Aircraft undercarriage cabin door separation mechanism

Abstract

The invention belongs to the field of aircraft landing system design and relates to an aircraft cabin door separation mechanism. The aircraft cabin door separation mechanism adopts a multi-connecting-rod rotating throwing and pushing impact unlocking separation principle and comprises an aircraft body structure, an undercarriage cabin door, a short connecting rod, a long connecting rod, an actuating cylinder, a free hinge, a rotating unlocking hinge and an undercarriage cabin door lock.

Description

Technical Field

[0001] The invention relates to an aircraft landing gear door separation mechanism, which is used for separating the landing gear door of an aircraft with a retractable landing gear, and belongs to the field of aircraft landing system design. Background Art

[0002] The landing gear door is an essential component of aircraft with retractable landing gear. The normal opening of the landing gear door before landing is a prerequisite for ensuring the normal lowering of the landing gear. Traditional aircraft have ample internal space and relatively mild flight conditions. The opening and closing method of the landing gear door can be designed as a simple fixed-axis rotation, or it can be designed as a linkage with the landing gear. However, for small-sized aircraft with low lift-to-drag ratio, the design of landing gear doors faces four major challenges: 1) The landing sinking speed of low lift-to-drag ratio aircraft is too high. In order to match the landing impact and braking capability, not only the tire size needs to be increased, but also a sturdy landing gear needs to be designed, which forces the size of the landing gear door to be further increased, which in turn makes it difficult to layout the landing gear door deployment and retraction mechanism; 2) There is insufficient space in the cabin of small-sized aircraft. When the large-sized landing gear is arranged, the left and right spacing is too short, causing the movement range of the inward-opening landing gear door that opens to the mid-axis plane of the aircraft to interfere with each other; 3) The landing sinking speed of low lift-to-drag ratio aircraft is too high. The landing impact will greatly compress the landing gear buffer, causing the open landing gear door to collide with the ground, causing damage to the landing gear door.

[0003] In order to avoid the above problems, it is necessary to abandon the traditional retractable landing gear door structure design to avoid potential interference or impact of the landing gear door on the landing gear. The detachable landing gear door can be separated from the aircraft before the landing gear is lowered, fundamentally avoiding the various risks brought by the landing gear door to the landing of the aircraft. However, there are two major technical challenges in the design of detachable landing gear doors for low lift-to-drag aircraft: First, the simple gooseneck rocker arm landing gear door deployment mechanism occupies a large space and cannot be arranged inside the narrow aircraft. Second, after the landing gear door is separated, it continues to move under the influence of aerodynamic loads, and there is a risk of collision with the aircraft. In particular, low lift-to-drag aircraft have a fast landing speed, high flight pressure, and a higher risk of collision, so a specially designed door separation mechanism is required to solve the above challenges. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a landing gear door separation mechanism suitable for small-sized and low lift-to-drag ratio aircraft, which fundamentally solves the problem of potential collision between the landing gear door and the ground during the landing phase of the aircraft and the collision between the landing gear door and the aircraft, and significantly reduces the landing risk of small-sized and low lift-to-drag ratio aircraft.

[0006] The technical problems solved by the present invention are: 1. Overcoming the risk of collision between the door and the ground during landing faced by the existing retractable aircraft landing gear door on a small-sized and low lift-to-drag ratio aircraft; 2. Overcoming the shortcomings of the traditional door retracting mechanism that occupies a large space and cannot be arranged inside a narrow aircraft; 3. Avoiding the risk of collision between the landing gear door and the aircraft under the action of aerodynamic load after the landing gear door is separated from the aircraft.

[0007] (II) Technical solution

[0008] The invention discloses an aircraft landing gear door separation mechanism, which adopts a multi-link rotary throw + push-to-unlock separation principle and comprises an aircraft body structure, a landing gear door, a short connecting rod, a long connecting rod, an actuator, a free hinge, a rotary unlocking hinge and a landing gear door lock.

[0009] Two sets of separation mechanisms are arranged symmetrically on both sides of the landing gear door. Each set of separation mechanisms consists of a short connecting rod, a long connecting rod and an actuator. One end of the short connecting rod and the long connecting rod are connected to the aircraft body structure, and the other end is connected to the landing gear door. One end of the long connecting rod is also connected to the actuator. After the landing gear door is opened to a certain angle, the aerodynamic force acting on the landing gear door during flight is used to accelerate the separation of the landing gear door from the aircraft.

[0010] The rotation unlocking hinge is composed of a spinning sliding pin and spinning sliding sleeve on one end of the short connecting rod, a spinning hook and a spinning sliding sleeve top pin at the corresponding position on the landing gear door. The hinge can be locked by the hook before the landing gear door is rotated and opened, and the hinge constraint is released after the landing gear door and the connecting rod are rotated to a certain angle, so as to realize the separation of the landing gear door.

