Fatigue testing fixture

Abstract

The application relates to the technical field of production testing, and discloses a fatigue test tool for a spring air pipe, which comprises a temperature control box, a driving mechanism and a clamp main body. The temperature control box is used for fixing the first free end of the spring air pipe, the inner cavity of the temperature control box can adjust the temperature to simulate different use environments, the inner cavity is connected with a first through hole for the second free end of the spring air pipe to pass out. The driving mechanism is arranged on a workbench and is used for providing a reciprocating driving force; the clamp main body is connected with the output side of the driving mechanism in a matched mode and is used for clamping and fixing the corresponding connecting section on the spring air pipe, so that the spiral section of the spring air pipe can generate reciprocating deformation under the driving action. The fatigue test tool in the application can perform dynamic fatigue testing on the spiral spring air pipe under the temperature control condition, the testing mode is close to the actual use state, and more real fatigue performance data can be obtained.

Description

Technical Field

[0001] This application relates to the field of production testing technology, and more particularly to a fatigue testing fixture. Background Technology

[0002] With the widespread application of pneumatic massage systems in car seats, spiral spring tubes are gradually replacing traditional straight tubes for connecting air circuits, and their fatigue performance has become a key indicator affecting system reliability. Existing testing devices mostly use static suspension methods, which can only reflect the deformation of the spring tube under static load and cannot simulate the dynamic working conditions of frequent reciprocating stretching in actual use, resulting in insufficient representativeness of the test results. Utility Model Content

[0003] To address the aforementioned technical problems, the purpose of this application is to provide a fatigue testing fixture that helps improve the accuracy of fatigue testing of spring tubes.

[0004] To achieve the above objectives, this application provides a fatigue testing fixture for a spring tube, comprising: A temperature control chamber for fixing the first free end of the spring tube includes an inner cavity and a first through hole communicating with the inner cavity. The temperature of the inner cavity can be adjusted to adapt to the fatigue test conditions of the spring tube. The inner cavity is used to accommodate the helical section of the spring tube to be tested. The first through hole is used to allow the second free end of the spring tube to pass out from the inner cavity. The drive mechanism, located on the worktable, is used to provide reciprocating driving force; The clamp body is connected to the output side of the drive mechanism to clamp and fix the corresponding connecting section on the spring air tube, and to cause the spiral section of the spring air tube to reciprocate under the action of the drive mechanism; wherein, the connecting section is located between the spiral section of the spring air tube and the second free end.

[0005] In some embodiments, the fatigue testing fixture further includes at least one first limiting structure; Each of the first limiting structures is disposed between the first through hole of the temperature control box and the fixture body, including at least one second through hole. The diameter of the second through hole is larger than the outer diameter of the connecting section. During the test, the second free end passes through the first through hole and the second through hole in sequence, so that the connecting section slides through the second through hole. Then, when the driving mechanism acts on the spring air tube, the connecting section moves synchronously in a preset direction.

[0006] In some embodiments, the first limiting structure and the driving mechanism are located on the same worktable, the output side of the driving mechanism moves in a horizontal direction, the fixture body is connected to the output side of the driving mechanism along the height direction, and the clamping end of the fixture body, the second through hole and the first through hole at least partially overlap in the direction of the same horizontal axis.

[0007] In some embodiments, the drive mechanism includes a transmission assembly and a drive element, the drive element being used to provide driving force; The transmission assembly includes a first transmission part and a second transmission part. The first transmission part is fixedly connected to the clamp body, and the second transmission part is connected to the driving component to transmit the driving force to the second transmission part. The first transmission part and the second transmission part are connected to each other so that the clamp body can reciprocate along a preset direction.

[0008] In some embodiments, the first transmission part is configured as a slider, the center of which has a threaded hole formed along its axis; the second transmission part is configured as a transmission rod, the outer periphery of which has an external thread adapted to the threaded hole; the driving member is used to drive the transmission rod to rotate, so that the slider moves synchronously along its axial direction when the transmission rod rotates.

