Battery pack vibration test tool with rigidity adjusting function

Abstract

The invention relates to the technical field of automobile part testing, in particular to a battery pack vibration testing tool with a rigidity adjusting function, which comprises a frame, the frame comprises two hollow long beams which are parallel to each other and are distributed at intervals, and at least one hollow adjusting cross beam is connected between the two hollow long beams. A longitudinal inhaul cable is arranged in an inner cavity of the hollow long beam in a penetrating mode, a transverse inhaul cable is arranged in an inner cavity of the hollow adjusting cross beam in a penetrating mode, one end of the longitudinal inhaul cable and one end of the transverse inhaul cable are provided with a first adjusting mechanism and a second adjusting mechanism which are used for adjusting axial tension of the longitudinal inhaul cable and the transverse inhaul cable respectively, and the longitudinal inhaul cable and the transverse inhaul cable are distributed in a staggered mode on different planes in space. By adjusting the tension of the inhaul cable, the structural rigidity and inherent frequency of the tool can be steplessly adjusted, and test resonance is effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of automotive component testing technology, specifically to a battery pack vibration testing fixture with stiffness adjustment function. Background Technology

[0002] As a core component of new energy vehicles, the structural strength and vibration resistance of the power battery pack directly affect the overall vehicle's driving safety. During the development and verification phase of the battery pack, rigorous vibration durability testing must be conducted to simulate the vehicle's driving environment under different road conditions.

[0003] Existing battery pack vibration testing fixtures typically employ a fixed frame structure welded from channel steel or square tubing. This rigidly connected fixture has the following significant drawbacks: Firstly, once a traditional welded frame is manufactured, its structural stiffness and natural frequency are fixed and cannot be changed. During wide-band sweep vibration testing, if the test frequency range covers the natural frequency of the tooling frame, the tooling is highly susceptible to resonance amplification. This not only causes the battery pack to experience vibration acceleration far exceeding the standard, resulting in "overtesting" and damaging expensive samples, but also leads to distorted test data, failing to accurately reflect the stress on the battery pack under actual vehicle body connection conditions.

[0004] Secondly, the rigidity requirements of the installation environment vary greatly depending on the vehicle model and the weight of the battery pack. The actual vehicle chassis environment often exhibits different stiffness characteristics in the longitudinal (driving direction) and lateral (vehicle width) directions. However, existing fixed fixtures can only provide single, isotropic stiffness support, and cannot independently simulate and adjust longitudinal and lateral stiffness on the same equipment. This means that for each new battery pack, it is often necessary to redesign and manufacture dedicated testing fixtures, significantly increasing R&D costs and testing cycles. Summary of the Invention

[0005] Therefore, it is necessary to provide a battery pack vibration testing fixture with stiffness adjustment function to address the existing technical problems.

[0006] To address the problems of existing technologies, the present invention adopts the following technical solution: a battery pack vibration testing fixture with stiffness adjustment function, comprising a frame, the frame comprising two parallel and spaced hollow beams, at least one hollow adjusting crossbeam connecting the two hollow beams, a longitudinal cable passing through the inner cavity of the hollow beams, with both ends of the longitudinal cable extending to the outer sides of both ends of the hollow beams, a transverse cable passing through the inner cavity of the hollow adjusting crossbeam, with both ends of the transverse cable extending to the outer walls of the two hollow beams, and one end of each of the longitudinal and transverse cables being provided with a first adjusting mechanism and a second adjusting mechanism for adjusting their axial tension, the longitudinal and transverse cables being spatially misaligned.

[0007] Furthermore, each of the hollow long beams is fixed with end sealing plates at both ends. One end of the longitudinal cable is fixedly connected to one of the end sealing plates, and the other end is coaxially pressed with a first threaded head that passes through the other end sealing plate. The first adjustment mechanism includes a first nut and a first elastic washer. The first elastic washer is sleeved on the first threaded head, and the first nut is screwed on the first threaded head and presses the first elastic washer against the outer wall of the corresponding end sealing plate.

[0008] Furthermore, each of the hollow long beams has a vertically downward connecting platform formed at its bottom. The two ends of the hollow adjusting beam are fixedly connected to two connecting platforms respectively, so that the transverse cable is located below the longitudinal cable. One end of the transverse cable is fixedly connected to one of the connecting platforms, and the other end is coaxially pressed with a second threaded head passing through the connecting platform. The second adjusting mechanism includes a second nut and a second elastic washer. The second elastic washer is sleeved on the second threaded head, and the second nut is screwed on the second threaded head and presses the second elastic washer against the outer wall of the corresponding connecting platform.

