Linear motor driven biaxial fatigue testing machine

Abstract

The application discloses a linear motor driven biaxial fatigue testing machine, and particularly relates to the technical field of biaxial fatigue testing machines, and comprises a testing table, a monitoring assembly and a biaxial loading device; the biaxial loading device comprises four groups of linear motor modules arranged along orthogonal directions, a ring cavity formed in the testing table, four groups of clamps, a transmission assembly and a driving mechanism, four fixed columns are rotatably installed in the ring cavity through bearings in a circumferential direction, and the output end of the linear motor module is connected with a loading rod. The driving mechanism, the transmission assembly and the fixed column and other structures are arranged, so that two groups of clamps on the X shaft can rotate in opposite directions in the same axial direction, meanwhile, two groups of clamps on the Y shaft can also rotate in opposite directions, thereby realizing differential torsion test of a test sample in an orthogonal biaxial plane, and then completing biaxial tension-torsion composite fatigue detection of the test sample, and the biaxial fatigue test of the material under multiple working conditions can be more accurately realized.

Description

Technical Field

[0001] This invention relates to the field of biaxial fatigue testing machine technology, and more particularly to a linear motor driven biaxial fatigue testing machine. Background Technology

[0002] Fatigue testing is a mechanical testing method that repeatedly applies alternating cyclic loads to materials / components to simulate the long-term reciprocating stress conditions of the workpiece, and to detect its fatigue life, fatigue strength, crack initiation, and fracture failure. Even when subjected to cyclic stresses lower than the static fracture strength, micro-defects inside the material of metals, plastics, composite materials, etc., will gradually expand and generate micro-cracks under long-term repeated loading. The micro-cracks continue to grow and converge, eventually leading to the overall fracture failure of the component. This type of failure is called fatigue failure. The test equipment and test procedures used to reproduce and detect the fatigue failure process and mechanical properties of materials are called fatigue test systems.

[0003] The biaxial fatigue testing machine is a mechanical testing device based on the principle of cross orthogonal loading, which can simultaneously apply X and Y orthogonal bidirectional alternating loads to the specimen. It is mainly suitable for fatigue performance testing of flexible components with anisotropic and complex stress characteristics, such as rubber materials, composite materials, film materials, flexible materials and biomedical materials. It can better reflect the actual complex service conditions of materials and has higher test authenticity and data accuracy compared with uniaxial fatigue testing.

[0004] Currently, most existing biaxial fatigue testing machines adopt a cross-shaped symmetrical four-end loading structure. By arranging four sets of loading mechanisms in the orthogonal directions of the X and Y axes, and relying on linear motors or hydraulic servo drives, bidirectional alternating tensile loads are applied to the cross-shaped specimen to complete the biaxial tensile fatigue test of the material. However, in actual engineering testing, the actual service conditions of components such as rubber and flexible composite materials are mostly complex stress states with tension and torsion coupling. A single biaxial tensile test cannot fully reflect the true stress characteristics of the raw materials. Although existing equipment can achieve simple torsional load loading, most of them control the torsional action with multiple independent devices, making it difficult to achieve synchronous differential torsion of the X and Y axes. In addition, the required control equipment is numerous, has low integration, high cost, and extremely poor adaptability to working conditions, making it difficult to meet the needs of biaxial tensile-torsion composite fatigue testing of materials under multiple working conditions.

[0005] Therefore, this application proposes a linear motor driven biaxial fatigue testing machine. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a linear motor-driven biaxial fatigue testing machine.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A linear motor driven biaxial fatigue testing machine includes a testing bench, a monitoring component, and a biaxial loading device; The biaxial loading device includes four linear motor modules arranged orthogonally, an annular cavity opened in the test bench, four sets of clamps, a transmission assembly, and a drive mechanism. Four fixed columns are rotatably installed in the annular cavity through bearings along the circumference. The output end of each linear motor module is connected to a loading rod, which passes through the corresponding fixed column and has one end connected to the clamp through a force sensor. The four sets of clamps are arranged orthogonally in a cross shape to apply bidirectional alternating tensile loads to the sample. The drive mechanism synchronously drives the four fixed columns to rotate through the transmission assembly, so that the two sets of clamps on the same orthogonal axis form opposite differential rotations to apply torsional loads to the sample.

