An electrically unlocked landing gear lower lock tension spring actuator and movement method

Abstract

The present invention provides an electrically unlocked landing gear lower lock tension spring actuator cylinder and a movement method, the actuator cylinder integrates the lower lock tension locking function and the electric drive unlocking function, and includes a stationary end support ear, a stationary cylinder, a motor, a reducer, a lead screw, a lead screw nut, a lead screw nut limiting bolt, a tension spring, a sliding cylinder, and a sliding end support ear; a design scheme combining a linear electromechanical actuator and a landing gear lower lock tension spring actuator cylinder is adopted, and during the process when the landing gear bears load, the tension spring outputs tension to the landing gear locking rod through the actuator support ear, which externally manifests as a tension locking function, maintaining the contact between the two locking rods of the landing gear without loosening; during the process of unlocking the lower lock in the ground state, the actuator cylinder externally manifests as a thrust unlocking function, and the electric drive mechanism changes the length limit of the actuator cylinder and outputs thrust to the landing gear locking rod through the support ear, pushing the deflection direction between the two locking rods to change; finally, the landing gear realizes the retraction function under the drive of the landing gear retraction and extension actuator.

Description

Technical Field

[0001] The invention belongs to the field of landing gear design, and in particular relates to an electrically unlocked landing gear lower lock tension spring actuator and a motion method. Background Art

[0002] In a landing gear system using a strut lock, the deflection between the two locking rods changes direction and contacts when the landing gear is fully lowered, forming a dead point in the mechanism to achieve a mechanical locking function. When the aircraft touches down, the landing gear begins to bear load, and the lower lock structure requires external force to maintain contact between the two locking rods. This locking force is typically provided by a tension spring, one end fixed to the locking rod and the other to an appropriate position at the lower end of the landing gear. When the landing gear is retracted, the lower lock structure requires external force to overcome the weight of the landing gear system and push the deflection between the two locking rods to change direction. The mechanism returns from the dead point and is driven by the landing gear retraction actuator to achieve retraction.

[0003] The supported down-lock landing gear of both civilian and military models uses spring elements to drive the locking action of the landing gear and an independently set hydraulic / pneumatic unlocking actuator to drive the unlocking action of the landing gear; the aerospace model uses a hydraulic actuator to drive the locking rod to complete the down-lock locking and unlocking actions.

[0004] The landing gear of a spacecraft has the application characteristics of completing one lowering and one lower lock locking in flight. For aerospace vehicles that do not have a hydraulic system, the lower lock must be unlocked and the landing gear retracted on the ground. The lower lock cannot be unlocked automatically and requires manual operation of special tooling to complete the unlocking, which poses an extremely high safety risk to the operator. Summary of the Invention

[0005] In order to overcome the deficiencies in the prior art, the inventors have conducted intensive research and provided an electrically unlocked landing gear lower lock tension spring actuator, which integrates the lower lock tension locking function and the electric drive unlocking function, and can meet the requirements of the aerospace landing gear lower lock tension locking in flight state and the electric drive unlocking in ground state.

[0006] The present invention provides an electrically unlocked landing gear downlock tension spring actuator, utilizing a design that combines a linear electromechanical actuator with a landing gear downlock tension spring actuator. While the landing gear is under load, the tension spring applies tension to the landing gear locking rods via the actuator lugs, effectively acting as a tension lock, maintaining contact between the two locking rods. While unlocking the downlock on the ground, the actuator functions as a thrust unlock. An electric drive mechanism adjusts the actuator's length limit and applies thrust to the landing gear locking rods via the lugs, altering the deflection direction between the two rods. Finally, the landing gear retraction actuator drives the landing gear extension and retraction actuator, allowing the landing gear to retract.

[0007] The technical solutions provided by the present invention are as follows:

[0008] In a first aspect, a tension spring actuator for a landing gear lower lock with electric unlocking includes a stationary end lug, a stationary cylinder, a motor, a reducer, a lead screw, a lead screw nut, a lead screw nut stop bolt, a tension spring, a sliding cylinder, and a sliding end lug;

[0009] The stationary end support ear, stationary cylinder, motor, reducer, screw rod and screw nut limiting bolt are rigidly connected, and the motor, reducer and screw rod are connected in series to form an electric drive device. The motor serves as the driving source, and the power is output by the screw rod rotation after passing through the reducer; the screw rod and screw nut constitute a screw pair, and the screw nut limiting bolt is fixed to the front end of the screw rod to limit the movement of the screw nut on the screw rod; the sliding cylinder and the sliding end support ear are rigidly connected; the two ends of the tension spring are rigidly connected to the stationary end support ear and the sliding end support ear respectively, and are always in a stretched state; the sliding cylinder and the stationary cylinder can slide relative to each other, and the sliding cylinder and the screw nut can slide relative to each other; the screw nut and the screw nut limiting bolt are provided with a stop shoulder that can contact and limit; the screw nut and the sliding cylinder are provided with a stop shoulder that can contact and limit; the stationary end support ear and the sliding end support ear have structural support ears, which are installed externally as a rotating pair and are rotatably connected to the landing gear lock rod.

