A new energy automobile fastener stress relaxation deformation testing device

Abstract

The application relates to the technical field of fastener stress testing, and discloses a new energy automobile fastener stress relaxation deformation testing device, which comprises a testing box, a testing cavity and a control cavity are respectively arranged at the upper and lower ends in the inside of the testing box, a control box and a first hydraulic cylinder are fixedly connected to the top of the testing box, a second hydraulic cylinder is fixedly connected to the inside of the control cavity, a detection assembly for detecting fastener stress deformation is arranged on one side of the control cavity, and a supporting plate is fixedly connected to one side in the inside of the testing cavity. The contact area between the fastener and the clamp is increased, the clamping stability is improved, different specifications of fasteners can be adapted, the installation and dismounting of the fastener can be automatically carried out through horizontal punching and cooperation with a dismounting assembly, the testing efficiency is greatly improved, the high-temperature air in the testing cavity cannot affect the normal work of the sensor, and the accuracy of the testing result is ensured.

Description

Technical Field

[0001] This invention relates to the field of fastener stress testing technology, and in particular to a device for testing stress relaxation deformation of fasteners in new energy vehicles. Background Technology

[0002] As the global automotive industry accelerates its transformation towards electrification and lightweighting, the market penetration rate of new energy vehicles continues to increase. In 2024, China's new energy vehicle production exceeded 12 million units, accounting for 38.1% of total vehicle production. Fasteners, as core connecting components of new energy vehicles, are widely used in key parts such as battery modules, electric drive systems, and chassis structures. The amount used per vehicle is 15%–20% higher than that of traditional fuel vehicles, and their connection reliability directly determines the safety, range, and operational stability of the entire vehicle. Among these applications, scenarios such as battery pack shell connection and motor rotor fixing place stringent requirements on the high temperature resistance, corrosion resistance, and high strength performance of fasteners. The usage rate of high-strength fasteners of grade 8.8 and above in new energy vehicles has reached 62%, and some high-end models even use ultra-high-strength fasteners of grade 12.9 to balance the needs of lightweighting and reliability.

[0003] However, during the service life of new energy vehicles, fasteners are subjected to complex and harsh operating conditions for extended periods: temperature fluctuations from -20°C to 80°C caused by battery pack charge-discharge cycles, high-frequency vibrations generated by motor operation, alternating impact loads from road driving, and corrosive environments such as humidity and salt spray all contribute to stress relaxation in fasteners. Stress relaxation refers to the phenomenon where stress gradually decreases over time under constant strain due to mechanisms such as microscopic dislocation movement and diffusion creep. Specifically, this manifests as a continuous decrease in fastener preload, which can lead to loss of fastening function in severe cases, causing a chain reaction of problems such as loose connections and seal failure. For example, loose battery pack fasteners may result in inadequate casing sealing, leading to battery leakage or thermal runaway risks; loose fasteners in the electric drive system can affect power transmission efficiency and even cause component wear and failure. Such faults have become one of the main hidden dangers in after-sales maintenance of new energy vehicles. Statistics show that the annual maintenance costs due to loose fasteners in the industrial sector exceed 10 billion yuan, with the proportion of new energy vehicle-related faults increasing year by year, highlighting the urgent need for accurate assessment of fastener stress relaxation performance.

[0004] For example, the fastener stress relaxation deformation testing device disclosed in CN116337427B includes a connecting part 2 connected to the fastener 1 to be tested, and a measuring part 3 for testing the deformation of the fastener. The connecting part 2 includes an upper connecting sleeve 21 and a lower connecting sleeve 22. The top of the upper connecting sleeve 21 is connected to a stud and is threadedly fixed to a first fixed tie rod 23 through the stud. The bottom of the lower connecting sleeve 22 is connected to a stud and is threadedly fixed to a second fixed tie rod 24 through the stud. The upper connecting sleeve 21 has a first through groove 211 that runs from left to right through the center.

