Test tool and test system
By adjusting the testing fixtures and systems at fixed points in multiple dimensions, and combining sensors and vibration tables, the safety factor of bolt slippage was calibrated, which solved the loosening problem caused by relying on experience values to select bolt models, and improved the safety of bolted connections.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2026-03-13
AI Technical Summary
In the existing technology, the bolt type and specifications of vehicle parts mainly rely on experience values, which leads to a high possibility of bolt loosening and poses a safety hazard.
This invention provides a testing fixture and system that, through multi-dimensional adjustment of fixed points, combined with sensors, vibration tables, and electronic equipment, calibrates the safety factor of bolt slippage. It is applicable to vibration testing of heat insulation covers with different locations and numbers of fixed points, establishes a vibration database, performs simulation analysis and experimental calibration, and determines the appropriate bolt type.
It improves the safety of bolted connections, reduces the possibility of bolt loosening, and enhances the overall safety of the vehicle.
Smart Images
Figure CN223992679U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of vehicle technology, and in particular relates to a testing fixture and testing system. Background Technology
[0002] The bolt slip safety factor is an important parameter for evaluating the performance of bolted connections. Vehicles contain various parts that need to be fastened with bolts. During long-term driving, bolts may loosen. Therefore, it is necessary to accurately assess the bolt slip safety factor. Based on the accurate bolt slip safety factor, the appropriate bolt type can be selected to fasten the parts and prevent loosening.
[0003] Currently, the bolt specifications for various parts in vehicles are generally based on empirical values. These subjective, empirical values are prone to inaccuracies, increasing the likelihood of bolts loosening and creating a series of potential risks. Utility Model Content
[0004] This application provides a test fixture and test system that can adjust and replace fixed points in multiple dimensions, making it convenient to perform vibration tests on heat insulation covers with fixed points of different positions and numbers.
[0005] In a first aspect, embodiments of this application provide a testing fixture, the testing fixture being provided with at least one slide groove extending in different extension directions, the slide groove being provided with a bracket that can slide in the extension direction, the bracket being used to bolt and fix different types of test parts.
[0006] Secondly, embodiments of this application provide a testing system, including a sensor, a vibration table, a testing device, an electronic device, and the aforementioned testing fixture. The testing fixture is disposed on the vibration table, the test part is disposed on the testing fixture by bolts, the sensor is disposed on the test part, and the testing device is connected to the sensor and the electronic device respectively.
[0007] The vibration table is used to drive the test fixture and the test parts set on the test fixture to vibrate according to a set frequency.
[0008] The sensor is used to collect vibration data from the sensor and transmit it to the electronic device;
[0009] The electronic device is used to determine whether the test part resonates based on the vibration data.
[0010] The test fixtures and test system of this application embodiment can adjust and replace the fixed points in multiple dimensions, which is convenient for vibration testing of heat insulation covers with different positions and numbers of fixed points. Attached Figure Description
[0011] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 This is a schematic diagram of the structure of the test system provided in the embodiments of this application;
[0013] Figure 2 The following are schematic diagrams of the test fixture provided in the embodiments of this application from different perspectives. Detailed Implementation
[0014] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.
[0015] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes said element.
[0016] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes said element.
[0017] In the automobile manufacturing process, many parts are fastened with bolts. Different parts have different characteristics, and their corresponding bolt slippage safety factors also differ. For example, in the design of heat shields in hybrid vehicle powertrains, thin-walled parts are typically used. Due to their thin-walled nature, these parts are more prone to bolt loosening during durable operation than other bolted parts. Relying solely on current experience to select the appropriate bolt type for the heat shield can easily lead to bolt loosening, causing a series of potential risks.
[0018] To address the aforementioned issues, this application provides a bolt slippage safety factor testing scheme. This scheme calibrates the bolt slippage safety factor, setting a specific bolt slippage safety factor for thin-walled parts in vehicles. This allows for the use of an accurate bolt slippage safety factor to select appropriate bolt types for thin-walled parts, preventing the possibility of bolt loosening and improving vehicle safety.
[0019] The technical solution of this application will now be described in detail through specific embodiments. It should be noted that the following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.
[0020] Figure 1 This is a schematic diagram of the structure of the test system provided in the embodiments of this application, such as... Figure 1 As shown, it includes a sensor 11, a test fixture 12, a vibration table 13, a test device 14, and an electronic device 15.
[0021] The test fixture 12 is equipped with the test parts to be subjected to vibration testing, and the test parts are fixed to the test fixture 12 by bolts. The test fixture 12 is fixedly mounted on the vibration table 13.
