugal force vector rotates at high speed within the water surface, and simultaneously within the rotation plane of the counterweight 104...The radial force is a periodic centrifugal force. The rotating centrifugal force vector acts directly on the force-bearing point on the measured part fixed by the locking plate 204 through the multi-directional rotatable and telescopic adjustable connecting structure consisting of the first bearing 105, the first connecting rod 106, the first connecting frame 107, the second connecting frame 108, the second bearing 109, the telescopic rod 110, the third bearing 111, the third connecting frame 112, the fourth connecting frame 113, the second connecting rod 114, and the fourth bearing 115. The rotating centrifugal force vector directly pulls on the force-bearing point on the measured part in a rotational manner, and simultaneously generates radial force in the local coordinate system of the force-bearing point on the measured part. The alternating load components in the axial and tangential directions are pseudo-randomly changed by the frequency converter built into the controller 6, altering the rotational speed of the first motor 101. This change in rotational speed leads to changes in the magnitude and frequency of the centrifugal force. Changing the rotational speed is equivalent to dynamically altering the impact state by combining the intensity, frequency, and direction of the impact, thus simulating the random impact load spectrum caused by road surface unevenness, where both amplitude and frequency vary. Compared to constant amplitude sinusoidal wave loading, this is closer to actual conditions. The rotating centrifugal force continuously pulls the tested vehicle parts in directions containing vertical, lateral, and longitudinal components with varying amplitude and frequency, simulating the complex stress state under conditions such as bumps, potholes, and tilting encountered by the vehicle during driving.

[0047] Please see Figure 3 and Figure 4 In this embodiment, the clamping assembly includes a fixing tube 301 and a worm gear 302. The fixing tube 301 is disposed above the base plate 1, and the worm gear 302 is rotatably connected to the outer side of the fixing tube 301. The clamping assembly also includes a worm 303 and a third motor 304. The worm gear 302 is meshed with the worm 303 on one side, and the third motor 304 is disposed at one end of the worm 303. The clamping assembly also includes a grooved plate 305, a first slider 306, a second slider 307, and a limiting seat 308. The grooved plate 305 is disposed above the worm gear 302, and multiple sets of first sliders 306 and 307 are disposed on the inner side of the grooved plate 305. 6. A second slider 307 is rotatably connected above the first slider 306. A limit seat 308 is provided on the outer side of the groove plate 305. The second slider 307 and the limit seat 308 are slidably connected. In use, the third motor 304 is started to drive the worm 303 to rotate. The rotation of the worm 303 drives the worm wheel 302 to rotate. The rotation of the worm wheel 302 drives the groove plate 305 to rotate. The rotation of the groove plate 305 drives the first slider 306 to slide. The sliding of the first slider 306 drives the second slider 307 to slide. The sliding of multiple sets of second sliders 307 clamps and fixes the automotive parts being tested.

[0048] Please see Figure 5 , Figure 6 and Figure 7In this embodiment, the adjustment assembly includes a first adjustment frame 401, a fourth motor 402, and a first threaded rod 403. The first adjustment frame 401 is located on one side of the top plate 3, and the fourth motor 402 is located on one side of the first adjustment frame 401. The output end of the fourth motor 402 is provided with the first threaded rod 403. The adjustment assembly also includes a second adjustment frame 404 and a fifth motor 405. The outer side of the first threaded rod 403 is threadedly connected to the second adjustment frame 404, and the fifth motor 405 is located on one side of the second adjustment frame 404. The adjustment assembly also includes a second threaded rod 406 and a moving block 407. The fifth motor 405... The output end is provided with a second threaded rod 406, and a moving block 407 is threadedly connected to the outer side of the second threaded rod 406. The moving block 407 and the moving frame 4 are connected to each other. In use, the first threaded rod 403 is rotated by starting the fourth motor 402, and the first adjusting frame 401 is moved linearly by rotating the first threaded rod 403. The second threaded rod 406 is rotated by starting the fifth motor 405, and the moving block 407 is moved linearly by rotating the second threaded rod 406, thereby adjusting the position of the moving frame 4 so that the first rotating shaft 102 and the center of the force point of the tested automobile part are in the same axial position.

