Single-drive two-way tensile test device

Abstract

The invention discloses a single-drive two-way tensile test device, which belongs to the technical field of tensile tests, and comprises a base, a fixing frame and an axial tensile frame, a lead screw I and a lead screw II penetrate through the axial tensile frame and are in running fit with the fixing frame, and the other ends are connected with a driving component; one ends of the fixing frame and the axial stretching frame are connected with the longitudinal stretching assembly I, the other ends are connected with the longitudinal stretching assembly II, and the middle parts of the fixing frame and the longitudinal stretching assembly I fix two adjacent edges of a sample through clamping bolts; the middle parts of the axial stretching frame and the longitudinal stretching assembly II are used for fixing the other two adjacent edges of the sample through a clamp I and a clamp II which are provided with force measuring elements. The device is simple and compact in structure, the movement stability is remarkably improved, the first lead screw and the second lead screw are driven by the driving component to rotate at the same time, and then synchronous reverse movement of the axial stretching frame relative to the fixing frame, the first longitudinal stretching assembly and the second longitudinal stretching assembly is achieved; the uniform stress of the sample in the two-way stretching process can be ensured, and the complexity of multi-motor cooperation is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of tensile testing equipment, and in particular relates to a single-drive bidirectional tensile testing device. Background Art

[0002] In the stamping of automotive sheet metal parts, biaxial tensile testing plays a crucial role in accurately determining the material's forming limits. Compared to uniaxial tensile testing, biaxial tensile testing can realistically simulate the multi-directional tensile stress state experienced by the sheet during the stamping process. It can accurately measure the ultimate strain across the entire range, from uniaxial to equibiaxial, and particularly identify the most critical plane strain state. Practice has demonstrated that forming limit diagrams (FLDs) based on biaxial tensile data significantly improve prediction accuracy. This accurate characterization of a material's multi-directional deformation behavior makes biaxial tensile testing a key test method for ensuring high-quality forming of automotive parts.

[0003] However, traditional dual-motor drive systems have significant limitations in biaxial tensile testing. Multi-motor systems are not only expensive and complex in structure, but also have limited test accuracy due to synchronization control difficulties. In dynamic testing, the phase difference between motors will directly affect data reliability, and complex control algorithms further increase system instability. In contrast, single-drive systems exhibit unique advantages: dual-axis synchronization is achieved through a mechanical linkage mechanism, fundamentally eliminating the phase difference problem of multi-motor systems; the simplified control system greatly improves operational stability; at the same time, its compact structural design significantly reduces manufacturing costs and maintenance difficulties. These characteristics make single-drive dual-axis systems particularly suitable for high-precision testing of material forming limits. Therefore, the development of a single-drive test device for biaxial tensioning is of great engineering significance for obtaining the forming limit of automotive steel. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a single-drive biaxial tensile testing device.

[0005] To achieve the above object, the technical solutions adopted by the present invention are as follows: 4. The repairing kit for automotive dents, according to claim 1, wherein a bottom of the foot stand comprises a through-hole, and the two foot pieces comprise two bosses, wherein the bosses comprise a through-hole, a screw bolt, and a nut. The bosses comprise a through-hole, a screw bolt, and a nut. The bosses comprise a through-hole, a screw bolt and a nut. The bosses comprise a through-hole, a screw bolt and a nut. The bosses comprise a through-hole, a screw bolt and a nut. The bosses comprise a through-hole, a screw bolt and a nut.

[0006] Furthermore, the driving component includes a worm, worm wheel 1 and worm wheel 2, the two ends of the worm are respectively rotatably matched with the two ends of the support seat, and the bottom of the support seat is fixed on the base; the worm wheel 1 is coaxially fixed with the screw, and the worm wheel 2 is coaxially fixed with the screw 2; the worm is driven by a motor.

