Design method of hub driving key for aircraft wheel

Abstract

The invention discloses a hub driving key design method for an aviation aircraft wheel, and particularly relates to the field of aviation brake aircraft wheels. Comprising the steps of determining the number of driving keys according to a tire combination diameter; acquiring stress during right-angle transition between the inner cavity of the airplane wheel hub and the driving key, and determining a cycle number corresponding to the current stress; determining the cycle number required in the whole life cycle of the driving key; according to the ratio of the two cycle numbers, determining a transition fillet between the inner cavity of the airplane wheel hub and the driving key; determining the width of the driving keys according to the number of the driving keys; according to the normal acting force transmitted to the driving keys by the braking torque and the number of the driving keys, the normal acting force transmitted to the single driving key by the braking torque is determined, and the extrusion stress of the single driving key is determined; according to the width and the height of the driving key, determining the anti-bending section modulus and the maximum bending moment of the single driving key, and according to the anti-bending section modulus and the maximum bending moment, determining the maximum bending stress of the driving key; and when the maximum bending stress reaches a second preset condition, obtaining the driving key.

Description

Technical Field

[0001] This application relates to the field of aircraft brake wheels, and more particularly to a design method for a hub drive key for aircraft wheels. Background Technology

[0002] Aircraft wheel brakes are typically installed within the inner cavity of the wheel hub of the wheel assembly, and are mounted on the aircraft's main landing gear together with the wheel assembly. The brake system mainly includes the brake housing, heat storage assembly, and cylinder block assembly. The heat storage assembly consists of a moving disc assembly, a pressure disc assembly, a stationary disc, and a pressure plate assembly. Drive keys are evenly distributed on the surface of the inner cavity of the wheel hub. The wheel guide rails are mounted on the drive keys via guide rail screws and engage with steel clips evenly distributed on the outer circumference of the moving disc assembly.

[0003] When the wheels rotate, the drive key on the hub drives the moving disc assembly to rotate synchronously with the wheels via the guide rail. The pressure disc assembly, bearing disc assembly, stationary disc, brake housing, and cylinder seat assembly remain relatively stationary, while the moving disc assembly rotates relative to the stationary disc. When the aircraft brakes, high-pressure brake fluid enters the piston chamber. Under the braking pressure, the piston moves forward, pressing the stationary pressure disc assembly, stationary disc, and bearing disc assembly against the rotating moving disc assembly. At this time, the frictional torque generated between the brake discs is transmitted to the wheel assembly through the moving disc assembly, causing the wheels to brake. When the brakes are released, the braking pressure is released, the moving disc assembly and stationary disc disengage, and the wheels are released from the brakes. During braking, to ensure effective wheel braking, the frictional torque generated by the brakes is transmitted to the guide rail through the moving disc clamp, and then to the hub drive key and guide rail screws. In addition, most of the kinetic energy during aircraft braking is absorbed by the aircraft wheels. During braking, the brake disc temperature can reach up to 1000℃. The hub drive key is located near the brake disc and operates in a high-temperature environment, which can cause some degradation in the material properties. Therefore, the root of the hub drive key has low strength and fatigue resistance under high temperature conditions, and is prone to cracking. Summary of the Invention

[0004] The main objective of this application is to provide a design method for hub drive keys for aircraft wheels, which aims to solve the problem of low strength and fatigue resistance of the root of the drive key under high temperature environment.

[0005] To achieve the above objectives, this application provides a design method for a hub drive key for an aircraft wheel, comprising: determining the number of drive keys based on the tire engagement diameter and a first preset relationship; obtaining the stress at the right-angle transition between the inner cavity of the wheel hub and the drive key, querying the stress-cycle number curve corresponding to the aircraft wheel hub material, determining the cycle number corresponding to the current stress, and using it as the first cycle number; determining the required cycle number over the entire life cycle of the drive key, and using it as the second cycle number; determining the transition radius between the inner cavity of the wheel hub and the drive key based on the ratio of the second cycle number to the first cycle number; determining the width of the drive key based on the number of drive keys and the second preset relationship; and determining the height and length of the drive key based on a third preset relationship. The compression area between a single drive key and the guide rail is determined; based on the normal force transmitted by the braking torque to the drive key and the number of drive keys, the normal force transmitted by the braking torque to a single drive key is determined; based on the normal force transmitted by the braking torque to a single drive key and the compression area between the single drive key and the guide rail, the compression stress of a single drive key is determined; when the compression stress reaches the first preset condition, based on the width and height of the drive key and the fourth preset relationship, the flexural section modulus of a single drive key and the maximum bending moment borne by a single drive key are determined; based on the flexural section modulus of a single drive key and the maximum bending moment borne by a single drive key, the maximum bending stress of a single drive key is determined; when the maximum bending stress reaches the second preset condition, the final drive key is obtained.