[0049] A fatigue testing method for automotive parts includes the following steps:

[0050] S1: The worm gear 302 of the clamping assembly drives the groove plate 305 to rotate, causing multiple sets of first sliders 306 to synchronously contract / expand radially, and driving the second slider 307 to adaptively clamp the lower end of automotive parts of different sizes under the constraint of the limiting seat 308.

[0051] S2: The second motor 202 of the starting locking assembly drives the bidirectional lead screw 203, causing the two locking plates 204 to move towards each other along the fixed frame 201, clamping the part to be tested;

[0052] S3: Start the fourth motor 402 of the adjustment component to drive the first threaded rod 403, which in turn drives the second adjustment frame 404 to move longitudinally along the first adjustment frame 401; start the fifth motor 405 to drive the second threaded rod 406, which causes the moving block 407 to move the moving frame 4 laterally until the rotation axis of the counterweight block 104 of the test component coincides with the theoretical force center of the test point.

[0053] S4: The controller 6 outputs a pseudo-random frequency conversion signal to the first motor 101, driving the first rotating shaft 102 to rotate at a variable speed, causing the eccentric mechanism formed by the connecting plate 103 and the counterweight 104 to generate a centrifugal force F=mω with dynamically changing amplitude / frequency. 2 r, where ω is the instantaneous angular velocity, m is the mass of the counterweight 104, and r is the radius of rotation;

[0054] S5: Centrifugal force is transmitted via a multi-degree-of-freedom transmission chain, specifically as follows:

[0055] The centrifugal force vector is decomposed into the first connecting rod 106 through the first bearing 105;

[0056] The direction is changed via the hinge point between the first connecting frame 107 and the second connecting frame 108;

[0057] The telescopic rod 110 adapts to the deformation of the parts;

[0058] Finally, the fourth bearing 115 applies the rotational pulling force to the clamping point of the locking plate 204;

[0059] S6: Strain gauges are placed at preset positions on the part, and the data is recorded by controller 6.

[0060] Real-time load spectrum, including vertical, lateral and longitudinal components;

[0061] Location of crack initiation and propagation rate in parts;

[0062] Number of failure cycles.

[0063] The driving of the worm gear 302 in step S1 specifically includes:

[0064] The third motor 304 is started to drive the worm gear 303 to rotate. The wedge-shaped groove of the groove plate 305 guides the first slider 306 to slide radially, so that the second slider 307 always presses the part mounting surface perpendicularly.

[0065] The pseudo-random frequency conversion implementation method in step S4 is as follows:

[0066] A road load spectrum database is pre-set in controller 6, and typical road conditions are transformed into a speed control function ω(t)=ω0+Δω·rand(t). Typical road conditions include gravel roads, Belgian roads, and angular step inputs, where:

[0067] ω0 is the base rotational speed;

[0068] Δω represents the amplitude disturbance;

[0069] rand(t) is a random function that follows a Weibull distribution with a shape parameter β = 1.2. This simulates the statistical characteristics of impact loads.

[0070] During operation, the lower end of the automotive part to be tested is placed above the base plate 1. The third motor 304 of the clamping assembly is activated to drive the worm gear 303 to rotate. The worm gear 303 drives the meshing worm wheel 302 to rotate outside the fixed tube 301. The worm wheel 302 drives the groove plate 305 to rotate synchronously. The wedge groove on the inner side of the groove plate 305 guides multiple sets of first sliders 306 to slide synchronously in the radial direction. The second slider 307 above the first slider 306 maintains a vertical movement trajectory under the constraint of the limit seat 308, adaptively conforms to the mounting surface of the part and applies a uniform clamping force to complete the stable fixation of the lower end of the part. Subsequently, the second motor 202 of the locking assembly is activated to drive the bidirectional lead screw 203 to rotate. The two reverse threads on the lead screw 203 push the two sets of locking plates 204 to move towards each other along the fixed frame 201, accurately clamping the part to be tested and ensuring a rigid connection of the test force transmission path.