[0007] Furthermore, the support seat is a U-shaped frame, and the lead screw 1 and the lead screw 2 are rotatably matched with the support seat through bearings. The worm gear 1 and the worm gear 2 are both arranged in the groove of the support seat. The two open ends of the support seat are provided with relative bearing holes, and the two ends of the worm are respectively matched with the bearings in the bearing holes. The driving end of the worm extends to the outside of the support seat and is connected to the motor.

[0008] Furthermore, the longitudinal stretching assembly 1 includes a long strip of movable stretching plate 1 and two positioning pins, the two positioning pins being upright on the surfaces of the fixed frame and the axial stretching frame respectively, and guide grooves cooperating with the positioning pins are symmetrically provided on both sides of the movable stretching plate 1, the guide grooves being inclined 45° relative to the length direction of the fixed frame, and the angle between the extended lines of the two guide grooves is 90°, and the ends facing the outside of the fixed frame are in an "eight" shape; a clamping bolt is provided in the middle of the side of the movable stretching plate 1 facing the longitudinal stretching assembly 2; A force measuring element is installed in the middle of one side of the axial stretching frame facing the fixed frame, and the force measuring element is connected to the first clamp; The structure of the longitudinal stretching component 2 is the same as that of the longitudinal stretching component 1, and the two structures are arranged in a mirror image. The movable stretching plate 2 of the longitudinal stretching component 2 is provided with a mounting groove in the middle of one side facing the movable stretching plate 1, and the clamp 2 is arranged in the mounting groove through a force measuring element.

[0009] Furthermore, the force measuring elements are force sensor 1 and force sensor 2 respectively, the clamp 1 is connected to the axial stretching frame through force sensor 1, and the clamp 2 is arranged in the installation groove through force sensor 2.

[0010] Furthermore, both the clamp 1 and the clamp 2 include a clamping bolt and a clamp block. The clamp 1 and the clamp 2 each have two clamping bolts, which are spaced apart on the clamp block. The clamp 1 is arranged on the side of the raised portion in the middle of the axial stretching frame. The movable stretching plate 1 and the fixed frame each have two clamping bolts. A raised portion is provided in the middle of the fixed frame, and the clamping bolts are arranged at the top of the raised portion.

[0011] Furthermore, the specimen is cross-shaped, and the clamping bolts on the clamp 1, the clamp 2, the fixing frame and the longitudinal stretching component 1 can respectively fix the four ends of the specimen.

[0012] Furthermore, a displacement sensor is provided on the outer side of the support seat, and the displacement sensor is arranged toward the axial stretching frame.

[0013] Furthermore, both sides of the lead screw 1 and the lead screw 2 are provided with a stopper, and the stopper is arranged close to the support seat and is used to limit the stroke of the axial stretching frame.

[0014] Furthermore, a rectangular through hole is provided in the middle of the base, and the rectangular through hole is arranged between the first screw and the second screw, and the two ends of the rectangular through hole are respectively aligned with the outer contours of the support seat and the fixing frame.

