Strong-environment-adaptability rudder wing folding and unfolding locking structure and design method

Abstract

The invention discloses a high-environment-adaptability rudder wing folding and unfolding locking structure and a design method.The unfolding locking structure comprises a movable rudder surface and a fixed rudder surface of a rudder wing, an unfolding mechanism and a locking mechanism, the fixed rudder surface is connected with an aircraft through a rudder shaft, and the fixed rudder surface is provided with an arc profile surface; the root of the movable control surface is an arc inner surface and coaxially wraps the arc outer surface, and the fixed control surface can rotate relative to the movable control surface; a torsion bar is arranged in the unfolding mechanism, and the two ends of the torsion bar are connected to the movable control surface and the fixed control surface respectively; the locking mechanism comprises a locking pin and a limiting pin which are elastically arranged in the movable control surface, a locking pin hole and a limiting pin hole which are matched with the locking pin and the limiting pin are formed in the fixed control surface, and the width of the limiting pin hole is larger than that of the locking pin hole. The use performance of the folding rudder in severe environments such as deserts, gobi and sand dunes is improved, and the folding rudder can be popularized and applied in a large-load high-heat-flow environment.

Description

Technical Field

[0001] The present invention belongs to the field of structural design of small aircraft, and particularly relates to a folding, unfolding and locking structure for a rudder wing with strong environmental adaptability and a design method thereof. Background Art

[0002] For the adaptation requirements of miniaturized aircraft, the air rudder mostly adopts the design concept of wing surface folding, which can greatly reduce the space occupied by the aircraft itself.

[0003] The folding rudder is mainly realized by an unfolding mechanism and a locking mechanism. The existing unfolding mechanisms can be divided into three types according to different driving elements: torsion spring drive, pyrotechnic gas drive, and hydraulic actuator drive, etc. The torque of the torsion spring is positively correlated with its structural size, and it is not convenient to use a large torsion spring near the pivot, so it is difficult to provide a large unfolding torque; although the pyrotechnic has a large unfolding torque, the corresponding impact overload is large and the safety and reliability are relatively low; the hydraulic actuation involves the design of seals and link mechanisms, and the structure is complex. The locking mechanism of the folding rudder generally adopts methods such as round pin locking, lock key, and limit block. The round pin locking method has a small contact area and a weak overall connection stiffness; the lock key and limit block methods have a more complex structure and are difficult to be placed in the internal structure of the rudder wing. Therefore, how to balance a driving mechanism with small space and large torque and a locking mechanism with simple reliability and high connection stiffness is the design focus of the folding rudder.

[0004] On the other hand, for harsh environments such as sand dunes and deserts, especially for aircraft with exposed rudder wings, foreign matters such as sand, gravel, and dust often adhere to the surface of the folding rudder, which is likely to cause phenomena such as unfolding jamming or inability to lock.

[0005] In addition, as a whole, the folding rudder bears severe force and heat coupling effects in a high-load and high-heat flux environment. The smoothness of its aerodynamic shape, the overall heat protection ability, and the bearing capacity of the locking mechanism will have a crucial impact on the overall aerodynamic, force, and heat characteristics of the aircraft. Summary of the Invention

[0006] The purpose of the present invention is to provide a folding, unfolding and locking structure for a rudder wing with strong environmental adaptability and a design method thereof, so as to further enhance the environmental adaptability and load-bearing heat protection effect of the folding rudder and improve the overall performance of the aircraft.

[0007] To achieve the above tasks, the present invention adopts the following technical solutions:

[0008] A strong environmental adaptability rudder wing folding and unfolding locking structure, comprising: a movable rudder surface and a fixed rudder surface of the rudder wing, a deployment mechanism and a locking mechanism, wherein: the fixed rudder surface is connected to the aircraft through a rudder shaft, and the fixed rudder surface has an arc-shaped outer surface; the root of the movable rudder surface is an arc-shaped inner surface and coaxially covers the outside of the arc-shaped outer surface, and the fixed rudder surface can rotate relative to the movable rudder surface; a torsion bar is arranged in the deployment mechanism, and both ends of the torsion bar are respectively connected to the movable rudder surface and the fixed rudder surface; the locking mechanism includes a locking pin and a limit pin elastically arranged in the movable rudder surface, and a locking pin hole and a limit pin hole matching with the locking pin and the limit pin are arranged on the fixed rudder surface, and the width of the limit pin hole is greater than that of the locking pin hole.

[0009] Further, the deployment mechanism includes a torsion bar, a rotating shaft, a torsion bar pin, mounting screws and a rear plug; wherein, the rotating shaft is arranged inside the arc-shaped outer surface of the fixed rudder surface, a blind hole is arranged at the front end inside the fixed rudder surface, and a through hole is arranged at the rear end; the front and rear ends of the rotating shaft are respectively installed in the blind hole and the through hole; the rotating shaft is fixedly connected to the fixed rudder surface by the mounting screws and the threaded holes on the fixed rudder surface; the torsion bar is arranged in the inner cavity of the rotating shaft to provide the deployment driving force for the movable rudder surface; the torsion bar pin fixedly connects the front end of the torsion bar and the front end of the rotating shaft, and the rear end of the torsion bar passes through the through hole and extends into the rear plug arranged behind the fixed rudder surface, and the rear plug is connected to the movable rudder surface.