[0008] As a further embodiment of the present invention, the transmission assembly includes an annular gear ring rotatably mounted on the bottom end of the annular cavity and transmission teeth respectively disposed on each fixed post. The annular gear ring and the four transmission teeth are all in a perpendicular meshing state; The driving mechanism includes driving teeth that mesh perpendicularly with an annular gear ring, and are used to drive the annular gear ring to rotate around its own axis.

[0009] As a further embodiment of the present invention, the annular toothed ring has a double-layer end face tooth structure, including an independent outer toothed ring and an inner toothed ring. The two transmission teeth in the X-axis direction mesh perpendicularly with the inner ring gear, and the two transmission teeth in the Y-axis direction mesh perpendicularly with the outer ring gear. The drive tooth is configured to be radially translatable along the annular tooth ring, and to selectively engage with either the inner or outer tooth ring via radial translation, or simultaneously engage with both the inner and outer tooth rings.

[0010] As a further embodiment of the present invention, the driving mechanism further includes a driving rod, a support base, a moving component, and a rotating component; The drive rod passes through the central shaft of the drive gear, the support base is installed on the side wall of the test bench, the moving component is located on the bottom side of the test bench, and the output end of the moving component is connected to the support base. One end of the drive rod is rotatably connected to the support base through a bearing, and the rotating component is located on the support base for driving the drive rod to rotate.

[0011] As a further embodiment of the present invention, the moving component includes a linear guide rail, the bottom side of which is fixedly connected to the bottom end of the support base via a slide block, and the rotating component includes a drive motor and a transmission component, the drive motor being disposed at the bottom end of the support base and being connected to the drive rod via the transmission component.

[0012] As a further aspect of the present invention, the drive rod is further provided with a support and positioning mechanism, the support and positioning mechanism comprising: The positioning frame is fixedly connected to one side of the top of the support base, and both ends of the positioning frame are movably connected to the drive rod through bearings. A limit component is provided between the top of the positioning frame and the inner wall of the annular cavity, and the drive teeth are arranged inside the positioning frame.

[0013] As a further embodiment of the present invention, the limiting component includes a limiting sleeve disposed at the top of the positioning frame, a limiting rod being connected through the inside of the limiting sleeve, and both ends of the limiting rod being fixedly connected to the inner wall of the annular cavity.

[0014] As a further aspect of the present invention, a locking component is also included, the locking component comprising: The two clamping plates are symmetrically arranged at both ends of the bottom side of the positioning frame. The two clamping plates are located on the inner and outer sides of the annular toothed ring, and the inner side of the two clamping plates is provided with clamping teeth. The inner side of the inner ring toothed ring is provided with an inner tooth groove that matches the corresponding side clamping teeth, and the outer side of the outer ring toothed ring is provided with an outer tooth groove that matches the corresponding side clamping teeth.

[0015] As a further embodiment of the present invention, the four ends of the test bench are all fixedly connected to bearing mounting seats by brackets, and the linear motor module passes through the bearing mounting seats and is rotatably assembled inside the bearing mounting seats.

[0016] As a further embodiment of the present invention, the monitoring component includes an industrial camera and a stand, the stand being disposed on the top side of the test bench, the industrial camera being disposed on the top of the stand, and its lens facing the test bench.