[0015] Compared with the prior art, the present invention has the following technical advances: The present invention utilizes a drive component to drive the simultaneous rotation of two parallel screws mounted on a base. These screws drive the axial stretching frame, which is threaded with them, to translate. Two adjacent sides of the specimen are secured by clamping bolts in the center of the fixed frame and longitudinal stretching assembly 1, while the other two adjacent sides of the specimen are secured by clamps 1 and 2 in the center of the axial stretching frame and longitudinal stretching assembly 2. While the drive component drives screws 1 and 2 to rotate at a constant speed, it simultaneously drives the axial stretching frame in the opposite direction relative to the fixed frame, and longitudinal stretching assembly 1 and longitudinal stretching assembly 2 in synchronous opposite direction, ensuring that the specimen is subjected to uniform force and a constant rate during biaxial stretching. A force sensor and displacement sensor are also used to detect the magnitude of the tensile force and the tensile displacement (speed). The present invention boasts a simple and compact structure, significantly improved motion stability, and avoids the complexity of multiple motor coordination. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0017] In the attached figure: Figure 1 A schematic structural diagram of a single-drive biaxial tensile testing device provided in an embodiment of the present invention; Figure 2 Schematic diagram of the state of the axial stretching frame, longitudinal stretching assembly 1, and longitudinal stretching assembly 2 when the device has a maximum stroke according to an embodiment of the present invention; Figure 3 This is a layout diagram of the support base and the fixing bracket on the base in an embodiment of the present invention; Figure 4 Schematic diagram of the structure of the axial stretching frame in an embodiment of the present invention; Figure 5 A schematic structural diagram of a fixing frame according to an embodiment of the present invention; Figure 6 This is a schematic structural diagram of a longitudinal stretching assembly 1 in an embodiment of the present invention; Figure 7 This is a schematic structural diagram of the longitudinal stretching assembly 2 in an embodiment of the present invention; In the picture: 1-base; 2-support base; 3-worm gear 1; 4-worm gear 2; 5-worm; 6-displacement sensor; 7-force sensor 1; 8-force sensor 2; 9-stop block; 10-screw 1; 11-screw 2; 12-axial stretching frame; 13-longitudinal stretching component 1; 14-longitudinal stretching component 2; 15-fixed frame; 16-clamp 2; 17-clamp 1; 18-clamping bolt; 19-clamp block; 20-movable stretching plate 1; 21-locating pin; 22-guide groove; 23-mounting groove; 24-rectangular through hole; 25-movable stretching plate 2. DETAILED DESCRIPTION

[0018] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. The embodiments of the present invention will be described below with reference to the accompanying drawings.

[0019] like Figure 1-5As shown, a single-drive bidirectional tensile testing device includes a base 1 and a fixing frame 15 and an axial stretching frame 12 arranged on the base 1, the two ends of the fixing frame 15 are respectively rotated with the mutually parallel screw 10 and the screw 2 11, the screw 10 and the screw 2 11 are threadedly engaged with the axial stretching frame 12, one end of the screw 10 and the screw 2 11 is rotated with the fixing frame, and the other end of the screw 10 and the screw 2 11 is connected to the driving component; one end of the fixing frame 15 and the axial stretching frame 12 is connected to the longitudinal stretching component 13, and the other end is connected to the longitudinal stretching component 2 14 is connected, and the middle of the fixed frame 15 and the longitudinal stretching component 1 13 are respectively provided with a clamping bolt 18 for fixing two adjacent sides of the sample; the middle of the axial stretching frame 12 and the longitudinal stretching component 2 14 are respectively provided with a clamp 17 and a clamp 2 16 with a force measuring element for fixing the other two adjacent sides of the sample; the driving component can drive the screw 10 and the screw 2 11 to rotate simultaneously, and the screw 10 and the screw 2 11 drive the axial stretching frame 12 to move in the opposite direction relative to the fixed frame, and at the same time drive the longitudinal stretching component 13 and the longitudinal stretching component 2 14 to move in the opposite direction synchronously.

[0020] As a preferred structure, Figure 1 As shown, the drive components include a worm 5, worm wheel 1 3, and worm wheel 2 4. The two ends of the worm 5 rotate in conjunction with the two ends of the support base 2, the bottom of which is fixed to the base 1. The worm wheel 1 3 is coaxially fixed with the lead screw 1 10, and the worm wheel 2 4 is coaxially fixed with the lead screw 2 11. The worm 5 is driven by a motor (not shown). The motor is a servo motor capable of driving the worm in forward and reverse rotation. The worm drives worm wheel 1 and worm wheel 2 to rotate simultaneously, which in turn drives lead screw 1 and lead screw 2 to rotate simultaneously. Given the self-locking nature of worm gear transmission, it can significantly improve motion stability.

[0021] Of course, the driving components are not limited to the worm and worm gear transmission described above. Gear transmission can also be used to achieve the simultaneous rotation of lead screw 1 and lead screw 2. The motor drives the driving gear to rotate, and the driving gear engages with the driven gears at the ends of lead screw 1 and lead screw 2, thereby achieving the purpose of synchronous movement of lead screw 1 and lead screw 2.