[0009] Furthermore, each of the connecting platforms is provided with a plug-in cavity that communicates with the inner cavity of the hollow long beam, and each connecting platform has a plug hole on its side wall. The two ends of the hollow adjusting beam are respectively inserted into the corresponding plug-in cavity through two plug holes, and the end of the hollow adjusting beam abuts against the inner wall of the connecting platform on the side away from the plug hole.

[0010] Furthermore, a first anti-rotation structure is provided between the first threaded head and the corresponding end sealing plate. The first anti-rotation structure includes a first limiting key provided on the first threaded head and a first limiting groove provided on the end sealing plate. The first limiting key extends along the axial direction of the longitudinal cable and is inserted into the first limiting groove.

[0011] Furthermore, a second anti-rotation structure is provided between the second threaded head and the corresponding connecting platform. The second anti-rotation structure includes a second limiting key provided on the second threaded head and a second limiting groove provided on the inner wall of the connecting platform. The second limiting key extends along the axial direction of the transverse cable and is inserted into the second limiting groove.

[0012] Furthermore, both the first elastic washer and the second elastic washer include several disc springs that are stacked together.

[0013] Furthermore, the frame is used to fix and place the battery pack, and the battery pack is located between two hollow long beams. Each hollow long beam has a number of connecting ears formed on the outer wall facing the battery pack for connecting the battery pack.

[0014] Furthermore, the frame also includes two end support beams, each end of which is connected to two hollow long beams at both ends. The hollow adjustment beams are located between the two end support beams and together with the hollow long beams form a sun-shaped structure.

[0015] Furthermore, each of the hollow beams has two vertically downward protrusions at its bottom, and each end of the end support beam is fixedly connected to the two corresponding protrusions at both ends. The tops of the end support beams and the hollow adjustment beams are all formed with support plates, and the tops of all support plates are flush.

[0016] The beneficial effects of this invention compared to the prior art are: Firstly, this invention breaks through the limitation of the fixed stiffness of traditional testing fixtures. By inserting longitudinal and transverse cables through the hollow long beams and hollow adjusting beams of the frame, respectively, and cooperating with the adjustment mechanism at the ends, active control of the overall prestress of the frame is achieved. Technicians can steplessly adjust the structural stiffness and natural frequency of the fixture by changing the axial tension of the cables. During battery pack vibration testing, this adjustment capability allows the fixture to flexibly shift its resonant frequency out of the test focus range, thereby effectively avoiding the "overtesting" phenomenon caused by fixture resonance, protecting the battery pack under test, and ensuring the authenticity and reliability of the test data. Secondly, this invention employs a structural design in which the longitudinal and transverse cables are spatially staggered. This design cleverly utilizes the spatial height difference of the frame, ensuring that the longitudinal and transverse cables do not contact or cross each other in three-dimensional space. This completely solves the physical interference and friction problems that easily occur when bidirectional cables are arranged on the same plane, extending the service life of the cables; on the other hand, it ensures that the adjustment of longitudinal and transverse stiffness does not affect each other, allowing the tooling to accurately simulate the different stiffness characteristics of the entire vehicle chassis in the longitudinal and transverse directions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a three-dimensional structure in which the battery pack is fixedly placed within a frame. Figure 1 ; Figure 2 This is a schematic diagram of a three-dimensional structure in which the battery pack is fixedly placed within a frame. Figure 2; Figure 3 It is a schematic diagram of the three-dimensional structure of the frame; Figure 4 This is a planar sectional view of the hollow adjustable crossbeam; Figure 5 yes Figure 4 A magnified view of the area indicated by A1 in the diagram; Figure 6 It is a planar sectional view of a hollow long beam; Figure 7 yes Figure 6 The enlarged view of the area indicated by A2 in the diagram; Figure 8 It is a three-dimensional exploded view of the hollow adjusting crossbeam and the hollow long beam; Figure 9 This is a plan view of the connecting platform; Figure 10 This is a three-dimensional structural diagram of the second threaded head; Figure 11 This is an exploded three-dimensional structural diagram of the first threaded head and the end cap.