[0009] In some embodiments, the drive mechanism includes a guide assembly; The guiding component includes a guide rail and a guide part adapted to the guide rail. The guide rail is fixed to the worktable, and the guide part can slide relative to the guide rail under the driving action. The guide part is disposed at the bottom of the slider. The guide part is integrally formed with the slider, or separately formed with the slider and then fixedly connected.

[0010] In some embodiments, the fatigue testing fixture further includes at least one second limiting structure. The second limiting structure is disposed on the side of the driving mechanism away from the first limiting structure, and the second limiting structure is provided with a rear limiting part for limiting the movement or swing of the spring air tube at its rear end during the test. The rear end corresponds to the clamping end of the fixture body on the side away from the first limiting structure.

[0011] In some embodiments, the fixture body includes a detection module; The detection module includes a sensor for detecting the force applied to the clamp body during clamping. The clamping end of the clamp body is configured with two opposing jaws. The sensor is installed on the clamp body in the area corresponding to the jaws to collect clamping force data in real time.

[0012] In some embodiments, the detection module further includes a signal acquisition unit electrically connected to the sensor, which is used to receive and record the clamping force signal output by the sensor.

[0013] In some embodiments, the temperature control chamber includes a temperature control component that is thermally connected to the inner cavity. The temperature control component includes at least one of a heating unit and a cooling unit, and is used to regulate the temperature of the inner cavity by raising or lowering it to simulate fatigue conditions under different ambient temperatures. And / or, The clamp body is detachably connected to the output side of the drive mechanism, and / or the drive mechanism is detachably connected to the worktable, so that the distance between the temperature control box and the clamp body is adjustable, so that the straight section of the spring air tube is in a taut state when clamped. And / or, The fatigue testing fixture also includes a height adjustment mechanism for adjusting the height of the fixture body. The fixed end of the height adjustment mechanism is connected to the output side of the drive mechanism, and the output end of the height adjustment mechanism is connected to the fixture body. The height adjustment mechanism can be adjusted between a locked state and an unlocked state to lock the horizontal position of the fixture body.

[0014] Compared with the prior art, this application has at least the following beneficial effects: By combining the temperature control chamber with the drive mechanism, the spring tube can be tested for reciprocating deformation in a controlled temperature environment. This effectively simulates the tensile cycle conditions of the spring tube under actual use conditions, improving the authenticity and repeatability of the test, and has good application and promotion value. Attached Figure Description

[0015] The preferred embodiments will now be described in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of this application.

[0016] Figure 1 This is a schematic diagram of the overall structure of one embodiment of this application; Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a cross-sectional structural diagram of one embodiment of this application; Figure 4 This is a schematic diagram of the drive mechanism in one embodiment of this application; Figure 5 This is a schematic diagram of the spring tube structure.

[0017] Reference numerals: Temperature control box 1; Inner cavity 10; First through hole 11; Connection position 12; Drive mechanism 2; First transmission part 21; Second transmission part 22; Drive component 23; Threaded hole 24; Guide rail 25; Guide part 26; Fixture body 3; Clamping end 31; First free end 401; Second free end 402; Spiral segment 41; Worktable 5; First limiting structure 61; Second through hole 610; Second limiting structure 62; Rear end limiting part 620. Detailed Implementation

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the specific implementation methods of this application will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort.

[0019] To keep the drawings concise, each drawing only schematically shows the parts relevant to the application; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" can mean not only "only one" but also "more than one."

[0020] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0021] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0023] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] With the rapid development of the new energy vehicle industry, vehicle comfort features are constantly improving, and pneumatic massage devices are increasingly being used in seat systems. To meet the dynamic adjustment needs of components such as leg rests and lumbar supports, the connecting pipes in pneumatic systems are gradually transitioning from traditional straight pipe structures to retractable helical spring air hose structures. These spring air hoses undergo frequent extension and retraction during vehicle seat use, therefore their fatigue performance directly affects the system's lifespan and reliability.

