A front landing gear bay door opening and closing mechanism

Abstract

The application provides a front landing gear cabin door opening and closing mechanism, which comprises a front landing gear cabin door, the front landing gear cabin door has an upturned front end according to the curved surface characteristics of the front fuselage of an aircraft, so that the front landing gear cabin door has a positive angle of attack; a rocker crank, a crank and a rocker are hinged on the same side edge of the front landing gear cabin door, the other end of the crank and the rocker is hinged to a fuselage fixed structure, the other end of the rocker crank is hinged to a driving device and the middle part of the rocker crank connecting rod is hinged to the fuselage fixed structure; a driving device is arranged on the fuselage fixed structure, and the driving device is hinged to the rocker crank. The front landing gear cabin door opening and closing mechanism provided by the application is parallel to the wing surface when the aircraft is in the taxiing stage, and can provide additional lift for the aircraft during take-off, so that the utilization rate of the aircraft components is improved from the aerodynamic aspect, the number of parts is small, the cost is low, the weight is light and the reliability is high.

Description

Technical Field

[0001] This application belongs to the field of aircraft structural design technology, and specifically relates to a nose landing gear door opening and closing mechanism. Background Technology

[0002] During the cruise phase of an aircraft, the landing gear compartment needs to be sealed to reduce air resistance. During the takeoff phase, the landing gear compartment needs to be opened to deploy the landing gear. To meet the different needs of the aircraft during the takeoff and takeoff phases, landing gear doors and opening / closing mechanisms are installed on the underside of the landing gear to realize the opening and closing of the landing gear doors.

[0003] Traditional landing gear doors only serve to seal the landing gear compartments, offering no other performance enhancements during the takeoff phase. Furthermore, improper design can introduce significant aerodynamic drag, increasing fuel consumption and reducing aircraft performance. With increasingly stringent requirements for takeoff lift-to-drag ratios, the aerodynamic utilization efficiency of these single-function doors during takeoff urgently needs improvement. Summary of the Invention

[0004] The purpose of this application is to provide a nose landing gear door opening and closing mechanism to solve or mitigate at least one of the problems in the prior art.

[0005] The technical solution of this application is: a nose landing gear door opening and closing mechanism, the nose landing gear door opening and closing mechanism comprising:

[0006] The nose landing gear bay door has an upward-curved front end based on the curved surface features of the aircraft's forward fuselage, thereby giving the nose landing gear bay door a positive angle of attack.

[0007] A rocker arm crank, a crank, and a rocker arm are hinged to the same side edge of the nose landing gear door. The other end of the crank and rocker arm is hinged to the fuselage fixed structure. The other end of the rocker arm crank is hinged to the drive unit, and the middle part of the rocker arm crank connecting rod is hinged to the fuselage fixed structure.

[0008] A drive unit mounted on a fixed structure of the fuselage, the drive unit being hinged to a rocker arm crank.

[0009] Furthermore, the nose landing gear door is generally rectangular, and has a first support and a second support on the same side edge of the nose landing gear door. The first support is hinged to the rocker arm, and the second support is hinged to the crank and the rocker arm crank.

[0010] Furthermore, there are two first supports and three second supports.

[0011] Furthermore, the first support is closer to the edge of the nose landing gear door than the second support, which is located between the first supports.

[0012] Furthermore, the rocker arm crank includes a crank portion and a rocker arm portion integrally formed with the crank portion. The crank portion and the rocker arm portion have a predetermined angle. One end of the crank portion is hinged to the nose landing gear door, the connection between the crank portion and the rocker arm portion is hinged to the fuselage fixed structure, and the other end of the rocker arm portion is hinged to the drive device.

[0013] Furthermore, the crank and the rocker arm crank have the same crank section structure and the length is adapted to the width of the front landing gear door.

[0014] Furthermore, the driving device is a hydraulic actuator, and the piston rod of the hydraulic actuator is hinged to the rocker arm crank.

[0015] Furthermore, the distance in the width direction between the rocker arm crank or the hinge point between the crank and the landing gear door and the hinge point between the rocker arm and the front landing gear door is the same as the distance between the hinge points of the crank and the rocker arm on the fixed structure of the fuselage, so that the hinge points form the four vertices of a parallelogram in space.