[0005] The current testing device involves drilling holes vertically in the fasteners and securing them with screws. However, each installation and removal of the fasteners requires manual operation, which is time-consuming and labor-intensive. Furthermore, the size and specifications of the connecting sleeve are fixed. Although the fasteners can be secured with screws, it is impossible to ensure sufficient contact between fasteners of different specifications and the sleeve. When performing stress testing, relying solely on screws for fixation results in poor stability. Therefore, this invention proposes a stress relaxation deformation testing device for fasteners in new energy vehicles to solve the above problems. Summary of the Invention

[0006] To address the issues that existing testing devices require manual operation for each fastener loading and unloading, which is time-consuming and labor-intensive, and that fasteners of different specifications cannot make sufficient contact with the sleeve, resulting in poor stability, this invention provides a stress relaxation deformation testing device for fasteners in new energy vehicles.

[0007] The present invention provides a stress relaxation deformation testing device for fasteners in new energy vehicles, which adopts the following technical solution: A stress relaxation deformation testing device for fasteners in new energy vehicles includes a test box. The test box has a test cavity and a control cavity respectively opened at the top and bottom ends. The top of the test box is fixedly connected to a control box and a first hydraulic cylinder. The control cavity is fixedly connected to a second hydraulic cylinder. A detection component for detecting the stress deformation of fasteners is provided on one side of the control cavity. A support plate is fixedly connected to one side of the interior of the test chamber, and an assembly for easy fastener installation and removal is provided above the support plate. The output end of the first hydraulic cylinder is fixedly connected to an upper sleeve, and the output end of the second hydraulic cylinder is fixedly connected to a lower sleeve. A fastening bolt is provided in the center of the opposite surfaces of the upper sleeve and the lower sleeve, and a first reinforcing sleeve is threadedly connected to the inner side of the upper sleeve, and a second reinforcing sleeve is threadedly connected to the inner side of the lower sleeve.

[0008] Preferably, the loading and unloading assembly includes a cylinder located on one side of the test chamber, a sliding frame fixedly connected to the output end of the cylinder, a servo motor fixedly connected to the top surface of the sliding frame, and a support rod fixedly connected to one end of the sliding frame. Loading and unloading sleeves are rotatably connected to both ends of the inner side of the support rod.

[0009] Preferably, the detection component includes a guide cylinder fixedly connected to the control cavity, a connecting rod extending through the top of the guide cylinder, a ranging sensor fixedly connected to the bottom of the guide cylinder, and a receiver fixedly connected to the bottom of the connecting rod.

[0010] Preferably, the sliding frame is located above the support plate, the support rod passes through the middle of the support plate, and the support rod is slidably connected to the support plate.

[0011] Preferably, the upper sleeve and the lower sleeve are symmetrically arranged, and the interior of the upper sleeve and the interior of the lower sleeve are both threaded with positioning screws. The inner side of the first reinforcing sleeve is in contact with the upper end of the fastening bolt, and the inner side of the second reinforcing sleeve is in contact with the lower end of the fastening bolt.

[0012] Preferably, a pair of active gear rings are fixedly connected to the output end of the servo motor, and a driven gear ring is fixedly connected to the inner end of the loading and unloading sleeve. A transmission belt is sleeved on the outer side of the opposite surfaces of the active gear ring and the driven gear ring located at the same vertical position.

[0013] Preferably, the outer end of the loading and unloading sleeve has an internal hexagonal groove, and the loading and unloading sleeve is made of magnetic material. The internal hexagonal groove at the outer end of the loading and unloading sleeve is adapted to the positioning screw.

[0014] Preferably, the top end of the connecting rod is fixedly connected to the bottom surface of the lower sleeve, and the connecting rod is made of heat-insulating material. A sealing sleeve for improving the sealing performance of the connecting rod is provided on the outside of the connecting rod, and the sealing sleeve is fixedly connected to the test chamber.

[0015] Preferably, a set of heating grooves is provided in the lower part of the test chamber, and a heating rod is fixedly connected inside the heating groove. The heating rod can adjust the temperature of the test chamber to simulate different test environments.

[0016] Preferably, a pressure relief valve and an air intake valve are fixedly connected to the other side of the test chamber. Both the pressure relief valve and the air intake valve are connected to the interior of the test chamber, and a fan is fixedly connected to the outer end of the air intake valve.