[0025] Existing fatigue performance testing methods for spring tubes typically employ a static suspension structure, where one end of the spring tube is fixed and a counterweight is suspended at the other end. Deformation or rebound rate is measured after a prolonged period of static loading. This method only assesses the deformation performance of the spring tube under static load, failing to simulate the reciprocating tensile motion experienced in actual applications. Furthermore, it does not consider the impact of temperature changes in the operating environment on material properties, leading to significant discrepancies between test results and actual usage conditions.

[0026] To address the problems in the prior art, in one embodiment, reference is made to the appendix to the specification. Figures 1 to 3 This application provides a fatigue testing fixture for testing the reciprocating fatigue performance of a helical spring tube under simulated use conditions. The fatigue testing fixture includes a temperature control chamber 1, a drive mechanism 2, and a fixture body 3.

[0027] Please refer to the attached document. Figure 5 The temperature control chamber 1 is used to fix the first free end 401 of the spring tube. Inside it, there is an inner cavity 10 for accommodating the spiral section 41 of the spring tube. The temperature of the inner cavity 10 can be adjusted to adapt to the environmental simulation requirements under different test conditions.

[0028] The temperature control box 1 is provided with a first through hole 11 communicating with the inner cavity 10. The second free end 402 of the spring air tube can pass through the through hole. The spiral section 41 is located in the temperature control environment, while the part that passes through is connected to the subsequent clamp body 3. Through this structural arrangement, the spring air tube is subjected to periodic stretching and compression, thereby truly reflecting its fatigue change characteristics during use.

[0029] The drive mechanism 2 is mounted on the worktable 5 and provides reciprocating driving force along the axial direction of the spring tube. The output side of the drive mechanism 2 is connected to the clamp body 3, which is used to clamp the connecting section of the spring tube. The connecting section refers to the part located between the helical section 41 and the second free end 402. This section is usually a relatively straight tube and is used to form a reliable connection with the clamping end 31 of the clamp body 3.

[0030] During testing, the drive mechanism 2 periodically pushes the fixture body 3 in a reciprocating motion, causing the clamped spring tube connecting section to deform along with the spiral section 41. Since the spiral section 41 within the temperature control chamber 1 is kept at a constant temperature, the test process can simultaneously examine the performance changes of the spring tube under the combined effects of temperature and mechanical stress. Throughout the entire test cycle, the spring tube remains under controlled conditions at both ends, and the stroke and speed can be set according to actual needs, enabling quantitative analysis of fatigue life.

[0031] Understandably, firstly, the temperature control chamber 1 allows the testing process to be conducted in a controlled thermal environment, overcoming the shortcomings of traditional suspension testing that cannot consider the influence of temperature, and thus more comprehensively reflecting the thermal fatigue characteristics of the material. Secondly, the linkage between the drive mechanism 2 and the fixture body 3 ensures that the spring air tube has a clear force direction and controllable stroke during reciprocating motion, avoiding the uneven stress problems caused by manual or gravity loading methods.

[0032] In another embodiment, the inner cavity 10 of the temperature control box 1 may be equipped with a temperature detection component to monitor the temperature of the inner cavity 10 in real time and feed it back to the control unit, making temperature regulation more precise. The outer wall of the temperature control box 1 may be made of a heat-insulating structure to reduce the influence of the external ambient temperature.

[0033] It should be noted that in this embodiment, the drive mechanism 2 is not specifically limited. In actual operation, various forms of power output structure can be adopted, such as screw drive, slide drive or push rod structure, to achieve the required reciprocating stroke control.

[0034] Based on the above embodiments, the temperature control box 1 also includes a temperature control component, which is thermally connected to the inner cavity 10 and is used to adjust the ambient temperature of the inner cavity 10 to simulate fatigue conditions under different temperature conditions.

[0035] The temperature control component includes at least one of a heating unit and a cooling unit, which can control the temperature of the inner cavity 10 to rise or fall according to the test requirements, so that the test environment can cover a variety of working conditions such as high temperature, normal temperature and low temperature, and the test results can truly reflect the mechanical stability and fatigue life of the spring tube under different environmental conditions, and have greater engineering reference value.