[0016] The nose landing gear door opening and closing mechanism provided in this application is based on the four-bar linkage principle to realize the opening and closing action of the nose landing gear door. During the aircraft's taxiing phase, the door remains parallel to the wing surface in the open state and can provide additional lift for takeoff, thus improving the utilization rate of aircraft components from an aerodynamic perspective. Only one mechanism is used to simultaneously meet the two functional requirements of nose landing gear door opening and closing and increased lift during takeoff. The nose landing gear door opening and closing mechanism of this application is simple in form, requiring only one drive device and not relying on sensors and control circuits for detecting door attitude. Utilizing the parallelogram mechanism principle ensures that the door's attitude remains unchanged during movement, resulting in fewer parts, lower cost, lighter weight, higher reliability, and less occupation of aircraft resources. Attached Figure Description

[0017] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0018] Figure 1 This is a schematic diagram of the front landing gear door opening and closing mechanism of this application.

[0019] Figure 2 This is a top view of the landing gear door in this application.

[0020] Figure 3 This is a side view of the landing gear door in this application.

[0021] Figure 4 This is a schematic diagram of the rocker arm and crank in this application.

[0022] Figure 5 This is a schematic diagram of the crank in this application.

[0023] Figure 6 This is a schematic diagram of the joystick used in this application.

[0024] Figure 7 This is a simplified diagram of the front landing gear door opening and closing mechanism of this application.

[0025] Figure 8 This is a schematic diagram of the nose landing gear door opening and closing mechanism in this application, showing the door in the open state.

[0026] Figure 9 This is a schematic diagram of the nose landing gear door opening and closing mechanism of this application, showing the door beginning to close.

[0027] Figure 10 This is a schematic diagram illustrating the continued movement of the front landing gear door opening and closing mechanism of this application.

[0028] Figure 11 This is a schematic diagram of the front landing gear door opening and closing mechanism in the closed state of the door. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0030] In order to meet the landing gear retraction and extension requirements while ensuring that the landing gear bay door has a certain shape and attitude when open, so as to provide additional lift for the aircraft during the takeoff roll and improve the aerodynamic performance of the aircraft during takeoff, a nose landing gear bay door opening and closing mechanism is proposed.

[0031] like Figure 1 As shown, the nose landing gear door opening and closing mechanism 10 provided in this application includes: nose landing gear door 11, rocker arm crank 12, crank 13, drive device 14, rocker arm 15, and shaft bolts and nuts, etc.

[0032] like Figure 2 and Figure 3 As shown, the nose landing gear door 11 is generally rectangular, with two first supports 111 for hinged rocker arm 15 on one side edge, and a second support 112 for hinged rocker arm crank 12 and crank 13 on the same side edge. Due to the curved surface characteristics of the aircraft's forward fuselage, the front end 113 of the nose landing gear door 11 is upturned, thus giving the nose landing gear door 11 a certain positive angle of attack.

[0033] In a preferred embodiment of this application, the first support 111 is closer to the edge of the nose landing gear door 11 than the second support 112. There are three second supports 112, all located between the two first supports 111, and the three second supports 112 are in a straight line.

[0034] like Figure 4 As shown, the rocker arm crank 12 has a crank portion 121 with a length adapted to the width of the nose landing gear door and a rocker arm portion 122 integrally formed with the crank portion 121. The crank portion 121 and the rocker arm portion 122 are at a certain angle. One end of the crank portion 121 is hinged to the second support 112 of the nose landing gear door 11, and the connection between the crank portion 121 and the rocker arm portion 122 is hinged to the support of the fuselage fixed structure. The other end of the rocker arm portion 122 is hinged to the drive mechanism 12. When the drive mechanism 12 is actuated, the rocker arm crank 12 can swing around the hinge point between itself and the fuselage fixed structure.

[0035] like Figure 5 As shown, there are two cranks 13, and their structure is roughly the same as the crank portion 121 of the rocker arm crank 12. One end of the crank 13 is hinged to the second support 112 of the nose landing gear door 11 and located on both sides of the rocker arm crank 12, and the other end is hinged to the support on the fuselage fixed structure.

[0036] like Figure 6 As shown, there are two rocker arms 15. One end of the rocker arm 15 is hinged to the first support 111 of the nose landing gear door 11, and the other end is hinged to the support on the fixed structure of the fuselage.

[0037] The drive mechanism 14 uses a hydraulic actuator, one end of which is fixed to the fixed structure of the fuselage, and the other end is hinged to the rocker arm portion 142 of the rocker arm crank 12. When the piston rod of the hydraulic actuator extends, the rocker arm crank 12 rotates clockwise, causing the landing gear door 11 to leave its closed position, thereby opening the door.

[0038] like Figure 7 As shown, the distance L1 in the width direction between the hinge point of the rocker arm crank 12 or crank 13 and the second support 112 and the hinge point of the rocker arm 15 and the first support 111 is approximately the same as the distance L2 between the hinge points of the crank 13 and the rocker arm 15 on the fixed structure of the machine body. This makes the hinge points form the four vertices of a parallelogram in space. At the same time, the lengths of the two hinge points on the structure of the crank part 121 of the rocker arm crank 12, the crank 13 and the rocker arm 15 are approximately the same, thus making the crank 13 and the rocker arm 15 form a parallelogram in space.