[0010] Further, the locking mechanism includes a locking pin, a limit pin and a spring; a first spring hole and at least one group of second spring holes are distributed in the movable rudder surface, and the first spring hole is located between the second spring holes; the locking pin is assembled in the second spring hole through the spring, and the limit pin is assembled in the first spring hole through the spring.

[0011] Further, when the movable rudder surface is in the folded state, the locking mechanism is located within the covering range of the arc-shaped inner surface on the movable rudder surface and the arc-shaped outer surface of the fixed rudder surface; during the unfolding process of the movable rudder surface, the arc-shaped inner surface on the movable rudder surface continuously covers the arc-shaped outer surface of the fixed rudder surface and rotates around the axis of the arc-shaped outer surface.

[0012] Further, during the unfolding process of the movable rudder surface, the limit pin first extends into the limit pin hole arranged on the fixed rudder surface under the drive of the spring; as the movable rudder surface continues to rotate, the locking pin is inserted into the locking pin hole of the fixed rudder surface under the drive of the spring to lock the unfolding position of the movable rudder surface.

[0013] A design method for a strong environmental adaptability rudder wing folding and unfolding locking structure, comprising:

[0014] Step 1, divide the rudder wing into four parts: a movable rudder surface, a fixed rudder surface, a deployment mechanism and a locking mechanism from the functional structure. The movable rudder surface is a folding rudder surface, and the fixed rudder surface is a fixed rudder surface connected to the aircraft's steering gear through a rudder shaft; select a torsion bar as the driving element of the deployment mechanism, and the locking mechanism includes n locking pins, one limit pin and n + 1 springs;

[0015] Step 2: Select a cylindrical torsion bar, whose cross-sectional diameter is d 0 , effective length and material are determined by optimizing according to the outer shape dimensions of the rudder wing and the design deployment time constraint; the rotating shaft is a circular tube structure with a wall thickness of δ, coaxial with the torsion bar and fixedly connected at the front end;

[0016] Step 3: The limit pin is designed as a ball-head cylindrical pin, and the locking pin is designed as a taper-head cylindrical pin; the outer diameter dimension d of the cylindrical section on the locking pin s is determined by the thickness of the moving rudder surface and the maximum normal aerodynamic load received by the moving rudder surface;

[0017] Step 4: Design the fixed rudder surface as a cylindrical structure with a bottom radius of R and a length of L, so that the outer surface of the fixed rudder surface forms an arc-shaped outer surface; a blind hole is arranged at the front end inside the fixed rudder surface, and a through hole is arranged at the rear end for installing the rotating shaft; limit pin holes for cooperating with the limit pins and locking pin holes for cooperating with the locking pins are distributed on the fixed rudder surface;

[0018] Step 5: Design an arc-shaped inner surface at the root of the moving rudder surface; during the deployment process of the moving rudder surface, the moving rudder surface drives the locking pin and the limit pin to rotate around the rotating shaft together, and at the same time continuously wraps the arc-shaped outer surface of the fixed rudder surface through the cooperation of the arc-shaped inner surface, so that the limit pin holes and the locking pin holes on the fixed rudder surface are hidden and not exposed until the locking pin is inserted into the locking pin hole to lock the moving rudder surface.

[0019] Furthermore, for the selected cylindrical torsion bar, its cross-sectional diameter d 0 , effective length and material are determined by optimizing according to the outer shape dimensions of the rudder wing and the design deployment time constraint, including:

[0020] Step 2.1: Determine the maximum effective length of the torsion bar through modeling analysis according to the aerodynamic shape of the moving rudder surface ; determine the range of the moving rudder surface deployment time [t min , t max according to the design technical requirements, and determine the folding angle γ according to the internal space of the launch device of the aircraft carrying the rudder wing;

[0021] Step 2.2: Taking the maximum effective length of the torsion bar , the maximum diameter d of the torsion bar max , the design limit torsion angle θ max and the range of the moving rudder surface deployment time [t min , t max as the constraint boundaries, and taking the effective length of the torsion bar , the cross-sectional diameter d of the torsion bar 0 and the shear modulus G of the torsion bar material as the design parameters, so that under the condition of meeting the constraint boundaries, the shear stress of the torsion bar is minimized, thereby obtaining the values of the design parameters, i.e.:

[0022] ;

[0023] In the formula, is the pre-twist angle of the movable rudder surface, is the operation margin angle, and τ s is the torsional yield strength of the torsion bar material, and t min , t max are the minimum time and maximum time for the movable rudder surface to deploy; t is the rudder surface deployment time, which is calculated by the movement equation of the movable rudder surface.

[0024] Furthermore, the locking depth is greater than 0.8 times the outer diameter dimension d of the cylindrical section on the locking pin s ; where the locking depth is the length of the locking pin inserted into the locking pin hole.

[0025] Furthermore, the outer diameter dimension d of the cylindrical section on the locking pin s is determined by the thickness of the movable rudder surface and the maximum normal aerodynamic load on the movable rudder surface. Specifically:

[0026] Calculate the shear strength of the locking pin from the maximum normal design load F on the pressure center of the movable rudder surface. According to the moment balance relationship between the aerodynamic load and the reaction force of the locking pin on the axis of the rotating shaft and the shear stress calculation formula, we can obtain:

[0027] ;

[0028] In the formula, l cp is the spanwise distance from the pressure center of the movable rudder surface to the axis of the rotating shaft, and R is the bottom radius of the fixed rudder surface; is the maximum allowable shear stress of the locking pin material; d can be determined by the above formula s .