[0022] The sensor 11 is mounted on the test part, and the test device 14 is connected to the sensor 11 and the electronic device 15 respectively.
[0023] The vibration unit 13 drives the test fixture 12 and the test parts mounted on the test fixture to vibrate according to a set frequency. The sensor 11 collects the vibration data of the test parts and transmits it to the electronic device 15. The electronic device 15 is used to determine whether the test parts resonate based on the vibration data.
[0024] For example, the electronic device can be a computer, a mobile terminal, or a cloud server, etc. For example, the test component can be a heat shield.
[0025] In this embodiment, the test fixture is provided with at least one slide groove extending in different directions, and the slide groove is provided with a bracket that can slide in the direction of extension. The bracket is used to bolt different types of test parts.
[0026] The bracket may be equipped with threaded holes or other components for bolt fixing, and the test parts are fixed to the bracket by bolts.
[0027] To ensure the testing fixture is compatible with test parts of various sizes, the fixed position can be adjusted by controlling the support to slide along the slide. For example, when the support slides to the beginning or end point of the slide, larger test parts can be fixed to the support. Furthermore, since the test parts are bolted to the support, the fixed position of the test parts can be adjusted by sliding the support.
[0028] For example, Figure 2 The following are schematic diagrams of the test fixture provided in the embodiments of this application from different perspectives, such as... Figure 2 As shown in (a), the test fixture 12 also includes a first slide 111 and a second slide 112. The first slide 111 extends a predetermined first distance in a first direction, and the second slide 112 extends a predetermined second distance in a second direction different from the first direction.
[0029] For example, the first direction is perpendicular to the second direction. See also... Figure 2 As shown in (a), the first direction can be upward and the second direction can be left.
[0030] In this embodiment, each slide can be equipped with a bracket 114, or it can be without a bracket, meaning the bracket is detachably mounted to the slide. By mounting the bracket to the slide and then controlling the bracket to move upwards and downwards, or to the left or right, various test parts 115 of different sizes and shapes can be accommodated.
[0031] For example, the test part can be a thin-walled part, such as a heat shield in a hybrid vehicle powertrain.
[0032] In this embodiment, different test fixtures can be used with different heat insulation covers. The test fixtures are also replaceable, and the grooves on different test fixtures are different. For example, the direction and number of grooves are different.
[0033] Further, please refer to the above. Figure 2 In (a) and (d), in order to better accommodate test parts of different sizes to be assembled onto the test fixture, the test fixture also includes a third slide 113. After the third slide 113 extends a preset third distance in the first direction, it continues to extend a preset fourth distance in the second direction.
[0034] In this embodiment, the extension distances of the first, second, and third slide grooves can be freely configured, but they should not extend beyond the entire test fixture, as this could easily cause the bracket to detach from the test fixture. However, in some embodiments, to facilitate bracket disassembly, the slide grooves can extend beyond the test fixture, allowing the bracket to be directly detached from the test fixture as it moves along the slide grooves.
[0035] In addition, in some embodiments, the dimensions of the supports provided on each slide are different. These dimensions can refer to the length, width, and height of the support.
[0036] For example, the height of the supports on each slide is different, which allows for the installation of test parts with varying heights. This makes the test fixture more compatible.
[0037] In addition, in some embodiments, reference is continued to be made to the above. Figure 2 In the middle (d), a fourth slide groove is provided on the support. The extension direction of the fourth slide groove is different from the extension direction of the slide groove of the test fixture. The support can slide relative to the slide groove along the extension direction of the fourth slide groove.
[0038] In this embodiment, the size of the groove on the bracket and the groove on the test fixture can be the same, which makes it easy to fix the bracket to the test fixture with fasteners such as bolts.
[0039] In addition to sliding on the slide, the bracket can also be equipped with slides. When the slide of the bracket is perpendicular to the slide on the test fixture, the bracket can move along the slide on the test fixture and also move through its own slide. This can improve the flexibility of the fixed position adjustment and provide more fixed position points for the test fixture to be fixed.
[0040] For example, the extension direction of the fourth groove is perpendicular to the extension direction of the groove of the test fixture.
[0041] In addition, in some embodiments, reference is continued to be made to the above. Figure 1 and Figure 2 In (c), the test fixture is mounted on the vibration table by fixing bolts 116. When the vibration table vibrates according to the set frequency, it drives the test fixture and the test parts mounted on the support of the test fixture to vibrate.
[0042] In this embodiment, taking the heat shield as an example, due to the thin-walled nature of the heat shield, a large installation tolerance will occur, which makes it easy for bolts to loosen during vibration. Therefore, it is necessary to establish a vibration database for such parts in order to quantify the anti-slip safety factor of different types of heat shields.
