DESIGN OF AN AIRCRAFT BRAKE SYSTEM

Description

[0001] The invention relates to the field of aircraft braking system architectures. BACKGROUND OF THE INVENTION

[0002] In reference to the figure 1 , a known centralized architecture of an aircraft electric braking system comprises a plurality of brakes 1 each intended to brake a wheel of a landing gear of the aircraft.

[0003] Each brake 1 comprises four electromechanical braking actuators 2 which are grouped into two separate groups of two electromechanical actuators 2.

[0004] The two electromechanical actuators 2 of each separate group are connected to the same computer 3 located in the fuselage of the aircraft, at the top of the landing gear.

[0005] The electric motor of each electromechanical actuator 2 receives a three-phase electric power supply current from the computer 3 to which the electromechanical actuator 2 is connected, and each electromechanical actuator 2 transmits measurements of a control parameter to the computer 3, for example measurements of the angular position of the rotor of the electric motor. The computers 3 implement functions for monitoring and controlling the electromechanical actuators 2, as well as power generation functions which use inverters.

[0006] It can be seen that this centralized architecture requires the use of at least ten electrical wires per electromechanical actuator 2: three power supply wires 4 for the three phases of the electric motor, four communication wires 5 to send the angular position measurements of the rotor of the electric motor back to a centralized computer 3, as well as two power supply wires and one grounding wire (not shown on the figure 1 ) to control a locking member of the electromechanical actuator 2 allowing parking braking to be implemented.

[0007] These electrical wires are integrated into harnesses that run from the aircraft fuselage to the brake 1 and are therefore bulky and heavy. The significant length of the harnesses in which the power supply wires 4 (and therefore the power supply currents of the electric motors) run requires common mode current filtering circuits to be integrated into the computers 3. The filtering circuits increase the mass, complexity and cost of the computers 3 and therefore of the braking system. Document EP 2 878 501 A1 discloses a brake-by-wire system for an aircraft. The system comprises a control unit ("BCU"), electromagnetic actuators ("EMA") and electromagnetic actuator controllers ("EMAC"). An "EMAC" may comprise a digital-to-analog converter and inverters for the actuators. The "EMACs" may be arranged in the landing gear bay.Document EP 2 824 809 A2 discloses an electromechanical actuator, for flight control or braking, comprising an actuating member, an electric motor adapted to drive the actuating member, a body and at least one electrical module adapted to generate an electric current to supply the electric motor, the electrical module being carried by the body. SUBJECT OF THE INVENTION

[0008] The object of the invention is to reduce the size, mass, complexity and cost of a braking system. SUMMARY OF THE INVENTION

[0009] To achieve this goal, an aircraft braking system architecture according to claim 1 is provided.

[0010] The use of the junction box makes it possible to pool the generation of the second control signals from the first control signals, and therefore to reduce the number of cables running from the aircraft fuselage to the brake. This also reduces the number of components to implement functions that can be pooled in the junction box, and therefore reduces the mass and complexity of the braking system, and improves its reliability.

[0011] Other characteristics and advantages of the invention will emerge upon reading the following description of particular, non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Reference will be made to the attached drawings, including: there figure 1 represents a prior art braking system architecture; figure 2 represents a braking system architecture not covered by the text of the claims; figure 3 represents another braking system architecture not covered by the text of the claims; figure 4 represents a braking system architecture according to an embodiment of the invention; the figure 5 represents another braking system architecture not covered by the text of the claims; figure 6 represents another braking system architecture not covered by the text of the claims; figure 7 represents another braking system architecture not covered by the text of the claims. DETAILED DESCRIPTION OF THE INVENTION

[0013] The invention is implemented here on an aircraft which comprises a plurality of main landing gears each carrying a plurality of so-called "braked" wheels, that is to say a plurality of wheels each equipped with a brake for braking the aircraft. The present description relates to a single braked wheel, but the invention of course applies in the same way to all or part of the braked wheels of the aircraft.

[0014] In reference to the figure 2 , an aircraft braking system architecture comprises a brake 100 intended to brake a wheel of the aircraft, a computer 101 and a junction box 102.

[0015] The brake 100 comprises four electromechanical braking actuators 103 (only two electromechanical actuators 103 are shown in the figure 2 ).