[0022] In a specific embodiment of the present invention, Figure 1 、 3 As shown, the support base 2 is a U-shaped frame. Screws 10 and 2, 11, rotate with the support base 2 via bearings. Worm gears 1 and 2, 4, are both mounted within grooves in the support base 2. Opposing bearing holes are provided at the two open ends of the support base 2. The ends of the worm 5 engage with bearings within these holes, reducing the worm's rotational resistance. The drive end of the worm 5 extends outside the support base 2 and is connected to the motor. During production, the support base is welded to the base.

[0023] In a specific embodiment of the present invention, Figure 6 、 7 As shown, the longitudinal stretching assembly 13 includes a long strip of movable stretching plate 120 and two positioning pins 21. The two positioning pins 21 are respectively upright on the surface of the fixed frame 15 and the axial stretching frame 12. The two sides of the movable stretching plate 20 are symmetrically provided with guide grooves 22 that cooperate with the positioning pins 21. The guide grooves 22 are inclined 45 degrees relative to the length direction of the fixed frame 15. The angle between the extended lines of the two guide grooves 22 is 90 degrees, and the ends facing the outer side of the fixed frame 15 are in an "eight" shape. The movable stretching plate 20 is symmetrically provided with guide grooves 22 that cooperate with the positioning pins 21. The guide grooves 22 are inclined 45 degrees relative to the length direction of the fixed frame 15. The extended lines of the two guide grooves 22 are in an "eight" shape. A clamping bolt 18 is provided in the middle of one side of the longitudinal stretching assembly 14. The structure of the longitudinal stretching assembly 14 is identical to that of the longitudinal stretching assembly 13, and the two structures are arranged in a mirror image. A mounting slot 23 is provided in the middle of the side of the movable stretching plate 25 of the longitudinal stretching assembly 14 facing the movable stretching plate 20. The clamp 16 is mounted within the mounting slot 23 via a force-measuring element. A force-measuring element is installed in the middle of the side of the axial stretching frame 12 facing the fixed frame 15, and is connected to the clamp 17. During specific production, the four corners of the movable stretching plate 1 and the movable stretching plate 1 can be cut off to minimize the overall weight. The use of a locating pin and a guide slot allows the axial stretching frame to increase the distance between the movable stretching plate 1 and the movable stretching plate 2 during translation away from the fixed frame, thereby achieving bidirectional stretching of the specimen. Simultaneously, two force-measuring elements are used to provide real-time detection of the tensile forces in both directions during the stretching process.

[0024] During the specific design, the force measuring elements are force sensor 1 7 and force sensor 2 8 respectively. The clamp 17 is connected to the axial stretching frame 12 through force sensor 17, and the clamp 2 16 is arranged in the installation groove 23 through force sensor 2 8. Force sensor 1 7 and force sensor 2 8 are key force measuring elements that can realize tension monitoring. During installation, force sensor 7 adopts a two-way threaded connection method, one end of which is rigidly connected to the axial stretching frame 12 and the other end is tightly matched with clamp 17, so as to monitor the axial tension generated by the axial stretching frame 12 during the loading process in real time. At the same time, force sensor 8 is fixed to the inner wall of the installation groove of the movable stretching plate 2 25 at one end and connected to clamp 2 16 at the other end through the same connection method, so as to accurately measure the tension parameters of the longitudinal stretching component 2 14 when it is working.