[0071] The test component is spatially aligned with the test point by adjusting the components: the fourth motor 402 is started to drive the first threaded rod 403 to rotate, which drives the second adjusting frame 404 to move longitudinally along the first adjusting frame 401 to the theoretical longitudinal position; the fifth motor 405 is started to drive the second threaded rod 406 to rotate, which causes the moving block 407 to move the moving frame 4 laterally until the rotation axis of the counterweight block 104 of the test component and the theoretical force center of the test point are completely coincident in three-dimensional space; during this process, the telescopic rod 110 compensates for the initial deformation of the parts through elastic deformation, ensuring that the centrifugal force vector is accurately applied to the target point and avoiding errors caused by test off-center loading;

[0072] The first motor 101 of the test assembly is started, and the first rotating shaft 102 drives the connecting plate 103 and the counterweight 104 to rotate, forming an eccentric mass system; the centrifugal force generated by the rotation is transmitted through a multi-degree-of-freedom transmission chain.

[0073] The centrifugal force vector is decomposed by the first bearing 105 and sent to the first connecting rod 106 to form the initial tensile force component;

[0074] The hinged structure of the first connecting frame 107 and the second connecting frame 108 enables load direction conversion to adapt to the spatial posture of the parts;

[0075] The telescopic rod 110 absorbs the elastic deformation of the parts through axial extension and contraction, maintaining the continuity of force transmission;

[0076] Finally, the fourth bearing 115 applies rotational pulling force to the clamping point of the locking plate 204, simultaneously generating vertical, lateral and longitudinal alternating load components in the local coordinate system of the measured point.

[0077] The controller 6 has a built-in pseudo-random algorithm to generate speed control signals, which drive the first motor 101 to rotate in real time at different speeds, simulating the load spectrum characteristics of typical road conditions such as gravel roads and Belgian roads; the matching strain gauge network collects stress distribution data of the parts in real time, and the controller 6 records the load amplitude, frequency and crack propagation parameters simultaneously until the preset number of failure cycles is reached or the parts break, thus completing the full life cycle fatigue test.

[0078] Through the above steps, the lower end of the part to be tested is fixed above the base plate 1 using the clamping assembly. The second motor 202 is started to drive the lead screw 203 to rotate. The rotation of the lead screw 203 causes the locking plate 204 to move linearly to clamp the part to be tested. The first motor 101 is started to drive the first rotating shaft 102 to rotate. The rotation of the first rotating shaft 102 causes the connecting plate 103 and the counterweight 104 to rotate. The eccentric structure formed by the counterweight 104 and the connecting plate 103 generates centrifugal force during rotation. The centrifugal force vector is located on the water surface. The counterweight 104 rotates at high speed, and simultaneously, within the plane of rotation of the counterweight 104, the radial force is a periodic centrifugal force. The centrifugal force vector of the rotation directly utilizes the multi-directional rotatable and telescopic adjustable connection structure composed of the first bearing 105, the first connecting rod 106, the first connecting frame 107, the second connecting frame 108, the second bearing 109, the telescopic rod 110, the third bearing 111, the third connecting frame 112, the fourth connecting frame 113, the second connecting rod 114, and the fourth bearing 115 to act on the force on the measured part fixed by the locking plate 204. At the test points, the rotating centrifugal force vector directly pulls on the stress points of the tested parts in a rotating manner. In the local coordinate system of the stress points of the tested parts, alternating radial and tangential load components are generated simultaneously. The frequency converter built into the controller 6 pseudo-randomly changes the speed of the first motor 101. The change in speed causes the magnitude and frequency of the centrifugal force to change. Changing the speed is equivalent to dynamically changing the impact state of the combination of impact intensity, frequency and direction of action, thereby simulating the random impact load spectrum with varying amplitude and frequency caused by road surface unevenness. Compared with constant amplitude sine wave loading, it is closer to the actual situation. The rotating centrifugal force will continuously pull on the tested car parts in directions containing vertical, lateral and longitudinal components with varying amplitude and frequency, simulating the complex stress state under conditions such as bumps, potholes and tilts encountered by the vehicle during driving. Thus, the vector characteristics of the rotating centrifugal force are used to passively and naturally generate dynamic loads with multiple directional components. By simply changing a single speed variable, the random changes in load amplitude and frequency can be effectively simulated, significantly improving the realism and efficiency of fatigue testing.