[0018] The diagram is labeled as follows: 1. Frame; 2. Hollow long beam; 3. Hollow adjusting crossbeam; 4. Longitudinal cable; 5. Transverse cable; 6. First adjusting mechanism; 7. Second adjusting mechanism; 8. End sealing plate; 9. First threaded head; 10. First nut; 11. First elastic washer; 12. Connecting platform; 13. Second threaded head; 14. Second nut; 15. Second elastic washer; 16. Insertion cavity; 17. Insertion hole; 18. First limiting key; 19. First limiting groove; 20. Second limiting key; 21. Second limiting groove; 22. Connecting lug; 23. End support crossbeam; 24. Boss; 25. Support plate. Detailed Implementation

[0019] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0020] refer to Figures 1 to 11As shown, a battery pack vibration test tooling with a stiffness adjustment function is provided, which is mainly used for the vibration durability test of new energy vehicle battery packs. The main structure of this tooling includes a frame 1 for fixedly placing the battery pack. The frame 1 consists of two parallel and spaced hollow long beams 2, two end support cross beams 23 at the ends, and at least one hollow adjustment cross beam 3 in the middle. Among them, the two end support cross beams 23 are respectively connected to both ends of the two hollow long beams 2, and the hollow adjustment cross beam 3 is located between the two end support cross beams 23, thus cooperating with the two hollow long beams 2 to jointly enclose a stable "day" - shaped structure. In order to meet the stiffness requirements at different test frequencies, a cable system is integrated inside the frame 1, and the overall mode and stiffness of the frame 1 are changed by adjusting the tension of the cables.

[0021] Specifically, the hollow long beam 2 is the main bearing component of this tooling, and it has a cavity running through its entire length. Refer to Figure 6 and Figure 7 As shown, in the cavity of each hollow long beam 2, a longitudinal cable 4 is inserted. End plates 8 are welded to both ends of each hollow long beam 2 to close the cavity and provide an anchoring point for the longitudinal cable 4. In order to adjust the tension of the longitudinal cable 4, the longitudinal cable 4 is installed in a way that one end is fixed and the other end is adjustable. That is, one end of the longitudinal cable 4 is directly fixed to one of the end plates 8, and a first threaded head 9 is coaxially crimped to the other end. The first threaded head 9 extends outside the hollow long beam 2 through the other end plate 8. On the first threaded head 9 extending out of the end plate 8, a first adjustment mechanism 6 is installed. The first adjustment mechanism 6 includes a first nut 10 screwed on the first threaded head 9 and a first elastic washer 11 sleeved on the first threaded head 9. The first elastic washer 11 is pressed against the outer wall of the end plate 8 by the first nut 10. By rotating the first nut 10, its axial position on the first threaded head 9 can be changed, thereby tightening the longitudinal cable 4 and compressing the first elastic washer 11 to achieve the adjustment of the axial tension of the longitudinal cable 4.

[0022] In order to prevent the longitudinal cable 4 from rotating and generating torsional stress when the first nut 10 is rotated, a first anti - rotation structure is specially designed between the first threaded head 9 and the corresponding end plate 8. Refer to Figure 11 As shown, this first anti - rotation structure includes a first limiting key 18 integrally formed on the side wall of the first threaded head 9 and a first limiting groove 19 opened on the inner wall of the central hole of the end plate 8. The first limiting key 18 extends along the axial direction of the longitudinal cable 4 and slides into the first limiting groove 19. This mating relationship ensures that the first threaded head 9 can only move axially and cannot rotate relative to the end plate 8, thus ensuring the stability of the adjustment process and the safety of the cable.

[0023] In the design of the lateral support structure, this invention employs a unique staggered layout to avoid spatial interference between the lateral cable 5 and the longitudinal cable 4. Specifically, refer to... Figure 8 and Figure 9 As shown, each hollow long beam 2 has a vertically downward connecting platform 12 integrally formed or welded to its bottom. The connecting platform 12 has an insertion cavity 16 inside, which communicates upwards with the inner cavity of the hollow long beam 2, but extends downwards to expand the space. Each connecting platform 12 has an insertion hole 17 on its side wall. The two ends of the hollow adjusting beam 3 pass through the insertion holes 17 of the connecting platforms 12 on both sides and are inserted into the corresponding insertion cavities 16. The end face of the hollow adjusting beam 3 directly abuts against the inner wall of the connecting platform 12 on the side away from the insertion hole 17, thus forming a stable mechanical support.

[0024] In order to adjust the stiffness of the hollow adjusting beam 3, refer to Figure 4 and Figure 5 As shown, a transverse cable 5 is threaded through the inner cavity of the hollow adjusting beam 3, with both ends of the transverse cable 5 extending into the connecting platforms 12 on both sides and exiting through the outer walls of the connecting platforms 12. Since the connecting platforms 12 are located at the bottom of the hollow long beam 2, the transverse cable 5 is positioned below the longitudinal cable 4 in the height direction, and the two are spatially misaligned, without contact or interference. The installation and adjustment method of the transverse cable 5 is similar to that of the longitudinal cable 4; one end is fixedly connected to one of the connecting platforms 12, and the other end is coaxially pressed with a second threaded head 13 that passes through the side wall of the opposite connecting platform 12. A second adjusting mechanism 7 is installed on the second threaded head 13, which also includes a second nut 14 and a second elastic washer 15. The second nut 14 is tightened onto the second threaded head 13, pressing the second elastic washer 15 against the outer wall of the connecting platform 12. Similarly, in order to prevent the transverse cable 5 from rotating during adjustment, a second anti-rotation structure is provided between the second threaded head 13 and the connecting platform 12, including a second limiting key 20 on the second threaded head 13 and a second limiting groove 21 on the inner wall of the through hole. The second limiting key 20 is inserted into the second limiting groove 21 along the axial direction of the transverse cable 5.