[0025] When making specific Figure 2-5As shown, both Clamp 1 17 and Clamp 2 16 include clamping bolts 18 and a clamp block 19. Clamp 1 17 and Clamp 2 16 each have two clamping bolts 18, spaced apart on the clamp block 19. Clamp 1 17 is located on the side of the raised portion in the middle of the axial stretching frame 12. Both the movable stretching plate 1 20 and the fixed frame 15 have two clamping bolts 18. The fixed frame 15 has a raised portion in the middle, and the clamping bolts 18 are located on top of the raised portion. The specimen is cross-shaped, and Clamp 1 17, Clamp 2 16, the raised portion in the middle of the fixed frame 15, and the clamping bolts 18 in the middle of the surface of the longitudinal movable plate 1 20 respectively secure the four ends of the specimen. This structure allows the specimen to remain horizontal during installation, ensuring balanced force on the specimen during biaxial tension.

[0026] Further optimize the above structure, such as Figure 1 As shown, a displacement sensor 6 is provided on the outside of the support base 2, facing the axial stretching frame 12. During assembly, the displacement sensor is rigidly fixed to a specific measurement reference surface of the support base; this ensures precise alignment between the displacement sensor and the axial stretching frame, enabling real-time monitoring and recording of displacement changes of the axial stretching frame 12 during loading.

[0027] In a specific embodiment of the present invention, Figure 1 As shown, both screws 10 and 11 are equipped with stops 9, located near the support base 2, to limit the travel of the axial stretching frame 12. The stops are welded to the base surface. Four stops of the same specification are fixed to the base, equidistantly spaced vertically. These stops limit the travel of the stretching process, ensuring that the equipment operates within the specified travel range.

[0028] During specific fabrication, a rectangular through-hole 24 is provided in the center of the base 1, located between lead screw 10 and lead screw 2 11. The ends of the rectangular through-hole 24 are aligned with the outer contours of the support base 2 and the fixing bracket 15, respectively. This structure ensures an unobstructed field of view, facilitating optical observation of specimen deformation during the experiment, while also ensuring the overall structural strength of the device and achieving a lightweight design.

[0029] The specific design process of the present invention is as follows: 1. The base is a rectangular plate with dimensions of 180mm (length) × 160mm (width) × 10mm (thickness). A rectangular through-hole measuring 85mm (length) × 20mm (width) × 10mm (depth) is provided in the middle of the base.

[0030] 2. The support base is rigidly connected to the base using a welding process. Its U-shaped structure consists primarily of a central vertical plate and symmetrically arranged upper and lower wings. From the left side view, the central vertical plate is a rectangular member with a cross-section of 160mm (length) × 55mm (width) × 15mm (height). From the front view, the upper and lower wings are designed with the same dimensions of 25mm (length) × 55mm (width) × 12mm (height), forming a symmetrical support structure. To achieve its function, the support base is precision-machined with four standard mounting holes: two symmetrically arranged Φ15mm through-holes in the lower portion, with their center axes 17mm from the upper surface of the base, for the precise positioning and installation of lead screws 1 and 2; and two symmetrically arranged Φ15mm through-holes in the upper portion, with their center axes 40mm from the upper surface of the base, for precise assembly with worm gear 5. Through rational geometric parameter design and precise machining and positioning, this structure not only ensures the installation accuracy of the transmission system, but also effectively guarantees the rigidity and stability of the overall structure, meeting the strict mechanical performance requirements of the experimental device.

[0031] 3. Worm Gear Design: Worm Gears 1 and 2 utilize a standard worm gear design. Their key geometric parameters are as follows: 27mm pitch diameter, 3mm module, 18 teeth, and an 11.31° helix angle. Structural parameters include an inner bore diameter of 15mm and a tooth width of 12mm. The two worm gears are symmetrically arranged with a 90mm center-to-center distance, achieving power transmission through precise meshing with the worm. In the transmission system, the worm gears form a linkage with the lead screw via a keyed connection, converting the worm's rotational input into rotational motion of the lead screw, thereby completing the power transmission of the entire drive train.

[0032] 4. Worm Design: Worm 5, a key transmission component, features the following structural parameters: a 15mm pitch diameter, a 3mm module, a double-start thread design, and an 11.31° lead angle. The worm's total length is 175mm, including a 109mm effective threaded section, a 12mm diameter intermediate shaft section, and 15mm end diameters. The worm is assembled into the upper mounting hole of support base 2 via precision bearings, providing stable rotational support. A standard keyway is machined into the worm shaft end at the power input, enabling reliable transmission via a keyed connection to the drive motor.