[0006] Optionally, if the compressive stress does not reach the first preset condition, the length of the drive key is increased, and the compressive area between a single drive key and the guide rail is re-determined based on the height and length of the drive key, until the compressive stress reaches the first preset condition; the first preset condition is that the compressive stress is less than or equal to the allowable compressive stress of the drive key material at high temperature.

[0007] Optionally, if the maximum bending stress does not reach the second preset condition, the width of the driving key is increased, and the section modulus of bending resistance of a single driving key is re-determined based on the width and height of the driving key, until the maximum bending stress reaches the second preset condition; the second preset condition is that the maximum bending stress is less than or equal to the allowable bending stress of the driving key material at high temperature.

[0008] Optionally, the first preset relationship is: ; In the formula, Ra is the tire engagement diameter that is matched with the wheel.

[0009] Optionally, the formula for determining the number of cycles required over the entire lifespan of the drive key is:

[0010] In the formula, This refers to the number of takeoffs and landings throughout the entire lifespan of the aircraft wheel hub. This refers to the distance a single landing gear wheel needs to roll. To design the non-uniformity coefficient, This is the roll radius.

[0011] Optionally, the transition fillet between the inner cavity of the wheel hub and the drive key is determined based on the ratio of the second cycle number to the first cycle number, including: when the ratio of the second cycle number to the first cycle number is greater than 5, the transition fillet between the inner cavity of the wheel hub and the drive key is selected as R22-R25; when the ratio is less than or equal to 5, the transition fillet between the inner cavity of the wheel hub and the drive key is selected as R18-R20.

[0012] Optionally, the second preset relationship is: ; In the formula, This represents the number of drive keys.

[0013] Optionally, the third preset relationship is: ; In the formula, h is the height of the drive key and L1 is the length of the drive key; The method for determining the normal force transmitted from the braking torque to a single drive key is as follows:

[0014]

[0015] In the formula, This is the maximum braking torque. The coefficient for uneven work performance. The radius of interaction between the drive key and the guide rail. This is the dynamic load factor. This represents the number of drive keys.

[0016] Optionally, the fourth preset relationship is: ; In the formula, b is the width of the driving key and h is the height of the driving key; The maximum bending moment borne by a single drive key is determined as follows:

[0017] In the formula, This refers to the normal force that transmits the braking torque to the individual wheel hub drive key. It is the distance from the centerline of the contact surface between the wheel guide rail and the moving plate steel clamp to the centerline of the side of the wheel hub drive key.

[0018] Optionally, the compressive stress of a single drive key is the ratio of the normal force transmitted to the single drive key by the braking torque to the compressive area of ​​the single drive key and the guide rail; the maximum bending stress of a single drive key is the ratio of the maximum bending moment it bears to the bending section modulus of the single drive key.

[0019] Compared with the prior art, the beneficial effects of this application are as follows: The design method for hub drive keys for aircraft wheels of the present invention addresses the issue of limited known parameters during the preliminary design stage of the wheel. By determining the number of drive keys based on the tire mating diameter, the design iteration speed can be accelerated while ensuring design reliability. Based on the stress-cycle number relationship between the wheel hub cavity and the drive key, the cycle number corresponding to the current stress is determined. Then, based on the ratio of the required cycle number over the entire lifespan of the drive key to this cycle number, the transition fillet between the wheel hub cavity and the drive key is determined. The transition fillet determined in this way can disperse destructive high local stress, inhibit the initiation and propagation of fatigue cracks, thereby extending the lifespan of the drive key, but it also increases weight. Designing the transition fillet of the hub drive key using this method ensures excellent machining performance while guaranteeing sufficient lifespan for the wheel hub. Adjusting the width and length of the drive key based on the compressive and bending stresses it bears further prevents fatigue fracture of the drive key during repeated takeoff and landing impacts and rolling cycles, improving the strength and fatigue resistance of the aircraft wheel drive key. Attached Figure Description

[0020] Figure 1 A schematic diagram showing the installation of the drive key for an aircraft wheel on the wheel hub; Figure 2 A schematic diagram of the drive key for an aircraft wheel; Figure 3 A cross-sectional view of the drive key for an aircraft wheel; Figure 4 This is a flowchart illustrating a design method for a hub drive key for aircraft wheels according to this application.

