Automobile rear cover lock fatigue strength test bench and test method
By designing a fatigue strength test bench for automobile rear cover locks including an outer frame, a height adjustment part, a moving part, a fixed bottom plate, a lifting part, a preloading part and a bench controller, it is solved that it is difficult to accurately test in the prior art. The problem of fatigue strength of the back cover lock achieves efficient and accurate fatigue strength detection.
Patent Information
- Application Number
- CN202411751035.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-02-11
AI Technical Summary
The prior art is difficult to accurately and efficiently test the fatigue strength of the car's rear cover lock, resulting in the possible cracks or failure of the locking function.
A fatigue strength test bench for automobile rear cover lock is designed, including an outer frame, height adjustment part, motion part, fixed bottom plate, lifting part, preloading part and bench controller. It is simulated by the rear cover lock in daily use. During the impact process, test the fatigue strength of the rear cover lock.
The test bench can accurately and efficiently test the fatigue strength of the rear cover lock, evaluate whether the car's rear cover lock meets the design requirements, and is suitable for the fatigue strength detection of the rear cover lock of different models.
Smart Images
Figure CN119413437A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of automobile parts detection, and in particular to an automobile rear cover lock fatigue strength test bench and a test method. Background Art
[0002] In daily use of cars, users often need to open and close the trunk lid. This operation will cause repeated impacts on the trunk lock, causing cracks and other damage to the trunk lock, and even causing the locking function to fail, posing a safety hazard. How to accurately and efficiently perform fatigue strength testing on the trunk lock is a problem that needs to be solved urgently.
[0003] In view of the above problems, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the invention
[0004] In order to solve the above technical problems, the present invention provides a car rear cover lock fatigue strength test bench and test method, which can accurately and efficiently test the fatigue strength of the rear cover lock, and then evaluate whether the car rear cover lock meets the design requirements.
[0005] The technical solution adopted by the present invention is:
[0006] On the one hand, a vehicle rear cover lock fatigue strength test bench is provided, comprising: an outer frame, a height adjustment part, a moving part, a fixed bottom plate, a lifting part, a pre-tightening part and a bench controller;
[0007] The height adjustment part includes a height adjustment screw, a height adjustment fixing plate and an electromagnet, the upper end of the height adjustment screw is connected to the top plate of the outer frame, the height adjustment fixing plate is located below the top plate, a nut is connected to the height adjustment fixing plate, the nut is threadedly connected to the height adjustment screw, and an electromagnet is fixed to the bottom of the height adjustment fixing plate;
[0008] The moving part includes a moving frame and a rear cover lock fixture installed at the bottom of the moving frame; the moving frame is located below the electromagnet and can be magnetically connected to the electromagnet; the rear cover lock fixture can simulate the rear cover lock installation structure of the test vehicle model to fix the rear cover lock;
[0009] The fixed bottom plate is fixedly connected to the outer frame and is located below the motion frame; a lock pin fixture is provided on the fixed bottom plate, and the lock pin fixture can simulate the rear cover lock pin installation structure of the test vehicle model to fix and install the rear cover lock pin;
[0010] The lifting part is used to lift the moving frame to a position where it is magnetically engaged with the electromagnet;
[0011] The pre-tightening part acts on the moving frame to simulate the upward force exerted on the rear cover by the rear cover sealing strip and the buffer block;
[0012] The platform controller is electrically connected to the rear cover lock, the electromagnet and the lifting part respectively, and is used to control the automatic unlocking of the rear cover lock, the power on and off of the electromagnet and the lifting of the moving frame by the lifting part.
[0013] Furthermore, the moving part also includes a cylindrical slide rail fixedly connected to the outer frame, and the moving frame is slidably connected to the cylindrical slide rail.
[0014] Furthermore, the height adjustment part also includes a ruler installed on the outer frame, which is used to indicate the position height of the height adjustment fixing plate.
[0015] Furthermore, the height adjustment part also includes a proximity switch, which is electrically connected to the stage controller, and a sensor sheet is fixed on the moving frame; when the sensor sheet moves to the trigger position of the proximity switch, the proximity switch sends a signal to the stage controller, and the stage controller controls the electromagnet to energize and adsorb and fix the moving frame.
