A landing gear strut locking mechanism

Abstract

The present invention belongs to the field of landing gear design, and particularly relates to a landing gear strut locking mechanism. The common strut lock mechanism is usually a four-link lock mechanism, which has more parts, occupies a larger space envelope, and is heavier, which is not conducive to the improvement of flight performance. In the present invention, the rocker arm has two blocks on the outer side of one end of the rotating shaft, which are offset from each other by a certain angle up and down. One block has a spring hole, and the other block has an actuator plane; the rocker arm is installed with a lock ring bushing at the other end through a lock ring shaft; the lower strut has a cam at the end; the upper strut has a concave cavity, in which one end of the unlocking actuator and the locking spring is fixed, and the piston rod of the unlocking actuator acts on the actuator plane to control the rotation of the rocker arm, and the other end of the locking spring is connected to the spring hole. It is lighter in weight, occupies less space in the movement envelope, the mechanism design is simpler, and the unlocking actuator is separated from the locking mechanism, which can better meet the requirements of actuator electrification.

Description

Technical Field

[0001] The present invention belongs to the field of landing gear design, and particularly relates to a landing gear strut locking mechanism. Background Art

[0002] The strut is an important part of the aircraft landing gear, which is used for locking and supporting the landing gear when it is lowered and driving the landing gear to retract and fold. When the landing gear is lowered, the strut usually needs to be locked by a locking mechanism to avoid accidental folding. When the landing gear needs to be retracted, the locking mechanism needs to be driven to unlock so that the strut can be folded to drive the landing gear to be retracted into the fuselage.

[0003] Common strut locking mechanisms are usually four-bar locking mechanisms, which are locked by pressing the link mechanism past the dead point through a spring; when unlocking, the link mechanism is driven to deviate from the dead point by an external force to unlock. This kind of locking mechanism has more parts, a larger occupied space envelope, and a heavier weight, which is not conducive to the improvement of flight performance. Especially for unmanned aerial vehicles with all-electric energy requirements, the unlocking actuator of the locking mechanism needs to follow during the folding process, which is not conducive to the design of the electric actuator. Summary of the Invention

[0004] The present invention proposes a landing gear strut locking mechanism in order to improve the performance of the strut locking mechanism.

[0005] A landing gear strut locking mechanism, the mechanism includes an upper strut hinged and installed in the fuselage, an unlocking actuator, a locking spring, a lower strut hinged to the other end of the upper strut, and a rocker arm hinged to the upper strut, wherein

[0006] The rocker arm has two blocks with a certain angle offset up and down on the outer side of one end of the rotating shaft, one of the blocks has a spring hole, and the other block has an actuator plane; the other end of the rocker arm is a fork ear structure, and a lock ring bushing is installed through a lock ring shaft;

[0007] The lower strut has a cam at the end, and the outer profile surface of the cam is divided into a movable surface and a biting surface for accommodating the lock ring bushing;

[0008] The upper strut has a concave cavity, in which one end of the unlocking actuator and the locking spring are fixed, and the piston rod of the unlocking actuator acts on the actuator plane to control the rotation of the rocker arm, and the other end of the locking spring is connected to the spring hole.

[0009] Advantageously, the upper strut has a mounting hole for hinging with the rocker arm in the area close to the lower strut, the concave cavity is in the rod area at one end of the mounting hole, the rod area at the other end of the mounting hole is a through-hole structure, and the outer end edge limits the position of the lower strut.

[0010] Advantageously, the lower strut has a mounting hole for hinging with the landing gear at the other end.

[0011] Advantageously, the base of the unlocking actuator is fixed in the concave cavity of the upper strut.

[0012] Advantageously, the upper strut is hinged to the fuselage through the strut upper shaft.

[0013] Advantageously, the lower strut is hinged to the upper strut through the strut middle shaft.

[0014] Advantageously, the rocker arm is hinged to the upper strut through the rocker arm shaft.

[0015] Advantageously, a roller is provided at the end of the piston rod.

[0016] Advantageously, when the landing gear is in the open position, the lock ring bushing of the rocker arm is snapped into the engagement surface of the lower strut and locked by the locking spring.

[0017] Advantageously, when it is necessary to retract the landing gear, the piston rod of the unlocking actuator is controlled to push the actuator plane of the rocker arm so that the rocker arm rotates. When the lock ring bushing is separated from the engagement surface of the lower strut, the locking of the lower strut is released.