[0021] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions 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, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It is worth noting that the aircraft wheel drive key is a critical load-bearing key for transmitting braking torque, with extremely stringent design requirements. Its core function is to reliably transmit the braking torque generated by the brake disc. For example... Figure 1As shown, the hub drive key 2 is located on the inner surface of the wheel hub 1, and a grooved guide rail 3 is mounted on it via guide rail screws 4. When the aircraft brakes, the frictional torque generated between the brake discs is transmitted through the moving disc to the steel clamp, and then through the guide rail to the hub drive key and guide rail screws, thus braking the wheel. Figure 2-3 As shown, the drive key 2 is a cuboid structure. One side of the cuboid is connected to the wheel hub 1, and two threaded holes are opened on the surface opposite to this side. The height h of the drive key 2 is in the radial direction of the wheel hub 1, the length L1 is in the axial direction of the wheel hub 1, and the width b is in the direction parallel to the wheel's heading.

[0024] Embodiments of the present invention provide a design method for a hub drive key for aircraft wheels, such as... Figure 4 As shown, the specific steps include: Step S1: Determine the number of drive keys based on the tire engagement diameter and the first preset relationship; the first preset relationship is: ; In the formula, Ra is the tire diameter that is matched with the wheel, and the unit is inches.

[0025] Understandably, the drive keys on aircraft wheels bear the torque load requirements. The greater the weight of the aircraft, the greater the braking torque required, and the larger the wheel diameter. A larger wheel diameter results in a larger circumference of the hub cavity, meaning more drive keys can be evenly distributed while maintaining the structural integrity of the wheel hub. For aircraft wheels with high load requirements, more drive keys distribute the braking torque more evenly across the hub, reducing stress concentration. Furthermore, when designing the number of drive keys, safety considerations must be taken into account, requiring a certain design margin. This means that if one drive key fails, the remaining drive keys can still bear the braking torque, ensuring safe takeoff and landing. This embodiment derives this empirical formula by summarizing long-term experience in aircraft wheel design, testing, and production, and performing regression analysis on the mating diameter of nearly one hundred types of wheel-matched tires and the dimensions of the hub drive keys. In the design of these wheels, the load-bearing capacity was calculated based on 1.5 times the operating load, leaving sufficient safety margin.

[0026] Furthermore, the drive keys on the wheel are machined by milling, and a large-radius fillet transition is required between the drive keys and the wheel hub wall. Due to the large number of drive keys on the wheel hub, this increases machining difficulty and structural weight, and each drive key transition point is a stress concentration point, potentially becoming the initiation point for fatigue cracks. Therefore, the transition fillet between the wheel hub cavity and the drive keys needs to be designed according to stress. The large-radius transition fillet must ensure excellent machining performance while also guaranteeing sufficient wheel hub lifespan. Details are as follows.

[0027] Step S2: Obtain the stress when the inner cavity of the aircraft wheel hub transitions at a right angle with the drive key; query the stress-cycle number curve corresponding to the aircraft wheel hub material; determine the cycle number corresponding to the current stress; and use it as the first cycle number. Specifically, under normal design loads, the stress at the right-angle transition between the wheel hub cavity and the drive key can be obtained through theoretical calculations or simulation analysis software. For example, a finite element model of the wheel can be established using ABAQUS finite element analysis software, where the wheel hub cavity and the drive key transition at a right angle. Braking torques are applied to one side of the drive key. A design margin of 1.2-1.8 times can be used in the calculation to finally obtain the maximum stress at the root of the drive key.

[0028] Step S3: Determine the number of cycles required throughout the entire lifespan of the drive key, and use this number as the second cycle number; the formula for determining the number of cycles required throughout the entire lifespan of the drive key is:

[0029] In the formula, This refers to the number of takeoffs and landings throughout the entire lifespan of the aircraft wheel hub. This refers to the distance a single landing gear wheel needs to roll. The coefficient of non-uniformity is determined by the aircraft type and varies in value, generally ranging from 0.5 to 0.8. This is the roll radius under normal design load.

[0030] Step S4: Determine the transition fillet between the inner cavity of the wheel hub and the drive key based on the ratio of the second cycle number to the first cycle number; Specifically, when the ratio of the second cycle number to the first cycle number is greater than 5, the transition fillet between the inner cavity of the wheel hub and the drive key is selected as R22-R25; when the ratio is less than or equal to 5, the transition fillet between the inner cavity of the wheel hub and the drive key is selected as R18-R20. In practical applications, for aircraft wheels with high impact requirements, a design margin of 1.2-1.8 times is adopted during the design process.