[0017] The technical effects and advantages provided by the present invention in the above technical solution are as follows: By setting up a drive mechanism, transmission components and fixed columns, the present invention enables two sets of clamps on the X-axis to rotate in opposite directions in the same axial direction, and two sets of clamps on the Y-axis to rotate in opposite directions at the same time, thereby realizing differential torsion testing of the specimen in the orthogonal biaxial plane, and thus completing biaxial tensile-torsional composite fatigue testing of the specimen, which can more accurately realize biaxial fatigue testing of materials under multi-condition coupling. This invention sets the annular gear ring as an outer gear ring and an inner gear ring that rotate independently, and uses radially movable drive teeth to mesh with the inner gear ring or the outer gear ring respectively, or with both the inner and outer gear rings simultaneously. This enables multi-mode switching fatigue testing, including biaxial synchronous torsion, single X-axis independent torsion, and single Y-axis independent torsion. It can adapt to the multi-dimensional fatigue performance testing needs of different materials and working conditions, effectively broaden the testing range of the equipment, and greatly improve the versatility and accuracy of the test. This invention provides a support and positioning mechanism on the drive rod of the drive gear. On the one hand, it can provide strong support for the drive rod, enhance the overall connection strength, and suppress the swaying and offset of the drive rod during meshing transmission and radial translation. On the other hand, it can precisely limit the radial movement distance of the drive gear, ensuring that the drive gear can stop at the corresponding meshing position each time it shifts gears. This enables more stable and accurate switching between three transmission modes: single X-axis torsion, single Y-axis torsion, and dual-axis synchronous torsion. This invention adds a locking component to the support and positioning mechanism, which can simultaneously lock and position the outer ring gear when the drive tooth and the inner ring gear are independently engaged. This ensures that the corresponding component in the Y-axis direction will not spin freely during torsion testing in the X-axis direction. Conversely, when the drive tooth and the outer ring gear are independently engaged, the inner ring gear can be simultaneously locked and positioned, thereby achieving mechanical constraint on non-working components and greatly improving the reliability of test data under different working conditions. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is one of the overall structural schematic diagrams of the present invention; Figure 2 This is the second schematic diagram of the overall structure of the present invention; Figure 3 This is a longitudinal sectional view of the test bench of the present invention; Figure 4 This is a three-dimensional structural diagram of the test bench of the present invention; Figure 5 This is a schematic diagram of the connection between the test bench and the annular gear ring of the present invention; Figure 6 This is a schematic diagram of the connection structure between the annular gear ring, the transmission gear and the drive gear of the present invention; Figure 7 This is a schematic diagram of the connection structure between the annular gear ring, the drive tooth, and the support base of the present invention; Figure 8 This is a schematic diagram of the structure of the present invention when the drive teeth are driven by the inner ring gear and the outer ring gear respectively; Figure 9 This is a schematic diagram of the connection structure between the fixed column, the loading rod, and the clamp of the present invention.

[0019] In the picture: 100. Test bench; 200. Industrial camera; 201. Stand; 300. Linear motor module; 301. Loading rod; 302. Fixture; 400, Annular cavity; 401, Transmission gear; 402, Fixed post; 500, Ring gear; 501, Inner ring gear; 502, Outer ring gear; 600. Drive rod; 601. Support base; 602. Linear guide rail; 603. Drive gear; 604. Drive motor; 605. Transmission components; 700. Positioning frame; 701. Clamping plate; 702. Clamping teeth; 703. Limiting sleeve; 704. Limiting rod; 801. Internal tooth groove; 802. External tooth groove; 900. Bearing mounting bracket. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 like Figures 1-5 and Figure 9 As shown, the present invention provides a linear motor driven biaxial fatigue testing machine, including a test bench 100, a monitoring component and a biaxial loading device; the monitoring component includes an industrial camera 200 and a stand 201, the stand 201 is disposed on the top side of the test bench 100, the industrial camera 200 is disposed on the top of the stand 201 and its lens faces the test bench 100.