[0017] In summary, the present invention has at least one of the following beneficial technical effects: By setting the first reinforcing sleeve to be threadedly connected to the upper sleeve and the second reinforcing sleeve to be threadedly connected to the lower sleeve, and then placing the screw head of the fastening bolt inside the lower sleeve, the second hydraulic cylinder drives the lower sleeve and the fastening bolt to move upward, so that the upper end of the fastening bolt enters the upper sleeve, so that the inner side of the first reinforcing sleeve is in contact with the upper end of the fastening bolt, and the inner side of the second reinforcing sleeve is in contact with the lower end of the fastening bolt, thereby increasing the contact area between the fastener and the clamp, improving the clamping stability, and adapting to fasteners of different specifications.

[0018] A cylinder drives the sliding frame to slide and connect the support rod to the support plate, so that the two mounting sleeves on the inner side of the support rod are located on the outer sides of the upper and lower sleeves, respectively. The servo motor is started, and through the cooperation of the active gear ring, the driven gear ring, and the transmission belt, the positioning screw is driven to rotate. The upper positioning screw passes through the upper sleeve and the first reinforcing sleeve, limiting the upper end of the fastening bolt. The lower positioning screw passes through the lower sleeve and the second reinforcing sleeve, limiting the lower end of the fastening bolt. Thus, the fastening bolt is fixed between the upper and lower sleeves. Conversely, the servo motor rotates in the opposite direction, and the positioning bolt can be removed. By using horizontal drilling in conjunction with the mounting and disassembly components, the installation and disassembly of fasteners can be performed automatically, which greatly improves the testing efficiency.

[0019] By moving the lower sleeve to tighten the fastening bolt, the fastening bolt undergoes stress relaxation deformation. At the same time, the movement of the lower sleeve drives the connecting rod to move downward. During this process, the distance between the ranging sensor and the receiver changes. The test process is displayed through the control box. Because the connecting rod is made of heat-insulating material and a sealing sleeve is fitted on the outside of the connecting rod to improve its sealing performance, the high-temperature air inside the test chamber will not affect the normal operation of the sensor, ensuring the accuracy of the test results.

[0020] The test chamber is heated by a heating rod and a heating tank until the temperature reaches the set test value. During this process, the air inside the test chamber heats up and expands, increasing the pressure inside the chamber. The pressure relief valve is activated to release the pressure inside the test chamber, ensuring pressure balance. After the test, the pressure relief valve and the air inlet valve are activated. The fan on the outer side of the air inlet valve allows outside air to enter the test chamber, while the pressure relief valve discharges the hot air from the test chamber, achieving rapid cooling inside the test chamber. This allows for temperature and pressure regulation of the testing device, further improving testing results and efficiency. Attached Figure Description

[0021] Figure 1 This is an isometric structural schematic diagram of an embodiment of the invention.

[0022] Figure 2 This is a schematic diagram of the upper and lower sleeves in an embodiment of the invention.

[0023] Figure 3This is a cross-sectional schematic diagram of the upper and lower sleeves in an embodiment of the invention.

[0024] Figure 4 This is a schematic diagram showing the disassembly of the upper and lower sleeves in an embodiment of the invention.

[0025] Figure 5 This is a schematic diagram of the overall structure of the loading and unloading assembly according to an embodiment of the invention.

[0026] Figure 6 This is a diagram showing the positional relationship between the servo motor and the mounting / unmounting sleeve in an embodiment of the invention.

[0027] Figure 7 This is a cross-sectional structural diagram of the detection component according to an embodiment of the invention.

[0028] Figure 8 This is an embodiment of the invention. Figure 1 Enlarged view of the structure at point A in the middle.

[0029] Figure 9 This is a structural schematic diagram of the test chamber in a sealed state according to an embodiment of the invention.

[0030] Figure 10 This is an embodiment of the invention. Figure 2 Enlarged view of the structure at point B.

[0031] Explanation of reference numerals in the attached drawings: 1. Test box; 2. Test chamber; 3. Control chamber; 4. Control box; 5. First hydraulic cylinder; 6. Second hydraulic cylinder; 7. Support plate; 8. Loading and unloading assembly; 81. Cylinder; 82. Sliding frame; 83. Servo motor; 84. Support rod; 85. Loading and unloading sleeve; 86. Driving gear ring; 87. Driven gear ring; 88. Transmission belt; 9. Detection assembly; 91. Connecting rod; 92. Guide cylinder; 93. Receiver; 94. Distance sensor; 95. Sealing sleeve; 10. Upper sleeve; 11. Lower sleeve; 12. Fastening bolt; 13. First reinforcing sleeve; 14. Second reinforcing sleeve; 15. Positioning screw; 16. Heating tank; 17. Heating rod; 18. Pressure relief valve; 19. Inlet valve; 20. Fan. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1 - Appendix Figure 10 The present invention will be described in further detail below.