[0016] The 101 computer, integrated into an avionics network, is positioned in a bay located in the aircraft fuselage.

[0017] The junction box 102 is located on the landing gear, near the brake. The junction box 102 comprises electrical processing means 105 here comprising a digital switch. The computer 101 and the junction box 102 are connected by a first digital bus 106 comprising a first number of wires. The junction box 102 is connected to each electromechanical actuator 103 by a second digital bus 107 comprising a second number of wires.

[0018] In addition to the four electromechanical actuators 103, the brake 100 comprises an actuator holder on which the four electromechanical actuators 103 and friction members are mounted, in this case a stack of carbon discs.

[0019] The four electromechanical actuators 103 are used to apply a braking force to the stack of carbon discs and thus exert a braking torque on the wheel which slows the rotation of the wheel and therefore brakes the aircraft when it is on the ground.

[0020] Each electromechanical actuator 103 comprises a body fixed to the actuator holder, a pusher and a locking member adapted to lock the pusher in position. An electric motor, a power module 108 and a digital communication module 109 are integrated inside the body of each electromechanical actuator 103.

[0021] The pusher is operated by the electric motor to slide and apply braking force to the stack of carbon discs.

[0022] The power module 108 makes it possible to generate an alternating supply current which circulates in three phases of the electric motor when it is necessary to actuate the pusher and therefore to brake the wheel, and when it is necessary to remove the pusher to stop braking the wheel. The power module 108 comprises for this purpose an inverter comprising a plurality of switches which are controlled so as to transform a direct supply voltage into a three-phase alternating voltage under which the supply current of the electric motor is generated.

[0023] The continuous supply voltages received by the power modules 108 of the four electromechanical actuators 103 of the brake 100 come from one or more power supply units located in the fuselage of the aircraft and not shown in the figure 2 .

[0024] The computer 100 produces first control signals. The junction box 102 is arranged to receive the first control signals. The electrical processing means 105 of the junction box are arranged to produce, from the first control signals, second control signals intended for the electromechanical actuators 103 to control the electromechanical actuators 103.

[0025] The first control signals and the second control signals here comprise digital signals for controlling the electric motors of the electromechanical actuators 103.

[0026] The digital control signals, produced by the computer 100, are distributed to the digital communication modules 109 of the electromechanical actuators 103 via the digital switch of the electrical processing means 105 of the junction box 102.

[0027] The digital communication module 109 of each electromechanical actuator 103 transforms the digital control signals intended for it into inverter control signals and transmits the inverter control signals to the power module 108 and therefore to the inverter of the power module 108. The inverter control signals control the switches of said inverter.

[0028] The digital communication modules 109 of the four electromechanical actuators 103, as well as the digital switch of the electrical processing means 105 of the junction box 102 are thus interconnected to form a digital network.

[0029] It is noted that digital signals can also be sent from the wheel to the computer 101 and therefore to the avionics network, via the second digital buses 107 and the first digital bus 106. The second digital buses 107 and the first digital bus 106 are thus bidirectional buses.

[0030] The digital signals include, for example, digital measurement signals generated by a data concentrator located on the wheel. The data concentrator itself receives analog measurement signals generated by sensors located on the wheel and generates the digital measurement signals from the analog measurement signals. The sensors measure parameters representative of a state of the wheel, for example, a brake temperature or a tire pressure of the wheel.

[0031] The digital signals may also include digital measurement signals produced by sensors associated with the electric motors of the electromechanical actuators 103. These digital measurement signals make it possible to control the electric motors of the electromechanical actuators.

[0032] The sensors associated with the electric motors of the electromechanical actuators 103 measure, for example, an angular position or a speed of the rotors of the electric motors, or these phase currents consumed by the electric motors.

[0033] It is noted here that a junction box located on the landing gear is typically present in traditional braking system architectures. The usual role of the junction box is to distribute to each electromechanical actuator the wiring that comes from a harness running along the landing gear leg, to provide the electromechanical actuators with their supply voltage.

[0034] The existing junction box is therefore equipped with new and innovative functions, to obtain the junction box 102, without significantly modifying the mechanical interfaces of an existing junction box. These functions do not require additional equipment, since the junction box is present in traditional architectures.