[0029] Furthermore, the bottom radius R and length L of the fixed rudder surface are determined by the following method:

[0030] Step 4.1, the rotating shaft is coaxial with the fixed rudder surface, and the outer circumferential surface of the rotating shaft and the inner circumferential surface of the cavity of the fixed rudder surface are mating surfaces. The minimum bottom radius R of the fixed rudder surface min is calculated from the outer diameter of the rotating shaft and the outer diameter dimension d of the cylindrical section on the locking pin s as follows:

[0031] ;

[0032] where is the wall thickness of the rotating shaft, then the bottom radius of the fixed rudder surface ;

[0033] Step 4.2, approximately consider the rudder wing in the deployed state as a rectangular cross-section cantilever beam with a length of L and a height of the root chord thickness h r and the tip chord thickness h t average value, and the length of the cantilever beam is the span L span , according to the upper limit requirement ω of the tip chord deflection of the fixed rudder surface max and the beam deflection calculation formula, we can get:

[0034] ;

[0035] In the formula, F is the maximum normal design load received at the center of pressure of the moving rudder surface, and l cp is the spanwise distance from the center of pressure of the moving rudder surface to the axis of the rotating shaft, and E is the elastic modulus of the material of the moving rudder surface.

[0036] Compared with the prior art, the present invention has the following technical features:

[0037] 1. The present invention improves the service performance of the rudder wing of the aircraft in harsh environments such as deserts, gobi, and sand dunes through the concealed design of the locking mechanism. Through the arc surface cooperation between the fixed rudder surface and the moving rudder surface, the locking pins, the limit pins, and the locking pin holes and limit pin holes cooperating with them are all placed inside the folding rudder structure during the folding state, the unfolding process, and the unfolded and locked state, without any exposure, reducing the probability of foreign objects entering, and maximizing the avoidance of the problems of rudder surface rotation jamming and inability to lock caused by foreign objects, improving the working reliability of the folding rudder, and reducing the requirements for aircraft transportation and use.

[0038] 2. The folding rudder of the present invention relies on the large-span distribution of multiple locking pins along the chord direction of the rudder surface combined with the spanwise locking method, increasing the overall bending cross-sectional area of the rudder wing, improving the bending stiffness, and enhancing the overall load-bearing capacity of the rudder wing. At the same time, the moving rudder surface and the fixed rudder surface are made of high-temperature-resistant metals, and the overall outer surface is smooth and continuous, facilitating thermal protection design, and solving the problem of the application of the folding rudder in an environment of large load and high heat flux.

[0039] 3. The folding rudder provided by the present invention has a symmetric aerodynamic shape, a smooth transition of the bulge at the wing root, and a good overall aerodynamic shape, avoiding the problem of control force moment difference caused by asymmetric shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the overall structural schematic diagram of the rudder wing in the deployed state of the present invention;

[0041] Figure 2 is the flow schematic diagram of the design method of the present invention;

[0042] Figure 3 is the structural schematic diagram of the unfolding mechanism and the locking mechanism part of the present invention;

[0043] Figure 4 Schematic diagram of the state where the rudder wing is not deployed;

[0044] Figure 5 Schematic diagram of the state where the rudder wing is deployed;

[0045] Figure 6 Schematic diagram showing the function of the limit pin.

[0046] Explanation of reference numerals: 1 moving rudder surface, 101 inner arc-shaped surface, 2 fixed rudder surface, 201 outer arc-shaped surface, 202 locking pin hole, 203 limit pin hole, 3 rudder shaft, 4 rear plug, 5 mounting screw, 6 torsion bar, 7 rotating shaft, 8 torsion bar pin, 9 locking pin, 10 limit pin, 11 spring. Detailed implementation manners

[0047] Refer to Figures 1 to 6 , the present invention first provides a rudder wing folding and unfolding locking structure with strong environmental adaptability, including the moving rudder surface 1 and the fixed rudder surface 2 of the rudder wing, a deployment mechanism and a locking mechanism, wherein:

[0048] The fixed rudder surface 2 is connected to the aircraft through the rudder shaft 3, and the fixed rudder surface 2 has an outer arc-shaped surface 201; the root of the moving rudder surface 1 is an inner arc-shaped surface 101 and coaxially covers the outside of the outer arc-shaped surface 201, and the fixed rudder surface 2 can rotate relative to the moving rudder surface 1;

[0049] The deployment mechanism is provided with a torsion bar 6, and both ends of the torsion bar 6 are respectively connected to the moving rudder surface 1 and the fixed rudder surface 2; the locking mechanism includes a locking pin 9 and a limit pin 10 elastically arranged in the moving rudder surface 1, and a locking pin hole 202 and a limit pin hole 203 for cooperating with the locking pin 9 and the limit pin 10 are arranged on the fixed rudder surface 2, and the width of the limit pin hole 203 is greater than that of the locking pin hole 202.