[0011] The free hinge is composed of a free hinge sleeve at one end of a long connecting rod and a free hinge top pin at a corresponding position on the landing gear door. The hinge mainly transmits the separation power from the actuator to the landing gear door through the long connecting rod to realize the opening of the landing gear door.

[0012] The connecting rod is used to guide the movement direction of the landing gear door, so that the landing gear door can also move in translation while rotating to open, ensuring that the door does not interfere with the aircraft body structure.

[0013] The actuator is used to provide power for the movement of the landing gear door. One end of the actuator is connected to the aircraft body structure, and the other end is connected to the reversing rocker arm of the long connecting rod, converting the thrust of the actuator into the rotational torque exerted on the long connecting rod.

[0014] The landing gear door lock is used to connect the landing gear door to the aircraft body structure before the landing gear door is opened, maintain the integrity of the aircraft body structure and aerodynamic shape, and prevent the landing gear door from moving freely. When the landing gear door needs to be opened, the connection between the landing gear door and the aircraft body structure is released, allowing the landing gear door to rotate around the hinge.

[0015] By designing the angles and positions of the rotary hook, rotary sliding sleeve, rotary sliding pin and rotary sliding sleeve top pin, the connecting rod can be interlocked with the landing gear door in the closed position. Figure 1 The landing gear door lock is arranged on the right end face of the middle landing gear door to realize the locking of the landing gear door in place. Since the landing gear door can only rotate along the top pin of the rotary throw sliding sleeve, when the landing gear door is in the closed state, the long connecting rod and the short connecting rod are as parallel as possible to the landing gear door, so that the door can move approximately along the outer normal direction of the landing gear door plane when it is just opened, avoiding the interference between the heavy landing gear door and the aircraft body structure.

[0016] The movement process of the mechanism is as follows: when the landing gear door is separated, the actuator cylinder first provides the separation power. As the actuator cylinder extends, the actuator cylinder pushes the long connecting rod to rotate on a fixed axis through the steering rocker arm on the long connecting rod, and then transmits the power to the landing gear door through the free hinge, pushing the landing gear door to open. Due to the existence of connecting rods of different lengths, during the movement of the landing gear door, the rotation unlocking hinge and the free hinge respectively rotate around the two hinge points where the long connecting rod and the short connecting rod are connected to the aircraft body structure, pushing the landing gear door to rotate and translate at the same time. As the landing gear door moves, the short connecting rod and the landing gear door rotate at a large angle, and the rotary throwing sliding pin gradually disengages from the rotary throwing hook. Finally, the landing gear door is disconnected from the short connecting rod, and the two hinge centers on the landing gear door continue to move along the movement tangent direction of the connecting rod where they were before the constraint was released, realizing the separation of the door from the aircraft body structure.

[0017] Due to the presence of aerodynamic forces during the separation process, the aerodynamic forces act on the outside of the landing gear door in the first half of the opening of the landing gear door, preventing the landing gear door from opening. As the landing gear door gradually rotates, the aerodynamic forces gradually act on the inside of the landing gear door, and at this time, the aerodynamic forces accelerate the opening of the landing gear door. Since the connecting rod spin-throw unlocking mechanism can simultaneously provide the door with a rotational angular velocity and a linear velocity perpendicular to the aircraft body structure, after the connecting rod is unlocked and separated from the landing gear door, it will continue to rotate and move away from the aircraft body structure under the action of inertia and aerodynamic forces.

[0018] In the above separation mechanism, the connecting rod may be a simple linear connecting rod, or may be designed into other configurations according to the internal structure of the aircraft.

[0019] In the above-mentioned separation mechanism, the hinge position can be changed, the length of the short link and the long link can be adjusted, and the angle between the short link, the long link and the cabin door can be adjusted, thereby changing the point of action of the separation force on the cabin door and the angle at which the cabin door and the aircraft are released from constraints.

[0020] In the above-mentioned separation mechanism, when the thrust of the actuator is constant, the length of the long connecting rod reversing rocker arm and the length of the long connecting rod can be adjusted jointly, thereby adjusting the ratio of the thrust of the actuator to the separation force transmitted to the door hinge.

[0021] In the above-mentioned separation mechanism, the actuator can be a fire-actuated actuator, a hydraulic actuator, an electromechanical actuator, a spring actuator, a linear motor, or any other device that can provide power such as torque or thrust.

[0022] (III) Beneficial effects

[0023] The beneficial effects of the present invention compared with the prior art are as follows:

[0024] 1. It meets the design requirements of the landing gear door opening mechanism for small-sized and low lift-to-drag ratio aircraft. This is the inevitable technical effect of abandoning the traditional landing gear door extension and retraction mechanism and using the door separation mechanism.