[0022] The biaxial loading device includes four linear motor modules 300 arranged orthogonally, an annular cavity 400 opened in the test bench 100, four sets of clamps 302, a transmission assembly and a drive mechanism. Four fixed columns 402 are rotatably installed in the annular cavity 400 along the circumferential direction through bearings. One end of the linear motor module 300 is detachably fixed to one end of the fixed column 402 through flange bolts. The output end of the linear motor module 300 is connected to a loading rod 301. The loading rod 301 passes through the corresponding fixed column 402, and one end of it is connected to the clamp 302 through a force sensor. The four sets of clamps 302 are arranged in a cross shape orthogonally for applying bidirectional alternating tensile loads to the sample. It should be noted that the linear motor module 300, the fixture 302, and the force sensor are all well-known in the field and are conventional technical means, so they will not be described in detail here. Before the test, the test sample can be pre-cut into a cross-shaped structure. For the sample pre-cut into a cross-shaped structure, four sets of clamps 302 arranged in a cross shape are used to clamp and fix the four outer ends of the sample respectively. During the test, each linear motor module 300 drives the corresponding loading rod 301 to move axially. The loading rod 301 can drive the clamps 302 to move synchronously through the force sensor, thereby applying an orthogonal bidirectional alternating tensile load to the sample. The force sensor can collect dynamic tensile force data in each axis in real time, realizing accurate closed-loop monitoring and control of biaxial tensile load. At the same time, the industrial camera 200 collects the deformation state and surface changes of the central area of ​​the sample in real time, dynamically monitoring the fatigue damage evolution process of the sample, thereby realizing the tensile fatigue test of the material under orthogonal biaxial load and realizing the accurate detection of the biaxial fatigue performance of the sample.

[0023] The drive mechanism synchronously drives the four fixed columns 402 to rotate through the transmission assembly, so that the two sets of clamps 302 on the same orthogonal axis form opposite differential rotation to apply torsional load to the sample.

[0024] In one specific embodiment of the present invention, the transmission assembly includes an annular gear ring 500 rotatably mounted inside the bottom end of the annular cavity 400 and transmission teeth 401 respectively disposed on each fixed post 402. The ring gear 500 has a single-layer end face tooth structure, and all four transmission teeth 401 are in a perpendicular meshing state with it. The drive mechanism includes a drive tooth 603, which meshes perpendicularly with the ring gear 500 and is used to drive the ring gear 500 to rotate around its own axis.

[0025] In this embodiment, the driving mechanism further includes a driving rod 600 and a rotating assembly. The driving rod 600 passes through the central shaft of the driving gear 603, and the rotating assembly is used to drive the driving rod 600 to rotate.

[0026] Therefore, during the test, the drive rod 600 can be driven to reciprocate by rotating the component, which in turn drives the drive gear 603 to reciprocate. The drive gear 603 can drive the vertically meshing annular gear ring 500 to rotate within the annular cavity 400, causing the annular gear ring 500 to drive the four meshing transmission gears 401 to rotate synchronously. The transmission gears 401 can drive the connected linear motor module 300 to rotate via the fixed column 402, which in turn drives the clamp 302 to rotate via the loading rod 301. Since the four sets of transmission gears 401 are arranged in a ring and mesh perpendicularly with the annular gear ring 500, the two sets of clamps 302 in the same axial direction, i.e., the X-axis direction, rotate in opposite directions, and the two sets of clamps 302 in the Y-axis direction also rotate in opposite directions. This enables differential torsion testing of the sample in the orthogonal biaxial plane, thereby completing the biaxial tensile-torsional composite fatigue test of the sample. The synchronization accuracy is high, the consistency is good, and the control error is small, enabling more accurate biaxial fatigue testing of materials under multi-condition coupling.

[0027] The test bench 100 has bearing mounting seats 900 fixedly connected to its four ends by brackets. The bearing mounting seats 900 have built-in slewing bearings. The linear motor module 300 passes through the bearing mounting seats 900 and is rotatably assembled inside the bearing mounting seats 900 via the slewing bearings. By setting the bearing mounting seats 900, the linear motor module 300 can be further supported and stabilized, thereby enhancing the overall structural stability and load coaxiality of the linear motor module 300 during operation, reducing structural shaking and assembly deviation caused by high-frequency reciprocating loading, and without affecting the axial tensile motion and circumferential torsional motion of the linear motor module 300.

