Device for activating emergency functions of a landing gear

Abstract

The invention relates to a device (100) for activating an emergency function for the deployment of an aircraft landing gear, wherein the device comprises: an electric motor, a screw rod (120) configured to be translated by the electric motor between an extended position and a retracted position and configured to disengage a retaining element retaining the landing gear in a closed position when the screw rod is in the extended position and to fix the retaining element retaining the landing gear in the closed position when the screw rod is in the retracted position, two magnetic field sensors (151, 152), and a finger (160) comprising a permanent magnet (165) at one of its ends and movable between the two magnetic field sensors by being driven by the screw rod so that the permanent magnet aligns with the magnetic field sensors.

Description

Technical Field

[0001] This invention relates to the general field of aircraft landing gear, and more specifically to an electromechanical actuator capable of performing an emergency function for landing gear deployment. Background Technology

[0002] In the aviation industry, the locking of an aircraft's landing gear is typically provided by a mechanical actuator (called a "master lock"), which is designed to support the weight of the landing gear during the aircraft's flight phase via hook-like components, without any other additional energy source.

[0003] To unlock the landing gear and allow it to deploy, the first hydraulic hammer is arranged to disengage the hook from the mechanical actuation device. However, if the integrity of the first hydraulic hammer is compromised or if it is found to be inoperable, i.e., malfunctioning, a second hydraulic hammer (referred to as "Freefall") replaces the first hydraulic hammer to provide the same function. Therefore, activating the second hammer constitutes an emergency measure (or function) for aircraft pilot handling.

[0004] However, to facilitate maintenance of the second hydraulic hammer and ensure the fulfillment of this emergency function, it is preferable to replace it with another type of actuator that has the same level of reliability and availability, while still minimizing costs. For example, it is desirable to avoid using complex electronic circuitry to control this new actuator.

[0005] Furthermore, with the advent of hybrid and / or electric aircraft, it is preferable to replace the second hydraulic hammer with an electric or electromechanical actuator.

[0006] Therefore, it is desirable to devise a novel device for activating this emergency function, allowing the second hydraulic hammer to be replaced by an electromechanical actuator with the same level of reliability and availability, while still minimizing costs. Summary of the Invention

[0007] This invention relates to a device for activating the emergency deployment function of an aircraft landing gear, comprising:

[0008] - Electric motor;

[0009] - A screw, configured to be driven by an electric motor to translate between an extended position and a retracted position, and configured to disengage the retaining element of the landing gear in the closed position when the screw is in the extended position, and to engage the retaining element of the landing gear in the closed position when the screw is in the retracted position.

[0010] - Two magnetic field sensors; and

[0011] - A finger-like component that includes a permanent magnet at one of its ends and is movable between two magnetic field sensors by being driven by a screw, such that the permanent magnet faces the magnetic field sensor.

[0012] The activation device according to the invention proposes activation of the landing gear's emergency function in the absence of a hydraulic circuit and deployment control software. The position of the fingers facing the two magnetic field sensors allows control of the electric motor's rotation direction, and thus the screw's position. In effect, in the extended position, the screw allows the retaining element (e.g., a hook) of the landing gear in the closed position to disengage (decouple or unlock) to deploy the landing gear; while in the retracted position, the landing gear remains locked, meaning the retaining element is engaged with or coupled to the landing gear, or is in a position referred to as locked.

[0013] According to a specific feature of the invention, the electric motor is a brushed motor.

[0014] This allows for a simplified activation mechanism, as brushed motors do not require additional components compared to brushless motors. In fact, brushless motors require the development and use of control electronics.

[0015] According to another specific feature of the invention, the screw is a ball screw, a roller screw, or a screw with a trapezoidal thread.

[0016] Ball screws have the advantage of very high efficiency (approximately 96%), and therefore allow for a reduction in the size of the electric motor; while screws with trapezoidal threads would require a more powerful electric motor, but at a lower cost.

[0017] According to another specific feature of the invention, the activation device includes two deceleration stages.

[0018] According to another specific feature of the invention, the activation device includes a stop located at the rear of the screw to prevent its translation during retraction or extension positioning.

[0019] It should be noted that in the case of a ball screw, there may be two stops at the rear to prevent translation regardless of whether it is in the retracted or extended position.

[0020] According to another specific feature of the invention, the two magnetic field sensors are Hall effect sensors.

[0021] According to another specific feature of the invention, the activation device includes a fixed connector designed to connect the electric motor to a power source.

[0022] According to another specific feature of the invention, the activation device comprises: a first transistor and a first diode connected in parallel with the first transistor, which is connected to one of the two magnetic field sensors and to an electric motor; and a second transistor and a second diode connected in parallel with the second transistor, which is connected to another magnetic field sensor and to an electric motor.