[0025] 2. The problem of the retractable landing gear door colliding with the ground at the moment of the aircraft landing is fundamentally avoided. This is an inevitable technical effect produced after the present invention separates the landing gear door from the aircraft.

[0026] 3. Avoiding interference between the landing gear door and the aircraft body structure when it is just opened is an inevitable technical effect produced by the technical feature of the motion relationship of the multi-link mechanism.

[0027] 4. The landing gear door is automatically interlocked with the short connecting rod when in the closed state, which can reduce the number of upper locks of the landing gear door and simplify the structural design. This is the inevitable technical effect of the rotary unlocking hinge designed according to the motion relationship between the door and the connecting rod.

[0028] 5. Avoiding the risk of collision between the landing gear door and the aircraft due to the aerodynamic load after the landing gear door is separated from the aircraft is an inevitable technical effect produced by converting the ineffective aerodynamic resistance into effective separation power through the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The invention relates to a landing gear door separation mechanism.

[0030] Figure 2 The separation mechanism of the present invention comprises a hinge and a connecting rod.

[0031] Figure 3It is a schematic diagram of the movement relationship between the landing gear door and the connecting rod and the movement position of the separation mechanism when the hinge is unlocked. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0033] like Figure 1 As shown, an aircraft door separation mechanism is characterized by comprising: an aircraft body structure 1, a landing gear door 2, a short connecting rod 3, a long connecting rod 4, an actuator 5, a free hinge 6, a rotary unlocking hinge 7 and a landing gear door lock 8.

[0034] The aircraft body structure 1 is connected to the short connecting rod 3, the long connecting rod 4 and the actuator 5 respectively through hinges, and the two hinged parts can rotate relative to each other. The aircraft body structure 1 and the landing gear door lock 8 are rigidly connected in the locked state.

[0035] The rotary unlocking hinge 7 is composed of a rotary-throw sliding pin 13 and a rotary-throw sliding sleeve 14 on the short connecting rod 3, a rotary-throw hook 11 and a rotary-throw sliding sleeve top pin 12 on the landing gear door 2, and is used to lock the landing gear door 2 through the cooperation of the hook pin before the landing gear door 2 is rotated to open, and to release the lock after the landing gear door 2 and the short connecting rod 3 are rotated to a certain angle, thereby realizing the separation of the landing gear door 2 from the aircraft body structure 1.

[0036] The free hinge 6 is composed of a free hinge sleeve 17 and a free hinge top pin 16 on the long connecting rod 4, and is mainly used to further transmit the thrust from the actuator 5 to the landing gear door 2 through the reversing rocker arm 18 provided on the long connecting rod 4, thereby pushing the landing gear door 2 to open.

[0037] The actuator 5 is used to provide power for the movement of the landing gear door 2. One end of the actuator 5 is connected to the aircraft body structure 1, and the other end is connected to the long connecting rod 4. The linear motion of the actuator 5 is converted into the rotational motion of the long connecting rod 4 through the long connecting rod 4.

[0038] The landing gear door lock 8 is used to connect the landing gear door 2 with the aircraft body structure 1, maintain the integrity of the aircraft's aerodynamic shape, and prevent the landing gear door 2 from moving freely. At the same time, when the landing gear door 2 needs to be opened, it is used to release the connection constraint with the aircraft body structure 1, so that the landing gear door 2 can rotate around the rotation unlocking hinge 7 and the free hinge 6 at the same time, thereby realizing separation from the aircraft body structure 1.

[0039] Two groups of separation mechanisms are symmetrically arranged along both sides of the landing gear door 2. By designing the matching angles and matching positions of the rotary-throw hook 11, the rotary-throw sliding sleeve 14, the rotary-throw sliding pin 13, and the rotary-throw sliding sleeve top pin 12, the landing gear door 2 can remain parallel to the short link 3 and the long link 4 or have an angle less than 5° when closed, and is in an interlocked state with the short link 3.

[0040] The separation movement process of the aircraft door separation mechanism is as follows:

[0041] During separation, the actuator 5 first provides separation power and extends, and then pushes the long connecting rod 4 to rotate on a fixed axis through the steering rocker arm 18, and then transmits power to the landing gear door 2 through the free hinge 6, and finally pushes the landing gear door to open; due to the existence of connecting rods of unequal lengths, during the movement of the landing gear door 2, the rotation unlocking hinge 7 and the free hinge 6 respectively rotate around the two hinges connected to the aircraft body structure 1 of the short connecting rod 3 and the long connecting rod 4, until the rotary throwing sliding pin 13 gradually disengages from the rotary throwing hook 11, and the landing gear door 2 is disconnected from the short connecting rod 3, and the hinges on the door continue to move along the tangent direction of the connecting rod movement at the separation moment, and finally the landing gear door 2 is separated from the aircraft body structure 1.