[0028] Example 2 like Figures 4-8 As shown, in material fatigue testing, it is often necessary to test the combined tensile and torsional fatigue performance of a certain axis separately, such as tension and torsion in only the X-axis direction, corresponding to the uniaxial stress profile working condition, or to calibrate and verify test data in separate axes. Therefore, in order to realize the multi-mode, switchable biaxial fatigue test function, the ring toothed ring 500 is designed as a double-layer end face tooth structure, which includes an independent outer toothed ring 502 and an inner toothed ring 501. The two transmission teeth 401 in the X-axis direction mesh perpendicularly with the inner ring toothed ring 501, and the two transmission teeth 401 in the Y-axis direction mesh perpendicularly with the outer ring toothed ring 502. The drive tooth 603 is configured to be radially translatable along the annular tooth ring 500, and to engage with either the inner tooth ring 501 or the outer tooth ring 502, or simultaneously with both the inner tooth ring 501 and the outer tooth ring 502, by means of radial translation.

[0029] By configuring the annular gear ring 500 as an outer gear ring 502 and an inner gear ring 501 that can rotate independently, wherein the inner gear ring 501 can mesh with two sets of transmission teeth 401 in the X-axis direction, and the outer gear ring 502 can mesh with two sets of transmission teeth 401 in the Y-axis direction, the structure on the corresponding side of the X-axis or Y-axis can be driven to complete the torsional load input, as detailed below: In the initial working state, the drive tooth 603 meshes with both the outer ring tooth 502 and the inner ring tooth 501. When the drive tooth 603 rotates, it can synchronously drive the outer ring tooth 502 and the inner ring tooth 501 to rotate. The inner ring tooth 501 and the outer ring tooth 502 respectively drive the transmission teeth 401 in the X-axis and Y-axis directions to rotate synchronously and differentially, thereby realizing the orthogonal biaxial synchronous torsional fatigue test of the sample. Combined with the bidirectional tensile loading of the linear motor module 300, the biaxial synchronous tensile-torsional composite fatigue test is completed. Control the radial movement of the drive tooth 603 so that the drive tooth 603 disengages from the outer ring tooth ring 502 and only meshes with the inner ring tooth ring 501. At this time, the drive tooth 603 only drives the inner ring tooth ring 501 to rotate independently. The inner ring tooth ring 501 drives the two sets of transmission teeth 401 in the X-axis direction to rotate differentially, thereby driving the clamps 302 on both sides of the X-axis to twist in the opposite direction, realizing the tensile-torsional combined fatigue test in the single X-axis direction. Control the drive tooth 603 to move radially in the opposite direction, so that the drive tooth 603 moves away from the inner ring tooth ring 501 and only meshes with the outer ring tooth ring 502. At this time, the drive tooth 603 only drives the outer ring tooth ring 502 to rotate. The outer ring tooth ring 502 drives the two sets of transmission teeth 401 in the Y-axis direction to rotate differentially, thereby driving the clamps 302 on both sides of the Y-axis to twist in the opposite direction, realizing the tensile-torsional combined fatigue test in the single Y-axis direction. The above structure enables multi-mode switching fatigue testing, including biaxial synchronous torsion, single X-axis independent torsion, and single Y-axis independent torsion. It can adapt to the multi-dimensional fatigue performance testing needs of different materials and working conditions, effectively broadening the testing range of the equipment and greatly improving the versatility and accuracy of the test.

[0030] In this embodiment, the driving mechanism further includes a driving rod 600, a support base 601, a moving component, and a rotating component; the driving rod 600 passes through the central shaft of the driving gear 603, the support base 601 is installed on the side wall of the test bench 100, the moving component is disposed on the bottom side of the test bench 100, and the output end of the moving component is connected to the support base 601, one end of the driving rod 600 is rotatably connected to the support base 601 through a bearing, and the rotating component is disposed on the support base 601 for driving the driving rod 600 to rotate.