[0033] 5. Stopper design: The stopper 9 adopts a standard rectangular structure with geometric dimensions of 15mm (length) × 7mm (width) × 22mm (height). Its main functions are as follows: (1) Accurately control the maximum displacement stroke of the axial tensile frame 12 through physical limit; (2) Provide overload protection for the tensile structure in four directions to prevent the mechanical structure from being damaged due to over-travel movement.

[0034] 6. Screw Design: Screws 10 and 2 (11) utilize the same specifications, with the following structural parameters: total length 155mm, nominal diameter 15mm, single-strike trapezoidal thread, lead 5mm, effective thread length 85mm. High-precision bearings support both ends of the screws in the lower mounting holes of support base 2 and the mating holes of fixed frame 15, respectively, forming a stable rotating support structure. The transmission system, through the precise meshing of worm gears 1 (3) and 4 (4) with screws 10 and 2 (11), converts rotational motion into precise horizontal displacement of the axial tensioning frame 12.

[0035] 7. Axial Stretching Frame Design: The axial stretching frame adopts a "convex"-shaped overall structural design, exhibiting a distinct stepped appearance from the front view. The upper structure consists of two stacked rectangular blocks of varying geometric dimensions: the upper block is a main step measuring 28mm (length) × 25mm (width) × 30mm (height), and the lower block is a transition step measuring 28mm (length) × 25mm (width) × 3mm (height). The lower main structure is a 140mm (length) × 25mm (width) × 25mm (height) rectangular block with a Φ20mm precision threaded hole machined in the center for a secure threaded connection with the lead screw drive system. Symmetrically positioned on either side of the structure are Φ20mm × 30mm cylindrical guide shafts, forming sliding pairs with the bevel grooves of longitudinal stretching components 13 and 14. Specifically, a constant 5mm clearance is maintained between the bottom of the axial stretching frame and the base. This design ensures the freedom of movement of the moving parts while effectively preventing wear caused by contact friction.

[0036] 8. Mounting Bracket Design: The mounting bracket is rigidly connected to the base via welding. It is installed 5 mm from the left end of the base and has overall dimensions of 148 mm (length) × 25 mm (width) × 30 mm (height). The structural design incorporates two precision support holes with a diameter of 15 mm. The center axes of the two holes are aligned and parallel 17 mm from the top surface of the base, ensuring precise mounting and support of the screw drive components. This structural design ensures both the positioning accuracy of the transmission system and sufficient support rigidity, ensuring the stability and reliability of the entire device during operation.

[0037] 9. Longitudinal Tensile Assembly I Design: Mobile Tensile Plate I 20 features a lightweight design, constructed from a rectangular plate measuring 110 mm (length) × 15 mm (width) × 40 mm (height) with four corner cuts. This cutting process utilizes an asymmetrical isosceles right-angled triangle, with the outer right-angled side cut to 20 mm and the inner right-angled side cut to 18 mm, resulting in an octagonal prism structure. Mobile Tensile Plate I 20 and Mobile Tensile Plate II 25 are arranged in strict vertical symmetry when viewed from above. Precision guide grooves with a 45° inclination are machined into the structure, forming a sliding mechanism with the cylindrical locating pins 21 of the axial tensile frame 12 and the fixed frame 15. When the axial tensile frame 12 moves horizontally, the angular mechanism formed by the locating pins and guide grooves translates motion, driving the longitudinal tensile assembly I 13 and longitudinal tensile assembly II 14 in synchronous, opposite vertical directions, thus achieving biaxial simultaneous tensile testing of the specimen. This design achieves structural lightweight through geometric optimization while ensuring precise and synchronized motion translation.