[0025] In this embodiment, both the first elastic washer 11 and the second elastic washer 15 are preferably made of several stacked disc springs. Disc springs have the characteristics of high stiffness, short stroke, and strong load-bearing capacity. They can provide a huge preload in a small space and can effectively absorb impact during vibration testing, maintain constant cable tension, and prevent the nut from loosening.

[0026] For easier installation and securing of the battery pack, please refer to... Figure 3As shown, frame 1 features standard interfaces at multiple locations. First, several connecting ears 22 are formed on the outer wall of each hollow beam 2 facing the battery pack, for the battery pack to be attached to the side lugs. Second, for the support structures at both ends of frame 1, two vertically downward protrusions 24 are formed at the bottom of each hollow beam 2, and the two ends of each end support beam 23 are fixed to the corresponding two protrusions 24. More importantly, the top of the end support beam 23 and the top of the middle hollow adjustment beam 3 are both machined with supporting plates 25, and the top surfaces of all supporting plates 25 are on the same horizontal plane. When the battery pack is placed inside frame 1, its bottom rests stably on these flush supporting plates 25, and its sides are locked to the connecting ears 22 on the hollow beam 2 by bolts, thus ensuring the tightness and integrity of the connection between the battery pack and the tooling frame 1.

[0027] Before conducting vibration testing of the battery pack, technicians first need to determine the target stiffness characteristics of frame 1 based on the weight distribution, dimensional characteristics, and frequency sweep range specified in the test standard for the battery pack under test. Since this fixture is equipped with two longitudinal cables 4 and one transverse cable 5, each with its own emphasis in stiffness adjustment, the specific adjustment process is as follows: First, regarding the adjustment of the longitudinal cables 4, the two longitudinal cables 4 are arranged along the main load-bearing hollow beam 2, and they primarily determine the bending stiffness of frame 1 in the longitudinal direction (i.e., the vehicle's travel direction). When test data shows that frame 1 has significant deflection deformation in the longitudinal span, or when the first-order bending mode frequency of frame 1 falls into the test resonance zone, technicians should focus on adjusting the two longitudinal cables 4 to increase their axial tension. It is particularly important to note that, since the longitudinal cables 4 are symmetrically distributed on both sides, the adjustment process must ensure synchronous adjustment or alternating fine-tuning on both sides, and the final tension values ​​of the two longitudinal cables 4 must be kept consistent using a torque wrench or tension gauge. If the tension on both sides is unbalanced, it will cause in-plane skewing or pre-twisting of frame 1, severely affecting test accuracy.

[0028] Secondly, regarding the adjustment of the transverse cable 5, this single transverse cable 5 is located in the middle of frame 1, and it mainly determines the transverse connection stiffness and overall torsional stiffness of frame 1. When relative misalignment is found between the two hollow long beams 2 or torsional vibration occurs in frame 1 during testing, technicians should focus on adjusting the transverse cable 5. Increasing the tension of the transverse cable 5 can more tightly lock the connection node between the hollow adjusting beam 3 and the hollow long beam 2, significantly improving the integrity and torsional modal frequency of frame 1.

[0029] Third, in routine operation, it is recommended to adopt the adjustment sequence of longitudinal first and then transverse. That is, first apply the initial basic preload to the two longitudinal cables 4 to establish the main skeleton stiffness of frame 1; then tighten the transverse cables 5 to lock the width structure of frame 1; finally, conduct a pre-sweep test, and based on the feedback resonant frequency point, selectively increase the tension of the cable in a certain direction until the natural frequency of frame 1 is moved out of the sensitive frequency band of interest in the test, thereby achieving a realistic and reliable simulation of the vibration environment of the battery pack.