[0035] In reference to the figure 3 , another aircraft braking system architecture comprises a brake 200 intended to brake a wheel of the aircraft, a computer 201 and a junction box 202.

[0036] The brake 200 comprises four electromechanical braking actuators 203.

[0037] The 201 computer, integrated into an avionics network, is positioned in a bay located in the aircraft fuselage.

[0038] The junction box 202 is located on the landing gear, near the brake 200. The junction box 202 comprises first electrical processing means 204 and second electrical processing means 205. The first electrical processing means 204 are arranged to perform a function of controlling and commanding the electric motors of the four electromechanical actuators 203. The second electrical processing means 205 are also arranged to perform a function of controlling and commanding the electric motors of the four electromechanical actuators 203.

[0039] The computer 201 and the junction box 202 are connected by a first harness 206 having a first number of wires. The first harness 206 has a first digital bus. The junction box 202 is connected to each electromechanical actuator 203 by a second harness 207 having a second number of wires. Each second harness 207 has a second digital bus.

[0040] Each electromechanical actuator 203 comprises a body fixed to the actuator holder, a pusher and a locking member adapted to lock the pusher in position.

[0041] An electric motor, a power module 208, a first digital communication module 209 and a second digital communication module 210 are integrated within the body of each electromechanical actuator 203.

[0042] The power module 208 makes it possible to generate an alternating supply current which circulates in three phases of the electric motor when it is necessary to actuate the pusher and therefore to brake the wheel, and when it is necessary to remove the pusher to stop braking the wheel. The power module 203 comprises for this purpose an inverter comprising a plurality of switches which are controlled so as to transform a direct supply voltage into a three-phase alternating voltage under which the supply current of the electric motor is generated.

[0043] The supply voltages received by the power modules 208 of the four electromechanical actuators 203 of the brake come from one or more power supply units located in the fuselage of the aircraft and not shown in the figure 3 .

[0044] The computer 201 produces first control signals. The junction box 202 is arranged to receive the first control signals. The first electrical processing means 204 and the second electrical processing means 205 of the junction box 202 are arranged to produce, from the first control signals, second control signals intended for the electromechanical actuators 203 to control the electromechanical actuators 203.

[0045] The first control signals here include digital brake control signals.

[0046] The second control signals here include digital signals for controlling the electric motors of the electromechanical actuators.

[0047] The first electrical processing means 204 of the junction box 202 thus generate, from the digital braking control signals, digital control signals for the electric motors of the electromechanical actuators 203 intended for the first digital communication module 209 of each electromechanical actuator 203.

[0048] The second electrical processing means 205 of the junction box 202 thus generate, from the digital braking control signals, digital control signals for the electric motors of the electromechanical actuators 203 intended for the second digital communication module 210 of each electromechanical actuator 203.

[0049] The first digital communication module 209 and the second digital communication module 210 of an electromechanical actuator 203 transmit to the power module 208 and therefore to the inverter of the power module 208 of said electromechanical actuator 203 inverter control signals intended for it, generated from the digital control signals of the electric motors. The inverter control signals control the switches of said inverter.

[0050] It is noted that the use of the first electrical processing means 204 and the second electrical processing means 205 in the junction box 202, and of the first digital communication module 209 and the second digital communication module 210 in each electromechanical actuator 203, makes it possible to simply obtain two dissimilar control channels, without multiplying the components and without the design of the components being too complex. The braking system architecture according to the figure 3 thus presents significant levels of security and reliability.

[0051] In reference to the figure 4 , an aircraft braking system architecture according to one embodiment of the invention comprises a brake 300 intended to brake a wheel of the aircraft, a computer 301 and a junction box 302.

[0052] The brake 300 comprises four electromechanical braking actuators 303.

[0053] The 300 computer, integrated into an avionics network, is positioned in a bay located in the aircraft fuselage.

[0054] The junction box 302 is located on the landing gear, near the brake. The junction box 302 comprises first electrical processing means 304 and second electrical processing means 305. The first electrical processing means 304 comprise a first digital-to-analog converter. The second electrical processing means 305 comprise a second digital-to-analog converter.

[0055] The computer 300 and the junction box 302 are connected by a first harness 306 comprising a digital bus. The junction box 302 is connected to each electromechanical actuator 303 by a second harness 307.