[0036] In one embodiment, such as Figure 2 and Figure 3 As shown, the fatigue testing fixture also includes at least one first limiting structure 61. The first limiting structure 61 is disposed between the first through hole 11 of the temperature control box 1 and the fixture body 3, and is used to guide and support the spring air tube during the test.

[0037] Each first limiting structure 61 includes at least one second through hole 610. The diameter of the second through hole 610 is slightly larger than the outer diameter of the spring tube connecting section, allowing the spring tube to pass through smoothly without interference in the installed state. During the test, the second free end 402 of the spring tube passes through the first through hole 11 of the temperature control box 1 and the second through hole 610 of the first limiting structure 61 in sequence, thereby allowing the connecting section to slide within the second through hole 610. In this way, when the drive mechanism 2 acts on the spring tube and generates reciprocating drive, the connecting section can reciprocate linearly in a preset direction under the constraint of the second through hole 610, avoiding the problems of additional bending, stress concentration, or stroke deviation caused by the spring tube sagging during the reciprocating test.

[0038] Through the above structural design, the first limiting structure 61 plays a dual role in stabilizing the position and guiding the direction throughout the test. On the one hand, it provides axial sliding guidance for the spring tube; on the other hand, by forming a continuous guiding path with the first through hole 11 of the temperature control box 1, the limiting structure makes the force range of the spring tube more concentrated, improving the repeatability and consistency of the fatigue loading process.

[0039] Meanwhile, the first limiting structure 61 itself can be made of wear-resistant material, or have a smooth lining on its inner wall, to further reduce motion resistance and extend the service life of the device.

[0040] In practical applications, the number of first limiting structures 61 can be adjusted according to the length of the spring tube or the test stroke. When the test stroke is long or the stiffness of the spring tube is low, two or more first limiting structures 61 can be set to form a multi-point supported guide path.

[0041] In a further design of the above embodiment, the first limiting structure 61 and the driving mechanism 2 are jointly disposed on the same workbench 5 to form an integrated testing station. The output direction of the driving mechanism 2 is horizontal, so that the driving output force acts directly on the axial direction of the spring tube, thereby more realistically simulating the axial force and fatigue deformation process of the spring tube under actual use conditions. At the same time, the fixture body 3 is connected to the output side of the driving mechanism 2 along the height direction, and the clamping end 31 of the fixture body 3, the second through hole 610 in the first limiting structure 61, and the first through hole 11 of the temperature control box 1 at least partially overlap in the direction of the same horizontal axis.

[0042] This arrangement ensures that the spring tube is always subjected to force in an approximately straight direction during the test, thus ensuring a more uniform distribution of deformation and stress change in the spring tube during the test. It also avoids bending or lateral force interference caused by the offset of the axes of different components, thereby significantly improving the repeatability and data reliability of fatigue testing.

[0043] In addition, the limiting structure and the drive mechanism 2 are located on the same worktable 5, which facilitates overall assembly and adjustment. The spatial position accuracy between the three can be controlled through a unified reference surface, thereby simplifying the equipment installation and calibration process and reducing the accumulation of errors caused by structural deviations.

[0044] Furthermore, such as Figure 3 As shown, the temperature control box 1 is provided with a connection position 12, which is used to fix the first free end 401 of the spring air tube. The connection position 12 and the first through hole 11 are respectively set on two opposite side walls of the temperature control box 1, and the connection position 12 and the first through hole 11 also overlap at least partially in the horizontal direction. In addition, a support structure can be set in the temperature control box 1 to support certain local parts of the spring air tube. In this way, it is ensured that the spring air tube is basically in the same horizontal position during the test.

[0045] In one embodiment, the fatigue testing fixture further includes at least one second limiting structure 62 for providing effective limiting constraints on the rear end portion of the spring tube during the test, thereby preventing excessive swinging or axial displacement of the spring tube during reciprocating deformation.

[0046] Specifically, the second limiting structure 62 is located on the side of the drive mechanism 2 away from the first limiting structure 61, that is, in the rear end area of ​​the entire device. The second limiting structure 62 is provided with a rear end limiting part 620, which is used to limit the spatial position of the rear end of the spring tube during the test to ensure that it always stays in the preset position during reciprocating motion.