[0043] In this embodiment, a complete testing setup is constructed, comprising a vibration table, testing instruments, sensors, fixtures, and a computer, forming a database. The fixture is secured to the vibration table with four bolts, and the heat shield, depending on its shape, is fixed to the fixture using different combinations of brackets. Sensors can be installed in different areas of the heat shield, and relevant vibration test data is obtained through the connection between the vibration table, sensors, and testing equipment. A simulation model is simultaneously built based on the fixture for calibration of experimental and simulation data.
[0044] In this embodiment, reference is made to the above. Figure 1 The test parts can be assembled onto the test fixture using various types of bolts. The bolt fixing points can be adjusted according to the different characteristics of the test parts, such as their size and thickness.
[0045] For example, taking the heat shield mentioned above as the test component, the first step is to determine the location of the fixing points on the test fixture. These fixing points are typically bolt holes or threaded holes used to secure the heat shield to the test fixture. The location of these fixing points (including coordinate and angle information) can be accurately measured using measuring tools.
[0046] Secondly, relevant software can be used to create an assembly geometry model between the test fixture and the test part based on information such as the measured fixed point locations and the actual dimensions of the heat shield. For heat shields with complex shapes or structures, equipment such as 3D scanners can be used to collect surface data to improve the accuracy of the assembly geometry model.
[0047] In this embodiment, after establishing the assembly geometry model, appropriate constraints can be added to simulate the actual installation state of the heat shield on the test fixture. For example, constraints may include bolt connections, clamp fixation, etc. Additionally, depending on the test requirements, corresponding loads or boundary conditions can be applied to simulate the stress conditions of the heat shield in the actual working environment.
[0048] Finite element analysis software can be used to perform structural simulation analysis on the established assembly geometry model. Through simulation analysis, the deformation and stress distribution of the heat shield under stress can be predicted. As an evaluation result, the previous assembly geometry model can be further optimized (e.g., adjusting the position of fixing points, adjusting the thickness or material of the heat shield, etc.).
[0049] In this embodiment, taking the heat shield as the test component, after establishing the vibration simulation model, the stress between the bolt and the heat shield in the actual working environment can be obtained through simulation analysis. For example, to understand the stress between the bolt and the heat shield, the reaction force of the heat shield on the bolt during resonance (hereinafter referred to as the simulated support reaction force) can be analyzed. Through this simulated support reaction force and the initial bolt slippage safety factor, at least one candidate bolt of a candidate type can be determined. The analysis of the reaction force on the bolt during heat shield resonance is mainly because the vibration amplitude of the heat shield is the largest relative to normal when it resonates, and the reaction force on the bolt can reach its maximum value, thereby further determining the range of reaction force values.
[0050] In this embodiment, when determining the candidate bolts of the candidate model, the bolt slip safety factor of the test part can be taken as an empirical value, and then the empirical value will be further calibrated and updated.
[0051] In some embodiments, candidate bolt models can be determined based on the simulated support reaction force of the test component and the bolt slip safety factor, which is taken as an empirical value, during vibration simulation testing using a vibration simulation model. Subsequently, by conducting tests on candidate bolts of the candidate models and obtaining test results (e.g., whether the candidate bolts have loosened), the original bolt slip safety factor, which was taken as an empirical value, can be further calibrated.
[0052] The slip safety factor is an important indicator for measuring the safety of bolted connections. It represents the ratio of the maximum load a bolt can withstand before slipping to the actual working load. By using the slip safety factor and simulated support reactions, the main types of loads that the bolt will bear (such as tension only, shear only, or a combination of tension and shear) and the magnitude of the loads can be determined, thus facilitating the selection of candidate bolt models or specifications.
[0053] For example, a table can be pre-built, and the corresponding candidate bolt models can be found from the table using empirical values of simulated support reactions and bolt slip safety factors. For instance, if a vibration simulation model is built using a small single-layer metal heat shield as the test part, and the empirical value of the bolt anti-slip safety factor is 5, the corresponding candidate bolt model could be M6.
[0054] In this embodiment, the connection state between the candidate bolt and the test part can be used to characterize whether the candidate bolt has transitioned from a tightened state to a loosened state. For example, after the candidate bolt is screwed into the bolt hole and the test part is fixed, if the candidate bolt is found to automatically unscrew from the threaded hole during vibration, it indicates that the candidate bolt has entered a loosened state.
[0055] In this embodiment, the set frequency range can include the resonant frequency, so that the maximum vibration amplitude of the test part can be obtained to check whether the candidate bolt will loosen under resonance.