[0023] The control of the electric motor is simplified due to the transistor. Depending on the position of the fingers—that is, facing either the first or second magnetic field sensor—the transistor will be in an open or closed position, thus allowing power to be supplied to the electric motor to move the screw between the extended and retracted positions. Furthermore, depending on the voltage (specifically, the polarity) supplied to the transistor's terminals, the motor will rotate in one direction or the other. In other words, due to the transistor, the two magnetic field sensors act as a switch on the transistor when the fingers (specifically, permanent magnets) face one or the other.

[0024] Another object of the present invention is an aircraft comprising landing gear and means according to the invention for activating an emergency function of the landing gear.

[0025] According to a specific feature of the invention, the aircraft includes an emergency power supply configured to supply power to the electric motor of the activation device.

[0026] Therefore, the device of the present invention does not require a specific power source to operate, as it can be powered by the aircraft's emergency power supply or basic power supply. This power supply is, for example, +14 V, +28 V, or even +36 V. Attached Figure Description

[0027] Other features and advantages of the invention will be revealed by the following description with reference to the accompanying drawings, which illustrate exemplary embodiments of the invention and are not intended to be limiting.

[0028] [ Figure 1 ] Figure 1 A side cross-sectional view of an activation device according to an embodiment of the present invention is shown schematically and in part.

[0029] [ Figure 2 ] Figure 2 schematically and partially shown Figure 1 A top-view cross-sectional view of the device.

[0030] [ Figure 3 ] Figure 3 An electrical circuit for controlling the position of an electric motor and a finger element according to an embodiment of the present invention is shown schematically and in part. Detailed Implementation

[0031] Figure 1and Figure 2 A cross-sectional view of an activation device 100 according to an embodiment of the present invention is shown schematically and partially. Figure 1 This is a side view. Figure 2 This is a top view.

[0032] The device 100 includes an electric motor 110, which is powered by a power source via a fixed connector 180.

[0033] The electric motor 110 can also be powered via a cable connected to a power source, and may or may not have a cable sealing system.

[0034] The electric motor 110 is, for example, a brushed motor, because this reduces the number of parts in the device 100. However, the motor 110 can also be a brushless motor.

[0035] The device 100 includes a screw 120 that is driven by translation via an electric motor 110. The screw 120 can move between a retracted position and an extended position. In the extended position, it is able to unlock the hooks (or upper locks) holding the landing gear in order to deploy the landing gear.

[0036] During the translation of screw 120, it drives finger 160, which moves between two magnetic field sensors 151 and 152. Other types of sensors, such as "switch" type sensors, can certainly be considered.

[0037] The finger 160 includes a permanent magnet 165 at its end facing the sensors 151, 152. When the permanent magnet 165 (and therefore the finger 160) faces the sensors 151, 152 that detect the magnetic field, the sensors 151, 152 detect the magnetic field generated by the permanent magnet 165.

[0038] The finger 160 is mechanically held onto the screw 160. For example, the finger 160 is attached to the screw 120 by adhesion, screwing, or welding.

[0039] Sensors 151 and 152 are, for example, Hall effect sensors.

[0040] When the screw 120 is in the retracted position, the finger 160 and its permanent magnet 165 face the sensor 151; while when the screw 120 is in the extended or retracted position, the finger 160 and its magnet 165 face the sensor 152. Because sensors 151 and 152 detect the magnetic field generated by the magnet 165, the position of the finger 160 and its magnet 165 facing one of sensors 151 or 152 allows for... Figure 3 It acts as a switch in circuit 300 to supply power to or de-supply the electric motor 100.

[0041] In this embodiment, the device 100 includes two reduction stages. A pinion 141 is fixed to the rotor 112 of the electric motor 110 and forms a first reduction stage with the gear on the shaft 140. The second reduction stage includes the pinion on the shaft 140, which meshes with the gear on the nut 130 of the screw 120. These two reduction stages allow for an increase in the torque between the electric motor 110 and the screw 120.

[0042] These two reduction stages can be replaced by elliptical reduction gears, which allow for a single reduction stage, thereby reducing the mass and volume of the device 100. For example, such reduction gears are commercially available under the name "Harmonic drive®".

[0043] It is also possible to eliminate the two reduction stages and replace nut 130 with the motor rotor.

[0044] Screw 120 is advantageously a ball screw, but it can also be a screw with trapezoidal threads.

[0045] When the screw 120 is in the retracted or extended position, there may also be a stop 122 for stopping the screw 120.

[0046] An anti-rotation element may also be present to allow the nut 130 to transmit torque, which is converted into thrust at the screw 120. This thrust is an additional force used to unlock the hook-like element locking the landing gear.