[0031] It's worth noting that the relationship between the hub cavity and the transition fillet of the drive key is to achieve lightweight, compact, and functional wheel hubs while ensuring sufficient strength and rigidity. The drive key and its transition fillet are located within the hub cavity, and the cavity's spatial dimensions directly limit the maximum design size of the transition fillet. The transition fillet's function is to reduce stress concentration between the hub cavity and the drive key. If the fillet is too small, the stress concentration effect is significant, generating an extremely high stress peak at the root of the drive key, becoming the origin of fatigue cracks. A large fillet effectively smooths stress flow, significantly reducing the stress peak at the drive key root and greatly improving the fatigue life of the component. Ideally, the larger the transition fillet, the better; however, due to the space limitations of the hub cavity and the height of the drive key, the transition fillet value must be designed within a limited range. To ensure a smooth transition and ease of machining, for hubs with a tire mating diameter greater than 13 inches, the transition fillet should be no less than R15; for hubs with a tire mating diameter greater than 18 inches, the transition fillet should be no less than R20. For rims with a tire engagement diameter of no more than 13 inches, the transition radius should be no less than R10.

[0032] Understandably, the braking torque borne by all drive keys is constant. As the number of drive keys increases, the force shared by each drive key decreases proportionally. With a constant force on a single drive key, reducing its width significantly increases the compressive and shear stresses of that individual drive key. Using a small number of wider drive keys results in each key sharing a larger load, requiring sufficient width to reduce stress and keep it within the allowable range of the structural design. Conversely, using a large number of narrower drive keys reduces the force shared by each key; even with a smaller width, the stress must still be within the allowable design range. The benefit of a larger number of drive keys is a more even load distribution, but it also leads to more stress concentration points. Overall, while a "few but wide" design reduces stress concentration points, excessively wide drive keys result in a more complex stress state in the transition area between the drive key and the inner wall of the hub, and wider drive keys also lead to uneven stress distribution. While the "multiple and narrow" design reduces stress concentration points, the narrower drive key results in a smaller transition radius between the drive key and the inner wall of the hub, leading to a higher stress concentration factor and affecting the fatigue life of the aircraft wheel hub. Therefore, this embodiment calculates the width of the drive key using the following method.

[0033] Step S5: Determine the width of the drive keys based on the number of drive keys and the second preset relationship; the second preset relationship is: ; In the formula, This represents the number of drive keys.

[0034] In this embodiment, the relationship between the number and width of the drive keys is as follows: The core function of the drive keys is to transfer braking torque from the brake disc to the wheel hub, thereby achieving aircraft deceleration. The number and width of the drive keys are two key design parameters. When the braking torque is constant, the more drive keys there are, the more keys participate in sharing the total braking torque, and the smaller the torque and pressure that each drive key needs to bear. The drive keys are arranged circumferentially in the inner cavity of the wheel hub. When the wheel hub mating diameter is determined, the circumference of the circumferential arrangement of the drive keys is fixed. The more drive keys there are, the smaller the axial arc length that each drive key can arrange. Within the limited arc length of the inner cavity of the wheel hub, if it is necessary to enhance the design strength of the drive keys, the drive keys need to be widened. However, increasing the number will compress the usable width of each drive key. On the other hand, a huge amount of heat is generated during braking. The drive keys are close to the brake disc. With a large number of drive keys, it is beneficial to disperse the heat transferred to the wheel hub, prevent local overheating of the wheel hub, and thus ensure the stability of tire pressure and the reliability of the wheel hub material performance. In summary, the number of drive keys is the result of a comprehensive trade-off within the limited space of the wheel hub to ensure heat transfer requirements, transmission of braking torque, and strength and lifespan requirements. Based on existing design experience and requirements analysis, the width and number of drive keys can be expressed by the above formula to facilitate rapid design iteration.

[0035] Step S6: Determine the pressing area between a single drive key and the guide rail based on the height and length of the drive key and the third preset relationship; the third preset relationship is: ; In the formula, h is the height of the drive key, and L1 is the length of the drive key (the effective contact length of the hub drive key after removing the length of the relief groove), which is usually set with an initial value.