[0079] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A fatigue testing device for automotive parts, comprising a base plate (1), characterized in that: It also includes a bracket (2), a top plate (3), a movable frame (4), a mounting plate (5), a controller (6), a testing component, a locking component, a clamping component, and an adjusting component. The bracket (2) is provided on one side of the base plate (1), and the top plate (3) is provided above the base plate (1). The top plate (3) and the bracket (2) are connected to each other. The movable frame (4) is provided below the top plate (3). The mounting plate (5) is provided on one side of the bracket (2), and the controller (6) is provided on one side of the mounting plate (5). The testing component is provided below the movable frame (4), and a locking component is provided at one end of the testing component. The clamping component is provided above the base plate (1), and an adjusting component is provided on one side of the top plate (3). The moving frame (4) includes a first motor (101), a first rotating shaft (102), a connecting plate (103), a counterweight (104), a first bearing (105), a first connecting rod (106), a first connecting frame (107), a second connecting frame (108), a second bearing (109), a telescopic rod (110), a third bearing (111), a third connecting frame (112), a fourth connecting frame (113), a second connecting rod (114), and a fourth bearing (115). The first motor (101) is located above the moving frame (4). The first rotating shaft (102) is located at the output end of the first motor (101). The connecting plate (103) is connected to the keyway on the outer side of the first rotating shaft (102). A counterweight (104) is provided at one end of the connecting plate (103). A first bearing (105) is provided below the connecting plate (103). A first connecting rod (106) is rotatably connected to the inner side of the first bearing (105). A first connecting frame (107) is provided below the first connecting rod (106). A second connecting frame (108) is rotatably connected to the inner side of the first connecting frame (107). A second bearing (109) is provided below the second connecting frame (108). A telescopic rod (110) is rotatably connected to the inner side of the second bearing (109). A third bearing (111) is rotatably connected to one end of the telescopic rod (110). A third connecting frame (111) is provided below the third bearing (111). 112), the outer side of the third connecting frame (112) is rotatably connected to the fourth connecting frame (113), the lower part of the fourth connecting frame (113) is provided with a connecting rod, one end of the connecting rod is provided with a fourth bearing (115), the locking assembly includes a fixed frame (201), a second motor (202), a lead screw (203) and a locking plate (204), the lower part of the fourth bearing (115) is provided with the fixed frame (201), the second motor (202) is provided on one side of the fixed frame (201), the output end of the second motor (202) is provided with a lead screw (203), the lead screw (203) has two opposite threads, and the outer thread of the lead screw (203) is connected to two sets of locking plates (204).

2. The fatigue testing device and method for automotive parts according to claim 1, characterized in that: The clamping assembly includes a fixing tube (301) and a worm gear (302). The fixing tube (301) is provided above the base plate (1), and the worm gear (302) is rotatably connected to the outside of the fixing tube (301).

3. The fatigue testing device for automotive parts according to claim 2, characterized in that: The clamping assembly also includes a worm (303) and a third motor (304). The worm (303) is meshed with one side of the worm wheel (302), and the third motor (304) is provided at one end of the worm (303).

4. The fatigue testing device for automotive parts according to claim 3, characterized in that: The clamping assembly also includes a grooved plate (305), a first slider (306), a second slider (307), and a limiting seat (308). The grooved plate (305) is provided above the worm gear (302). Multiple sets of first sliders (306) are provided on the inner side of the grooved plate (305). The second slider (307) is rotatably connected above the first slider (306). The limiting seat (308) is provided on the outer side of the grooved plate (305). The second slider (307) and the limiting seat (308) are slidably connected.

