A temporary fastener fatigue life detection device

Abstract

The application discloses a kind of temporary fastener fatigue life detection device. Including fixture, torsion test component and exciter, test piece and through-hole pressure sensor are fixed in fixture, one end of temporary fastener is through through-hole pressure sensor and test piece and clamps test piece and through-hole pressure sensor, the other end of temporary fastener is torsion end;Torsion test component is connected to the torsion end of temporary fastener, and torsion test component is used to drive the reciprocating rotation of the torsion end of temporary fastener to detect the torsion number life of temporary fastener;The output end of exciter is connected with a transmission rod, and the other end of the transmission rod abuts against the test piece in the fixture.The technical scheme of the application realizes the repeated tightening number life detection of temporary fastener under axial vibration condition on the same device, meets the characteristic detection demand of temporary fastener, improves the convenience of use, and helps to deeply study the dynamic characteristics of temporary fastener.

Description

Technical Field

[0001] This application relates to fasteners, and more specifically to a temporary fastener fatigue life testing device. Background Technology

[0002] In the field of aerospace mechanical assembly, whether assembling thin-walled parts or components, temporary connections between two thin-walled parts or components are often required. Temporary fasteners are commonly used for temporary connections, offering stable clamping and the ability to work with automated assembly systems to tighten ordinary bolts, thus completing the necessary temporary connection and fixation operations. Temporary fasteners are relatively small in size and frequently reused, and are often subjected to vibrations in their working environment. Therefore, their service life and fatigue life parameters are crucial. Domestic and international fatigue research on fasteners has largely focused on permanent fasteners, with limited research on the dynamic characteristics of temporary fasteners, and fatigue life testing devices adapted for temporary fasteners are still underdeveloped. Utility Model Content

[0003] The purpose of this application is to provide a temporary fastener fatigue life testing device, which can realize the life testing of temporary fasteners under axial vibration conditions by repeated tightening cycles on the same device.

[0004] To achieve the above objectives, this application provides a temporary fastener fatigue life testing device, which includes a fixture, a torsion testing assembly, and a vibrator. A test piece and a through-hole pressure sensor are fixed inside the fixture. One end of the temporary fastener passes through the through-hole pressure sensor and the test piece, clamping the test piece and the through-hole pressure sensor. The other end of the temporary fastener is a torsion end. The torsion testing assembly is connected to the torsion end of the temporary fastener and is used to drive the torsion end of the temporary fastener to reciprocate to detect the torsion life of the temporary fastener. The output end of the vibrator is connected to a transmission rod, and the other end of the transmission rod abuts against the test piece in the fixture.

[0005] The testing device of this application realizes the torsion life test of temporary fasteners through the torsion test component, and at the same time, it loads axial vibration on the test piece through the vibrator. That is, the life test of temporary fasteners under axial vibration conditions is realized on the same device, which meets the requirements for the characteristic test of temporary fasteners, improves the ease of use, and helps to study the dynamic characteristics of temporary fasteners in depth.

[0006] In an optional configuration, the exciter is a variable-frequency electromagnetic exciter.

[0007] In an optional configuration, the torsion test assembly includes a drive motor and a torque sensor. The shaft of the drive motor is connected to one end of the torque sensor via a coupling, and a torsion head is fixed to the other end of the torque sensor. The torsion head is connected to the torsion end of a temporary fastener.

[0008] In an optional embodiment, the clamp includes a first clamp, on which two clamping plates are fixed to the side facing the torsion end of the temporary fastener. The outer wall of the temporary fastener is provided with two flat surfaces, the upper clamping plate is attached to the flat surface on the upper part of the temporary fastener, and the lower clamping plate is attached to the flat surface on the lower part of the temporary fastener.

[0009] In an optional configuration, the first clamp has two vertical grooves on its side, and each clamp plate has two screws that pass through it. The screws are inserted into the vertical grooves and threadedly connected to the fastening nuts inside the vertical grooves.