[0018] Beneficial effects: The landing gear strut locking mechanism of the present invention has fewer parts, so it is lighter in weight, occupies less space in the movement envelope, has a simpler mechanism design, and the unlocking actuator is separated from the locking mechanism, which can better meet the requirements of actuator electrification. Description of the Drawings

[0019] Figure 1 Is an axonometric view of the strut locking mechanism of the present invention;

[0020] Figure 2 Is an axonometric view of the unlocking actuator;

[0021] Figure 3 Is an axonometric view of the upper strut;

[0022] Figure 4 Is an axonometric view of the lower strut;

[0023] Figure 5 Is an axonometric view of the rocker arm;

[0024] Figure 6 Is a partial enlarged view of the rocker arm area;

[0025] Figure 7 Is a schematic diagram of the locked state;

[0026] Figure 8 Is a schematic diagram of the released state. Detailed Embodiments

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The overall structure of the strut locking mechanism is as Figure 1 shown. The strut locking mechanism mainly consists of 10 components: unlocking actuator 1, upper strut 2, lower strut 3, rocker arm 4, locking spring 5, lock ring bushing 6, strut upper shaft 7, strut middle shaft 8, rocker arm shaft 9, and lock ring shaft 10. Among them, the unlocking actuator 1 consists of a base 11 and a piston rod 12.

[0029] One end of the upper strut 2 is installed on the body through the strut upper shaft 7, the other end of the upper strut 2 is hinged to one end of the lower strut 3 through the strut middle shaft 8, one end of the rocker arm 4 is hinged to the upper strut 2 through the rocker arm shaft 9, and a lock ring bushing 6 is sleeved on the lock ring shaft 10 at the other end of the rocker arm 4.

[0030] The structure of the strut locking mechanism is described as follows:

[0031] The unlocking actuator 1 is a linear motion component, which can be a hydraulic actuator, an electric actuator, or an actuator of other energy forms, such as Figure 2 shown. The upper strut 2 is a connecting rod part with parallel holes Φ1 and Φ2 at both ends. There is a third hole Φ3 in the upper strut parallel to the other two holes, as Figure 3 shown; the lower strut 3 is a connecting rod part with parallel holes Φ4 and Φ5 at both ends. A cam is made on the outside of one hole Φ4. The outer profile surface of the cam is divided into surface A (active surface) and surface B (engaging surface), as Figure 4 shown. The rocker arm 4 is a connecting rod part with parallel holes Φ6 and Φ7 at both ends. There are also two blocks with a certain angle offset on the outside of one end of the rocker arm 4. One of the blocks has a spring hole Φ8, and the other block has an actuator plane C, as Figure 5As shown. The locking spring 5 is a cylindrical helical tension spring, with one end fixed on the upper strut 2 and the other end connected to the spring hole of the rocker arm 4; the lock ring bushing 6 is an annular part with relatively soft material and is sleeved on the lock ring shaft 10 at the other end of the rocker arm 4. The upper strut shaft 7, the middle strut shaft 8, the rocker arm shaft 9, and the lock ring shaft 10 are cylindrical parts. One end hole Φ1 of the upper strut 2 is connected to the fuselage of the aircraft through the upper strut shaft 7, and the other end hole Φ2 is connected to the hole Φ4 on the cam side of the lower strut 3 through the middle strut shaft 8. The lower strut 3 can rotate relative to the upper strut 2 around the middle strut shaft 8. The lower strut 3 is connected to the landing gear strut through the hole Φ5 on the non-cam side; one end hole Φ6 of the rocker arm 4 is connected to the upper strut through the rocker arm shaft 10. The rocker arm 4 can rotate around the rocker arm shaft 10. The other end hole Φ7 of the rocker arm 4 is connected to the lock ring bushing 6 through the lock ring shaft 11. The lock ring bushing 6 overlaps on the cam surface of the lower strut. The spring hole Φ8 on the other side of the rocker arm 4 is connected to the locking spring 5, and the locking spring 5 is connected to the upper strut 3. The base 11 of the unlocking actuator 1 is fixed to the upper strut 2 by bolts. There is a certain gap δ between the piston rod 12 of the unlocking actuator 1 and the actuator plane of the rocker arm 4, as Figure 6 shown.