[0056] In this embodiment, if a candidate bolt loosens within a very short vibration period during the continuous vibration of the test fixture, it indicates that the original bolt slippage safety factor, which is based on empirical values, is inaccurate and requires further calibration and optimization. Conversely, if the candidate bolt does not loosen within a long vibration period, it indicates that the original bolt slippage safety factor, which is based on empirical values, is relatively accurate and can be recorded in a table for future reference.
[0057] In this embodiment, taking the aforementioned heat shield as the test component as an example, the heat shield is typically made of metal to facilitate heat dissipation. Furthermore, heat shields can be multi-layered, such as single-layer metal heat shields, double-layer metal heat shields, and triple-layer metal heat shields, etc. The more layers, the thicker the heat shield. By understanding the material properties of the heat shield, a more realistic vibration simulation model can be established.
[0058] In addition, since the heat shield may be fixed to different parts, the size of the heat shield may also vary. For example, heat shields can be divided into small heat shields, medium heat shields and large heat shields.
[0059] In this embodiment, heat shields can be classified according to the number of layers and their size. For example, heat shields can be categorized into small single-layer metal heat shields, medium single-layer metal heat shields, large single-layer metal heat shields, small double-layer metal heat shields, medium double-layer metal heat shields, and small three-layer composite metal heat shields. Different categories of heat shields will have different corresponding resonant frequency ranges.
[0060] In this embodiment, the assembly geometry model can also be updated by adjusting attribute information and fixed position points.
[0061] In this embodiment, the simulated resonance ranges of different types of test parts are different. For example, the simulated resonance range of a small single-layer metal heat shield is around 100 Hz, while that of a medium-sized single-layer metal heat shield is around 90 Hz, and that of a large single-layer metal heat shield is around 80 Hz.
[0062] After obtaining the simulated resonance range of different types of test parts through vibration simulation model, the data can be recorded in a table for easy reference when determining the simulated resonance range of the same type of test parts in the future.
[0063] In this embodiment, the test fixture can perform frequency sweep vibration within the simulated resonance range. The test can be used to determine at which vibration frequency the test part resonates, thereby determining the test resonance frequency.
[0064] For example, taking a simulated resonance range of approximately 100 Hz as an example, the test fixture can be controlled to vibrate the test part at a vibration frequency of 100 Hz to determine whether the test part resonates. If the test part resonates, then 100 Hz is the experimental resonance frequency. If the test part does not resonate, for example, the test part can be continued to vibrate at a vibration frequency of 101 Hz to determine whether the test part resonates. Thus, the single experimental resonance frequency of the test part can be found by frequency sweeping.
[0065] In this embodiment, the resonance range and direction of the working conditions that require durability testing can also be calibrated based on the vibration simulation results. This can improve efficiency, quickly find the resonance range, and avoid inaccuracies in the resonance range.
[0066] In this embodiment, simulation and experimentation are combined. Since the different constraint boundaries when the heat shield is fixed to different parts affect the natural frequency of the heat shield assembly, traditional component-level simulations do not consider the constraint on opposing parts in assembly-level experiments. In this embodiment, by modeling the test fixture built for the experiment, the assembly frequency under different conditions can be reproduced, the accuracy of the test results can be calibrated, and frequency sweep tests can be used to cross-verify with the simulation. Then, durability vibration tests are performed on the first few frequencies to specifically test the durability performance of the heat shield.
[0067] In this embodiment, finite element structural simulation simulates a real physical system (e.g., an assembly geometry model and corresponding load conditions) using mathematical approximations. Here, a mode refers to the natural vibration pattern of a structure at a specific frequency. Each mode has its specific natural frequency (also called characteristic frequency) and corresponding mode shape. A mode shape refers to the pattern of relative displacements at various points on the structure under a given mode. It describes the relative motion relationships between the parts of the structure during vibration.
[0068] In some embodiments, there may be multiple candidate bolt types, such as M6 bolts, M5 bolts, and M4 bolts, etc. Different candidate bolt types can be used to fix the test part, and then the test fixture can be controlled to vibrate according to a set frequency range to obtain the connection status between each candidate bolt type and the test part.
[0069] In this embodiment, after determining a recommended bolt model based on the simulated support reaction force and the bolt slip safety factor, other bolt models with smaller sizes than the recommended bolt model can be obtained, and then the recommended bolt model and other bolt models are determined as candidate models.
[0070] For example, Table 1 below is a vibration data table provided in the embodiments of this application. As shown in Table 1 below, the bolt slippage safety factor can be calibrated through simulation and experiment.
