Research method on dimensional wear law and service reliability of friction pair of landing gear door lock

Abstract

The present invention relates to the technical field of repairing landing gear door retracted position locks, specifically a method for studying the dimensional wear pattern and service reliability of the friction pair of the landing gear door lock, comprising the following steps: step (1) statistically analyzing the dimensional wear pattern of the friction pair based on measured data; step (2) theoretically analyzing the sealing performance of the friction pair based on finite element analysis; step (3) conducting experimental verification based on the product working performance of the friction pair dimensional wear pattern and the results of the statistical analysis in step (1) and the theoretical analysis in step (2); and step (4) determining the tolerance size for reliable use of the friction pair of the landing gear door lock based on the results of the theoretical analysis in step (2) and the experimental verification in step (3). The present invention can obtain the tolerance size for reliable use of the product, effectively solving the problem of product failure caused by product dimensional deviation during the repair process of the retracted position lock of the landing gear door, reducing the product failure rate, and ensuring the quality of the product repair.

Description

Technical Field

[0001] The present invention relates to the technical field of repairing a landing gear door retracted position lock, and in particular to a method for studying the dimensional wear law and service reliability of a landing gear door lock friction pair. Background Art

[0002] Landing gear door lock is also called landing gear door retracted position lock, which is mainly used to lock the landing gear door. During use, the friction pair that plays a sealing role will have dimensional wear and tear, which will affect the sealing performance of the product. Figure 1 As shown, attached Figure 1 A, B, C, and D are moving friction pairs that act as seals.

[0003] Especially as the aircraft's service life continues to increase and the depth of aircraft repairs continues to increase, repairs based on the original design standards will result in high product part size deviation rates and high product failure rates, making it difficult to meet the maintenance needs of the landing gear door retracted position lock. Therefore, it is necessary to study the loss law of the size of the moving friction pair of the landing gear door retracted position lock, conduct theoretical analysis, experimental demonstration, etc. based on the actual use of the product, improve the product maintenance technical requirements, improve the product repair level and reliability, and improve the quality of aircraft repair. Summary of the Invention

[0004] To address the aforementioned technical issues, this paper proposes a method for studying the dimensional wear patterns and operational reliability of the friction pair of a landing gear door lock. This method is used to study the dimensional wear patterns and operational reliability of the friction pair of the retracted position lock, thereby ensuring the quality, stability, and reliability of maintenance during the retracted position lock.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0006] The research method for the dimensional wear law and service reliability of the landing gear door lock friction pair includes the following steps:

[0007] Step (1) Statistical analysis of friction pair dimensional wear patterns based on measured data;

[0008] Step (2) conducting a theoretical analysis of the sealing performance of the friction pair based on finite element analysis;

[0009] Step (3) conducting experimental verification of the product's working performance based on the friction pair's dimensional wear pattern and in accordance with the statistical analysis in step (1) and the theoretical analysis in step (2);

[0010] Step (4) determines the tolerance size for reliable use of the landing gear door lock friction pair based on the results of the theoretical analysis of step (2) and the experimental verification of step (3).

[0011] Preferably, in step (1), a statistical analysis is performed on the dimensional wear of the kinematic friction pairs during the first three overhauls.

[0012] Preferably, in step (1), the dimensional loss law of the friction pair is obtained by using a dimensional analysis method of making a scatter plot, removing noise points, calculating and predicting the data center point, and predicting the maximum value.

[0013] Preferably, the specific process of step (2) is: establishing a product simulation model, combining the superelastic sealing model to obtain a finite element simulation model and performing finite element analysis, setting parameters for the model, obtaining corresponding contact stress simulation analysis results, and using the least squares method to perform numerical simulation on the simulation results to obtain the theoretical tolerance size of the friction pair.

[0014] Preferably, the parameter setting includes property setting, boundary condition setting, mesh division, fit clearance setting, and hydraulic pressure setting.