[0056] Each electromechanical actuator 303 comprises a body fixed to the actuator holder, a pusher and a locking member adapted to lock the pusher in position. An electric motor and a power module 308 are integrated inside the body of each electromechanical actuator 303.

[0057] The power module 308 makes it possible to generate an alternating supply current which circulates in three phases of the electric motor when it is necessary to actuate the pusher and therefore to brake the wheel, and when it is necessary to remove the pusher to stop braking the wheel. The power module 308 comprises for this purpose an inverter comprising a plurality of switches which are controlled so as to transform a direct supply voltage into a three-phase alternating voltage under which the supply current of the electric motor is generated.

[0058] The supply voltages received by the power modules 308 of the four electromechanical actuators 303 of the brake come from one or more power supply units located in the fuselage of the aircraft and not shown in the figure 4 .

[0059] The computer 301 produces first control signals. The junction box 302 is arranged to receive the first control signals. The first electrical processing means 304 and the second electrical processing means 305 of the junction box 302 are arranged to produce, from the first control signals, second control signals intended for the electromechanical actuators 303 to control the electromechanical actuators 303.

[0060] The first control signals here comprise digital control signals for the electric motors of the electromechanical actuators 303. The digital control signals here implement a pulse width modulation control function.

[0061] The digital control signals, produced by the computer 301, are transmitted to the first electrical processing means 304 and to the second electrical processing means 305.

[0062] The first digital-to-analog converter of the first electrical processing means 304 converts the digital control signals into analog inverter control signals. The second digital-to-analog converter of the second electrical processing means 305 also converts the digital control signals into analog inverter control signals.

[0063] The second control signals therefore include the analog inverter control signals.

[0064] The power module 308 of each electromechanical actuator 303 therefore receives analog inverter control signals, and controls the inverter of said power module 308 using these analog inverter control signals.

[0065] Advantageously, the first electrical processing means 304 comprise a first analog-to-digital converter, and the second electrical processing means 305 comprise a second analog-to-digital converter. The analog measurement signals may be analog measurement signals produced by sensors located on the wheel, or else analog measurement signals produced by sensors associated with the electric motors of the electromechanical actuators 303. The sensors associated with the electric motors of the electromechanical actuators 303 measure, for example, an angular position or a speed of the rotors of the electric motors, or else these phase currents consumed by the electric motors.

[0066] In reference to the figure 5 , another aircraft braking system architecture comprises a brake 400 intended to brake a wheel of the aircraft, a computer 401 and a junction box 402.

[0067] The brake comprises four electromechanical braking actuators 403.

[0068] The 401 computer, integrated into an avionics network, is positioned in a bay located in the aircraft fuselage.

[0069] The junction box 402 is located on the landing gear, near the brake 400. The junction box 402 comprises first electrical processing means 404 and second electrical processing means 405. The first electrical processing means 404 are arranged to perform a braking control function. The second electrical processing means 405 are also arranged to perform a braking control function.

[0070] The computer 401 and the junction box 402 are connected by a first harness 406 comprising a first digital bus. The junction box 402 is connected to each electromechanical actuator 403 by a second harness 407 comprising a second digital bus.

[0071] Each electromechanical actuator 403 comprises a body fixed to the actuator holder, a pusher and a locking member adapted to lock the pusher in position.

[0072] An electric motor, a power module 408, a first digital communication module 409 and a second digital communication module 410 are integrated within the body of each electromechanical actuator 403.

[0073] The power module 408 makes it possible to generate an alternating supply current which circulates in three phases of the electric motor when it is necessary to actuate the pusher and therefore to brake the wheel, and when it is necessary to remove the pusher to stop braking the wheel. The power module 408 comprises for this purpose an inverter comprising a plurality of switches which are controlled so as to transform a direct supply voltage into a three-phase alternating voltage under which the supply current of the electric motor is generated.

[0074] The supply voltages received by the power modules 408 of the four electromechanical actuators 403 of the brake 400 come from one or more power supply units located in the fuselage of the aircraft and not shown in the figure 5 .