[0050] Refer to the attached Figure 2 , in an embodiment of the present invention, the deployment mechanism includes a torsion bar 6, a rotating shaft 7, a torsion bar pin 8, a mounting screw 5 and a rear plug 4; wherein, the rotating shaft 7 is arranged inside the outer arc-shaped surface 201 of the fixed rudder surface 2, a blind hole is arranged at the front end inside the fixed rudder surface 2, and a through hole is arranged at the rear end; the front and rear ends of the rotating shaft 7 are respectively installed in the blind hole and the through hole; the rotating shaft 7 is fixedly connected to the fixed rudder surface 2 by relying on the mounting screw 5 and the threaded hole on the fixed rudder surface 2; the torsion bar 6 is arranged in the inner cavity of the rotating shaft 7 to provide the deployment driving force for the moving rudder surface 1; the torsion bar pin 8 fixedly connects the front end of the torsion bar 6 and the front end of the rotating shaft 7, the rear end of the torsion bar 6 passes through the through hole and extends into the rear plug 4 arranged behind the fixed rudder surface 2, and the rear plug 4 is connected to the moving rudder surface 1.

[0051] In one embodiment of the present invention, the locking mechanism includes a locking pin 9, a limit pin 10 and a spring 11; a first spring hole and at least one set of second spring holes are distributed in the movable rudder surface 1, and the first spring hole is located between the second spring holes; the locking pin 9 is assembled in the second spring hole through the spring 11, and the limit pin 10 is assembled in the first spring hole through the spring 11; a limit pin hole 203 cooperating with the limit pin 10 and a locking pin hole 202 cooperating with the locking pin 9 are provided on the fixed rudder surface 2.

[0052] When the movable rudder surface 1 is in the folded state, the locking mechanism is within the covering range of the arc-shaped inner surface 101 of the movable rudder surface 1 and the arc-shaped outer surface 201 of the fixed rudder surface 2, and is not affected by the outside; during the unfolding process of the movable rudder surface 1, the arc-shaped inner surface 101 of the movable rudder surface 1 continuously covers the arc-shaped outer surface 201 of the fixed rudder surface 2 and rotates around the axis of the arc-shaped outer surface 201. After the unfolding and locking are completed, the locking mechanism still remains hidden and not exposed, thereby realizing the concealed design of the locking mechanism and improving the environmental adaptability of the folding rudder.

[0053] Since the width of the limit pin hole 203 is greater than that of the locking pin hole 202, when the movable rudder surface 1 unfolds, the limit pin 10 is first driven by the spring 11 to extend into the limit pin hole 203 provided on the fixed rudder surface 2; as the movable rudder surface 1 continues to rotate, then the locking pin 9 is driven by the spring 11 to insert into the locking pin hole 202 of the fixed rudder surface 2 to lock the unfolded position of the movable rudder surface 1; among them, the limit pin hole 203 is a strip-shaped structure, which can make the limit pin 10 insert before the locking pin 9 to achieve the purpose of restricting the unfolding angle of the movable rudder surface 1.

[0054] When the present invention is in use, the front end of the torsion bar 6 is fixedly connected to the rotating shaft 7, and the rotating shaft 7 is fixedly connected to the fixed rudder surface 2 through the mounting screw 5; the rear end of the torsion bar 6 is connected to the rear plug 4, and the rear plug 4 is fixed on the movable rudder surface 1, so that the fixed rudder surface 2 and the movable rudder surface 1 are movably connected by the torsion bar 6; when the rudder wing is not unfolded, the movable rudder surface 1 is in a folded state relative to the fixed rudder surface 2, see the appendix Figure 5 , at this time the torsion bar 6 is in a twisted state to store elastic potential energy, and the position of the movable rudder surface 1 is maintained by a limiting component on the aircraft, such as a bulkhead, etc.; after the aircraft is released, the movable rudder surface 1 loses the position restriction, and is driven by the elastic restoring force of the torsion bar 6 to unfold and finally lock the position through the locking pin 9, as Figure 5 shown, at this time the rudder wing is in the unfolded state.

[0055] Among them, the movable rudder surface 1 and the fixed rudder surface 2 are made of high-temperature resistant metal; an outer zirconia thermal protection coating is provided on the outer surface of the movable rudder surface 1.

[0056] The arc-shaped outer surface 201 can be, for example, the outer surface of a section of circular tube; the arc-shaped inner surface 101 can be, for example, a part of the inner surface of a section of circular tube.

[0057] On the basis of the above technical solution, the present invention further provides a design method for a strong environmental adaptability rudder wing folding and unfolding locking structure, including the following steps:

[0058] Step 1, rudder wing function division.

[0059] The rudder wing is functionally divided into four parts: a movable rudder surface 1, a fixed rudder surface 2, a deployment mechanism, and a locking mechanism; the movable rudder surface 1 is a folding rudder surface, and the fixed rudder surface 2 is a fixed rudder surface connected to the aircraft's steering gear through a rudder shaft 3; the deployment mechanism includes a torsion bar 6 and a rotating shaft 7. Selecting the torsion bar 6 as the driving element has the advantages of small size and low space occupancy, saving the required lateral space; the locking mechanism includes n locking pins 9, a limit pin 10, and n + 1 springs 11. By optimizing the distribution of the locking pins 9 and the limit pin 10, the overall stiffness of the rudder wing can be effectively improved.