[0010] In an optional embodiment, the fixture also includes a second fixture with a receiving groove that opens toward the exciter. The receiving groove contains a core pressure sensor and a test piece. The core pressure sensor is located on the side away from the exciter. Temporary fasteners are used to clamp the test piece and the core pressure sensor in the receiving groove. A transmission rod abuts against the outermost test piece.

[0011] In an optional configuration, a fastening screw is radially screwed into the side wall of the second clamp, which presses the through-hole pressure sensor within the receiving groove.

[0012] In an optional configuration, the receiving groove is further provided with at least two guide posts, which are parallel to the axial direction of the temporary fastener. The guide posts penetrate the test piece, and elastic sleeves are fitted on the guide posts to restrict the axial movement of the test piece.

[0013] In an alternative configuration, the transfer rod is parallel to the central axis of the temporary fastener, and the central axis of the transfer rod and the central axis of the temporary fastener are on the same horizontal plane.

[0014] In an optional configuration, the testing device also includes a machine base, on which the fixture, torsion test assembly and vibrator are mounted. The machine base is equipped with a slide rail parallel to the central axis of the temporary fastener. The fixture is placed on a base, which is slidably connected to the slide rail, and fastening screws are screwed into the side wall of the base, with the inner end of the fastening screws pressing against the slide rail.

[0015] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, some embodiments are listed below for detailed description. Attached Figure Description

[0016] Figure 1 This is a perspective view of a detection device according to at least one embodiment.

[0017] Figure 2 An exploded view of the clamp and temporary fastener of at least one embodiment.

[0018] Figure 3 An exploded view of the clamp and temporary fastener of at least one embodiment.

[0019] Figure 4 This is a partial cross-sectional view of the detection device according to at least one embodiment.

[0020] It should be noted that the products shown in the above views have been appropriately scaled down / enlarged to fit the drawing size and ensure clarity of the views, and there is no limitation on the size of the products shown in the views. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application.

[0022] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0023] 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", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Therefore, they should not be construed as limitations on this application.

[0024] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] One or more embodiments of this application provide a temporary fastener fatigue life testing device, the specific structure of which is as follows: Figures 1-4 As shown. Temporary fastener 80 can be used for securing more than one thin-walled component in the aerospace or automotive industries. (See figure) Figure 1 As shown, the testing device includes a fixture 10, a torsion testing assembly 20, and a vibrator 30. A test piece 70 and a ring-shaped through-hole pressure sensor 60 are fixed inside the fixture 10. A temporary fastener 80 passes through the through-hole pressure sensor 60 and the test piece 70 at one end, clamping both. The other end of the temporary fastener 80 is the torsion end. The disc-shaped test piece 70 is used to simulate thin-walled parts, and its central hole diameter and thickness match the corresponding parameters of the thin-walled parts. The through-hole pressure sensor 60 can dynamically monitor and detect changes in clamping force under different simulated working conditions. The torsion testing assembly 20 is connected to the torsion end of the temporary fastener 80, and the torsion testing assembly 20 is used to drive the torsion end of the temporary fastener 80 to reciprocate to detect the torsion life of the temporary fastener 80. The output end of the vibrator 30 is connected to a transmission rod 31, and the other end of the transmission rod 31 abuts against the test piece 70 in the fixture 10. Therefore, the testing device achieves the life test of the number of tightening cycles of the temporary fastener 80 through the torsion test component 20, and at the same time, it applies axial vibration to the test piece 70 through the vibrator 30. The life test of the temporary fastener 80 under the condition of repeated tightening is realized on the same device, which meets the requirements for the characteristic testing of the temporary fastener 80. It can provide data support for the standardized design, reliability assessment and optimization of the temporary fastener 80, and help reduce the quality risks and maintenance costs caused by fastener failure.