[0031] The support base 601 is precisely driven to move by the moving component, so that the support base 601 drives the drive tooth 603 to translate through the drive rod 600. This allows the drive tooth 603 to be controlled to mesh with the inner ring tooth ring 501 or the outer ring tooth ring 502 respectively, or to mesh with both the inner ring tooth ring 501 and the outer ring tooth ring 502 at the same time.

[0032] The moving component includes a linear guide rail 602, the bottom side of which is fixedly connected to the bottom end of the support base 601 via a slide block. The rotating component includes a drive motor 604 and a transmission component 605. The drive motor 604 is located at the bottom end of the support base 601 and is connected to the drive rod 600 via the transmission component 605. The transmission component 605 consists of two synchronous pulleys and a synchronous belt. The two synchronous pulleys are respectively connected to the output end of the drive motor 604 and the end of the drive rod 600. The synchronous belt is sleeved between the two synchronous pulleys, so that the drive motor 604 can drive the transmission component 605 to rotate the drive rod 600.

[0033] Example 3 like Figure 5 and Figure 7 As shown, in order to ensure the stability of the radial movement and rotation of the drive gear 603, a support and positioning mechanism can be added to its drive rod 600. The support and positioning mechanism includes: The positioning frame 700 is fixedly connected to one side of the top of the support base 601, and both ends of the positioning frame 700 are movably connected to the drive rod 600 through bearings. A limit component is provided between the top of the positioning frame 700 and the inner wall of the annular cavity 400, and the drive teeth 603 are arranged inside the positioning frame 700.

[0034] The limiting component includes a limiting sleeve 703 disposed at the top of the positioning frame 700, and a limiting rod 704 is connected through the inside of the limiting sleeve 703. Both ends of the limiting rod 704 are fixedly connected to the inner wall of the annular cavity 400.

[0035] With the support of the positioning frame 700 on the support positioning mechanism, and the movement limit of the limiting sleeve 703 and the limiting rod 704, the drive rod 600 can be strongly supported, the overall connection strength can be enhanced, and the swaying and offset of the drive rod 600 during meshing transmission and radial translation can be suppressed. On the other hand, the radial movement distance of the drive gear 603 can be precisely limited, ensuring that the drive gear 603 can stop at the corresponding meshing position each time it shifts gears. This can further stabilize and achieve precise and reliable switching between the three transmission modes of single X-axis torsion, single Y-axis torsion, and dual-axis synchronous torsion.

[0036] Example 4 like Figures 5-8As shown, when the drive tooth 603 engages with either the inner ring gear 501 or the outer ring gear 502, the other outer ring gear 502 or the inner ring gear 501 is in a free state without drive constraint. This can easily lead to movement during force testing, affecting the accuracy of the test load. Therefore, the support positioning mechanism of this invention also includes a locking assembly, which includes: The two clamping plates 701 are symmetrically arranged at both ends of the bottom side of the positioning frame 700. The two clamping plates 701 are located on the inner and outer sides of the annular toothed ring 500, and the inner side of the two clamping plates 701 is provided with clamping teeth 702. The inner side of the inner ring toothed ring 501 is provided with an inner tooth groove 801 that matches the corresponding side clamping teeth 702, and the outer side of the outer ring toothed ring 502 is provided with an outer tooth groove 802 that matches the corresponding side clamping teeth 702.