[0015] Preferably, the specific process of step (three) is: selecting the landing gear door lock and grinding the size of the part mating surface to form the required fitting clearance value, assembling the product after grinding, and conducting a working performance test according to the actual working conditions of the product after assembly.

[0016] Preferably, the working performance test content is: conducting 5000 retraction and extension tests, and checking the sealing of the product and the size of product parts during the test, and conducting an unlocking pressure test after 5000 retraction and extension tests to verify the tolerance size of the product.

[0017] Preferably, if the product sealing fails to meet the requirements during the retraction and extension test, the fit clearance value is re-determined and the test is carried out; if the product sealing meets the requirements, the product part dimensions are disassembled and checked; if the part dimensions fail to meet the requirements, the fit clearance value is re-determined and the test is carried out again.

[0018] Preferably, during the unlocking pressure test, check whether the unlocking force is ≤9.8 MPa. If it fails, redefine the fit clearance value and re-conduct the test.

[0019] The beneficial effects of the present invention are:

[0020] The present invention provides a method for studying the dimensional wear pattern and reliability of the friction pair of a landing gear door lock, thereby obtaining the tolerance size for reliable use of the product, and effectively solving the problem of product failure due to dimensional tolerance during the repair of the retracted position lock of the landing gear door; the present invention can be used for studying the dimensional wear pattern and reliability of the motion friction pair of similar products, and can solve similar technical problems; the present invention can control the quality stability and reliability of the maintenance of the retracted position lock of the landing gear door, thereby reducing the product failure rate and ensuring the quality of product repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0022] Figure 1 This is a schematic diagram of the existing landing gear door lock structure;

[0023] Figure 2 It is a logic block diagram of the present invention;

[0024] Figure 3 This is a flow chart of theoretical analysis of the sealing performance of the friction pair of the present invention;

[0025] Figure 4 This is a flow chart of the test verification of the present invention. DETAILED DESCRIPTION

[0026] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0027] like Figure 2 As shown in FIG, the research method of the dimensional wear law and service reliability of the friction pair of the landing gear door lock includes the following steps:

[0028] Step (1) Statistical analysis of friction pair dimensional wear patterns based on measured data.

[0029] Based on the measured data, the dimensional loss law is studied. During the use of the landing gear door lock, Figure 1 The four moving friction pairs involved in sealing performance, A, B, C, and D, exhibit dimensional loss. By statistically analyzing the dimensions of the moving friction pairs from the first three overhauls, and employing dimensional analysis methods such as creating scatter plots, removing noise points, calculating and predicting data centers, and predicting maximum values, we determined the dimensional loss patterns, laying the foundation for subsequent theoretical analysis and experimental verification. The following table provides a dimensional statistical table.

[0030]

[0031]

[0032] Step (2) Conduct theoretical analysis of the friction pair sealing performance based on finite element analysis. Figure 3 shown.

[0033] Based on finite element analysis, a theoretical analysis of the sealing performance of the moving friction pair is carried out. According to the actual working conditions of the product, a finite element analysis is performed on the landing gear door lock. By establishing a product simulation model and combining it with a hyperelastic sealing model, a finite element analysis is carried out. The finite element simulation model is set with material and other properties, boundary conditions such as loads, and meshing. At the same time, different fitting clearances and hydraulic pressures are set to obtain the corresponding contact stress simulation results. The simulation results are numerically simulated using the least squares method to obtain the theoretical tolerance size of the moving friction pair.

[0034] Step (3) is to conduct experimental verification based on the product performance of the friction pair size wear law and the results of the statistical analysis in step (1) and the theoretical analysis in step (2). Figure 4 shown.