[0016] Furthermore, the lifting part includes a lifting cylinder, which is upright and fixed on the bottom of the outer frame.
[0017] Furthermore, the pre-tightening part includes a pre-tightening cylinder fixed on the fixed base plate, and the pre-tightening force is adjusted by adjusting the air pressure of the pre-tightening cylinder.
[0018] Furthermore, a buffer block is fixed to the top end of the piston rod of the preload cylinder.
[0019] On the other hand, a method for testing the fatigue strength of a rear cover lock of an automobile is provided, which adopts the above-mentioned fatigue strength testing bench of the rear cover lock of an automobile, and comprises the following steps:
[0020] S1. Design and manufacture the rear cover lock fixture and lock pin fixture according to the relevant data of the rear cover lock and rear cover lock pin of the test vehicle model installed on the whole vehicle, and install the two fixtures on the test bench;
[0021] S2. Adjusting the impact speed: setting the impact speed of the rear cover lock immediately before it hits the rear cover lock pin according to the test requirements, calculating the required falling height of the moving part according to the impact speed, and adjusting the height of the height adjustment fixing plate through the height adjustment screw according to the falling height;
[0022] S3, preload force simulation: set the preload force according to the test requirements, so that the rear cover lock and the rear cover lock pin on the test bench are in a locked state, the preload cylinder acts on the motion frame, and the air pressure of the preload cylinder is adjusted so that the force measured by the force sensor is equal to the set preload force;
[0023] S4, impact process simulation: the platform controller sends an unlocking signal, the rear cover lock is automatically unlocked, the lifting part lifts the moving frame to a position where it is magnetically engaged with the electromagnet, the proximity switch is triggered, the electromagnet is powered on to adsorb and fix the moving frame, the platform controller sends a falling signal to the electromagnet, the electromagnet is powered off, the moving frame falls vertically, and the rear cover lock hits the rear cover lock pin and is locked;
[0024] S5. Repeat step S4 to a preset number of times.
[0025] In some embodiments, in step S2, the set impact speed is the speed of the rear cover lock before it hits the rear cover lock pin obtained by testing the actual vehicle of the test vehicle, or a speed manually set according to test requirements; after adjusting the height of the height adjustment fixing plate according to the calculated falling height, the moving frame is raised to a position where it is magnetically engaged with the electromagnet and then falls freely, and the actual impact speed of the rear cover lock on the test stand is measured. If there is a deviation, the height of the height adjustment fixing plate is fine-tuned and measured again until the speed requirement is met.
[0026] In some embodiments, in step S3, the set preload force is the upward force value of the rear cover sealing strip and the buffer block on the rear cover obtained by testing the actual vehicle model, or a force value manually set according to test requirements; when the test environment temperature changes, the preload force is readjusted.
[0027] Compared with the prior art, the beneficial effects of the present invention are:
[0028] The present invention simplifies the impact process of the rear cover lock when the user opens and closes the rear cover of the trunk daily. The installation state of the rear cover lock, the impact speed, and the preload brought by the sealing strip and the buffer block can all reach the actual measured values of the vehicle. The impact of the rear cover lock during the opening and closing of the rear cover of the trunk can be well restored, and the fatigue strength of the rear cover lock of the car can be tested. The test bench can be applied to the fatigue strength detection of the rear cover locks of different models. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0030] Figure 1 A front view schematic diagram of a vehicle rear cover lock fatigue strength test bench according to an embodiment of the present invention is shown;
[0031] Figure 2 A schematic side view of a vehicle rear cover lock fatigue strength test bench according to an embodiment of the present invention is shown;
[0032] Figure 3 Shows Figure 1 Sectional view along AA direction;
[0033] Figure 4 Shows Figure 1 Sectional view along the KK axis;
[0034] Figure 5 Shows Figure 1 A magnified schematic diagram of part G in the middle;
[0035] Figure 6 Shows Figure 1 Enlarged schematic diagram of part H in the middle. DETAILED DESCRIPTION
[0036] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.