[0060] Specifically, the optimized distribution of the locking pins 9 and the limit pin 10 is to arrange as many locking pins 9 as possible with a large axial span to increase the bending cross-sectional area and improve the overall torsional bending stiffness; among them, the limit pin 10 is arranged in the middle of the movable rudder surface 1, and a group or more than one group of locking pins 9 are symmetrically arranged on both sides of the limit pin 10.

[0061] Step 2, deployment mechanism design.

[0062] Select a cylindrical torsion bar 6, the cross-sectional diameter d 0 , effective length and material are optimized and determined by the external dimensions of the rudder wing and the design deployment time constraints; the rotating shaft 7 is a circular tube structure with a wall thickness δ, coaxial with the torsion bar 6 and fixedly connected at the front end. The inner diameter d z of the rotating shaft 7 is 1.15 - 1.25 times the cross-sectional diameter d 0 of the torsion bar 6; as the main component of the rudder wing to bear lateral shear force, the rotating shaft 7 should have good stiffness, and preferably a metal material with good specific strength and specific stiffness.

[0063] Among them, the cross-sectional diameter d 0 , effective length and material are optimized and determined by the external dimensions of the rudder wing and the design deployment time constraints, specifically as follows:

[0064] Step 2.1, determine the maximum effective length of the torsion bar 6 through modeling analysis according to the aerodynamic shape of the movable rudder surface 1; determine the deployment time range [t min , t max of the movable rudder surface 1 according to the design technical requirements, and determine the folding angle γ according to the internal space of the launch device of the aircraft carrying the rudder wing.

[0065] Step 2.2, with the maximum effective length of the torsion bar 6 , the maximum diameter d of the torsion bar 6 max , the design limit torsion angle θ max and the deployment time range [t min , t max of the moving rudder surface 1 as the constraint boundaries, with the effective length , the cross-sectional diameter d of the torsion bar 6 0 and the shear modulus G of the material of the torsion bar 6 as the design parameters, such that under the condition of satisfying the constraint boundaries, the shear stress of the torsion bar 6 is minimized, thereby solving for the values of the said design parameters, i.e.:

[0066] ;

[0067] In the formula, is the pre-torsion angle of the moving rudder surface, is the operation margin angle, τ s is the torsional yield strength of the material of the torsion bar 6, t min , t max are the minimum time and the maximum time for the deployment of the moving rudder surface 1; t is the rudder surface deployment time, which can be calculated by the deployment motion equation of the moving rudder surface 1:

[0068] ;

[0069] In the formula, M is the actual torque for the deployment of the moving rudder surface 1, is the angle that the moving rudder surface 1 rotates around the rotating shaft 7 at time t, and J is the moment of inertia of the moving rudder surface 1 around the rotating shaft 7.

[0070] ;

[0071] ;

[0072] In the formula, is the torque of the torsion bar 6, is the resistance torque during the deployment of the moving rudder surface 1, and , where is the frictional resistance moment, is the aerodynamic resistance moment, is the gravity resistance moment; k is the torsion coefficient of the torsion bar 6, θ is the initial torsion angle of the torsion bar 6, and .

[0073] The gravity moment of the moving rudder surface 1 is:

[0074] ;

[0075] where m is the mass of the moving rudder surface 1, g is the acceleration due to gravity, is the launch angle of the aircraft, It is the distance from the centroid of the movable rudder surface 1 to the axis of the rotating shaft 7.

[0076] The aerodynamic moment acting on the movable rudder surface 1 during the deployment process is:

[0077] ;

[0078] Where ρ is the air density under standard atmospheric pressure, S is the single-sided surface area of the movable rudder surface 1, C y is the aerodynamic drag coefficient of the vertical oncoming flow blowing towards the movable rudder surface 1, which can be determined through wind tunnel tests; l cp is the spanwise distance from the center of pressure of the movable rudder surface 1 to the axis of the rotating shaft 7, v ∞ is the oncoming flow velocity relative to the aircraft, α 当地 is the local angle of attack of the rudder wing.

[0079] The frictional drag moment acting on the movable rudder surface 1 during the deployment process is:

[0080] ;

[0081] Where f is the frictional force generated by the overload, and R is the bottom radius of the fixed rudder surface 2.

[0082] Step 3, locking mechanism design.

[0083] Optimizing the combined distribution method of multiple locking pins 9 can effectively improve the overall stiffness of the rudder wing; when the movable rudder surface 1 is fully deployed, the locking mechanism connects the movable rudder surface 1 and the fixed rudder surface 2 into a whole along the spanwise direction; the limit pin 10 is designed as a ball-headed cylindrical pin, and the locking pin 9 is designed as a tapered-headed cylindrical pin; the outer diameter dimension d of the cylindrical section on the locking pin 9 s is determined by the thickness of the movable rudder surface 1 and the maximum normal aerodynamic load acting on the movable rudder surface 1, and the locking depth is generally greater than 0.8 times d s ; where the locking depth is the length of the locking pin 9 inserted into the locking pin hole 202.