[0033] Example 1: A test device for stress relaxation deformation of fasteners in new energy vehicles, referring to Figure 1 - Figure 4 The test chamber includes a test chamber 1, with a test cavity 2 and a control cavity 3 respectively opened at the upper and lower ends of the test chamber 1. A control box 4 and a first hydraulic cylinder 5 are fixedly connected to the top of the test chamber 1, and a second hydraulic cylinder 6 is fixedly connected inside the control cavity 3.

[0034] Reference Figure 1 - Figure 4 The output end of the first hydraulic cylinder 5 is fixedly connected to the upper sleeve 10, and the output end of the second hydraulic cylinder 6 is fixedly connected to the lower sleeve 11. A fastening bolt 12 is provided in the center of the opposite face of the upper sleeve 10 and the lower sleeve 11, and the inner side of the upper sleeve 10 is threadedly connected to the first reinforcing sleeve 13, and the inner side of the lower sleeve 11 is threadedly connected to the second reinforcing sleeve 14. Open the test box 1, determine the size and specifications of the fastening bolt 12, select the first reinforcing sleeve 13 and the second reinforcing sleeve 14 with the inner diameters of the fastening bolt 12, thread the first reinforcing sleeve 13 to the upper sleeve 10, thread the second reinforcing sleeve 14 to the lower sleeve 11, place the threaded head of the fastening bolt 12 inside the lower sleeve 11, start the second hydraulic cylinder 6, drive the lower sleeve 11 and the fastening bolt 12 to move upward, so that the upper end of the fastening bolt 12 enters the upper sleeve 10.

[0035] Reference Figure 3 and Figure 4 The upper sleeve 10 and the lower sleeve 11 are symmetrically arranged, and the interior of the upper sleeve 10 and the interior of the lower sleeve 11 are both threaded with positioning screws 15. The inner side of the first reinforcing sleeve 13 is in contact with the upper end of the fastening bolt 12, and the inner side of the second reinforcing sleeve 14 is in contact with the lower end of the fastening bolt 12. The inner side of the first reinforcing sleeve 13 is fitted with the upper end of the fastening bolt 12, and the inner side of the second reinforcing sleeve 14 is fitted with the lower end of the fastening bolt 12, thereby increasing the contact area between the fastener and the clamp and improving the clamping stability.

[0036] Reference Figure 1 , Figure 2 and Figure 6 The test chamber 2 is fixedly connected to a support plate 7 on one side. A loading and unloading assembly 8 for easy fastener loading and unloading is provided above the support plate 7. The loading and unloading assembly 8 includes a cylinder 81 located on one side of the test chamber 1. A sliding frame 82 is fixedly connected to the output end of the cylinder 81. A servo motor 83 is fixedly connected to the top surface of the sliding frame 82. A support rod 84 is fixedly connected to one end of the sliding frame 82. Loading and unloading sleeves 85 are rotatably connected to both ends of the inner side of the support rod 84. The sliding frame 82 is located above the support plate 7. The support rod 84 passes through the middle of the support plate 7 and is slidably connected to the support plate 7. Activate cylinder 81 to allow the sliding frame 82 to slide above the support plate 7. It is slidably connected to the support plate 7 via support rod 84, ensuring the stability of the sliding frame 82 and support rod 84's movement. This ensures that the two loading / unloading sleeves 85 on the inner side of the support rod 84 are located on the outer sides of the upper sleeve 10 and lower sleeve 11, respectively. The output end of the servo motor 83 is fixedly connected to a pair of active gear rings 86, and the inner end of the loading and unloading sleeve 85 is fixedly connected to a driven gear ring 87. The opposite faces of the active gear ring 86 and the driven gear ring 87, which are located in the same vertical position, are fitted with a transmission belt 88 on the outer side. The outer end of the loading and unloading sleeve 85 is provided with an internal hexagonal groove, and the loading and unloading sleeve 85 is made of magnetic material. The internal hexagonal groove on the outer end of the loading and unloading sleeve 85 is adapted to the positioning screw 15. The servo motor 83 is started, driving the two active gear rings 86 to rotate. The active gear rings 86, in conjunction with the transmission belt 88, cause the driven gear ring 87 to rotate. The rotation of the driven gear ring 87 causes the loading and unloading sleeve 85 to drive the positioning screw 15 to rotate. The upper positioning screw 15 passes through the upper sleeve 10 and the first reinforcing sleeve 13, limiting the upper end of the fastening bolt 12. The lower positioning screw 15 passes through the lower sleeve 11 and the second reinforcing sleeve 14, limiting the lower end of the fastening bolt 12. Thus, the fastening bolt 12 is fixed between the upper sleeve 10 and the lower sleeve 11. Then, the cylinder 81 drives the sliding frame 82 and the support rod 84 to reset, and the loading and unloading sleeve 85 separates from the positioning screw 15.