[0071] Table 1
[0072]
[0073] Referring to Table 1 above, the simulated recommended bolt model is obtained by simulating the support reaction force and using an empirically determined bolt slip safety factor. Experiments are then conducted using the simulated recommended bolt model and a smaller bolt size to examine the loosening within the resonance range. Iterative tests are performed with different bolts and washers, and the results are recorded to calibrate the anti-slip safety factor. The simulated recommended bolt model is the recommended bolt model; for example, if the simulated recommended model is M6, other bolt models can be smaller than M6, such as M5.
[0074] In addition, in this embodiment, to obtain accurate test data and determine the optimal bolt fit for the test part, washers, such as wire washers and rubber washers, can be added between the bolt and the test part. Wire washers and rubber washers can bridge the gap between two adjacent bolt sizes, thus more accurately identifying the optimal bolt fit. For example, referring to Table 6 above, tests using M5+rubber washers and M5+wire washers revealed that they also loosened; therefore, the M5 bolt size is not suitable as the optimal fit.
[0075] In this embodiment, the preset vibration duration can be a standard process value, such as 100 hours. Referring to Table 1 above, the M6 bolt did not loosen even after 100 hours of vibration, while the M5 bolt loosened in less than 100 hours regardless of whether steel wire washers or rubber washers were added. This shows that the M5 bolt is not suitable for fixing test parts. If the empirical value of the original bolt slippage safety factor is 5, then this value can be kept unchanged.
[0076] Furthermore, if an M6 bolt loosens after 100 hours of continuous vibration, it indicates that the original bolt slip safety factor was too low. For example, if the empirical value of the original bolt slip safety factor is 5, then the bolt slip safety factor can be increased. This way, when using bolts to fix the test part subsequently, the appropriate bolt type will be selected based on the updated and adjusted bolt slip safety factor, improving the reliability of the test part.
[0077] Furthermore, in other embodiments, if the recommended bolt type does not loosen within a preset vibration time, it can be determined whether other bolt types loosen within the preset vibration time; then, if other bolt types do not loosen, the bolt slip safety factor is updated to the second bolt slip safety factor; or, if other bolt types loosen, the bolt slip safety factor remains unchanged.
[0078] In this embodiment, M6 is used as the recommended bolt type, and M5 is used as another bolt type. If it is found in the test that neither M6 nor M5 bolts loosen, then M5 can actually be used as the best fit for the test part. In this case, the original bolt slippage safety factor can be reduced.
[0079] The above description is merely a specific embodiment of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.
Claims
1. A test fixture, characterized by, The test tool is provided with at least one sliding groove extending in different directions, the sliding groove is provided with a support which can slide towards the extending direction, and the support is used for bolt-fastening different types of test parts; The test tool comprises a first sliding groove and a second sliding groove, the first sliding groove extends in a first direction by a preset first distance, and the second sliding groove extends in a second direction different from the first direction by a preset second distance; The test tool further comprises a third sliding groove, after the third sliding groove extends in the first direction by a preset third distance, the third sliding groove continues to extend in the second direction by a preset fourth distance.
2. The test fixture of claim 1, wherein, The first direction is perpendicular to the second direction.
3. The test fixture of claim 1, wherein, The sizes of the supports arranged on each sliding groove are different from each other.
4. The test fixture of claim 1, wherein, The test tool is arranged on a vibration table through a fixing bolt, and the vibration table drives the test tool and the test parts arranged on the supports of the test tool to vibrate when vibrating according to a set frequency.
5. The test fixture of claim 1, wherein, The support is provided with a fourth sliding groove, the extending direction of the fourth sliding groove is different from the extending direction of the sliding groove of the test tool, and the support can slide along the extending direction of the fourth sliding groove relative to the sliding groove.
6. The test fixture of claim 5, wherein, The extending direction of the fourth sliding groove is perpendicular to the extending direction of the sliding groove of the test tool.
7. A test system, characterized by The test tool of any one of claims 1-6 is arranged on the vibration table, the test parts are arranged on the test tool through bolts, the sensor is arranged on the test parts, the test device is connected with the sensor and the electronic device respectively, and the test device is used for collecting the vibration data of the sensor and transmitting the vibration data to the electronic device. The vibration table is used for driving the test tool and the test parts arranged on the test tool to vibrate according to a set frequency. The sensor is used for collecting vibration data of the sensor and transmitting the vibration data to the electronic device. The electronic device is used for determining whether the test parts resonate according to the vibration data.
8. The system of claim 7, wherein, The test parts are heat insulation covers.