[0010] In a second aspect, a method for moving a tension spring actuator of a lower lock of an electrically unlocked landing gear includes:

[0011] During the landing gear lowering process, the electric drive device is not activated. Under the drive of the landing gear retraction and extension actuator, the stationary end lug and the sliding end lug cause the tension spring to deform. When the landing gear is lowered into place, the tension spring outputs a pulling force to the landing gear down lock rod and keeps the down lock locked.

[0012] During the unlocking process of the landing gear lower lock on the ground, the external power source drives the motor, the reducer, and the screw, and the screw nut drives the sliding cylinder to start moving from the end of the screw near the reducer. The screw nut extends to the shoulder of the screw nut limit bolt and stops moving. The sliding cylinder drives the sliding end lug to move so that the lug wheelbase is L when the landing gear reaches the locked position. lock Increase and pass the landing gear to reach the unlocked position when the lug wheelbase L unlock When the screw nut is located at the end of the screw rod close to the reducer, the screw nut is at the limit return position P1; when the screw nut extends to contact the shoulder of the screw nut limit bolt, the screw nut is at the limit limit position P2; the distance from P1 to the center of the stationary end lug must be between the free length L of the tension spring free With L lock The distance between P2 and the center of the stationary lug must be greater than or equal to L unlock ;

[0013] During the retraction of the landing gear on the ground, the lead screw nut remains in position, the stationary end lug and the sliding end lug are stretched by the tension spring driven by the landing gear retraction and extension actuator, the sliding cylinder and the lead screw nut slide relative to each other, the sliding cylinder and the stationary cylinder slide relative to each other, and the lug wheelbase extends and eventually reaches the lug wheelbase when the landing gear is in the retracted position;

[0014] Before the aircraft takes off, the positions of the stationary end lug and the sliding end lug remain unchanged, and the motor drives the lead screw to retract the lead screw nut to the end of the lead screw close to the reducer and maintain the position.

[0015] The electrically unlocked landing gear lower lock tension spring actuator and movement method provided by the present invention have the following beneficial effects:

[0016] (1) The present invention provides an electrically unlocked lower lock tension spring actuator for a landing gear, which is suitable for a supported lower lock for providing the lower lock with the tension required for the locked state. The unlocking process is achieved by changing the length limit of the actuator through an electrically driven single-end limiter. After the unlocking process, the limiter structure is disengaged, and the actuator can perform long-stroke follow-up under the action of an external force. Compared with existing domestic and foreign solutions, the invention realizes the "integration of the lower lock electrically driven autonomous unlocking and tension locking functions", which will significantly improve safety, and the basic technology is relatively mature and easy to implement.

[0017] (2) The present invention provides an electrically unlocked landing gear lower lock tension spring actuator, which does not require power supply in flight mode and uses ground power supply to drive the unlocking process in ground mode, without affecting the reliability of the aircraft;

[0018] (3) The present invention provides an electrically unlocked landing gear lower lock tension spring actuator that can be extended to connect to the aircraft control system. The unlocking and returning to the full position can be judged by using the signals sent by the in-position sensor or the line current / bus current signal sampling to achieve closed-loop control. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the wheelbase-timing diagram of the lower lock tension spring support ear in the lowering action;

[0020] Figure 2 This is the wheelbase-timing diagram of the lower lock tension spring lug in the retracting action;

[0021] Figure 3 This is the lug wheelbase-timing diagram of the electric drive limiter during the lowering action;

[0022] Figure 4 This is the lug wheelbase-timing diagram for the electric drive limit in the stowing action;

[0023] Figure 5 Schematic diagram of the components of the actuator;

[0024] Figure 6 Schematic diagram of the guide groove structure.