[0035] Based on the laws of dimensional wear and tear, the product's performance testing and verification research, based on the results of statistical and theoretical analysis, selected the dimensions of the mating surfaces of the landing gear door's retracted position lock components and polished them to achieve the required clearance values. After polishing, the product was assembled and then subjected to performance testing under actual operating conditions. The performance test consisted of 5,000 retraction and extension cycles, during which the product's sealing and component dimensions were checked. Following these cycles, an unlocking pressure test was performed to verify the product's tolerances. If the product's sealing failed during the retraction and extension test, the clearance values ​​were redefined and tested again. If the product's sealing passed, the component dimensions were disassembled and inspected. If the component dimensions failed, the clearance values ​​were redefined and tested again. During the unlocking pressure test, the unlocking force was checked to ensure it was ≤9.8 MPa. If not, the clearance values ​​were redefined and tested again.

[0036] Step (4) determines the tolerance dimensions for reliable use of the friction pairs A, B, C, and D on the landing gear door lock based on the theoretical analysis of step (2) and the experimental verification results of step (3).

[0037] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and description merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A research method for the dimensional wear pattern and service reliability of the friction pair of landing gear door locks, characterized by: The following steps are involved: Step (1) Statistical analysis of friction pair dimensional wear patterns based on measured data; Step (2) conducting a theoretical analysis of the sealing performance of the friction pair based on finite element analysis; Step (3) conducting experimental verification of the product's working performance based on the friction pair's dimensional wear pattern and in accordance with the statistical analysis in step (1) and the theoretical analysis in step (2); Step (4) determines the tolerance size for reliable use of the landing gear door lock friction pair based on the results of the theoretical analysis of step (2) and the experimental verification of step (3).

2. The method for studying the dimensional wear pattern and service reliability of the landing gear door lock friction pair according to claim 1, characterized in that: In step (1), a statistical analysis is performed on the dimensional wear of the kinematic friction pairs during the first three overhauls.

3. The method for studying the dimensional wear pattern and service reliability of the landing gear door lock friction pair according to claim 1, characterized in that: In step (1), the dimensional loss law of the friction pair is obtained by using a dimensional analysis method of making a scatter plot, removing noise points, calculating and predicting the data center point, and predicting the maximum value.

4. The method for studying the dimensional wear pattern and service reliability of the landing gear door lock friction pair according to claim 1, characterized in that: The specific process of step (2) is as follows: establish a product simulation model, combine the superelastic seal model to obtain a finite element simulation model and perform finite element analysis, set the model parameters, obtain the corresponding contact stress simulation analysis results, and use the least squares method to perform numerical simulation on the simulation results to obtain the theoretical tolerance size of the friction pair.

5. The method for studying the dimensional wear pattern and service reliability of the landing gear door lock friction pair according to claim 4, characterized in that: Parameter settings include property settings, boundary condition settings, mesh division, fit clearance settings, and hydraulic pressure settings.

6. The method for studying the dimensional wear pattern and service reliability of the friction pair of a landing gear door lock according to claim 1, characterized in that: The specific process of step (3) is as follows: the dimensions of the mating surfaces of the landing gear door lock parts are selected and polished to form the required fitting clearance value, the product is assembled after polishing, and after assembly, a working performance test is performed according to the actual working conditions of the product.

7. The method for studying the dimensional wear pattern and service reliability of the landing gear door lock friction pair according to claim 6, characterized in that: The working performance test content is: conduct 5000 retraction and extension tests, and check the sealing of the product and the size of the product parts during the test. After 5000 retraction and extension tests, conduct an unlocking pressure test to verify the tolerance size of the product.

8. The method for studying the dimensional wear pattern and service reliability of the landing gear door lock friction pair according to claim 7, characterized in that: If the product sealing fails to meet the requirements during the retraction and extension test, the fit clearance value will be re-determined and the test will be carried out. If the product sealing meets the requirements, the product parts will be disassembled and the dimensions will be checked. If the dimensions of the parts fail to meet the requirements, the fit clearance value will be re-determined and the test will be carried out again.

9. The method for studying the dimensional wear pattern and service reliability of the landing gear door lock friction pair according to claim 7, characterized in that: During the unlocking pressure test, check whether the unlocking force is ≤9.8MPa. If it fails, redefine the fit clearance value and repeat the test.

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