[0037] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.
[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0039] The invention provides a fatigue strength test bench for a rear cover lock of an automobile, which can simulate the impact process that the rear cover lock is subjected to when a user closes the rear cover, and can be applicable to operations of different automobile models and different users (with different impact speeds).
[0040] refer to Figure 1-Figure 6 The automobile rear cover lock fatigue strength test bench includes: an outer frame 1, a height adjustment part, a moving part, a fixed bottom plate 12, a lifting part, a pre-tightening part and a bench controller (not shown in the figure).
[0041] Among them, the moving part: simulates the falling of the rear cover of the car, and can drive the rear cover lock to fall freely after being lifted to the required height. The height adjustment part: is used to fix the moving part, and the fixed height is adjustable. The lifting part: is used to lift the moving part and fix the moving part to the height adjustment part. The pre-tightening part: is used to simulate the upward force exerted on the rear cover by the rear cover sealing strip and buffer block, and the magnitude of this force is adjustable.
[0042] In a specific embodiment, the height adjustment part includes a height adjustment screw 5, a height adjustment fixing plate 6 and an electromagnet 7. The upper end of the height adjustment screw 5 is fixedly connected to the top plate 17 of the outer frame 1. The height adjustment fixing plate 6 is located below the top plate 17. A nut 23 is rotatably connected to the height adjustment fixing plate 6. The nut 23 is threadedly matched with the height adjustment screw 5. The bottom of the height adjustment fixing plate 6 is fixed with an electromagnet 7. The moving part includes a moving frame 8 and a rear cover lock fixture 9 installed at the bottom of the moving frame 8. The moving frame 8 is located below the electromagnet 7 and can be magnetically connected to the electromagnet 7. The rear cover lock fixture 9 can simulate the rear cover lock installation structure of the test vehicle model to fix and install the rear cover lock 10. The fixed bottom plate 12 is fixedly connected to the outer frame 1, the fixed bottom plate 12 is located below the moving frame 8, and a lock pin fixture is provided on the fixed bottom plate 12. The lock pin fixture can simulate the rear cover lock pin installation structure of the test vehicle model to fix and install the rear cover lock pin 11. The lifting part is used to lift the moving frame 8 to a position where it is magnetically engaged with the electromagnet 7, and the lifting part includes a lifting cylinder 14. The pre-tightening part acts on the moving frame 8 to simulate the upward force exerted by the rear cover sealing strip and the buffer block on the rear cover. The pre-tightening part includes two pre-tightening cylinders 13, which are symmetrically arranged on both sides of the lock pin fixture. The platform controller is electrically connected to the rear cover lock 10, the electromagnet 7, and the lifting cylinder 14, respectively, to control the automatic unlocking of the rear cover lock 10, the power on and off of the electromagnet 7, and the lifting and lowering of the lifting cylinder 14.
[0043] This test bench simplifies the opening and closing process of the rear lid lock in daily user operation, and can better restore the impact of the rear lid lock during the opening and closing process of the rear lid, simulating the opening and closing process of the rear lid lock. The impact force of the rear lid lock during the closing process is affected by the installation status of the rear lid lock / rear lid lock pin of different models, the closing speed of the rear lid, and the reverse force (preload) of the rear lid seal strip and buffer block.
[0044] When measuring the fatigue strength of the rear cover lock, preparation work must be done first. First, according to the relevant data of the rear cover lock and lock pin installed on the test vehicle model, a fixture for fixing the rear cover lock and lock pin is designed and manufactured. The rear cover lock 10 and rear cover lock pin 11 are installed on the vehicle through the fixture to simulate the installation state of the vehicle. Then, the height adjustment screw 5 is adjusted to drive the height adjustment fixing plate 6 to move to the required height (at this height, the speed of the moving part before the rear cover lock contacts the rear cover lock pin is the same as the speed measured on the actual vehicle). By adjusting the air pressure of the preload cylinder 13, the preload force generated by the two preload cylinders is the same as the upward force of the rear cover seal strip and buffer block on the rear cover measured in the actual vehicle.