[0032] The working principle of the strut locking mechanism is as follows:

[0033] When the landing gear is lowered and in place and the strut is extended and locked, the rocker arm 4 of the strut locking mechanism is connected to the lock ring bushing 6 and enters the B surface of the lower strut 3. Through the geometric self-locking principle, the rotation direction of the rocker arm 4 is exactly blocked by the lower strut 3, and the strut locking mechanism is self-locked. The upper and lower struts will not unlock under the force at both ends, and the strut is reliably locked. At the same time, the locking spring 5 pulls the rocker arm 4 so that the rocker arm 4 is always on the B surface of the cam surface and will not be unlocked by getting out of the B surface of the cam surface under external force disturbance, as Figure 7 shown.

[0034] When the landing gear needs to be retracted, the unlocking actuator 1 acts to overcome the spring force and frictional force to push the rocker arm 4 to rotate. When the rocker arm 4 gets out of the B surface of the cam surface, there is no limit between the lower strut 3 and the upper strut 2, and the strut can be folded and retracted, as Figure 8 shown.

[0035] When the landing gear needs to be lowered, the unlocking actuator 1 follows or is in the minimum position. At this time, the lock ring bushing 6 on the rocker arm 4 slides along the A surface of the cam surface of the lower strut 3 under the drive of the locking spring 5. When the lock ring bushing 6 enters the B surface from the A surface of the cam surface, the strut is successfully locked, as Figure 8 shown.

[0036] The above are only specific embodiments of the present invention. The present invention has been described in detail, and the parts not elaborated are conventional technologies. However, the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims described above.

Claims

1. A landing gear strut locking mechanism, characterized in that: The mechanism includes an upper strut (2) hinged and installed inside the fuselage, an unlocking actuator (1), a locking spring (5), a lower strut (3) hinged to the other end of the upper strut (2), and a rocker arm (4) hinged to the upper strut (2), wherein the rocker arm (4) has two blocks offset vertically by a certain angle on the outer side of one end of the rotating shaft, one of the blocks has a spring hole, and the other block has an actuator plane; the other end of the rocker arm (4) is a fork ear structure, and a lock ring bushing (6) is installed through a lock ring shaft (10); the lower strut (3) has a cam at the end, and the outer profile surface of the cam is divided into a movable surface and a biting surface for accommodating the lock ring bushing (6); the upper strut (2) has a concave cavity, wherein one end of the unlocking actuator (1) and the locking spring (5) are fixed, and the piston rod (12) of the unlocking actuator (1) acts on the actuator plane to control the rotation of the rocker arm (4), and the other end of the locking spring (5) is connected to the spring hole; 2. The landing gear strut locking mechanism according to claim 1, wherein: the upper strut (2) has a mounting hole for hinging with the rocker arm (4) in the area near the lower strut (3), the concave cavity is in the rod part area at one end of the mounting hole, the rod part area at the other end of the mounting hole is a through-hole structure, and the outer end edge limits the position of the lower strut (3); 3. The landing gear strut locking mechanism according to claim 1, characterized in that: the lower strut (3) has a mounting hole for hinging with the landing gear at the other end; 4. The landing gear strut locking mechanism according to claim 1, characterized in that: the base (11) of the unlocking actuator (1) is fixed in the concave cavity of the upper strut (2); 5. The landing gear strut locking mechanism according to claim 1, characterized in that: the upper strut (2) is hinged to the fuselage through a strut upper shaft (7); 6. The landing gear strut locking mechanism according to claim 1, wherein: the lower strut (3) is hinged to the upper strut (2) through a strut middle shaft (8); 7. The landing gear strut locking mechanism according to claim 1, characterized in that: the rocker arm (4) is hinged to the upper strut (2) through a rocker arm shaft (9); 8. The landing gear strut locking mechanism according to claim 1, characterized in that: a roller is provided at the end of the piston rod (12); 9. The landing gear strut locking mechanism according to any one of claims 1-8, characterized in that: When the landing gear is in the open position, the lock ring bushing (6) of the rocker arm (4) is snapped into the biting surface of the lower strut (3) and locked by the locking spring (5); 10. The landing gear strut locking mechanism according to any one of claims 1-8, characterized in that: When it is necessary to retract the landing gear, the piston rod (12) of the unlocking actuator (1) is controlled to push the actuator plane of the rocker arm (4), so that the rocker arm (4) rotates. When the lock ring bushing (6) separates from the biting surface of the lower strut (3), the locking of the lower strut (3) is released.

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