[0036] The above steps can be used to obtain the number of drive keys, the transition radius between the inner cavity of the wheel hub and the drive key, and the width of the drive key. When transmitting braking torque, the drive key of the wheel hub mainly bears the compressive and bending stress. Therefore, the width and length of the drive key need to be adjusted according to the compressive and bending stress it bears, as follows.

[0037] Step S7: Determine the normal force of the braking torque transmitted to a single driving key based on the normal force transmitted by the braking torque to the driving key and the number of driving keys. ;

[0038]

[0039] In the formula, This is the maximum braking torque. The coefficient for uneven work performance. The radius of interaction between the drive key and the guide rail. This is the dynamic load factor. This represents the number of drive keys.

[0040] Step S8: Determine the compressive stress of a single drive key based on the normal force transmitted to the single drive key by the braking torque and the compression area between the single drive key and the guide rail. Specifically, the compressive stress of a single drive key is the ratio of the normal force transmitted from the braking torque to the single drive key to the compressive area between the single drive key and the guide rail, i.e. .

[0041] Step S9: When the compressive stress reaches the first preset condition, determine the flexural section modulus of a single drive key and the maximum bending moment borne by a single drive key based on the width and height of the drive key and the fourth preset relationship; wherein, the first preset condition is that the compressive stress is less than or equal to the allowable compressive stress of the drive key material at high temperature. The fourth preset relationship is: ; In the formula, b is the width of the driving key and h is the height of the driving key.

[0042] The maximum bending moment borne by a single drive key is determined as follows:

[0043] In the formula, This refers to the normal force that transmits the braking torque to the individual wheel hub drive key. It is the distance from the centerline of the contact surface between the wheel guide rail and the moving plate steel clamp to the centerline of the side of the wheel hub drive key.

[0044] Specifically, when the compressive stress exceeds the allowable compressive stress of the drive key material at high temperature, the length of the drive key is increased, and the process returns to step S6 to re-determine the extrusion area between a single drive key and the guide rail based on the height and length of the drive key, until the compressive stress reaches the first preset condition, thus obtaining the final length of the drive key. For example, the length of the drive key is increased by 1 mm each time.

[0045] Step S10: Determine the maximum bending stress of a single driving key based on its section modulus of bending resistance and the maximum bending moment it can withstand. Specifically, the maximum bending stress of a single driving key is the ratio of the maximum bending moment to the section modulus of the single driving key: .

[0046] Step S11: When the maximum bending stress reaches the second preset condition, the final driving key is obtained.

[0047] The second preset condition is that the maximum bending stress is less than or equal to the allowable bending stress of the driving key material at high temperature. Specifically, when the maximum bending stress exceeds the allowable bending stress of the driving key material at high temperature, the width of the driving key is increased, and the section modulus of bending resistance of a single driving key is re-determined based on the width and height of the driving key, until the maximum bending stress reaches the second preset condition. For example, the width of the driving key is increased by 1 mm each time.

[0048] Furthermore, although the drive key and the wheel guide rail are interference-fitted during operation, they are subjected to alternating and vibration loads during wheel rolling. Slight relative slippage may still occur in the contact area between the drive key and the inner side of the guide rail, leading to fretting fatigue. The height of the drive key affects the size of its contact area with the guide rail and the pressure distribution; an unreasonable drive key height may exacerbate fretting wear. Therefore, this embodiment reduces fretting wear between the hub drive key and the guide rail through the following methods: 1. Avoid using materials with the same or similar hardness for the wheel hub and guide rail. Generally, a combination of "hard" and "soft" materials should be chosen. For example, the hardness of the wheel hub drive key material and the guide rail material can differ by two hardness levels.

[0049] 2. The guide rail is made of a material with high toughness that can form a lubricating oxide layer.

[0050] 3. By using surface modification methods, shot peening or rolling is performed on the contact surface to introduce residual compressive stress on the surface, thereby inhibiting the initiation and propagation of fretting fatigue cracks.

[0051] Example Step 1, calculate using the first preset relationship. mm; Step 2: Determine the first cycle number N1 as 952 rises and falls, and the ratio of the second cycle number to the first cycle number is 4.2. Therefore, the transition fillet between the inner cavity of the wheel hub and the drive key is selected as R18. Step 3, calculate using the second preset relationship. mm; Step 4, h = 8.5 mm, ,but ; Step 5, M = , , Take 0.88, If we take 2, then , ; Step 6, calculate Allowable compressive stress of the driving bond material at high temperature [ =380MPa Less than [ Therefore, the compressive stress of the hub drive key meets the requirements.