[0045] After everything is ready, start the fatigue strength test of the rear cover lock. The actions of one cycle are as follows:
[0046] 1. Initial state: the rear cover lock 10 and the rear cover lock pin 11 are in a locked state;
[0047] 2. Give an unlocking signal through the bench controller, and the rear cover lock will be automatically unlocked;
[0048] 3. The lifting cylinder 14 drives the moving part to lift, and the electromagnet 7 adsorbs the moving frame 8, and then the lifting cylinder 14 falls to the initial position;
[0049] 4. The electromagnet 7 is powered off, the moving part falls, and the rear cover lock 10 and the rear cover lock pin 11 are locked.
[0050] In a more specific embodiment, on the basis of the above embodiment, the height adjustment part also includes a scale 19 installed on the outer frame 1, which is used to indicate the position height of the height adjustment fixing plate 6. The height adjustment part also includes a proximity switch 21, which is electrically connected to the gantry controller, and a sensor sheet 22 is fixed on the moving frame 8; when the sensor sheet 22 moves to the trigger position of the proximity switch 21, the proximity switch 22 sends a signal to the gantry controller, and the gantry controller controls the electromagnet 7 to energize and adsorb and fix the moving frame 8. A buffer block 16 is fixed to the top of the piston rod of the preload cylinder 13, and a force sensor is connected to the buffer block. The moving part also includes a cylindrical slide rail 18 fixedly connected to the outer frame 1, and the cylindrical slide rail 18 passes through the left and right sides of the moving frame 8. The cylindrical slide rail 18 plays a guiding and positioning role during the rising / falling process of the moving frame 8. Preferably, the moving frame 8 is I-shaped, the bottom of the moving frame 8 is connected to the car rear cover lock 10 through the rear cover lock clamp 9 (special clamp), the rear of the bottom of the moving frame 8 is connected to the angle iron 20, the induction sheet 22 (metal sheet) is fixed to the upper edge of the moving frame 8, the top of the piston of the lifting cylinder 14 is located below the angle iron 20, and the piston of the lifting cylinder 14 rises to press against the angle iron 20, driving the moving frame 8 to rise, and the induction sheet 22 rises to the proximity switch 21 to trigger a signal, and the electromagnet 7 is energized to suck the moving frame 8.
[0051] In some embodiments, the automobile rear cover lock fatigue strength test bench is designed to be movable, and the lower part is in the form of a trolley, including a frame 3 and a plurality of universal wheels 4 installed at the bottom of the frame 3. It is convenient to move the position of the test bench. An openable and closable shield 2 is installed around the outer frame 1. During the test, the shield 2 is closed to ensure the safety of the staff. The test bench also includes an unlocking cylinder 15, which is connected to the emergency opening part of the rear cover lock 10. According to the test needs, the emergency opening function of the rear cover lock can be simulated, and the emergency opening part is pulled by the unlocking cylinder 15 to unlock the rear cover lock 10.
[0052] The height adjustment screw 5 is fixed on the outer frame top plate 17 through the screw fixing sleeve 24, and the height of the height adjustment fixing plate 6 is adjusted by rotating the nut 23. Preferably, the nut 23 is T-shaped. It can be understood that the nut 23 can also be fixed, and the height adjustment screw 5 can be rotated to adjust the height of the height adjustment fixing plate 6. When adjusting the impact speed, first estimate the height according to the formula, the falling height h=v² / 2g, v is the speed of the rear cover lock before the impact, g is the acceleration of gravity, v can be the measured value of the actual vehicle, or it can be the test requirement value. According to the formula, the height of the height adjustment fixing plate 6 can be calculated. Adjust the height adjustment fixing plate 6 to the corresponding position according to the scale of the ruler 19 according to the estimated height, and then measure the actual impact speed. According to the deviation from the required speed, the height of the height adjustment fixing plate 6 is fine-tuned, and finally the falling impact speed reaches the required speed.