[0026] In some embodiments, such as Figure 1As shown, the testing device also includes a machine base 90, on which the fixture 10, torsion testing assembly 20, and vibrator 30 are all mounted. Specifically, the vibrator 30 is fixed to an L-shaped base 33 via a cantilever seat 32, and the L-shaped base 33 is fixed to the machine base 90 by screws. The torsion testing assembly 20 is fixed to the machine base 90. In addition, the machine base 90 is provided with two slide rails 91 parallel to the central axis 81 of the temporary fastener 80. The fixture 10 is placed on a base 19, which is slidably connected to the two slide rails 91, and fastening screws 18 are screwed into the side wall of the base 19. The inner end of the fastening screws 18 presses against the slide rails 91 to fix the base 19 and the slide rails 91 to each other. When the position of the clamp 10 needs to be adjusted, for example when the thickness of the test piece 70 changes, these fastening screws 18 can be loosened and the clamp 10 can be pushed to move linearly along the slide rail 91 to the appropriate position. Finally, the fastening screws 18 are tightened to fix the clamp 10 in the position before testing.

[0027] In some embodiments, the vibrator 30 is a variable frequency electromagnetic vibrator, such as an SA-JZ002 modal vibrator, which can generate a force of 20N and a vibration frequency range of 50Hz-15000Hz. The variable frequency vibrator 30 can apply axial vibrations at different frequencies to the test piece 70 to achieve fatigue life testing at different vibration frequencies.

[0028] In some embodiments, such as Figure 1 As shown, the torsion test assembly 20 includes a drive motor 21 and a torque sensor 22. The drive motor 21 is fixed to a base 211, which is fixed to the machine base 90 with screws. The torque sensor 22 is fixed to a base 221, which is also fixed to the machine base 90 with screws. The shaft of the drive motor 21 is connected to one end of the torque sensor 22 via a coupling 212. A torsion head 222 is fixed to the other end of the torque sensor 22, and the torsion head 222 is connected to the torsion end of a temporary fastener 80. The drive motor 21 is the driving force source for the torsion life test. The drive motor 21 must have forward and reverse rotation capabilities, generate stable torque, and maintain stable speed at low speeds. For example, the drive motor 21 may be a 57 stepper motor with a torque of 1.35 N·m, and the torque sensor 22 may be a torque sensor with a range of 2 N·m. During the torsion cycle life test, the drive motor 21 rotates in both directions to drive the torsion end of the temporary fastener 80 to rotate in both directions, simulating the working cycle of the temporary fastener 80 being repeatedly tightened and loosened. During the test, the torque sensor 22 detects whether the real-time torque reaches the set range, and the through-hole pressure sensor 60 detects whether the maximum clamping force reaches the set range. The torque, clamping force, and number of tightening cycles are recorded simultaneously, thereby obtaining the tightening cycle life data of the temporary fastener 80.

[0029] In some embodiments, such as Figure 2As shown, the clamp 10 includes a first clamp 11, which is used to assist in clamping the temporary fastener 80. Two adjustable clamping plates 15 are fixed to the side of the first clamp 11 facing the torsional end 82 of the temporary fastener 80. The outer wall of the temporary fastener 80 has upper and lower flat surfaces 801 and 802. The upper clamping plate 15 fits against the upper flat surface 801 of the temporary fastener 80, while the lower clamping plate 15 fits against the lower flat surface 802 of the temporary fastener 80. Therefore, the two clamping plates 15 can clamp the temporary fastener 80 from both directions, preventing the temporary fastener 80 from rotating along its central axis and avoiding it from falling off, thus ensuring the smooth progress of the testing process.