[0084] Among them, the outer diameter dimension d of the cylindrical section on the locking pin 9 s is determined by the thickness of the movable rudder surface 1 and the maximum normal aerodynamic load acting on the movable rudder surface 1, specifically:

[0085] Calculate the shear strength of the locking pin 9 from the maximum normal design load F acting on the center of pressure of the movable rudder surface 1. According to the moment balance relationship between the aerodynamic load and the reaction force of the locking pin 9 on the axis of the rotating shaft 7 and the shear stress calculation formula, we can get:

[0086] ;

[0087] In the formula, l cpis the spanwise distance from the aerodynamic center of the movable control surface 1 to the axis of the rotating shaft 7, and R is the bottom radius of the fixed control surface 2, approximately the distance from the reaction force acting point of the locking pin 9 to the axis of the rotating shaft 7; is the maximum allowable shear stress of the material of the locking pin 9; d can be determined by the above formula s . When the locking pin 9 is installed in the second spring hole of the movable control surface 1, the outer diameter dimension d of the cylindrical section on the locking pin 9 s should have a clearance with the side walls on both sides of the second spring hole.

[0088] Step 4, design of the fixed control surface 2.

[0089] Design the fixed control surface 2 as a cylindrical structure with a bottom radius of R and a length of L, so that the outer surface of the fixed control surface 2 forms an arc-shaped outer surface 201; a blind hole is provided at the front end inside the fixed control surface 2, and a through hole is provided at the rear end for installing the rotating shaft 7; the fixed control surface 2 is distributed with a limit pin hole 203 for cooperating with the limit pin 10 and a locking pin hole 202 for cooperating with the locking pin 9.

[0090] Among them, the bottom radius R and the length L of the fixed control surface 2 are determined by the following methods:

[0091] Step 4.1, the rotating shaft 7 is coaxial with the fixed control surface 2, and the outer circumferential surface of the rotating shaft 7 and the inner cavity circumferential surface of the fixed control surface 2 are mating surfaces. Therefore, the minimum bottom radius R of the fixed control surface 2 min can be obtained from the outer diameter of the rotating shaft 7 and the outer diameter dimension d of the cylindrical section on the locking pin 9 s The calculation is as follows:

[0092] ;

[0093] Among them is the wall thickness of the rotating shaft 7, then the bottom radius of the fixed control surface 2 .

[0094] Step 4.2, the length L of the fixed control surface 2 is related to the bending stiffness of the fixed control surface 2. The deflected rudder wing in the unfolded state is approximately regarded as a rectangular cross-section cantilever beam with a length of L, a height of the root chord thickness h r and the tip chord thickness h t average value, and the length of the cantilever beam is the span L span . According to the upper limit requirement ω max of the tip chord deflection of the fixed control surface 2 and the beam deflection calculation formula, we can get:

[0095] ;

[0096] In the formula, E is the elastic modulus of the material of the movable control surface 1.

[0097] Step 5, design of the movable control surface 1.

[0098] The root of the dynamic rudder surface 1 is designed with an arc inner surface 101; during the deployment of the dynamic rudder surface 1, the dynamic rudder surface 1 drives the locking pin 9 and the limit pin 10 to move around the rotating shaft 7, and at the same time, the arc inner surface 101 cooperates with and continuously covers the arc outer surface 201 of the fixed rudder surface 2, ensuring that the limit pin hole 203 and the locking pin hole 202 on the fixed rudder surface 2 are concealed and not exposed until the locking pin 9 is inserted into the locking pin hole 202 to lock the dynamic rudder surface 1.

[0099] The shape structure at the connection between the dynamic control surface 1 and the fixed control surface 2 is designed in a transitional manner to ensure smooth and continuous aerodynamic shape and reduce aerodynamic resistance.

[0100] In one embodiment of the present invention, the folding angle of the dynamic control surface 1 is 100°, leaving a 6° pre-twist angle for torsion bar 6 After that, the initial torsion angle of the torsion bar 6 is 106°; During assembly, consider reserving an operating margin angle of 10° , then the limit torsion angle of torsion bar 6 is =116°.

[0101] After the dynamic control surface 1 model is given titanium alloy material properties, the mass of the dynamic control surface 1 can be measured to be m=2.2kg (including zirconium oxide outer heat protection coating), and the moment of inertia of the dynamic control surface 1 around the rotation axis 7 is J=0.0198 , the distance from the center of mass of the dynamic rudder surface 1 to the axis of the rotating shaft 7 (gravity moment arm) mm, spanwise distance between the pressure center of dynamic rudder surface 1 and the axis of rotation shaft 7 mm, dynamic rudder surface 1 single side surface area S = 66008mm 2 ; The length of the fixed rudder surface 2 is L = 416mm, and the length of the cantilever beam is the extension length L span =175mm, root chord thickness h r =15mm, tip chord thickness h t =4mm; aerodynamic drag coefficient , air density , the friction coefficient μ between the dynamic rudder surface 1 and the fixed rudder surface 2 is 0.2; the deployment time range of the dynamic rudder surface 1 [t min , t max ] is 40ms≤t≤80ms, the launch angle of the aircraft The initial velocity of the rudder wing is about 50m / s, and the horizontal gust is about 15m / s at this time; during the flight, the maximum normal design load F=6000N on the pressure center of the dynamic rudder surface 1, and the wing tip deflection under the design load is required to be no more than 3mm.

[0102] From the above data, the cross-sectional diameter d of the torsion bar 6 can be calculated. 0 =4.8mm, effective length of torsion bar 6 When it is s mm, the minimum shear stress of the torsion bar 6 is 1075 MPa; the outer diameter dimension d of the cylindrical section on the locking pin 9 is calculated.