[0053] The cylinder bodies of the two preload cylinders 13 are fixed on the fixed base plate 12, and the piston ends of the preload cylinders 13 are fixed with buffer pads 16. When the rear cover lock 10 and the rear cover lock pin 11 are in the locked state, a force sensor is connected to the top of the buffer pad 16, the air source is turned on, and the air pressure is adjusted. When the sum of the values of the force sensors on the two cylinders is equal to the required preload force, the adjustment is stopped, and the sensors are removed to complete the calibration of the preload force. Since the preload force = pressure (air pressure) x force area (buffer pad area, unchanged), the preload force remains unchanged when the air pressure and ambient temperature remain unchanged. When the ambient temperature changes, the air pressure needs to be adjusted and the preload force needs to be recalibrated.
[0054] The present invention uses a vertical drop method to simulate the impact process of the rear cover lock, and the impact speed can be changed by adjusting the drop height. The moving part simulates the drop of the rear cover, and the height adjustment screw 5 drives the height adjustment fixing plate 6 to move to the required height. After the electromagnet 7 is powered off, the moving part falls vertically and reaches the required speed before the rear cover lock is locked. Two cylinders and corresponding buffer structures are used to restore the upward force of the rear cover sealing strip and buffer block on the rear cover, and the air pressure of the pre-tightening cylinder 13 is adjusted to adjust the pre-tightening force, which can truly simulate the impact of the rear cover lock.
[0055] The fatigue strength test method of the automobile rear cover lock comprises the following steps:
[0056] Step 1: Design and manufacture the rear cover lock fixture and lock pin fixture according to the relevant data of the rear cover lock and rear cover lock pin of the test vehicle model installed on the whole vehicle, and install the two fixtures on the test bench;
[0057] Step 2, adjusting the impact speed: according to the test requirements, the impact speed of the rear cover lock before it hits the rear cover lock pin is set, and the required falling height of the moving part is calculated according to the impact speed, and the height of the height adjustment fixing plate is adjusted by the height adjustment screw according to the falling height;
[0058] Step 3, preload force simulation: set the preload force according to the test requirements, so that the rear cover lock and the rear cover lock pin on the test bench are in a locked state, the preload cylinder acts on the motion frame, and the air pressure of the preload cylinder is adjusted so that the force measured by the force sensor is equal to the set preload force;
[0059] Step 4, impact process simulation: the platform controller sends an unlocking signal, the rear cover lock is automatically unlocked, the lifting part lifts the moving frame to a position where it is magnetically engaged with the electromagnet, the proximity switch is triggered, the electromagnet is powered on to adsorb and fix the moving frame, the platform controller sends a falling signal to the electromagnet, the electromagnet is powered off, the moving frame falls vertically, and the rear cover lock hits the rear cover lock pin and is locked;
[0060] Step 5. Repeat step 4 to the preset number of times.
[0061] The above are only preferred embodiments of the present invention, which are only illustrative and not restrictive. The structures and connection modes of the components in the present invention can be changed, and any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.
Claims
1. A car rear cover lock fatigue strength test bench, characterized in that: include: Outer frame, height adjustment part, moving part, fixed base plate, lifting part, pre-tightening part and stand controller; The height adjustment part includes a height adjustment screw, a height adjustment fixing plate and an electromagnet, the upper end of the height adjustment screw is connected to the top plate of the outer frame, the height adjustment fixing plate is located below the top plate, a nut is connected to the height adjustment fixing plate, the nut is threadedly connected to the height adjustment screw, and an electromagnet is fixed to the bottom of the height adjustment fixing plate; The moving part includes a moving frame and a rear cover lock fixture installed at the bottom of the moving frame; the moving frame is located below the electromagnet and can be magnetically connected to the electromagnet; the rear cover lock fixture can simulate the rear cover lock installation structure of the test vehicle model to fix the rear cover lock; The fixed bottom plate is fixedly connected to the outer frame and is located below the motion frame; a lock pin fixture is provided on the fixed bottom plate, and the lock pin fixture can simulate the rear cover lock pin installation structure of the test vehicle model to fix and install the rear cover lock pin; The lifting part is used to lift the moving frame to a position where it is magnetically engaged with the electromagnet; The pre-tightening part acts on the moving frame to simulate the upward force exerted on the rear cover by the rear cover sealing strip and the buffer block; The platform controller is electrically connected to the rear cover lock, the electromagnet and the lifting part respectively, and is used to control the automatic unlocking of the rear cover lock, the power on and off of the electromagnet and the lifting of the moving frame by the lifting part.