[0042] In the first half of the opening of the landing gear door 2, the aerodynamic force acts on the outer side of the landing gear door, and the aerodynamic force prevents the door from opening.

[0043] As the landing gear door 2 rotates, the aerodynamic force gradually acts on the inner side of the door, and the aerodynamic force accelerates the opening of the landing gear door.

[0044] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

[0045] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. An aircraft door separation mechanism, characterized in that include: An aircraft body structure (1), a landing gear door (2), a short connecting rod (3), a long connecting rod (4), an actuator (5), a free hinge (6), a rotation unlocking hinge (7) and a landing gear door lock (8).

2. The aircraft door separation mechanism according to claim 1, characterized in that: The aircraft body structure (1) is connected to the short connecting rod (3), the long connecting rod (4) and the actuator (5) respectively through hinges, and the two hinged parts can rotate relative to each other. The aircraft body structure (1) and the landing gear door lock (8) are rigidly connected in a locked state.

3. The aircraft door separation mechanism according to claim 1, characterized in that: The rotary unlocking hinge (7) is composed of a rotary throw sliding pin (13) and a rotary throw sliding sleeve (14) on a short connecting rod (3), a rotary throw hook (11) and a rotary throw sliding sleeve top pin (12) on a landing gear door (2), and is used to achieve locking through the cooperation of the hook pin before the landing gear door (2) is rotated to open, and to release the lock after the landing gear door (2) and the short connecting rod (3) are rotated to a certain angle, thereby achieving separation of the landing gear door (2) from the aircraft body structure (1).

4. The aircraft door separation mechanism according to claim 1, characterized in that: The free hinge (6) is composed of a free hinge sleeve (17) and a free hinge top pin (16) on the long connecting rod (4), and is mainly used to further transmit the thrust from the actuator (5) to the landing gear door (2) through the reversing rocker arm (18) provided on the long connecting rod (4), thereby pushing the landing gear door (2) to open.

5. The aircraft door separation mechanism according to claim 1, characterized in that: The actuator cylinder (5) is used to provide power for the movement of the landing gear door (2). One end of the actuator cylinder (5) is connected to the aircraft body structure (1), and the other end is connected to the long connecting rod (4). The linear motion of the actuator cylinder (5) is converted into the rotational motion of the long connecting rod (4) through the long connecting rod (4).

6. The aircraft door separation mechanism according to claim 1, characterized in that: The landing gear door lock (8) is used to connect the landing gear door (2) and the aircraft body structure (1), maintain the integrity of the aircraft's aerodynamic shape, and prevent the landing gear door (2) from moving freely; at the same time, when the landing gear door (2) needs to be opened, it is used to release the connection constraint with the aircraft body structure (1), so that the landing gear door (2) can rotate around the rotation unlocking hinge (7) and the free hinge (6) at the same time, thereby achieving separation from the aircraft body structure (1).

7. The aircraft door separation mechanism according to any one of claim 1, characterized in that: Two groups of separation mechanisms are symmetrically arranged along both sides of the landing gear door (2). By designing the matching angles and matching positions of the rotary throwing hook (11), the rotary throwing sliding sleeve (14), the rotary throwing sliding pin (13), and the rotary throwing sliding sleeve top pin (12), the landing gear door (2) can be kept parallel to the short connecting rod (3) and the long connecting rod (4) or have an angle less than 5 degrees when closed, and be in an interlocking state with the short connecting rod (3).

8. The method for separating an aircraft door separation mechanism according to any one of claims 1 to 7, characterized in that: During separation, the actuator (5) first provides separation power and extends, then pushes the long connecting rod (4) to rotate on a fixed axis through the steering rocker arm (18), and then transmits power to the landing gear door (2) through the free hinge (6), and finally pushes the landing gear door to open; due to the existence of connecting rods of different lengths, during the movement of the landing gear door (2), the rotation unlocking hinge (7) and the free hinge (6) respectively rotate around the two hinges connecting the short connecting rod (3) and the long connecting rod (4) with the aircraft body structure (1) to perform double rotation movement, until the rotary throwing sliding pin (13) gradually disengages from the rotary throwing hook (11), the landing gear door (2) is disconnected from the short connecting rod (3), and the hinges on the door continue to move along the tangent direction of the connecting rod movement at the separation moment, and finally the landing gear door (2) is separated from the aircraft body structure (1).

9. The separation method of the aircraft door separation mechanism according to claim 8, characterized in that: In the first half of the opening of the landing gear door (2), aerodynamic force acts on the outer side of the landing gear door, and the aerodynamic force prevents the door from opening.

10. The separation method of the aircraft door separation mechanism according to claim 9, characterized in that: As the landing gear door (2) rotates, the aerodynamic force gradually acts on the inner side of the door, and the aerodynamic force accelerates the opening of the landing gear door.

Images