[0037] Reference Figure 1 and Figure 8 A set of heating grooves 16 is provided in the lower part of the test chamber 2. A heating rod 17 is fixedly connected inside the heating grooves 16. The heating rod 17 can adjust the temperature of the test chamber 2 to simulate different test environments.

[0038] Reference Figure 9 and Figure 10 On the other side of the test chamber 1, a pressure relief valve 18 and an air intake valve 19 are fixedly connected. Both the pressure relief valve 18 and the air intake valve 19 are connected to the interior of the test chamber 2. A fan 20 is fixedly connected to one end of the air intake valve 19 on the outer side. After the fastening bolt 12 is fixed, the test chamber 1 is closed, and the heating rod 17 is started. The heating groove 16 heats the inside of the test chamber 2 until the temperature reaches the test set value. During this process, the air inside the test chamber 2 heats up and expands, and the pressure inside the test chamber 2 increases. The pressure relief valve 18 is started to release the pressure inside the test chamber 2 to ensure the air pressure balance inside the test chamber 2. Then, the second hydraulic cylinder 6 is started to drive the lower sleeve 11 to move downward. During this process, the lower end of the fastening bolt 12 is pulled downward to perform stress deformation test. After the test is completed, the pressure relief valve 18 and the air inlet valve 19 are started. The fan 20 on the outer end of the air inlet valve 19 allows the outside air to enter the inside of the test chamber 2. At the same time, the pressure relief valve 18 discharges the high temperature air inside the test chamber 2, so as to achieve rapid cooling inside the test chamber 2 and improve the test efficiency.

[0039] Reference Figure 1 and Figure 7A detection component 9 for detecting the stress deformation of fasteners is provided on one side of the control cavity 3. The detection component 9 includes a guide cylinder 92 fixedly connected to the control cavity 3. A connecting rod 91 is provided through the top end of the guide cylinder 92, and a distance sensor 94 is fixedly connected to the bottom end of the guide cylinder 92. A receiver 93 is fixedly connected to the bottom end of the connecting rod 91. The top end of the connecting rod 91 is fixedly connected to the bottom surface of the lower sleeve 11. The connecting rod 91 is made of heat-insulating material. A sealing sleeve 95 for improving the sealing performance of the connecting rod 91 is provided on the outside of the connecting rod 91. The sealing sleeve 95 is fixedly connected to the test cavity 2. As the lower sleeve 11 moves, the tension fastening bolt 12 is stretched, causing the bolt 12 to undergo stress relaxation deformation. Simultaneously, the movement of the lower sleeve 11 drives the connecting rod 91 to move downward. During this process, the distance between the ranging sensor 94 and the receiver 93 changes. The test process is displayed through the control box 4. Since the connecting rod 91 is made of heat-insulating material and a sealing sleeve 95 is provided on the outside of the connecting rod 91 to improve its sealing performance, the high-temperature air inside the test chamber 2 will not affect the normal operation of the sensor, ensuring the accuracy of the test results.