5. The fatigue testing device for automotive parts according to claim 1, characterized in that: The adjustment assembly includes a first adjustment frame (401), a fourth motor (402) and a first threaded rod (403). The first adjustment frame (401) is provided on one side of the top plate (3), the fourth motor (402) is provided on one side of the first adjustment frame (401), and the first threaded rod (403) is provided at the output end of the fourth motor (402).

6. The fatigue testing device for automotive parts according to claim 5, characterized in that: The adjustment assembly also includes a second adjustment bracket (404) and a fifth motor (405). The second adjustment bracket (404) is threadedly connected to the outer side of the first threaded rod (403), and the fifth motor (405) is provided on one side of the second adjustment bracket (404).

7. The fatigue testing device for automotive parts according to claim 6, characterized in that: The adjustment assembly also includes a second threaded rod (406) and a moving block (407). The output end of the fifth motor (405) is provided with the second threaded rod (406). The moving block (407) is threadedly connected to the outer side of the second threaded rod (406). The moving block (407) and the moving frame (4) are connected to each other.

8. A fatigue testing method for automotive parts, characterized in that: Includes the following steps: S1: The worm gear (302) of the clamping assembly drives the groove plate (305) to rotate, causing multiple sets of first sliders (306) to shrink / expand synchronously in the radial direction, and driving the second slider (307) to adaptively clamp the lower end of automotive parts of different sizes under the constraint of the limiting seat (308); S2: The second motor (202) of the starting locking assembly drives the bidirectional lead screw (203) to make the two locking plates (204) move towards each other along the fixed frame (201) to clamp the part to be tested; S3: Start the fourth motor (402) of the adjustment component to drive the first threaded rod (403), which in turn drives the second adjustment frame (404) to move longitudinally along the first adjustment frame (401); start the fifth motor (405) to drive the second threaded rod (406), which causes the moving block (407) to drive the moving frame (4) to move laterally until the rotation axis of the counterweight block (104) of the test component coincides with the theoretical force center of the test point; S4: The controller (6) outputs a pseudo-random frequency conversion signal to the first motor (101), driving the first rotating shaft (102) to rotate at a variable speed, causing the eccentric mechanism formed by the connecting plate (103) and the counterweight (104) to generate a centrifugal force F=mω with dynamically changing amplitude / frequency. 2 r, where ω is the instantaneous angular velocity, m is the mass of the counterweight (104), and r is the radius of rotation; S5: Centrifugal force is transmitted via a multi-degree-of-freedom transmission chain, specifically as follows: The centrifugal force vector is decomposed to the first connecting rod (106) through the first bearing (105); The direction is changed through the hinge point between the first connecting frame (107) and the second connecting frame (108); The telescopic rod (110) adapts to the deformation of the parts; Finally, the rotational pulling force is applied to the clamping point of the locking plate (204) by the fourth bearing (115); S6: Strain gauges are placed at preset positions on the part, and the data is recorded by controller (6): Real-time load spectrum, including vertical, lateral and longitudinal components; Location of crack initiation and propagation rate in parts; Number of failure cycles.

9. The fatigue testing method for automotive parts according to claim 8, characterized in that: The driving of the worm gear (302) in step S1 specifically includes: The third motor (304) is started to drive the worm gear (303) to rotate. The wedge-shaped groove of the groove plate (305) guides the first slider (306) to slide radially, so that the second slider (307) always presses the part mounting surface vertically.

10. A fatigue testing method for automotive parts according to claim 8, characterized in that: The pseudo-random frequency conversion implementation method in step S4 is as follows: A road load spectrum database is preset in the controller (6), and typical road conditions are converted into a speed control function ω(t)=ω0+Δω·rand(t). Typical road conditions include gravel roads, Belgian roads, and angular step inputs, where: ω0 is the base rotational speed; Δω represents the amplitude disturbance; rand(t) is a random function that follows a Weibull distribution with a shape parameter β = 1.

2. This simulates the statistical characteristics of impact loads.

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