[0047] During fatigue testing, the spiral section 41 of the spring tube repeatedly extends and retracts under the driving action of the fixture body 3. When the driving frequency is high or the length of the spring tube is long, the tail of the spring tube is prone to swinging due to inertia or deformation rebound. If there is a lack of reasonable limiting structure constraints, the swinging of the tail will not only cause stress concentration and increase local wear, but may also cause the spring tube to interfere with the surrounding structure during long-term reciprocating motion, thereby affecting the accuracy and repeatability of the fatigue test.

[0048] In this embodiment, by setting the second limiting structure 62, a fixed support point is set in the rear end area, which can also be understood as a local guide, to limit the range of motion of the tail of the spring tube, thereby effectively eliminating the test deviation caused by inertial swing.

[0049] Furthermore, the rear end limiting part 620 can take various specific forms. For example, like the first limiting structure 61 mentioned above, it can be limited by a perforation method. According to the remaining length of the spring tube tail, multiple rear end limiting parts 620 can be set to completely limit it in its length direction. Of course, it can also be a limiting structure with a certain degree of flexibility to adapt to the slight swaying of the spring tube during reciprocating deformation, such as a circular elastic limiting ring, in which the tail of the spring tube is inserted, forming necessary constraints while ensuring the degree of freedom of movement.

[0050] In some implementations, the second limiting structure 62 is connected to the worktable 5 through an adjustable structure, so that it has a certain degree of adjustability while ensuring the limiting accuracy, so as to meet the testing needs of spring tubes of different lengths or specifications.

[0051] In one embodiment, the drive mechanism 2 includes a transmission assembly and a drive member 23, wherein the drive member 23 is used to provide reciprocating driving force, and the transmission assembly is used to smoothly transmit the driving force to the fixture body 3, thereby realizing the periodic deformation of the spring tube during the fatigue test.

[0052] like Figure 4 As shown, the transmission assembly further includes a first transmission part 21 and a second transmission part 22. The first transmission part 21 is fixedly connected to the clamp body 3 and is used to drive the clamp body 3 to move synchronously under the action of driving force. The second transmission part 22 is connected to the drive member 23 and directly receives the power signal output by the drive member 23. The first transmission part 21 and the second transmission part 22 are connected to each other so that the movement of the drive member 23 can be transmitted to the clamp body 3 through the transmission assembly, thereby driving the spring air tube to complete continuous reciprocating loading in a preset direction.

[0053] To a certain extent, this embodiment can effectively isolate the high-frequency vibration or transient impact of the drive component 23 while realizing reciprocating motion, ensuring that the driving force transmitted to the fixture body 3 is more stable and avoiding test stress fluctuations or local deformation distortion of the spring tube caused by uneven force transmission.

[0054] The first transmission unit 21 and the second transmission unit 22 can adopt different transmission forms according to different testing requirements, such as rigid connection, sliding fit, or a structure with a flexible coupling section, so as to maintain the stability and repeatability of the movement of the fixture body 3 under different testing frequencies or stroke conditions. For example, in a feasible embodiment, the transmission component can adopt a combination of an eccentric wheel and a connecting rod, and the reciprocating drive of the connecting rod is realized by the periodic rotation of the eccentric wheel. Moreover, according to different test load characteristics, a buffer element can be added to the transmission component to optimize the stability of force transmission and the controllability of the motion trajectory, thereby further improving the testing accuracy and long-term operational reliability of the whole machine.

[0055] In one embodiment, see Appendix Figure 2 and Figure 4 The first transmission part 21 is configured as a slider, with a threaded hole 24 formed through its center along its axial direction. The second transmission part 22 is configured as a transmission rod, with an external thread on its outer periphery that matches the threaded hole 24. Through this structure, when the driving component 23 starts and drives the transmission rod to rotate, the relative motion between the threaded meshing pairs converts the rotational motion into linear reciprocating motion, allowing the slider to move smoothly along its axial direction during the rotation of the transmission rod. The slider is fixedly connected to the fixture body 3, thereby driving the fixture body 3 and the clamped spring tube to move synchronously, realizing the periodic loading and unloading of the spring tube during fatigue testing.