[0103] Considering that the root chord of this example is relatively long, in order to ensure the torsional stiffness of the folding rudder, the length L of the fixed rudder surface 2 should be as large as possible. Considering the convenience of optimizing the transition of the outer shape surface and the length of the chordwise equal-thickness section of the movable rudder surface 1, L = 200 mm is taken in this example. The above data are all the key parameters for the design of the rudder wing.

[0104] At the same time, from Figure 1 it can be seen that the surroundings of the wing root bulge are all smoothly transitioned, without protrusions affecting the aerodynamic shape. The whole movable rudder surface 1 is sprayed with a zirconia external thermal protection coating.

[0105] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.​

Claims

1. A rudder wing folding and unfolding locking structure with strong environmental adaptability, characterized in that: include: A rudder wing comprises a moving rudder surface (1) and a fixed rudder surface (2), an unfolding mechanism and a locking mechanism, wherein: the fixed rudder surface (2) is connected to an aircraft via a rudder shaft (3), and the fixed rudder surface (2) has an arc outer surface (201); the root of the moving rudder surface (1) is an arc inner surface (101) and coaxially covers the outside of the arc outer surface (201), and the fixed rudder surface (2) can rotate relative to the moving rudder surface (1); a torsion bar is arranged in the unfolding mechanism (6), the two ends of the torsion bar (6) are respectively connected to the moving rudder surface (1) and the fixed rudder surface (2); the locking mechanism comprises a locking pin (9) and a limit pin (10) elastically arranged in the moving rudder surface (1), and a locking pin hole (202) and a limit pin hole (203) matched with the locking pin (9) and the limit pin (10) are arranged on the fixed rudder surface (2), and the width of the limit pin hole (203) is greater than that of the locking pin hole (202).

2. The rudder wing folding and unfolding locking structure with strong environmental adaptability according to claim 1 is characterized in that: The deployment mechanism comprises a torsion bar (6), a rotating shaft (7), a torsion bar pin (8), a mounting screw (5) and a rear plug (4); wherein the rotating shaft (7) is arranged inside the arc outer surface (201) of the fixed rudder surface (2); the front end of the fixed rudder surface (2) is provided with a blind hole, and the rear end is provided with a through hole; the front and rear ends of the rotating shaft (7) are respectively installed in the blind hole and the through hole; the rotating shaft (7) is fixedly connected to the fixed rudder surface (2) by means of the mounting screw (5) and the threaded hole on the fixed rudder surface (2); the torsion bar (6) is arranged in the inner cavity of the rotating shaft (7) to provide a driving force for the deployment of the dynamic rudder surface (1); the torsion bar pin (8) fixes the front end of the torsion bar (6) and the front end of the rotating shaft (7); the rear end of the torsion bar (6) passes through the through hole and extends into the rear plug (4) arranged behind the fixed rudder surface (2); the rear plug (4) is connected to the dynamic rudder surface (1).

3. The rudder wing folding and unfolding locking structure with strong environmental adaptability according to claim 2 is characterized in that: The locking mechanism comprises a locking pin (9), a limiting pin (10) and a spring (11); a first spring hole and at least one group of second spring holes are distributed in the dynamic rudder surface (1), and the first spring hole is located between the second spring holes; the locking pin (9) is assembled in the second spring hole through the spring (11), and the limiting pin (10) is assembled in the first spring hole through the spring (11).

4. The rudder wing folding and unfolding locking structure with strong environmental adaptability according to claim 1 is characterized in that: When the movable rudder surface (1) is in a folded state, the locking mechanism is located within the coverage of the circular arc inner surface (101) on the movable rudder surface (1) and the circular arc outer surface (201) of the fixed rudder surface (2); during the unfolding process of the movable rudder surface (1), the circular arc inner surface (101) on the movable rudder surface (1) continuously covers the circular arc outer surface (201) of the fixed rudder surface (2) and rotates around the axis of the circular arc outer surface (201).

5. The rudder wing folding and unfolding locking structure with strong environmental adaptability according to claim 3 is characterized in that: During the unfolding process of the moving rudder surface (1), the limit pin (10) is first extended into the limit pin hole (203) provided on the fixed rudder surface (2) under the drive of the spring (11); as the moving rudder surface (1) continues to rotate, the locking pin (9) is inserted into the locking pin hole (202) of the fixed rudder surface (2) under the drive of the spring (11) to achieve locking of the unfolded position of the moving rudder surface (1).