[0037] In the initial state, the drive tooth 603 simultaneously engages with both the outer ring gear 502 and the inner ring gear 501. At this time, the locking teeth 702 on both locking plates 701 disengage from their corresponding inner and outer tooth grooves 801 and 802. When the drive tooth 603 moves and engages with the inner ring gear 501, the locking teeth 702 on the corresponding side locking plate 701 embed into the outer tooth groove 802 on the outer side of the outer ring gear 502, thereby locking and positioning the outer ring gear 502. This ensures that the corresponding component in the Y-axis direction will not spin freely during the torsion test in the X-axis direction. Conversely, when the drive tooth 603 moves and engages with the outer ring gear 502, the locking teeth 702 on the corresponding side locking plate 701 embed into the inner tooth groove 801 on the inner side of the inner ring gear 501, thereby locking and positioning the inner ring gear 501. This enables mechanical constraint of non-working components, greatly improving the reliability of test data under different working conditions.

[0038] Working principle: The four outer ends of the pre-cut cross-shaped specimen are clamped and fixed on four sets of fixtures 302 respectively. The corresponding loading rods 301 are driven to move axially through each linear motor module 300. The loading rods 301 can drive the fixtures 302 to move synchronously through force sensors, and apply orthogonal biaxial alternating tensile loads to the specimen to realize the tensile fatigue test of the material under orthogonal biaxial load. The outer ring gear 502 and the inner ring gear 501 are synchronously driven to rotate by the drive gear 603. The inner ring gear 501 and the outer ring gear 502 drive the transmission gears 401 in the X-axis and Y-axis directions to rotate synchronously and differentially, respectively, to achieve orthogonal biaxial synchronous torsional fatigue test of the sample. With the bidirectional tensile loading of the linear motor module 300, the biaxial synchronous tensile-torsional composite fatigue test is completed. The drive gear 603 is controlled to move radially, driving only the inner ring gear 501 to rotate independently. The inner ring gear 501 drives the two sets of transmission gears 401 in the X-axis direction to rotate differentially. At the same time, the locking teeth 702 on the corresponding side locking plate 701 are engaged in the outer tooth groove 802 on the outer side of the outer ring gear 502, realizing the synchronous rotation of the outer ring gear 502. The locking and positioning of the inner ring gear 501 drives the clamps 302 on both sides of the X-axis to twist in the opposite direction, realizing a combined tensile and torsional fatigue test in the single X-axis direction. The drive tooth 603 is controlled to move radially in the opposite direction, driving only the outer ring gear 502 to rotate. The outer ring gear 502 drives the two sets of transmission teeth 401 in the Y-axis direction to rotate differentially. At the same time, the locking teeth 702 on the corresponding side plate 701 are embedded in the inner tooth groove 801 on the inner side of the inner ring gear 501, realizing the locking and positioning of the inner ring gear 501. This drives the clamps 302 on both sides of the Y-axis to twist in the opposite direction, realizing a combined tensile and torsional fatigue test in the single Y-axis direction. Finally, a multi-mode switching fatigue test can be realized, including dual-axis synchronous torsion, single X-axis independent torsion, and single Y-axis independent torsion.

[0039] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A linear motor-driven biaxial fatigue testing machine, characterized in that, Includes a test bench (100), monitoring components, and a biaxial loading device; The biaxial loading device includes four linear motor modules (300) arranged orthogonally, an annular cavity (400) opened in the test bench (100), four sets of clamps (302), a transmission assembly and a drive mechanism. Four fixed columns (402) are rotatably installed in the annular cavity (400) through bearings in the circumferential direction. The output end of the linear motor module (300) is connected to a loading rod (301). The loading rod (301) passes through the corresponding fixed column (402) and one end of it is connected to the clamp (302) through a force sensor. The four sets of clamps (302) are arranged orthogonally in a cross shape to apply bidirectional alternating tensile load to the sample. The drive mechanism synchronously drives the four fixed columns (402) to rotate through the transmission assembly, so that the two sets of clamps (302) on the same orthogonal axis form opposite differential rotation to apply torsional load to the sample.

2. The linear motor driven biaxial fatigue testing machine according to claim 1, characterized in that, The transmission assembly includes an annular gear ring (500) rotatably mounted on the bottom of the annular cavity (400) and transmission teeth (401) respectively disposed on each fixed post (402). The annular gear ring (500) and the four transmission teeth (401) are all in a perpendicular meshing state; The driving mechanism includes a driving tooth (603) that meshes perpendicularly with an annular gear ring (500) to drive the annular gear ring (500) to rotate around its own axis.