[0030] In some embodiments, the positions of the upper and lower clamping plates 15 are adjustable to facilitate the through-installation of temporary fasteners 80 and to clamp and fix temporary fasteners 80 with different outer diameters. Specifically, as shown in the figure... Figure 2 As shown, the first clamp 11 has two parallel vertical grooves 111 on its side, and the cross-section of the vertical grooves 111 is T-shaped. Each clamping plate 15 has two screws 13 passing through it, one on the left and one on the right. The left screw 13 goes into the left vertical groove 111, and the right screw 13 goes into the right vertical groove 111. After the screws 13 are inserted into the vertical grooves 111, they are threadedly connected to the fastening nuts 14 inside the vertical grooves 111. After tightening the screws 13, the screws 13 and the fastening nuts 14 clamp the clamping plates 15, thereby fixing the position of the clamping plates 15. Figure 2 The fastening nut 14 in the middle also has a T-shaped cross section, which is adapted to the vertical groove 111. In other embodiments, the fastening nut is a square nut with a size slightly smaller than the cross-sectional size of the vertical groove, so that the fastening nut after being inserted into the vertical groove cannot rotate around its own axis, making it easier to tighten or loosen the screw.

[0031] In some embodiments, such as Figure 3 As shown, the fixture 10 also includes a second fixture 12, which is used to fix the test piece 70 and the through-hole pressure sensor 60. The fixture 10 adopts a split structure; the first fixture 11 is used to hold the temporary fastener 80, and the second fixture 12 is used to fix the test piece 70 and the through-hole pressure sensor 60, better simulating the working environment of the temporary fastener 80, making the life test data closer to actual working conditions. Combined with... Figure 3 and Figure 4As shown, the second clamp 12 has a receiving groove 121 with an opening facing the vibrator 30. A through-hole pressure sensor 60 and a test piece 70 are housed within the receiving groove 121. A slot 122 is provided on the side wall of the receiving groove 121 for the cable 61 of the through-hole pressure sensor 60 to pass through. The through-hole pressure sensor 60 is located on the side away from the vibrator 30. There are two test pieces 70, used to simulate the fixed connection of two thin-walled components. The transmission rod 31 connected to the output end of the vibrator 30 abuts against the outermost test piece 70. A temporary fastener 80 is used to clamp the test piece 70 and the through-hole pressure sensor 60 within the receiving groove 121, with the through-hole pressure sensor 60 pressed against the bottom of the receiving groove 121 by the test piece 70. The through-hole pressure sensor 60 is used to monitor the clamping force in real time. When the through-hole pressure sensor 60 detects that the clamping force has decreased significantly and is below the set threshold, it indicates that the temporary fastener 80 has reached its fatigue limit in terms of the number of torsion cycles. At this time, the vibration frequency, vibration duration, and number of tightening cycles can be recorded to obtain the fatigue life data of the temporary fastener 80 at that frequency.

[0032] In some embodiments, such as Figure 3 As shown, two fastening screws 123 are radially screwed into the side wall of the second clamp 12. The fastening screws 123 penetrate the side wall of the second clamp 12 and press against the through-hole pressure sensor 60 within the receiving groove 121. An arc-shaped pressure plate 124 is provided within the receiving groove 121, opposite to the fastening screws 123. The pressure plate 124 fits against one side of the outer wall of the through-hole pressure sensor 60, while the fastening screws 123 press against the other side of the through-hole pressure sensor 60. The pressure plate 124 and the fastening screw 123 correspond one-to-one. The cooperation of the pressure plate 124 and the fastening screw 123 completely fixes the through-hole pressure sensor 60 within the receiving groove 121.

[0033] In some embodiments, such as Figure 3 As shown, the receiving groove 121 is also provided with two parallel guide posts 125, which are parallel to the central axis 81 of the temporary fastener 80. The inner ends of the guide posts 125 penetrate into the bottom of the receiving groove 121 and are fixed together by threaded connection. The guide posts 125 pass through the two test pieces 70, and each guide post 125 is fitted with a plastic elastic sleeve 126 (see...). Figure 4 The elastic cylinder 126 and the guide post 125 are interference-fitted. The elastic cylinder 125 abuts against the outermost test piece 70, and the elastic cylinder 126 is used to restrict the axial movement of the test piece 70. The guide post 125 facilitates the positioning and installation of the test piece 70 to ensure that the central axis of the test piece 70 is collinear with the central axis 81 of the temporary fastener 80.