[0047] The device 100 may also include an electronic card 170 on which two magnetic field sensors 151 and 152 are soldered, and which can realize [the following functions] on the electronic card. Figure 3 Electrical circuit 300.

[0048] Figure 3 An electrical circuit 300 according to an embodiment of the invention is schematically and partially shown, which allows control of the position of the electric motor 110 and the screw 120 and thereby control of the position of the finger 160.

[0049] When the finger and its permanent magnet 165 face the sensor 151 or 152 that detects the magnetic field generated by the magnet 165, each transistor 171, 172 is in the open position.

[0050] Therefore, when magnet 160 faces sensor 152, it turns on transistor 172. Transistor 172 thus does not allow current to flow; while transistor 171 is closed and thus allows current to flow because sensor 151 does not detect a magnetic field.

[0051] By applying a positive voltage, such as +28 V, at connector 180, current will be able to circulate through diode 182, electric motor 110, and transistor 171. Electric motor 110, being positively powered, will drive the reduction gear formed by pinion 141, shaft 140, and nut 130 to rotate, and cause screw 120 to translate to the extended position to unlock the hook holding the landing gear. Consequently, finger 160 will also move toward sensor 151.

[0052] When the finger 160 and magnet 165 reach sensor 151, they turn on transistor 171, thereby blocking current from flowing through diode 181. This thus stops the translation of screw 120, which in turn keeps screw 120 in the extended position. The aircraft's landing gear thus deploys because the landing gear retaining element, here referring to the hook, which is in the closed (non-deployed) position, is now disengaged (or unlocked) from the mechanical actuator designed to support the weight of the landing gear during the aircraft's flight phases.

[0053] To return the screw 120 to the retracted position, a negative voltage V, such as -28 V, is applied to connector 180. Current will then circulate through diode 181, motor 110, and transistor 172. Because finger 160 is no longer facing sensor 152, sensor 152 no longer detects the magnetic field generated by magnet 165, and transistor 172 is now closed.

[0054] Due to the negative voltage, the electric motor 110 rotates in the opposite direction, causing the screw 120 to return to its retracted position. When the finger 160 and magnet 165 face the sensor 152, this will reactivate the transistor 172, thereby blocking current from flowing through the electric motor 110 due to the effect of the diode 181. The activation device for the emergency function of landing gear deployment is thus reinitialized.

[0055] Therefore, the activation device for the emergency deployment function of the present invention can be simply activated and controlled by the polarity of the voltage applied to the terminals of the electric motor 110; and sensors 151 and 152 are used as electric stops, allowing the device to be actuated. It requires no software and no complex electronics to be controlled and activated.

[0056] Diodes 301 and 302 may also be present to protect the device from lightning and to discharge current from the coil of motor 110.

[0057] Current limiters 161 and 162 can also be added to prevent thermal effects and current variations in the electrical network supplying the device of the present invention.

Claims

1. An aircraft comprising landing gear and means (100) for activating an emergency deployment function of the landing gear, comprising: - Electric motor (110); - A screw (120) configured to be driven by an electric motor to translate between an extended position and a retracted position, and configured to disengage the retaining element of the landing gear in the closed position when the screw is in the extended position, and to engage the retaining element of the landing gear in the closed position when the screw is in the retracted position. - Two magnetic field sensors (151, 152); and - A finger (160) includes a permanent magnet (165) at one of its ends and is movable between two magnetic field sensors by being driven by a screw so that the permanent magnet faces the magnetic field sensor.

2. The aircraft according to claim 1, wherein, Electric motors are brushed motors.

3. The aircraft according to any one of claims 1 or 2, wherein, The screw is a ball screw, roller screw, or screw with trapezoidal threads.

4. The aircraft according to any one of claims 1 to 3, comprising two deceleration stages.

5. The aircraft according to any one of claims 1 to 4, comprising a stop (122) located at the rear of the screw to prevent translation during retraction or extension positioning.

6. The aircraft according to any one of claims 1 to 5, wherein, The two magnetic field sensors are Hall effect sensors.

7. The aircraft according to any one of claims 1 to 6, comprising a fixed connector (180) designed to connect an electric motor to a power source.

8. The aircraft according to any one of claims 1 to 7, comprising: A first transistor (171) and a first diode (181) connected in parallel with the first transistor, which are connected to one of the two magnetic field sensors (151) and to an electric motor; and a second transistor (172) and a second diode (182) connected in parallel with the second transistor, which are connected to another magnetic field sensor (152) and to an electric motor.

9. The aircraft according to any one of claims 1 to 8, comprising an emergency power supply configured to supply power to the electric motor of the activation device.

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