[0056] Understandably, in this embodiment, the slider and transmission rod are connected by a threaded pair, resulting in high transmission accuracy. Furthermore, the slider's speed and stroke range can be precisely controlled by adjusting the thread lead, allowing for flexible adjustment of the spring tube's deformation frequency and displacement amplitude according to different testing standards. In addition, the slider's sliding process on the transmission rod is a self-centering transmission, effectively reducing energy loss from lateral sway and mechanical friction, thus improving motion smoothness and long-term repeatability.

[0057] In one alternative embodiment, the slider can be made of metal alloy or engineering plastic to balance wear resistance and self-lubricating properties. Furthermore, in a specific configuration, the transmission rod can be rotatably connected to pre-set bearing seats on both sides, with one end extending from one of the bearing seats to connect with the drive component 23 (such as a motor) to ensure a smooth output of driving force.

[0058] In one embodiment, the drive mechanism 2 further includes a guide component to precisely limit and guide the reciprocating motion of the slider, thereby ensuring that its motion path is consistent with the preset transmission direction.

[0059] like Figure 4 As shown, the guiding assembly includes a guide rail 25 and a matching guide portion 26. The guide rail 25 is fixedly mounted on the worktable 5, forming a stable linear guiding reference. The guide portion 26 is located at the bottom of the slider and can slide smoothly relative to the guide rail 25 under driving action. Through this structural design, the axial movement of the slider driven by the transmission rod can be carried out under the constraint of the guide rail 25, avoiding phenomena such as offset, tilting, or shaking, thereby ensuring that the movement of the fixture body 3 and the spring air tube during fatigue loading is always in the same horizontal direction.

[0060] Understandably, the slider, when under stress, will bear the reaction force from the fixture body 3 and the spring tube. Without proper guiding constraints, it is easy to produce slight lateral deviations during reciprocating motion, which can cause testing errors after long-term operation. However, with the cooperation of the guide rail 25 and the guide part 26, the displacement direction of the slider is effectively guided, and the motion trajectory is more stable. This not only improves the repeatability and reliability of fatigue test data, but also reduces the risk of mechanical wear and structural deformation.

[0061] In this embodiment, the guide part 26 can be integrally formed with the slider according to actual needs, or it can be formed separately and then fixedly connected by screws, pins or interference fit. The latter is convenient for maintenance and replacement, and the guide part 26 can be replaced independently after long-term use to maintain guiding accuracy, thereby extending the service life of the whole machine.

[0062] In one embodiment, the clamp body 3 includes a detection module (not shown in the figure) for monitoring and recording the force on the spring tube during clamping and loading.

[0063] Specifically, the detection module includes sensors that detect changes in the clamping force experienced by the fixture body 3 during clamping, thereby enabling real-time monitoring of the test status. The clamping ends 31 of the fixture body 3 are configured with two opposing jaws. Sensors are installed on the fixture body 3 in areas corresponding to the jaws, sensing the reaction force generated by the jaws when clamping the spring tube. This structure allows for real-time acquisition of clamping force data during testing, enabling effective analysis of the stress variation characteristics of the spring tube under dynamic loading.

[0064] During fatigue testing, the clamping force of the fixture body 3 is a crucial factor affecting test accuracy. Insufficient clamping force may cause slippage of the spring tube during reciprocating deformation, leading to unstable strain; excessive clamping force may cause local flattening or deformation of the tube. By introducing a detection module into the fixture body 3, the system can continuously monitor the clamping force during test operation and analyze the numerical changes to determine whether the device is operating under reasonable conditions. For example, when the gripper reaches its limit position, the sensor can output the corresponding peak clamping force signal, allowing the operator to assess clamping stability and the stress response characteristics of the spring tube.