[0034] In some embodiments, such as Figure 4As shown, the transmission rod 31 is parallel to the central axis 81 of the temporary fastener 80, and the central axis of the transmission rod 31 and the central axis 81 of the temporary fastener 80 are on the same horizontal plane to ensure that the vibration generated by the vibrator 30 on the test piece 70 is axial vibration, and the vibration point is next to the central hole of the test piece 70, simulating the self-excited vibration caused by the drilling of the adjacent hole when the temporary fastener 80 is working, so that the vibration life test data is closer to the actual working conditions.

[0035] The above examples are merely illustrative of the technical content of this application to facilitate reader understanding, but do not imply that the implementation methods of this application are limited to these. Any technical extensions or re-creations made based on this application are protected by this application. The scope of protection of this application is determined by the claims.

Claims

1. A temporary fastener fatigue life testing device, characterized in that, It includes: A clamp, in which a test piece and a through-hole pressure sensor are fixed, and a temporary fastener passes through the through-hole pressure sensor and the test piece at one end and clamps the test piece and the through-hole pressure sensor at the other end. A torsion test assembly is connected to the torsion end of the temporary fastener. The torsion test assembly is used to drive the torsion end of the temporary fastener to reciprocate to detect the torsion life of the temporary fastener. A vibrator, the output end of which is connected to a transmission rod, the other end of which abuts against a test piece in the fixture.

2. The temporary fastener fatigue life testing device as described in claim 1, characterized in that, The exciter is a variable frequency electromagnetic exciter.

3. The temporary fastener fatigue life testing device as described in claim 1, characterized in that, The torsion test assembly includes a drive motor and a torque sensor. The shaft of the drive motor is connected to one end of the torque sensor via a coupling. The other end of the torque sensor is fixed with a torsion head, which is connected to the torsion end of the temporary fastener.

4. The temporary fastener fatigue life testing device as described in claim 1, characterized in that, The clamp includes a first clamp, on which two clamping plates are fixedly fixed to the side facing the torsional end of the temporary fastener. The outer wall of the temporary fastener has two flat surfaces, with the upper clamping plate fitting against the flat surface on the upper part of the temporary fastener and the lower clamping plate fitting against the flat surface on the lower part of the temporary fastener.

5. The temporary fastener fatigue life testing device as described in claim 4, characterized in that, The first clamp has two vertical grooves on its side, and each clamp plate has two screws passing through it. The screws are inserted into the vertical grooves and threadedly connected to the fastening nuts in the vertical grooves.

6. The temporary fastener fatigue life testing device as described in claim 1, characterized in that, The fixture also includes a second fixture with an opening facing the vibrator in a receiving groove. The receiving groove contains a core pressure sensor and a test piece. The core pressure sensor is located on the side away from the vibrator. The temporary fastener is used to clamp the test piece and the core pressure sensor in the receiving groove. The transmission rod abuts against the outermost test piece.

7. The temporary fastener fatigue life testing device as described in claim 6, characterized in that, The second clamp has a fastening screw screwed radially into its side wall, which presses against the through-hole pressure sensor in the receiving groove.

8. The temporary fastener fatigue life testing device as described in claim 6, characterized in that, The receiving groove is also provided with at least two guide posts, which are parallel to the central axis of the temporary fastener. The guide posts pass through the test piece, and an elastic cylinder for restricting the axial movement of the test piece is sleeved on the guide posts.

9. The temporary fastener fatigue life testing device as described in claim 6, characterized in that, The transfer rod is parallel to the central axis of the temporary fastener, and the central axis of the transfer rod and the central axis of the temporary fastener are on the same horizontal plane.

10. The temporary fastener fatigue life testing device as described in claim 1, characterized in that, The testing device also includes a machine base, on which the fixture, torsion testing assembly and vibrator are all mounted. The machine base is provided with a slide rail parallel to the central axis of the temporary fastener. The fixture is placed on a base, which is slidably connected to the slide rail, and fastening screws are screwed into the side wall of the base. The inner end of the fastening screws presses against the slide rail.

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