Control device for a magnetic gear-driven aircraft flight trimmer

Abstract

This aircraft flight trim control device (1) comprises a motor (M), a friction device (10), and an output shaft (12), the friction device (10) being coupled on one side to the motor (M) and on the other side to the output shaft (12), the control device comprising a magnetic gear (11) connected on one side to the friction device (10) and on the other side to the output shaft (12). Figure for the abbreviation: Fig 2

Description

Title of the invention: Control device for a magnetic gear flight trimmer for an aircraft technical field

[0001] The present invention relates to electric flight control devices for aircraft.

[0002] The present invention relates more particularly to the control of a flight trimmer for an aircraft, for example for a helicopter. Previous techniques

[0003] Flight trim systems (also called "trim" in English) allow the flight control of an aircraft to be anchored in a neutral position that can be adjusted by the pilot to balance the aerodynamic forces on the control surface. For example, in the case of a crosswind, a flight trim system allows the control stick, or control lever, to remain in the neutral position while producing a displacement of the aircraft to counteract the effect of the crosswind.

[0004] Flight compensators also make it possible to return an effort to the pilot in the case where the flight controls use servo controls rather than exclusively mechanical controls.

[0005] Finally, flight trimmers can also interface with the autopilot to transmit autopilot instructions to the flight controls by, for example, moving the control stick when the aircraft is in autopilot mode.

[0006] In the case of an aircraft equipped with servo controls, a control device, also called a trim actuator, provides the pilot with a resisting force on the manual flight controls of the flight trimmer.

[0007] Figure 1 shows a prior art control device 1 for a flight trimmer. The control device 1 generally comprises a motor M, a reduction gear 2, a friction device 3, a mechanical gear 4 and an output shaft 5 equipped with a safety pin 6.

[0008] The motor M is, for example, connected to the gearbox 2 by a worm gear 7. The gearbox 2 is coupled to the friction device 3, said friction device 3 being coupled to the output shaft 5 via the mechanical gear 4 consisting, for example, of several toothed pinions. The output shaft 5 is connected in particular to the control lever used by the aircraft pilot to move the aircraft's stabilizing elements, for example, the rotor blades.

[0009] This architecture is, however, subject to defects such as tooth breakage in the mechanical gear 4, for example, due to the presence of foreign bodies damaging the mechanical gear 4. Furthermore, each element of this control device 1 can malfunction or seize up. This results in the aircraft's flight control system becoming blocked.

[0010] Furthermore, since the control device 1 may be seized, the pilot must force the control lever until the safety pin 6 positioned on the output shaft 5 breaks in order to release the control lever's movement. Thus, the manual control is disengaged from the control device 1, which may be seized, for example, at the mechanical gear.

[0011] However, destroying the pin requires the pilot to force the control lever, which, once the safety pin is broken, causes a sudden movement of the pilot's arm with the lever, which can generate a deviation of the aircraft from its trajectory and a significant risk to the aircraft. Description of the invention

[0012] The present invention therefore aims to overcome the aforementioned disadvantages by reducing the risk of the gear seizing and by eliminating the risk of a sudden movement of the pilot following the destruction of the safety pin.

[0013] The present invention relates to a control device for an aircraft flight trimmer, comprising a motor, a friction device, and an output shaft, the friction device being coupled on one side to the motor and on the other side to the output shaft. The control device also includes a magnetic gear connected on one side to the friction device and on the other side to the output shaft.

[0014] Because it has no mechanical parts in contact, the magnetic gear is not subject to the problem of seizing due to tooth breakage, unlike traditional gears. Furthermore, it has the additional characteristic of torque limitation: beyond a certain torque, the magnetic gear disengages the friction device from the output shaft. These characteristics eliminate the need for a safety pin on the output shaft.

[0015] Advantageously, the control device includes a reversible or irreversible reducer coupled on the one hand to the motor and on the other hand to the friction device.

[0016] Advantageously, the control device includes a rotational displacement sensor for the output shaft.

[0017] Advantageously, the magnetic gear includes poles of magnets or electromagnets.

[0018] For example, the magnetic gear couples the friction device and the output shaft without contact.