6. A design method for the rudder wing folding and unfolding locking structure with strong environmental adaptability according to claim 3, comprising: Step 1, dividing the rudder wing into four parts from the functional structure, namely, a dynamic rudder surface (1), a fixed rudder surface (2), an unfolding mechanism and a locking mechanism, wherein the dynamic rudder surface (1) is a folding rudder surface, and the fixed rudder surface (2) is a fixed rudder surface connected to a servo on an aircraft through a rudder shaft (3); a torsion bar (6) is selected as a driving element of the unfolding mechanism, and the locking mechanism includes n locking pins (9), a limit pin (10) and n+1 springs (11); Step 2: Select a cylindrical torsion bar (6) with a cross-sectional diameter d0 and an effective length The material is determined by optimizing the rudder wing's external dimensions and design deployment time constraints; the rotating shaft (7) is a circular tube structure with a wall thickness of δ, coaxial with the torsion bar (6) and fixedly connected at the front end; Step 3, the stop pin (10) is designed as a ball head cylindrical pin, and the locking pin (9) is designed as a cone head cylindrical pin; the outer diameter size d of the upper cylindrical section of the locking pin (9) is s It is determined by the thickness of the dynamic control surface (1) and the maximum normal aerodynamic load on the dynamic control surface (1); Step 4, designing the fixed rudder surface (2) into a cylindrical structure with a bottom radius of R and a length of L, so that the outer surface of the fixed rudder surface (2) forms an arc profile surface (201); a blind hole is provided at the front end of the fixed rudder surface (2), and a through hole is provided at the rear end for installing the rotating shaft (7); a limit pin hole (203) cooperating with the limit pin (10) and a locking pin hole (202) cooperating with the locking pin (9) are distributed on the fixed rudder surface (2); Step 5, the root of the moving rudder surface (1) is designed with an arc inner surface (101); during the unfolding process of the moving rudder surface (1), the moving rudder surface (1) drives the locking pin (9) and the limit pin (10) to move around the rotating shaft (7), and at the same time, the arc inner surface (101) cooperates with and continuously covers the arc outer surface (201) of the fixed rudder surface (2), so that the limit pin hole (203) and the locking pin hole (202) on the fixed rudder surface (2) are concealed and not exposed until the locking pin (9) is inserted into the locking pin hole (202) to achieve the locking of the moving rudder surface (1).

7. The design method according to claim 6, characterized in that: The cylindrical torsion bar (6) is selected, and its cross-sectional diameter d0 and effective length The material is determined by optimizing the rudder wing's dimensions and design deployment time constraints, including: Step 2.1, determine the maximum effective length of the torsion bar (6) through modeling analysis based on the aerodynamic shape of the dynamic control surface (1) ; Determine the deployment time range of the dynamic control surface (1) according to the design technical requirements [t min , t max ], the folding angle γ is determined according to the internal space of the launch device of the aircraft equipped with the rudder wing; Step 2.2, with the maximum effective length of the torsion bar (6) , the maximum diameter d of the torsion bar (6) max 、Design limit torsion angle θ max And the deployment time range of the dynamic control surface (1) [t min , t max ] is the constraint boundary, and the effective length of the torsion bar (6) , the cross-sectional diameter d0 of the torsion bar (6) and the shear modulus G of the torsion bar (6) material are design parameters, so that under the condition of satisfying the constraint boundary, the shear stress of the torsion bar (6) Minimum, thus solving the value of the design parameter, namely: ； In the formula, is the pre-twist angle of the dynamic control surface (1), is the operating margin angle, τ s is the torsional yield strength of the torsion bar (6) material, t min ,t max are the minimum and maximum time for the dynamic control surface (1) to be deployed; t is the deployment time of the control surface, which is calculated by the dynamic control surface (1) deployment motion equation.

8. The design method according to claim 6, characterized in that: The locking depth is greater than 0.8 times the outer diameter d of the upper cylindrical section of the locking pin (9) s ; wherein the locking depth is the length of the locking pin (9) inserted into the locking pin hole (202).

9. The design method according to claim 6, characterized in that: The outer diameter d of the upper cylindrical section of the locking pin (9) s It is determined by the thickness of the dynamic control surface (1) and the maximum normal aerodynamic load on the dynamic control surface (1), specifically: The shear strength of the locking pin (9) is calculated from the maximum normal design load F at the pressure center of the dynamic rudder surface (1). According to the moment balance relationship between the aerodynamic load and the reaction force of the locking pin (9) on the axis of the rotating shaft (7) and the shear stress calculation formula, the following is obtained: ； In the formula, l cp is the spanwise distance between the pressure center of the dynamic rudder surface (1) and the axis of the rotating shaft (7), and R is the bottom radius of the fixed rudder surface (2); is the maximum allowable shear stress of the locking pin (9) material; d can be determined by the above formula s .

10. The design method according to claim 6, characterized in that: The bottom radius R and length L of the fixed rudder surface (2) are determined by the following method: Step 4.1, the rotating shaft (7) is coaxial with the fixed rudder surface (2), and the outer circumferential surface of the rotating shaft (7) and the inner circumferential surface of the fixed rudder surface (2) are mating surfaces, and the minimum radius R of the bottom surface of the fixed rudder surface (2) is min The outer diameter of the rotating shaft (7) and the outer diameter dimension d of the cylindrical section on the locking pin (9) s The calculation is as follows: ； in is the wall thickness of the shaft (7), then the bottom radius of the fixed rudder surface (2) ; Step 4.2: Approximate the deployed rudder wing as having a length of L and a height of root chord thickness h. r and the tip chord thickness h t The average value of the rectangular cross-section cantilever beam, the cantilever beam length is L span , according to the upper limit requirement of the tip chord deflection of the fixed rudder surface (2) ω max And the beam deflection calculation formula can be obtained: ； Where F is the maximum normal design load on the pressure center of the dynamic control surface (1), l cp is the spanwise distance between the pressure center of the dynamic control surface (1) and the axis of the rotating shaft (7), and E is the elastic modulus of the material of the dynamic control surface (1).

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