[0040] The working principle is as follows: First, determine the size and specifications of the fastening bolt 12. Select the first reinforcing sleeve 13 and the second reinforcing sleeve 14 with inner diameters that match the fastening bolt 12. Thread the first reinforcing sleeve 13 to the upper sleeve 10 and the second reinforcing sleeve 14 to the lower sleeve 11. Then, drill holes at both ends of the fastening bolt 12. Place the threaded head of the fastening bolt 12 inside the lower sleeve 11. Start the second hydraulic cylinder 6 to move the lower sleeve 11 and the fastening bolt 12 upwards, so that the upper end of the fastening bolt 12 enters the upper sleeve 10. This allows the inner side of the first reinforcing sleeve 13 to fit against the upper end of the fastening bolt 12, and the inner side of the second reinforcing sleeve 14 to fit against the lower end of the fastening bolt 12, thereby increasing the contact area between the fastener and the clamp and improving clamping stability. The cylinder 81 is activated, causing the sliding frame 82 to slide above the support plate 7. It is slidably connected to the support plate 7 via the support rod 84, ensuring the stability of the movement of the sliding frame 82 and the support rod 84. This positions the two loading / unloading sleeves 85 on the inner side of the support rod 84 on the outer sides of the upper sleeve 10 and lower sleeve 11, respectively. The servo motor 83 is then activated, driving the two active gear rings 86 to rotate. The active gear rings 86, in conjunction with the transmission belt 88, cause the driven gear ring 87 to rotate. The rotation of the driven gear ring 87 causes the loading / unloading sleeves 85 to rotate. The positioning screw 15 is rotated. The upper positioning screw 15 passes through the upper sleeve 10 and the first reinforcing sleeve 13, limiting the upper end of the fastening bolt 12. The lower positioning screw 15 passes through the lower sleeve 11 and the second reinforcing sleeve 14, limiting the lower end of the fastening bolt 12. Thus, the fastening bolt 12 is fixed between the upper sleeve 10 and the lower sleeve 11. Then, the cylinder 81 drives the sliding frame 82 and the support rod 84 to reset, and the loading and unloading sleeve 85 separates from the positioning screw 15. After the fastening bolt 12 is fixed, the test chamber 1 is closed, and the heating rod 17 is started. The heating groove 16 heats the inside of the test chamber 2 until the temperature reaches the test set value. During this process, the air inside the test chamber 2 heats up and expands, and the pressure inside the test chamber 2 increases. The pressure relief valve 18 is started to release the pressure inside the test chamber 2 to ensure the air pressure balance inside the test chamber 2. When the temperature reaches the test set value, the second hydraulic cylinder 6 is started to drive the lower sleeve 11 to move downward. As the lower sleeve 11 moves, it stretches the fastening bolt 12, and the fastening bolt 12 undergoes stress relaxation deformation. At the same time, the movement of the lower sleeve 11 drives the connecting rod 91 to move downward. During this process, the distance between the ranging sensor 94 and the receiver 93 changes. The control box 4 displays the test process. Since the connecting rod 91 is made of heat-insulating material and the outer side of the connecting rod 91 is fitted with a sealing sleeve 95 to improve the sealing performance of the connecting rod 91, the high temperature air inside the test chamber 2 will not affect the normal operation of the sensor and ensure the accuracy of the test results. After the test is completed, the pressure relief valve 18 and the air intake valve 19 are activated. The fan 20 at the outer end of the air intake valve 19 allows outside air to enter the test chamber 2. At the same time, the pressure relief valve 18 discharges the high-temperature air inside the test chamber 2, achieving rapid cooling inside the test chamber 2. Simultaneously, the cylinder 81 is activated, causing the sliding frame 82 to move closer to the fastening bolt 12 again. The groove on the inner side of the mounting sleeve 85 fits with the outer screw head of the positioning screw 15. Then, the servo motor 83 is activated to rotate in the opposite direction, causing the mounting sleeve 85 to drive the positioning screw 15 to rotate in the opposite direction, separating it from the fastening bolt 12 and the sleeve, thus completing the removal of the positioning screw 15. Finally, the cabinet door of the test box 1 is opened, and the fastening bolt 12, which has completed the test, can be removed.