[0038] 10. Design of Longitudinal Tensile Component II: While maintaining the basic structural features of longitudinal tensile component I-13, a functional mounting slot is added to its interior. This mounting slot, measuring 35mm (length) × 25mm (width) × 30mm (depth), is precision-machined to form a standard interface for reliable connection with the force sensor. This optimized structure enables effective transmission and real-time monitoring of tensile force, ensuring controllable and accurate measurement of the workpiece's tensile process.

[0039] 11. Clamp Design: Clamp 1 17 and Clamp 2 16 utilize unified design specifications, with dimensions of 20 mm (length) × 12 mm (width) × 12 mm (height). Clamp 2 16 is rigidly connected to force sensor 8 via a threaded interface, while Clamp 1 17 utilizes the same connection method for force sensor 7. Both clamps feature a bolt-nut fastening system at the top, utilizing a standard threaded pair to securely clamp the specimen.

[0040] The specific method of use of the present invention is as follows: 1. First, fasten the cross-shaped specimen to the clamp 2 16, the clamp 1 17, the movable tensile plate 1 20 and the fixed frame 15 using the clamping bolts to ensure that all connection parts are securely fixed.

[0041] 2. After the servo motor is started, the worm 5 begins to rotate, and the power is transmitted to the lead screw 10 and the lead screw 2 11 through the worm gear 1 3 and the worm gear 2 4 that are meshed with it.

[0042] 3. The rotational motion of the lead screw is converted into precise horizontal displacement of the axial stretching frame 12. At the same time, the horizontal motion is decomposed into vertical synchronous reverse motion of the longitudinal stretching component 13 and the longitudinal stretching component 2 14 through the 45° inclined groove mechanism, thereby realizing biaxial synchronous uniform speed stretching of the sample.

[0043] In the above embodiment, the maximum stretching distance is 40 mm (ie, the maximum distance between the fixing frame 15 and the axial stretching frame 12 ), and the deformation of the sample can be observed through the top-view area of the rectangular through hole.

[0044] In summary, the present invention has the advantages of simple structure, convenient operation and high synchronization accuracy, which are specifically reflected in the following aspects: 1. Through the unique combination of a worm gear and a chute, single-axis rotation is converted into dual-axis linear motion (motion conversion). A key breakthrough is the realization of mechanical decoupling control in orthogonal directions, ensuring synchronization accuracy without the need for electronic coordination.

[0045] 2. In terms of the drive system, the developed single-motor drive dual system can achieve biaxial synchronous stretching, which is more energy-efficient and reduces equipment costs compared to the traditional dual-motor solution.

[0046] The present invention realizes biaxial stretching through single drive, which has important engineering significance for obtaining the forming limit of automobile steel and can also be widely used in other similar material science research and industrial testing fields.

[0047] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A single-drive biaxial tensile testing device, characterized by: The invention comprises a base and a fixing frame and an axial stretching frame arranged on the base, the two ends of the fixing frame are respectively rotatably matched with a lead screw 1 and a lead screw 2 which are parallel to each other, one end of the lead screw 1 and the lead screw 2 passes through the axial stretching frame and rotatably matches with the fixing frame, and the lead screw 1 and the lead screw 2 are threadedly matched with the axial stretching frame, and the other end of the lead screw 1 and the lead screw 2 is connected to a driving component; one end of the fixing frame and the axial stretching frame is connected to a longitudinal stretching assembly 1, and the other end is connected to a longitudinal stretching assembly 2, the middle parts of the fixing frame and the longitudinal stretching assembly 1 are respectively provided with a clamp 1 and a clamp 2 with a force measuring element, which are respectively provided with a clamp 1 and a clamp 2 with a force measuring element, which are used to fix the other two adjacent sides of the sample; the driving component can drive the lead screw 1 and the lead screw 2 to rotate simultaneously, and the lead screw 1 and the lead screw 2 drive the axial stretching frame to move in the opposite direction relative to the fixing frame, and the longitudinal stretching assembly 1 and the longitudinal stretching assembly 2 to move in the opposite direction synchronously.