[0019] The flight control device is automatic and is connected to the control lever of the flight control.

[0020] The invention also relates to a helicopter comprising a flight control device as defined above. Brief description of the drawings

[0021] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0022] [Fig. 1] which has already been mentioned, schematically illustrates a control device for a flight trimmer according to the prior art;

[0023] [Fig.2] schematically illustrates a control device for a flight trimmer according to the invention. Detailed description of at least one embodiment

[0024] Figure 2 shows a schematic view of a control device 8 of a helicopter flight trimmer.

[0025] The control device 8 comprises a motor M, a reducer 9, a friction device 10, a magnetic gear 11 and an output shaft 12. A worm gear 13 connects the motor M to the reducer 9 while an input shaft 14 connects the reducer 9 to the friction device 10.

[0026] The friction device 10 is connected to the magnetic gear 11 via a second shaft 15. The output shaft 12 connects the magnetic gear 11 to the control lever (not shown) used by the aircraft pilot to apply a resisting force to the control lever as a function of the displacement imparted to the lever by the pilot.

[0027] The motor M is, for example, controlled by a control signal to automatically apply force to the control lever. The motor M is, for example, electric and drives the worm gear 13 in rotation.

[0028] The reducer 9 is irreversible or reversible, preferably irreversible and comprising for example several reduction stages.

[0029] The friction device 10 is, for example, a servo-controlled variable friction device controlled by a flight control computer (not shown) so as to provide a variable friction force depending on the conditions and phases of flight. It comprises a drum 16 and a ring 17, the ring 17 engaging with the drum 16 through their friction surface 18, in order to fully or partially engage or disengage the ring 17 and the drum 16.

[0030] The magnetic gear 11, also called a "magnetic gear" in Anglo-Saxon terms, is a set of pinions 19 whose teeth are poles 20 of magnets or electromagnets. Since the poles 20 can repel each other, two gears 19 Magnets can act on each other without contact. The magnetic gear 11 therefore allows the movement from the second shaft 15 to the output shaft 12 to be transmitted without noise, without contact, without wear, and minimizing the risk of the gear seizing.

[0031] In addition, the magnetic gear 11 provides a torque limiter function when the torque of the second shaft exceeds a predetermined threshold. This is an additional safety feature in case of blockage of the friction device, which, under normal operating conditions, limits the transmitted torque.

[0032] The advantage provided by the fact that the magnetic gear 11 allows a contactless transmission of motion is also to allow the absence of a fusible element such as a safety pin: when the control device 8 seizes, the helicopter pilot can operate the control lever and pilot and act on the flight controls, without having to break a safety pin since the magnetic gear 11 makes it possible to intrinsically separate the control lever from the part of the control device 8 comprising the motor M, the reducer 9 and the friction device 10.

[0033] The control device 8 includes, for example, a rotational displacement sensor 21 of the output shaft 12. The rotational displacement sensor 21 measures the rotation of the output shaft 12 via a gear 22 and generates a measurement signal representative of the angular position of the output shaft 12.

Claims

Demands

1. Control device (1) of a flight trimmer for aircraft, comprising a motor (M), a friction device (10), and an output shaft (12), the friction device (10) being coupled on one side to the motor (M) and on the other side to the output shaft (12), characterized in that it comprises a magnetic gear (11) linked on one side to the friction device (10) and on the other side to the output shaft (12).

2. Device according to claim 1, comprising a reversible or irreversible reducer (9) coupled on the one hand to the motor (M) and on the other hand to the friction device (10).

3. Device according to any one of claims 1 and 2, comprising a rotational displacement sensor (21) of the output shaft (12).

4. Device according to any one of claims 1 to 3, wherein the magnetic gear (11) comprises poles (20) of magnets or electromagnets.

5. Device according to any one of claims 1 to 4, wherein the magnetic gear (11) couples the friction device (10) and the output shaft (12) without contact.

6. Device according to any one of claims 1 to 5, wherein the control device (1) is automatic and is connected to a control lever of a flight control.

7. Aircraft comprising a control device (1) according to any one of claims 1 to 6.

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