2. The automobile rear cover lock fatigue strength test bench according to claim 1, characterized in that: The moving part also includes a cylindrical slide rail fixedly connected to the outer frame, and the moving frame is slidably connected to the cylindrical slide rail.
3. The automobile rear cover lock fatigue strength test bench according to claim 1, characterized in that: The height adjustment part also includes a ruler installed on the outer frame, which is used to indicate the position height of the height adjustment fixing plate.
4. The automobile rear cover lock fatigue strength test bench as claimed in claim 1, characterized in that: The height adjustment part also includes a proximity switch, which is electrically connected to the stage controller, and an induction sheet is fixed on the moving frame; when the induction sheet moves to the trigger position of the proximity switch, the proximity switch sends a signal to the stage controller, and the stage controller controls the electromagnet to energize and adsorb and fix the moving frame.
5. The automobile rear cover lock fatigue strength test bench according to claim 1, characterized in that: The lifting part comprises a lifting cylinder which is uprightly fixed on the bottom of the outer frame.
6. The automobile rear cover lock fatigue strength test bench as claimed in claim 4, characterized in that: The pre-tightening part comprises a pre-tightening cylinder fixed on the fixed base plate, and the pre-tightening force is adjusted by adjusting the air pressure of the pre-tightening cylinder.
7. The automobile rear cover lock fatigue strength test bench as claimed in claim 6, characterized in that: A buffer block is fixed on the top end of the piston rod of the preload cylinder.
8. A method for testing the fatigue strength of a rear cover lock of an automobile, characterized in that: The automobile rear cover lock fatigue strength test bench as claimed in claim 7 comprises the following steps: S1. Design and manufacture the rear cover lock fixture and lock pin fixture according to the relevant data of the rear cover lock and rear cover lock pin of the test vehicle model installed on the whole vehicle, and install the two fixtures on the test bench; S2. Adjusting the impact speed: setting the impact speed of the rear cover lock immediately before it hits the rear cover lock pin according to the test requirements, calculating the required falling height of the moving part according to the impact speed, and adjusting the height of the height adjustment fixing plate through the height adjustment screw according to the falling height; S3, preload force simulation: set the preload force according to the test requirements, so that the rear cover lock and the rear cover lock pin on the test bench are in a locked state, the preload cylinder acts on the motion frame, and the air pressure of the preload cylinder is adjusted so that the force measured by the force sensor is equal to the set preload force; S4, impact process simulation: the platform controller sends an unlocking signal, the rear cover lock is automatically unlocked, the lifting part lifts the moving frame to a position where it is magnetically engaged with the electromagnet, the proximity switch is triggered, the electromagnet is powered on to adsorb and fix the moving frame, the platform controller sends a falling signal to the electromagnet, the electromagnet is powered off, the moving frame falls vertically, and the rear cover lock hits the rear cover lock pin and is locked; S5. Repeat step S4 to a preset number of times.
9. A method for testing fatigue strength of a rear cover lock of an automobile as claimed in claim 8, characterized in that: In step S2, the set impact speed is the speed of the rear cover lock before it hits the rear cover lock pin obtained by testing the actual vehicle of the test vehicle, or the speed manually set according to the test requirements; after adjusting the height of the height adjustment fixing plate according to the calculated falling height, the moving frame is raised to the position where it is magnetically engaged with the electromagnet and then falls freely, and the actual impact speed of the rear cover lock on the test bench is measured. If there is a deviation, the height of the height adjustment fixing plate is fine-tuned and measured again until the speed requirement is met.
10. A method for testing fatigue strength of a rear cover lock of an automobile as claimed in claim 8, characterized in that: In step S3, the set preload force is the upward force value of the rear cover sealing strip and the buffer block on the rear cover obtained by testing the actual vehicle model, or the force value manually set according to the test requirements; when the test environment temperature changes, the preload force is readjusted.