3. A linear motor-driven biaxial fatigue testing machine according to claim 2, characterized in that, The annular toothed ring (500) has a double-layer end face tooth structure, including an outer toothed ring (502) and an inner toothed ring (501) that are independent of each other. The two transmission teeth (401) in the X-axis direction mesh perpendicularly with the inner ring tooth (501), and the two transmission teeth (401) in the Y-axis direction mesh perpendicularly with the outer ring tooth (502). The drive tooth (603) is configured to be radially translatable along the annular tooth ring (500) and to engage with either the inner tooth ring (501) or the outer tooth ring (502) by radial translation, or simultaneously engage with both the inner tooth ring (501) and the outer tooth ring (502).

4. A linear motor-driven biaxial fatigue testing machine according to claim 3, characterized in that, The drive mechanism also includes a drive rod (600), a support base (601), a moving component, and a rotating component; The drive rod (600) passes through the central shaft of the drive gear (603), the support base (601) is installed on the side wall of the test bench (100), the moving component is set on the bottom side of the test bench (100), and the output end of the moving component is connected to the support base (601). One end of the drive rod (600) is rotatably connected to the support base (601) through a bearing. The rotating component is set on the support base (601) and is used to drive the drive rod (600) to rotate.

5. A linear motor-driven biaxial fatigue testing machine according to claim 4, characterized in that, The moving component includes a linear guide rail (602), the bottom side of which is fixedly connected to the bottom end of the support base (601) via a slide block. The rotating component includes a drive motor (604) and a transmission component (605). The drive motor (604) is located at the bottom end of the support base (601), and the drive motor (604) is connected to the drive rod (600) via the transmission component (605).

6. A linear motor-driven biaxial fatigue testing machine according to claim 4, characterized in that, The drive rod (600) is also provided with a support and positioning mechanism, which includes: The positioning frame (700) is fixedly connected to one side of the top of the support base (601), and both ends of the positioning frame (700) are movably connected to the drive rod (600) through bearings. A limit component is provided between the top of the positioning frame (700) and the inner wall of the annular cavity (400), and the drive teeth (603) are arranged inside the positioning frame (700).

7. A linear motor-driven biaxial fatigue testing machine according to claim 6, characterized in that, The limiting component includes a limiting sleeve (703) disposed at the top of the positioning frame (700), and a limiting rod (704) is connected through the inside of the limiting sleeve (703). Both ends of the limiting rod (704) are fixedly connected to the inner wall of the annular cavity (400).

8. A linear motor-driven biaxial fatigue testing machine according to claim 6, characterized in that, It also includes a locking assembly, the locking assembly comprising: The two clamping plates (701) are symmetrically arranged at both ends of the bottom side of the positioning frame (700). The two clamping plates (701) are located on the inner and outer sides of the annular toothed ring (500), and the inner side of the two clamping plates (701) is provided with clamping teeth (702). The inner side of the inner ring toothed ring (501) is provided with an inner tooth groove (801) that matches the corresponding side clamping teeth (702). The outer side of the outer ring toothed ring (502) is provided with an outer tooth groove (802) that matches the corresponding side clamping teeth (702).

9. A linear motor-driven biaxial fatigue testing machine according to claim 1, characterized in that, The test bench (100) has bearing mounting bases (900) fixedly connected to its four ends by brackets. The linear motor module (300) passes through the bearing mounting base (900) and is rotatably assembled inside the bearing mounting base (900).

10. A linear motor-driven biaxial fatigue testing machine according to claim 1, characterized in that, The monitoring component includes an industrial camera (200) and a stand (201). The stand (201) is located on the top side of the test bench (100), and the industrial camera (200) is located on the top of the stand (201) with its lens facing the test bench (100).

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