[0065] Furthermore, in one embodiment, the detection module further includes a signal acquisition unit electrically connected to the sensor, used to receive and record the clamping force signal output by the sensor.

[0066] The signal acquisition unit can process data by converting analog signals to digital signals and store or output the acquired mechanical parameters to an external processing system to generate mechanical response curves or analysis reports. This allows the operator to fine-tune the clamping state based on the test data or perform multi-cycle comparisons of the test results.

[0067] In one embodiment, the fixture body 3 is detachably connected to the output side of the drive mechanism 2, and / or the drive mechanism 2 is detachably connected to the worktable 5. Through the above-mentioned detachable connection method, the distance between the temperature control box 1 and the fixture body 3 can be adjusted according to the test requirements.

[0068] Thus, the fatigue testing fixture proposed in this application has high flexibility and adaptability in both assembly and testing stages, thereby meeting the fatigue testing requirements of spring tubes of different lengths, shapes, or elastic coefficients.

[0069] Understandably, a spring tube typically consists of two parts: a spiral section 41 and a straight section. The straight section corresponds to the section of the spring tube that connects to the connection point 12 of the temperature control box 1 and the clamping end 31 of the fixture body 3 (excluding the spiral section 41). If this straight section is in a relaxed state after installation, it is prone to sagging during reciprocating loading, thereby introducing additional bending stress. This causes the stress state experienced by the spring tube during testing to deviate from the actual usage conditions, thus affecting the accuracy and repeatability of the test data.

[0070] By setting the distance between the temperature control box 1 and the fixture body 3 to be adjustable, the operator can adjust the distance between them according to the length and stiffness characteristics of the spring air tube during the clamping stage, so that the straight section of the spring air tube is in a moderately taut state under the clamping state, ensuring that its axis is basically kept horizontal and straight, thereby achieving a more accurate stress transmission path.

[0071] Specifically, the detachable connection can be achieved through various methods such as threaded connection and locating pin connection, so that the fixture body 3 or the drive mechanism 2 can be finely adjusted along the worktable 5.

[0072] Based on the above embodiments, in one embodiment, the fatigue testing fixture further includes a height adjustment mechanism for adjusting the height of the fixture body 3. Specifically, the fixed end of the height adjustment mechanism is connected to the output side of the drive mechanism 2, and the output end of the height adjustment mechanism is connected to the fixture body 3. The height adjustment mechanism has a switching function between a locked state and an unlocked state. When switched to the locked state, it can stably lock the horizontal position of the fixture body 3 and prevent it from shifting horizontally during the test.

[0073] It should be noted that the length of the spiral section 41 varies in different models of spring air tubes. By adjusting the height adjustment mechanism, the height of the clamp body 3 can be flexibly changed so that the clamp body 3 can accurately clamp the connecting section of different spring air tubes (located between the spiral section 41 and the second free end 402).

[0074] Once the height adjustment mechanism is locked, it ensures that the fixture body 3 moves only along the reciprocating direction of the drive mechanism 2, causing the spiral section 41 of the spring air tube to undergo only axial reciprocating tensile deformation, perfectly conforming to the actual working conditions and further improving the accuracy of the test results. In practical applications, the height adjustment mechanism can adopt methods such as screw adjustment, sliding adjustment, or electric push rod, and no specific limitation is made in this application.

[0075] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of this application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A fatigue testing fixture, characterized in that, For use in spring tubing, including: A temperature control chamber for fixing the first free end of the spring tube includes an inner cavity and a first through hole communicating with the inner cavity. The temperature of the inner cavity can be adjusted to adapt to the fatigue test conditions of the spring tube. The inner cavity is used to accommodate the helical section of the spring tube to be tested. The first through hole is used to allow the second free end of the spring tube to pass out from the inner cavity. The drive mechanism, located on the worktable, is used to provide reciprocating driving force; The clamp body is connected to the output side of the drive mechanism to clamp and fix the corresponding connecting section on the spring air tube, and to cause the spiral section of the spring air tube to reciprocate under the action of the drive mechanism; wherein, the connecting section is located between the spiral section of the spring air tube and the second free end.