[0030] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A battery pack vibration testing fixture with stiffness adjustment function, characterized in that, The system includes a frame (1), which includes two parallel and spaced hollow beams (2). At least one hollow adjusting beam (3) connects the two hollow beams (2). A longitudinal cable (4) is threaded through the inner cavity of the hollow beam (2), and the two ends of the longitudinal cable (4) extend to the outer sides of the two ends of the hollow beam (2). A transverse cable (5) is threaded through the inner cavity of the hollow adjusting beam (3), and the two ends of the transverse cable (5) extend to the outer walls of the two hollow beams (2). One end of the longitudinal cable (4) and the transverse cable (5) are respectively provided with a first adjusting mechanism (6) and a second adjusting mechanism (7) for adjusting their axial tension. The longitudinal cable (4) and the transverse cable (5) are spatially misaligned.

2. The battery pack vibration testing fixture with stiffness adjustment function according to claim 1, characterized in that, Each hollow long beam (2) is fixed with end sealing plates (8) at both ends. One end of the longitudinal cable (4) is fixedly connected to one of the end sealing plates (8), and the other end is coaxially pressed with a first threaded head (9) that passes through another end sealing plate (8). The first adjustment mechanism (6) includes a first nut (10) and a first elastic washer (11). The first elastic washer (11) is sleeved on the first threaded head (9), and the first nut (10) is screwed on the first threaded head (9) and presses the first elastic washer (11) against the outer wall of the corresponding end sealing plate (8).

3. The battery pack vibration testing fixture with stiffness adjustment function according to claim 2, characterized in that, Each hollow beam (2) has a vertically downward connecting platform (12) formed at its bottom. The two ends of the hollow adjusting beam (3) are fixedly connected to the two connecting platforms (12) respectively, so that the transverse cable (5) is located below the longitudinal cable (4). One end of the transverse cable (5) is fixedly connected to one of the connecting platforms (12), and the other end is coaxially pressed with a second threaded head (13) passing through the connecting platform (12). The second adjusting mechanism (7) includes a second nut (14) and a second elastic washer (15). The second elastic washer (15) is sleeved on the second threaded head (13), and the second nut (14) is screwed on the second threaded head (13) and presses the second elastic washer (15) against the outer wall of the corresponding connecting platform (12).

4. The battery pack vibration testing fixture with stiffness adjustment function according to claim 3, characterized in that, Each of the connecting platforms (12) is provided with a plug-in cavity (16) that communicates with the inner cavity of the hollow long beam (2), and each connecting platform (12) has a plug hole (17) on its side wall. The two ends of the hollow adjusting beam (3) are respectively inserted into the corresponding plug-in cavity (16) through the two plug holes (17), and the end of the hollow adjusting beam (3) abuts against the inner wall of the connecting platform (12) on the side away from the plug hole (17).

5. A battery pack vibration testing fixture with stiffness adjustment function according to claim 2, characterized in that, A first anti-rotation structure is provided between the first threaded head (9) and the corresponding end sealing plate (8). The first anti-rotation structure includes a first limiting key (18) provided on the first threaded head (9) and a first limiting groove (19) provided on the end sealing plate (8). The first limiting key (18) extends along the axial direction of the longitudinal cable (4) and is inserted into the first limiting groove (19).

6. The battery pack vibration testing fixture with stiffness adjustment function according to claim 3, characterized in that, A second anti-rotation structure is provided between the second threaded head (13) and the corresponding connecting platform (12). The second anti-rotation structure includes a second limiting key (20) provided on the second threaded head (13) and a second limiting groove (21) provided on the inner wall of the connecting platform (12). The second limiting key (20) extends along the axial direction of the transverse cable (5) and is inserted into the second limiting groove (21).

7. A battery pack vibration testing fixture with stiffness adjustment function according to claim 3, characterized in that, Both the first elastic washer (11) and the second elastic washer (15) include several disc springs stacked together.

8. A battery pack vibration testing fixture with stiffness adjustment function according to claim 1, characterized in that, The frame (1) is used to fix the battery pack, and the battery pack is located between two hollow beams (2). Each hollow beam (2) has a number of connecting ears (22) formed on the outer wall facing the battery pack.

9. A battery pack vibration testing fixture with stiffness adjustment function according to claim 1, characterized in that, The frame (1) also includes two end support beams (23), each end support beam (23) is connected to two hollow long beams (2) at both ends, and the hollow adjustment beam (3) is located between the two end support beams (23) and together with the hollow long beams (2) to form a sun-shaped structure.

10. A battery pack vibration testing fixture with stiffness adjustment function according to claim 9, characterized in that, Each hollow beam (2) has two vertically downward protrusions (24) formed at its bottom. The two ends of each end support beam (23) are fixedly connected to the corresponding two protrusions (24). The tops of the end support beam (23) and the hollow adjustment beam (3) are formed with support plates (25), and the tops of all support plates (25) are flush.

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