2. A single-drive biaxial tensile testing device according to claim 1, characterized in that: The driving component includes a worm, worm wheel 1 and worm wheel 2. The two ends of the worm are respectively rotatably matched with the two ends of the support seat, and the bottom of the support seat is fixed on the base; the worm wheel 1 is fixed coaxially with the screw, and the worm wheel 2 is fixed coaxially with the screw; the worm is driven by a motor.

3. The single-drive biaxial tensile testing device according to claim 2, characterized in that: The support seat is a U-shaped frame, and the lead screw 1 and lead screw 2 are rotatably matched with the support seat through bearings. The worm gear 1 and worm gear 2 are both arranged in the groove of the support seat. The two open ends of the support seat are provided with relative bearing holes, and the two ends of the worm are respectively matched with the bearings in the bearing holes. The driving end of the worm extends to the outside of the support seat and is connected to the motor.

4. The single-drive biaxial tensile testing device according to claim 2, characterized in that: The longitudinal stretching assembly 1 includes a long strip of movable stretching plate 1 and two positioning pins, the two positioning pins being upright on the surfaces of the fixed frame and the axial stretching frame respectively. Guide grooves cooperating with the positioning pins are symmetrically provided on both sides of the movable stretching plate 1. The guide grooves are inclined 45° relative to the longitudinal direction of the fixed frame. The extended lines of the two guide grooves form an angle of 90° and are oriented in an "eight" shape toward the outer end of the fixed frame. A clamping bolt is provided in the middle of the side of the movable stretching plate 1 facing the longitudinal stretching assembly 2. A force measuring element is installed in the middle of one side of the axial stretching frame facing the fixed frame, and the force measuring element is connected to the first clamp; The structure of the longitudinal stretching component 2 is the same as that of the longitudinal stretching component 1, and the two structures are arranged in a mirror image. The movable stretching plate 2 of the longitudinal stretching component 2 is provided with a mounting groove in the middle of one side facing the movable stretching plate 1, and the clamp 2 is arranged in the mounting groove through a force measuring element.

5. The single-drive biaxial tensile testing device according to claim 4, characterized in that: The force measuring elements are force sensor 1 and force sensor 2 respectively. The clamp 1 is connected to the axial stretching frame through force sensor 1, and the clamp 2 is arranged in the installation groove through force sensor 2.

6. The single-drive biaxial tensile testing device according to claim 5, characterized in that: Both the clamp 1 and the clamp 2 include a clamping bolt and a clamp block. The clamp 1 and the clamp 2 each have two clamping bolts, which are arranged at intervals on the clamp block. The clamp 1 is arranged on the side of the raised portion in the middle of the axial stretching frame. The movable stretching plate 1 and the fixed frame each have two clamping bolts. A raised portion is provided in the middle of the fixed frame, and the clamping bolts are arranged at the top of the raised portion.

7. The single-drive biaxial tensile testing device according to claim 2, characterized in that: The sample is cross-shaped, and the clamping bolts on the clamp 1, the clamp 2, the fixing frame and the longitudinal tensile component 1 can respectively fix the four ends of the sample.

8. The single-drive biaxial tensile testing device according to claim 2, characterized in that: A displacement sensor is provided on the outer side of the support seat, and the displacement sensor is arranged toward the axial stretching frame.

9. The single-drive biaxial tensile testing device according to claim 2, characterized in that: Stoppers are provided on both sides of the lead screw 1 and the lead screw 2. The stoppers are arranged close to the support seat and are used to limit the stroke of the axial stretching frame.

10. A single-drive biaxial tensile testing device according to any one of claims 2 to 9, characterized in that: A rectangular through hole is provided in the middle of the base, and the rectangular through hole is provided between the first lead screw and the second lead screw. Both ends of the rectangular through hole are aligned with the outer contours of the support seat and the fixing frame respectively.

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