[0052] Step 7, based on h=8.5mm, calculate... ; ,but ; Step 8, calculate Allowable bending stress of driving key material at high temperature [ ]=435MPa, safety factor Less than [ Therefore, the bending stress of the hub drive key meets the requirements.

[0053] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A design method for a hub drive key for aircraft wheels, characterized in that, The method comprises the following steps: determining the number of driving keys according to the tire combined diameter and a first preset relationship; obtaining the stress when the inner cavity of the aircraft wheel hub and the driving key are in a right angle transition, querying the stress-cycle number curve corresponding to the material of the aircraft wheel hub, determining the cycle number corresponding to the current stress as a first cycle number, and determining the cycle number corresponding to the current stress as a first cycle number; determining the required cycle number of the driving key in the whole life cycle as a second cycle number; determining the transition fillet of the inner cavity of the aircraft wheel hub and the driving key according to the ratio of the second cycle number to the first cycle number; determining the width of the driving key according to the number of the driving key and a second preset relationship; determining the extrusion area of a single driving key and a guide rail according to the height and length of the driving key and a third preset relationship; determining the normal force of the brake torque transmitted to a single driving key according to the normal force of the brake torque transmitted to the driving key and the number of the driving key; determining the extrusion stress of a single driving key according to the normal force of the brake torque transmitted to a single driving key and the extrusion area of a single driving key and a guide rail; when the extrusion stress reaches a first preset condition, determining the bending section modulus of a single driving key and the maximum bending moment borne by a single driving key according to the width and height of the driving key and a fourth preset relationship; determining the maximum bending stress of a single driving key according to the bending section modulus of a single driving key and the maximum bending moment borne by a single driving key; when the maximum bending stress reaches a second preset condition, obtaining the final driving key.

2. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, when the extrusion stress does not reach the first preset condition, increasing the length of the driving key, and re-determining the extrusion area of a single driving key and a guide rail according to the height and length of the driving key until the extrusion stress reaches the first preset condition; the first preset condition is that the extrusion stress is less than or equal to the allowable stress of the driving key material in a high-temperature state.

3. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, when the maximum bending stress does not reach the second preset condition, increasing the width of the driving key, and re-determining the bending section modulus of a single driving key according to the width and height of the driving key until the maximum bending stress reaches the second preset condition; the second preset condition is that the maximum bending stress is less than or equal to the allowable bending stress of the driving key material in a high-temperature state.

4. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, The first preset relationship is: ; In the formula, Ra is the tire combined diameter matched with the aircraft wheel.

5. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, The determination formula of the required cycle number of the driving key in the whole life cycle is: wherein, is the number of landings for the life of the wheel hub, is the number of miles the wheel needs to roll for a single landing, is the design unevenness coefficient, is the rolling radius.

6. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, determining the transition fillet of the inner cavity of the aircraft wheel hub and the driving key according to the ratio of the second cycle number to the first cycle number comprises: when the ratio of the second cycle number to the first cycle number is greater than 5, the transition fillet of the inner cavity of the aircraft wheel hub and the driving key is selected from R22-R25; and when the ratio is less than or equal to 5, the transition fillet of the inner cavity of the aircraft wheel hub and the driving key is selected from R18-R20.

7. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, The second preset relationship is: ; In the formulae, is the number of keys.

8. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, The third preset relationship is: ; In the formula, h is the height of the driving key, and L1 is the length of the driving key; the determination method of the normal force of the brake torque transmitted to a single driving key is: In the formula, is the maximum brake torque, is the uneven work coefficient, is the action radius of the driving key and the guide rail, is the dynamic load coefficient, is the number of driving keys.

9. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, The fourth preset relationship is: ; In the formula, b is the width of the driving key, and h is the height of the driving key; the determination method of the maximum bending moment borne by a single driving key is: wherein is the normal force of the brake torque transferred to the single hub drive key, is the distance from the center line of the wheel rail and the sliding surface of the steel clamp to the center line of the side surface of the hub drive key.

10. The method of designing a hub drive key for an aircraft wheel as defined in claim 1, wherein, the extrusion stress of a single driving key is the ratio of the normal force of the brake torque transmitted to a single driving key and the extrusion area of a single driving key and a guide rail; The maximum bending stress of the single driving key is the ratio of the maximum bending moment borne to the bending section modulus of the single driving key. The maximum bending stress of the single driving key is the ratio of the maximum bending moment borne to the bending section modulus of the single driving key.

Images