[0041] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A stress relaxation deformation testing device for fasteners in new energy vehicles, comprising a test chamber (1), wherein a test cavity (2) and a control cavity (3) are respectively provided at the upper and lower ends of the interior of the test chamber (1), characterized in that: The top of the test box (1) is fixedly connected to a control box (4) and a first hydraulic cylinder (5), and the inside of the control cavity (3) is fixedly connected to a second hydraulic cylinder (6). A detection component (9) for detecting the stress deformation of fasteners is provided on one side of the control cavity (3). Inside the test chamber (2), a support plate (7) is fixedly connected to one side. Above the support plate (7), a loading and unloading assembly (8) is provided to facilitate the loading and unloading of fasteners. The loading and unloading assembly (8) includes a cylinder (81) located on one side of the test box (1). A sliding frame (82) is fixedly connected to the output end of the cylinder (81). A servo motor (83) is fixedly connected to the top surface of the sliding frame (82). A support rod (84) is fixedly connected to one end of the sliding frame (82). Loading and unloading sleeves (85) are rotatably connected to both ends of the inner side of the support rod (84). The output end of the servo motor (83) is fixedly connected to a pair of active gear rings (86), and the inner end of the loading and unloading sleeve (85) is fixedly connected to a driven gear ring (87). The active gear ring (86) and the driven gear ring (87) located in the same vertical position are fitted with a transmission belt (88) on the outer side of their opposite surfaces. The outer end of the loading and unloading sleeve (85) is provided with an internal hexagonal groove, and the loading and unloading sleeve (85) is made of magnetic material. The internal hexagonal groove on the outer end of the loading and unloading sleeve (85) is compatible with the positioning screw (15). The output end of the first hydraulic cylinder (5) is fixedly connected to an upper sleeve (10), and the output end of the second hydraulic cylinder (6) is fixedly connected to a lower sleeve (11). The upper sleeve (10) and the lower sleeve (11) are symmetrically arranged, and the interior of the upper sleeve (10) and the interior of the lower sleeve (11) are both threadedly connected to positioning screws (15). The upper sleeve (10) and the lower sleeve (11) are centrally located on opposite sides, and fastening bolts (12) are provided. The inner side of the upper sleeve (10) is threadedly connected to a first reinforcing sleeve (13), and the inner side of the lower sleeve (11) is threadedly connected to a second reinforcing sleeve (14). The inner side of the first reinforcing sleeve (13) is in contact with the upper end of the fastening bolt (12), and the inner side of the second reinforcing sleeve (14) is in contact with the lower end of the fastening bolt (12).

2. The stress relaxation deformation testing device for fasteners in new energy vehicles according to claim 1, characterized in that: The detection component (9) includes a guide cylinder (92) fixedly connected to the control cavity (3), a connecting rod (91) is provided through the top of the guide cylinder (92), and a distance sensor (94) is fixedly connected to the bottom of the guide cylinder (92), and a receiver (93) is fixedly connected to the bottom of the connecting rod (91).

3. The stress relaxation deformation testing device for fasteners in new energy vehicles according to claim 1, characterized in that: The sliding frame (82) is located above the support plate (7), and the support rod (84) passes through the middle of the support plate (7) and is slidably connected to the support plate (7).

4. The stress relaxation deformation testing device for fasteners in new energy vehicles according to claim 2, characterized in that: The top end of the connecting rod (91) is fixedly connected to the bottom surface of the lower sleeve (11), and the connecting rod (91) is made of heat-insulating material. A sealing sleeve (95) for improving the sealing performance of the connecting rod (91) is provided on the outside of the connecting rod (91). The sealing sleeve (95) is fixedly connected to the test chamber (2).

5. The stress relaxation deformation testing device for fasteners in new energy vehicles according to claim 1, characterized in that: A set of heating grooves (16) is provided in the lower part of the test chamber (2). A heating rod (17) is fixedly connected inside the heating grooves (16). The heating rod (17) can adjust the temperature of the test chamber (2) to simulate different test environments.

6. The stress relaxation deformation testing device for fasteners in new energy vehicles according to claim 1, characterized in that: The other side of the test chamber (1) is fixedly connected to a pressure relief valve (18) and an air intake valve (19). Both the pressure relief valve (18) and the air intake valve (19) are connected to the interior of the test chamber (2), and a fan (20) is fixedly connected to the outer end of the air intake valve (19).

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