[0025] Explanation of Figure Numbers

[0026] 1-stationary end support ear; 2-stationary cylinder; 3-motor; 4-reducer; 5-screw; 6-screw nut; 7-tension spring; 8-screw nut limit bolt; 9-sliding cylinder; 10-sliding end support ear. DETAILED DESCRIPTION

[0027] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0028] The present invention provides a landing gear lower lock tension spring actuator with electric unlocking, such as Figure 5 As shown, it includes a stationary end support ear 1, a stationary cylinder 2, a motor 3, a reducer 4, a screw 5, a screw nut 6, a screw nut limit bolt 8, a tension spring 7, a sliding cylinder 9, and a sliding end support ear 10;

[0029] The stationary end support ear 1, the stationary cylinder 2, the motor 3, the reducer 4, the screw 5 and the screw nut limit bolt 8 are rigidly connected. The motor 3, the reducer 4 and the screw 5 are connected in series to form an electric drive device. The motor 3 serves as the driving source. After passing through the reducer 4, the screw 5 rotates to output power.

[0030] The screw rod 5 and the screw nut 6 form a screw pair, and the screw nut limiting bolt 8 is fixed to the front end of the screw rod 5 to limit the movement of the screw nut 6 on the screw rod 5;

[0031] The sliding cylinder 9 is rigidly connected to the sliding end lug 10; the two ends of the tension spring 7 are rigidly connected to the stationary end lug 1 and the sliding end lug 10 respectively, and are always in a tensioned state;

[0032] A guide groove is designed between the outer surface of the sliding cylinder 9 and the stationary cylinder 4. The number of the guide grooves can be selected as 2, 3 or 4 groups according to the size of the inner diameter of the tension spring. The sliding cylinder 9 and the stationary cylinder 4 can slide relative to each other. Figure 6 As shown; a guide groove is designed between the inner surface of the sliding cylinder 9 and the screw nut 6. Similarly, the number of guide grooves can be selected according to the size of the inner diameter of the tension spring, 2 groups, 3 groups or 4 groups, the sliding cylinder 9 and the screw nut 6 can slide relative to each other, such as Figure 6 As shown; the screw nut 6 and the screw nut limit bolt 8 are provided with a shoulder capable of contacting and limiting; the screw nut 6 and the sliding cylinder 9 are provided with a shoulder capable of contacting and limiting;

[0033] The stationary end support lug 1 and the sliding end support lug 10 have structural support lugs, which are externally mounted as a rotating pair and are rotationally connected to the landing gear locking rod.

[0034] In the current supported landing gear system, the wheelbase and position sequence of the two ears of the lower lock tension spring are respectively as follows during the lowering action and the retracting action. Figure 1 、 Figure 2 As shown, where L free is the free length of the spring; L lock L is the wheelbase of the landing gear when it reaches the locked position; unlock L is the wheelbase of the landing gear when it reaches the unlocked position; up L is the wheelbase of the landing gear when it is in the retracted position; max It is the wheelbase of the landing gear when it reaches the process limit position.

[0035] In the unlocking action of the lower lock, the actuator of the present invention drives the L lock To L unlock The actuator can achieve L by adjusting the minimum wheelbase of the two ears of the tension spring at one end. lock To L unlock At any time before flight, the limit should be reset to restore the tension spring stroke to provide the locking tension for the lower lock.

[0036] The axis distance and position sequence of the two ears of the lower lock tension spring of the limit are as follows in the lowering action and the retracting action. Figure 3 、 Figure 4 As shown, P1 is the limit return position of the screw nut 6, at which time the screw nut 6 is located at the end of the screw 5 close to the reducer 4; P2 is the limit limit position of the screw nut 6, at which time the shoulder of the screw nut 6 contacts the shoulder of the screw nut limit bolt 8. The distance between P1 and the center of the stationary end lug must be between L free With L lock Between; the effective travel of the limit must cover L lock To L unlock If the distance between P2 and the center of the stationary lug is greater than or equal to L unlock ; In P2 to L max Duan and L max To L up The section limit is disengaged, and the wheelbase of the two ears moves with the landing gear.

[0037] The specific movement method of the actuator of the present invention during the lowering and retracting actions is given below.

[0038] During the landing gear lowering process, the electric drive device is not started. Under the driving of the landing gear retraction actuator, the stationary end lug 1 and the sliding end lug 10 drive the tension spring 7 to deform. When the landing gear is lowered into place, the lug wheelbase reaches L lock , output tension to the landing gear down lock rod and keep the down lock locked.