[0039] like Figure 8As shown, the aircraft is in the takeoff roll, at which time the nose landing gear door 11 is open and at its limit position. Due to the properties of the parallelogram, the landing gear door 11, which is the opposite side of the line connecting the two hinge points on the fuselage, can maintain the same attitude as the closed state after reaching the limit position. That is, the landing gear door 11 is parallel to the wing chord plane. Combined with the positive angle of attack of the landing gear door 11, it can provide additional lift during the takeoff roll of the aircraft, thus achieving the lift enhancement function.

[0040] like Figure 9 As shown, when the aircraft takes off, the landing gear retracts and the nose landing gear door 11 needs to be closed. The piston rod of the hydraulic actuator retracts, causing the rocker arm crank 12 to rotate counterclockwise, and the nose landing gear door 11 moves to the upper right.

[0041] like Figure 10 As shown, the piston rod of the hydraulic actuator continues to retract, and the rocker arm crank 12 drives the nose landing gear door 11 to continue moving to the upper right.

[0042] like Figure 11 As shown, the nose landing gear bay door 11 reaches its limit position. At this time, the landing gear bay door 11 is closed, and due to the properties of the parallelogram, the attitude of the nose landing gear bay door 11 remains unchanged, sealing the landing gear bay.

[0043] The opening process of the nose landing gear bay door is the reverse of the closing process described above, and will not be described in detail here.

[0044] The nose landing gear door opening and closing mechanism provided in this application is based on the four-bar linkage principle to realize the opening and closing action of the nose landing gear door. During the aircraft's taxiing phase, the door remains parallel to the wing surface in the open state and can provide additional lift for takeoff, thus improving the utilization rate of aircraft components from an aerodynamic perspective. Only one mechanism is used to simultaneously meet the two functional requirements of nose landing gear door opening and closing and increased lift during takeoff. The nose landing gear door opening and closing mechanism of this application is simple in form, requiring only one drive device and not relying on sensors and control circuits for detecting door attitude. Utilizing the parallelogram mechanism principle ensures that the door's attitude remains unchanged during movement, resulting in fewer parts, lower cost, lighter weight, higher reliability, and less occupation of aircraft resources.

[0045] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A nose landing gear door opening and closing mechanism, characterized in that, The nose landing gear door opening and closing mechanism includes: The nose landing gear bay door has an upward-curved front end based on the curved surface features of the aircraft's forward fuselage, thereby giving the nose landing gear bay door a positive angle of attack. A rocker arm crank, a crank, and a rocker arm are hinged to the same edge of the nose landing gear door. The other ends of the crank and rocker arm are hinged to a fixed fuselage structure. The other end of the rocker arm crank is hinged to a drive unit, and the middle part of the rocker arm crank connecting rod is hinged to the fixed fuselage structure. The rocker arm crank includes a crank portion and a rocker arm portion integrally formed with the crank portion. The crank portion and the rocker arm portion have a predetermined angle. One end of the crank portion is hinged to the nose landing gear door. The connecting portion between the crank portion and the rocker arm portion is hinged to the fixed fuselage structure. The other end of the rocker arm portion is hinged to the drive unit. The crank portion structure of the crank and the rocker arm crank are the same, and the length is adapted to the width of the nose landing gear door. A drive device mounted on a fixed structure of the fuselage, the drive device being hinged to a rocker arm crank; The distance in the width direction between the rocker arm crank or the hinge point between the crank and the landing gear door and the hinge point between the rocker arm and the nose landing gear door is the same as the distance between the hinge points of the crank and the rocker arm on the fixed structure of the fuselage, so that the hinge points form the four vertices of a parallelogram in space.

2. The nose landing gear door opening and closing mechanism as described in claim 1, characterized in that, The nose landing gear door is generally rectangular, and has a first support and a second support on the same side edge of the nose landing gear door. The first support is hinged to the rocker arm, and the second support is hinged to the crank and rocker arm crank.

3. The nose landing gear door opening and closing mechanism as described in claim 2, characterized in that, There are two first supports and three second supports.

4. The nose landing gear door opening and closing mechanism as described in claim 3, characterized in that, The first support is closer to the edge of the nose landing gear door than the second support, which is located between the first supports.

5. The nose landing gear door opening and closing mechanism as described in claim 1, characterized in that, The driving device is a hydraulic actuator, and the piston rod of the hydraulic actuator is hinged to the rocker arm crank.

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