BRAKE SYSTEM FOR AIRCRAFT UNDERCARRIAGE

• US 20110253833A1
• Filed: 02/16/2011
• Published: 10/20/2011
• Est. Priority Date: 02/16/2010
• Status: Active Grant

• Current Assignee: Alenia Aeronautica SPA (Leonardo S.p.A.)
• Original Assignee: Alenia Aeronautica SPA (Leonardo S.p.A.)
• Inventors: Cuomo, Fabrizio, ANASTASIO, Vincenzo
• Granted Patent: US 8,505,697 B2
• Time in Patent Office: Days
• US Class Current: 244/111
• CPC Class Codes: B64C 25/42 Arrangement or adaptation of brakes

Abstract

A braking system for an aircraft provided with undercarriage, wherein an axial-flux reversible electrical machine is associated to at least one wheel of the undercarriage and is set in rotation by the rotation of the wheel. Current-dissipator means are provided, which can be connected to the windings of the axial-flux reversible electrical machine during rotation of the wheel in the landing phase for dissipating in the current-dissipator means the induced currents generated by the machine, which behaves as current generator, and producing a braking effect that slows down the movement of the wheel. An epicyclic reducer is provided set between the wheel of the undercarriage and the rotor of the reversible electrical machine; the epicyclic reducer provides a transmission ratio T in such a way that the rotor will turn at a velocity Tω with respect to the velocity of rotation ω of the wheel.

Claims

1. A braking system for an aircraft (2) provided with undercarriage (7) in which an axial-flux reversible electrical machine (20) is associated to at least one wheel of the undercarriage and is set in rotation by the rotation of the wheel, there being provided current-dissipator means (40a, 40b, 40c) that can be connected (38a, 38b, 38c) to the windings (36a, 36b, 36c) of said axial-flux reversible electrical machine (20) during rotation of said wheel (10) in the landing phase for dissipating in the current-dissipator means (40a, 40b, 40c) the induced currents generated by the machine (20), which behaves as current generator (20), and producing a braking effect that slows down the movement of said wheel (10),

said braking system being characterized in that it comprises an epicyclic reducer (21) set between the wheel (10) of the undercarriage and the rotor (32) of said reversible electrical machine (20);

said epicyclic reducer (21) providing a transmission ratio T in such a way that the rotor (32) will turn at a velocity Tω

with respect to the velocity of rotation ω

of the wheel (10).

2. The system according to claim 1, wherein said epicyclic reducer (21) comprises:

a ring gear (22) angularly fixed with respect to the wheel (10);

a plurality of planetary gears or satellites (24), which mesh on the ring gear (22); and

a sun gear (25), which meshes with the planetary gears or satellites (24) and is angularly fixed with respect to the rotor of the reversible electrical machine (20).

3. The system according to claim 2, wherein the axial-flux reversible electrical machine (20) comprises at least one stator (34a, 34b) facing the rotor and angularly fixed with respect to a portion of said undercarriage (5, 7).

4. The system according to claim 3, wherein the stator (34) of the axial-flux reversible electrical machine (20) is fixed with respect to the frame (8).

5. The system according to claim 1, wherein said current dissipators (30a, 30b, 30c) comprise resistor means.

6. The system according to claim 5, wherein said resistor means have a resistance R(f) that varies according to a command (43) in order to modulate the braking action.

7. The system according to claim 1, wherein it is provided with an accumulation device (46) in which electrical charge can be accumulated and which can be connected (44a, 44b, 44c) to said axial-flux reversible electrical machine (20) for storing the charge not dissipated in said current-dissipator means (40a, 40b, 40c).

8. system according to claim 7, wherein control means (50) are provided, designed to make the transfer of charge from said accumulation device (46) to said axial-flux reversible electrical machine (20), thus supplying further power for braking.

9. The system according to claim 7, wherein said control means (50) make the transfer of charge when the velocity of rotation of the wheel drops below a first threshold value.

10. The system according to claim 7, wherein said control means (50) make the transfer of electrical energy from an electrical network of the aircraft (55) to said axial-flux reversible electrical machine (20), thus supplying further power for braking.

11. The system according to claim 7, wherein said control means (50) make the transfer of electrical energy from the electrical network of the aircraft (55) to said reversible electrical machine when the velocity of rotation of the wheel drops below a second threshold value lower than the first.

12. The system according to claim 8, wherein said control means (50), following upon completion of the braking operations, are configured for issuing a command for a flow of current from the on-hoard electrical network (55) to the electrical machine (20) with a direction such as to obtain rotation of the reversible electrical machine and generation of a torque that brings about displacement of the aircraft (2) on the runway.

13. The system according to claim 1, wherein the axial-flux reversible electrical machine (20) is of a three-phase type and comprises a first winding (36a), a second winding (36b), and a third winding (36c), which have first terminals connected to one another and second terminals connected, respectively, to a first electric line (37a), a second electric line (37b), and a third electric line (37c) that can be connected (38a, 38b, 38c) to said current-dissipator means (40a, 40b, 40c), respectively.

14. The system according to claim 1, wherein the axial-flux reversible electrical machine (20) is of a six-phase type.