[0075] The computer 401 produces first control signals. The junction box 402 is arranged to receive the first control signals. The first electrical processing means 404 and the second electrical processing means 405 of the junction box 402 are arranged to produce, from the first control signals, second control signals intended for the electromechanical actuators 403 to control the electromechanical actuators 403.

[0076] The first control signals here include a braking instruction.

[0077] The first electrical processing means 404 of the junction box 402 transform the braking instruction into digital braking control signals. The second electrical processing means 405 of the junction box 402 transform the braking instruction into digital braking control signals.

[0078] The second control signals therefore include digital brake control signals.

[0079] The first digital communication module 409 and the second digital communication module 410 acquire the digital brake control signals and each implement a control and command function of the electric motor. The control and command function produces inverter control signals from the digital brake control signals.

[0080] Inverter control signals drive the inverter switches.

[0081] It is noted that the use of the first electrical processing means 404 and the second electrical processing means 405 in the junction box 402, and the use of the first digital communication module 409 and the second digital communication module 410 in each electromechanical actuator 403, make it possible to simply obtain two dissimilar control channels, without multiplying the components and without the design of the components being too complex. The braking system architecture according to the figure 5 thus presents significant levels of security and reliability.

[0082] In reference to the figure 6 , another aircraft braking system architecture comprises a brake 500 intended to brake a wheel of the aircraft, a computer 501 and a junction box 502.

[0083] The brake comprises four electromechanical brake actuators 503.

[0084] The 501 computer, integrated into an avionics network, is positioned in a bay located in the aircraft fuselage.

[0085] The junction box 502 is located on the landing gear, near the brake 500. The junction box 502 comprises electrical processing means comprising four power converters 504. Each power converter 504 comprises an inverter.

[0086] The computer 501 and the junction box 502 are connected by a first harness 506. The junction box 502 is connected to each electromechanical actuator 503 by a second harness 507.

[0087] Each electromechanical actuator 503 comprises a body fixed to the actuator holder, a pusher and a locking member adapted to lock the pusher in position.

[0088] An electric motor is integrated inside the body of each electromechanical actuator 503.

[0089] The computer 501 produces first control signals. The junction box 502 is arranged to receive the first control signals. The electrical processing means of the junction box 502 are arranged to produce, from the first control signals, second control signals intended for the electromechanical actuators 503 to control the electromechanical actuators.

[0090] The first control signals include a DC supply voltage generated by the computer 503 and transmitted to the junction box 502 via the first harness 506, and inverter control signals. The DC supply voltage is generated by the computer 503 from an on-board power source.

[0091] Each power converter 504 of the electrical processing means of the junction box 502 generates, from the direct current supply voltage and the inverter control signals, phase currents intended for the electric motor of one of the electromechanical actuators 503.

[0092] The second control signals therefore comprise phase currents of the electric motors of the electromechanical actuators 503.

[0093] It is noted that the braking system architecture according to the figure 6 simplifies wiring by routing a DC supply voltage to the junction box, not a three-phase supply voltage.

[0094] In reference to the figure 7 , another aircraft braking system architecture comprises a brake 600 intended to brake a wheel of the aircraft, a computer 601 and a junction box 602.

[0095] The brake comprises four electromechanical brake actuators 603.

[0096] The 601 computer, integrated into an avionics network, is positioned in a bay located in the aircraft fuselage.

[0097] The computer 601 comprises first electrical processing means 604. The first electrical processing means 604 are arranged to perform a braking control function.

[0098] The junction box 602 is located on the landing gear, near the brake 600. The junction box 602 comprises second electrical processing means 605 here comprising a digital switch.

[0099] The computer 601 and the junction box 602 are connected by a first harness 606 comprising a first digital bus. The junction box 602 is connected to the electromechanical actuators 603 by second harnesses 607 each comprising a second digital bus.

[0100] Each electromechanical actuator 603 comprises a body fixed to the actuator holder, a pusher and a locking member adapted to lock the pusher in position.

[0101] An electric motor, a power module 608, a first digital communication module 609 and a second digital communication module 610 are integrated within the body of each electromechanical actuator 603.