2. The fatigue testing fixture according to claim 1, characterized in that, The fatigue testing fixture also includes at least one first limiting structure; Each of the first limiting structures is disposed between the first through hole of the temperature control box and the fixture body, including at least one second through hole. The diameter of the second through hole is larger than the outer diameter of the connecting section. During the test, the second free end passes through the first through hole and the second through hole in sequence, so that the connecting section slides through the second through hole. Then, when the driving mechanism acts on the spring air tube, the connecting section moves synchronously in a preset direction.

3. The fatigue testing fixture according to claim 2, characterized in that, The first limiting structure and the driving mechanism are located on the same workbench. The output side of the driving mechanism moves in a horizontal direction. The fixture body is connected to the output side of the driving mechanism along the height direction. The clamping end of the fixture body, the second through hole, and the first through hole at least partially overlap in the direction of the same horizontal axis.

4. The fatigue testing fixture according to any one of claims 1-3, characterized in that, The drive mechanism includes a transmission assembly and a drive component, the drive component being used to provide driving force; The transmission assembly includes a first transmission part and a second transmission part. The first transmission part is fixedly connected to the clamp body, and the second transmission part is connected to a drive member to transmit driving force to the second transmission part. The first transmission part and the second transmission part are connected to each other so that the clamp body can reciprocate along a preset direction.

5. The fatigue testing fixture according to claim 4, characterized in that, The first transmission part is configured as a slider, and a threaded hole is formed through the center of the slider along its axis. The second transmission part is configured as a transmission rod, and an external thread that matches the threaded hole is provided on the outer periphery of the transmission rod. The driving member is used to drive the transmission rod to rotate, so that the slider moves synchronously along its axial direction when the transmission rod rotates.

6. The fatigue testing fixture according to claim 5, characterized in that, The drive mechanism includes a guide component; The guiding component includes a guide rail and a guide part adapted to the guide rail. The guide rail is fixed to the worktable, and the guide part can slide relative to the guide rail under the driving action. The guide part is disposed at the bottom of the slider. The guide part is integrally formed with the slider, or separately formed with the slider and then fixedly connected.

7. The fatigue testing fixture according to claim 2 or 3, characterized in that, The fatigue testing fixture further includes at least one second limiting structure. The second limiting structure is located on the side of the driving mechanism away from the first limiting structure. The second limiting structure is provided with a rear limiting part to limit the movement or swing of the spring tube at its rear end during the test. The rear end corresponds to the clamping end of the fixture body on the side away from the first limiting structure.

8. The fatigue testing fixture according to claim 1, characterized in that, The fixture body includes a detection module; The detection module includes a sensor for detecting the force applied to the clamp body during clamping. The clamping end of the clamp body is configured with two opposing jaws. The sensor is installed on the clamp body in the area corresponding to the jaws to collect clamping force data in real time.

9. The fatigue testing fixture according to claim 8, characterized in that, The detection module further includes a signal acquisition unit, which is electrically connected to the sensor and is used to receive and record the clamping force signal output by the sensor.

10. The fatigue testing fixture according to any one of claims 1-3, 5, 6, 8, and 9, characterized in that, The temperature control chamber includes a temperature control component, which is thermally connected to the inner cavity. The temperature control component includes at least one of a heating unit and a cooling unit, and is used to adjust the temperature of the inner cavity by raising or lowering it to simulate fatigue conditions under different ambient temperatures. And / or, The clamp body is detachably connected to the output side of the drive mechanism, and / or the drive mechanism is detachably connected to the worktable, so that the distance between the temperature control box and the clamp body is adjustable, so that the straight section of the spring air tube is in a taut state when clamped. And / or, The fatigue testing fixture also includes a height adjustment mechanism for adjusting the height of the fixture body. The fixed end of the height adjustment mechanism is connected to the output side of the drive mechanism, and the output end of the height adjustment mechanism is connected to the fixture body. The height adjustment mechanism can be adjusted between a locked state and an unlocked state to lock the horizontal position of the fixture body.

Images