[0039] During the unlocking process of the lower lock ground state, the actuator is connected to the ground power supply, driving the motor 3 and transmitting through the reducer 4 and the screw 5. The screw nut 6 starts to move from the end of the screw 5 close to the reducer 4 (located at the limit return position P1), and stops when the screw nut 6 extends to contact the shoulder of the screw nut limit bolt 8 (reaching the limit limit position P2). During this process, the contact shoulder between the screw nut 6 and the sliding cylinder 9 is always in contact, and the screw nut 6 pushes the sliding cylinder 9, so that the wheelbase of the stationary end lug 1 and the sliding end lug 10 is changed from the wheelbase L when the landing gear reaches the locked position. lock When the lug wheelbase L is increased and exceeds the unlocked position unlock ; The sliding cylinder 9 and the stationary cylinder 2 slide relative to each other.

[0040] During the ground retraction process of the landing gear, the ground power supply is disconnected and the screw nut 6 maintains the limit position P2 unchanged. The static end lug 1 and the sliding end lug 10 are actuated by the external force (landing gear retraction actuator) to drive the tension spring 8 to stretch, and the lug wheelbase passes the process limit position L max and finally reaches the wheelbase L when the landing gear is in the retracted position up During the process, the sliding cylinder 9 and the lead screw nut 6 slide relative to each other; the sliding cylinder 9 and the stationary cylinder 2 slide relative to each other.

[0041] Before the aircraft takes off, the wheelbase of the support ears is kept in the retracted position L up The actuator is connected to the ground power supply, driving the motor 3 and retracting the screw nut 6 to the limit return position P1 through the reducer 4 and the screw rod 5 and maintaining the position.

[0042] The position of the lead screw nut 6 can be determined using either an in-position sensor or sensorless technology. When the actuator is connected to the control system, an actuator using an in-position sensor can interpret the limit return position P1 and the limit limit position P2 using the sensor output signal; an actuator using sensorless technology can interpret the position by sampling the line current / bus current signal, achieving closed-loop control.

[0043] The present invention has been described in detail above with reference to specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements may be made to the technical solutions and implementations of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0044] shall prevail.

[0045] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. An electrically unlocked landing gear lower lock tension spring actuator, characterized in that: It comprises a stationary end support ear (1), a stationary cylinder (2), a motor (3), a reducer (4), a screw rod (5), a screw nut (6), a screw nut limiting bolt (8), a tension spring (7), a sliding cylinder (9), and a sliding end support ear (10); The stationary end support ear (1), the stationary cylinder (2), the motor (3), the reducer (4), the screw (5) and the screw nut limiting bolt (8) are rigidly connected. The motor (3), the reducer (4) and the screw (5) are connected in series to form an electric drive device. The motor (3) serves as a driving source. After passing through the reducer (4), the screw (5) rotates to output power. The screw (5) and the screw nut (6) form a screw pair. The screw nut limiting bolt (8) is fixed to the front end of the screw (5) to limit the movement of the screw nut (6) on the screw (5). The sliding cylinder (9) and the sliding end support ear (10) are rigidly connected. The two ends of the tension spring (7) are respectively rigidly connected to the stationary end support ear (1) and the sliding end support ear (10), and are always in a tensioned state; the sliding cylinder (9) and the stationary cylinder can slide relative to each other, and the sliding cylinder (9) and the lead screw nut (6) can slide relative to each other; the lead screw nut (6) and the lead screw nut limiting bolt (8) are provided with a stop shoulder that can contact and limit; the lead screw nut (6) and the sliding cylinder (9) are provided with a stop shoulder that can contact and limit; the stationary end support ear (1) and the sliding end support ear (10) have structural support ears, which are externally installed as a rotary pair and are rotatably connected to the landing gear lock rod.

2. The electrically unlocked landing gear lower lock tension spring actuator according to claim 1, characterized in that: A guide groove is designed between the outer surface of the sliding cylinder (9) and the stationary cylinder.

3. The electrically unlocked landing gear lower lock tension spring actuator according to claim 1, characterized in that: A guide groove is designed between the inner surface of the sliding cylinder (9) and the lead screw nut (6).

4. The electrically unlocked landing gear lower lock tension spring actuator according to claim 1, characterized in that: During the landing gear lowering process, the electric drive device is not started, and the static end support ear (1) and the sliding end support ear (10) are driven by the landing gear retraction and extension actuator to cause the tension spring (7) to deform. When the landing gear is lowered into place, the tension spring (7) outputs a pulling force to the landing gear lower lock rod and keeps the lower lock locked.

5. The electrically unlocked landing gear lower lock tension spring actuator according to claim 1, characterized in that: During the unlocking process of the landing gear lower lock on the ground, an external power source drives the motor (3), the reducer (4), and the screw (5), and the screw nut (6) drives the sliding cylinder (9) to start moving from the end of the screw (5) close to the reducer (4). The screw nut (6) stops moving when it extends to contact the shoulder of the screw nut limit bolt (8). The sliding cylinder (9) drives the sliding end support ear (10) to move, so that the support ear wheelbase is L when the landing gear reaches the locked position. lock Increase and pass the landing gear to reach the unlocked position when the lug wheelbase L unlock ; When the screw nut (6) is located at one end of the screw rod (5) close to the reducer (4), the screw nut (6) is located at the limit return position P1; when the screw nut (6) extends to contact the shoulder of the screw nut limit bolt (8), the screw nut (6) is located at the limit limit position P2; the length of P1 from the center of the stationary end support ear must be between the free length L of the tension spring free With L lock The distance between P2 and the center of the stationary lug must be greater than or equal to L unlock .

6. The electrically unlocked landing gear lower lock tension spring actuator according to claim 5, characterized in that: During the retraction process of the landing gear, the screw nut (6) remains in the same position, the stationary end support lug (1) and the sliding end support lug (10) are stretched by the tension spring driven by the landing gear retraction and extension actuator, the sliding cylinder (9) and the screw nut (6) slide relatively, the sliding cylinder (9) and the stationary cylinder (2) slide relatively, the support lug wheelbase is extended and finally reaches the support lug wheelbase when the landing gear is in the retracted position.

7. The electrically unlocked landing gear lower lock tension spring actuator according to claim 1, characterized in that: Before the aircraft takes off, the positions of the stationary end support lug (1) and the sliding end support lug (10) remain unchanged, and the motor (3) drives the screw rod (5) to retract the screw nut (6) to the end of the screw rod (5) close to the reducer (4) and maintain the position.

8. A method for moving the tension spring actuator of the electrically unlocked landing gear lower lock according to any one of claims 1 to 7, characterized in that: include: During the landing gear lowering process, the electric drive device is not started, and the static end support ear (1) and the sliding end support ear (10) are driven by the landing gear retraction and extension actuator to cause the tension spring (7) to deform. When the landing gear is lowered into place, the tension spring (7) outputs a pulling force to the landing gear lower lock rod and keeps the lower lock locked.

9. The method for moving the tension spring actuator of the lower lock of the electrically unlocked landing gear according to claim 8, characterized in that: include: During the unlocking process of the landing gear lower lock on the ground, an external power source drives the motor (3), the reducer (4), and the screw (5), and the screw nut (6) drives the sliding cylinder (9) to start moving from the end of the screw (5) close to the reducer (4). The screw nut (6) stops moving when it extends to contact the shoulder of the screw nut limit bolt (8). The sliding cylinder (9) drives the sliding end support ear (10) to move, so that the support ear wheelbase is L when the landing gear reaches the locked position. lock Increase and pass the landing gear to reach the unlocked position when the lug wheelbase L unlock ; When the screw nut (6) is located at one end of the screw rod (5) close to the reducer (4), the screw nut (6) is located at the limit return position P1; when the screw nut (6) extends to contact the shoulder of the screw nut limit bolt (8), the screw nut (6) is located at the limit limit position P2; the length of P1 from the center of the stationary end support ear must be between the free length L of the tension spring free With L lock The distance between P2 and the center of the stationary lug must be greater than or equal to L unlock .

10. The method for moving the tension spring actuator of the lower lock of the electrically unlocked landing gear according to claim 8, characterized in that: include: During the retraction process of the landing gear on the ground, the screw nut (6) remains in a fixed position, the stationary end support lug (1) and the sliding end support lug (10) are stretched by the tension spring driven by the landing gear retraction and extension actuator, the sliding cylinder (9) and the screw nut (6) slide relatively, the sliding cylinder (9) and the stationary cylinder (2) slide relatively, and the support lug wheelbase is extended and finally reaches the support lug wheelbase when the landing gear is in the retracted position; Before the aircraft takes off, the positions of the stationary end support lug (1) and the sliding end support lug (10) remain unchanged, and the motor (3) drives the screw rod (5) to retract the screw nut (6) to the end of the screw rod (5) close to the reducer (4) and maintain the position.

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