[0102] The power module 608 makes it possible to generate an alternating supply current which circulates in three phases of the electric motor when it is necessary to actuate the pusher and therefore to brake the wheel, and when it is necessary to remove the pusher to stop braking the wheel. The power module 608 comprises for this purpose an inverter comprising a plurality of switches which are controlled so as to transform a direct supply voltage into a three-phase alternating voltage under which the supply current of the electric motor is generated.

[0103] The supply voltages received by the power modules 608 of the four electromechanical actuators 603 of the brake 600 come from one or more power supply units located in the fuselage of the aircraft and not shown in the figure 7 .

[0104] The computer 601 receives a braking instruction. The first electrical processing means 604 of the computer 601 transform the braking instruction into digital braking control signals. The first electrical processing means 604 produce first control signals. The first control signals here comprise the digital braking control signals.

[0105] The junction box 602 is arranged to receive the first control signals. The second electrical processing means 605 of the junction box 602 are arranged to produce, from the first control signals, second control signals intended for the electromechanical actuators 603 to control the electromechanical actuators 603.

[0106] The digital braking control signals, produced by the computer 601, are distributed to the first digital communication module 609 and to the second digital communication module 610 of each electromechanical actuator 603 via the digital switch of the second electrical processing means 605 of the junction box 602.

[0107] The second control signals therefore include the digital brake control signals.

[0108] The first digital communication module 609 and the second digital communication module 610 acquire the digital brake control signals and each implement a control and command function of the electric motor. The control and command function produces inverter control signals from the digital brake control signals.

[0109] Inverter control signals drive the inverter switches.

[0110] The invention is not limited to the particular embodiment which has just been described, but, on the contrary, covers any variant falling within the scope of the invention as defined by the claims.

[0111] In particular, it is perfectly possible to mix certain architectures together.

[0112] It is also perfectly possible to use not one junction box, but a plurality of junction boxes. For example, an architecture can be implemented in which a first junction box is connected to a first computer and two first electromechanical brake actuators, and a second junction box is connected to a second computer and two second electromechanical brake actuators.

[0113] In each architecture, it is possible to provide a different number of components than those presented here. For example, it can be provided that, in 1a figure 2 , each electromechanical actuator has two digital communication modules, or that in 1a figure 3 , each electromechanical actuator has only one digital communication module, or that, in 1a figure 6 , the processing means of the junction box include two power converters, etc.

[0114] A number of functions implemented in the junction box, and a number of components integrated into the junction box, have been described herein. This description is not limiting in any way. The junction box could implement other functions (e.g., filtering, measuring, monitoring functions, etc.), and include other components (e.g., filtering components, sensors, etc.).

[0115] It should be noted that the computer mentioned here can be positioned anywhere in the aircraft fuselage. The computer can, for example, be positioned in the avionics bay or near the cockpit of the aircraft. In particular, in the case of the architecture according to 1a figure 5 , the calculator can perfectly be a “pedal box” which receives braking information from the pilot and transforms it into a braking instruction transmitted to the junction box.

Claims

1. A braking system architecture for aircraft, the architecture comprising: a brake (300) for braking a wheel of an undercarriage of the aircraft, the brake including friction members and electromechanical actuators (303) for applying a braking force against the friction members and thereby exerting a braking torque on the wheel, each electromechanical actuator (303) including a body having integrated therein an electric motor and a power module for generating a power supply current for the electric motor; a computer (301) arranged to be situated in a fuselage of the aircraft and arranged to produce first control signals; and a junction box (302) arranged to be situated on the undercarriage, the junction box being connected to the computer and to the electromechanical actuators, the junction box being configured and arranged to receive the first control signals, the junction box comprising electrical processor means configured and arranged to use the first control signals to produce second control signals for application to the electromechanical actuators in order to control the electromechanical actuators, the electrical processor means of the junction box (302) including a digital-to-analog converter, the first control signals comprising digital signals for controlling the electric motors of the electromechanical actuators, and the second control signals comprising analog signals for controlling the electric motors.

2. The architecture according to Claim 1, comprising the wheel, wherein the wheel or the electric motors of the electromechanical actuators include a sensor adapted to produce analog measurement signals of a parameter of the wheel or of the electric motors, wherein the electrical processor means of the junction box include an analog-to-digital converter configured and arranged to convert the analog measurement signals into digital measurement signals, and wherein the electrical processor means of the junction box are configured and arranged to transmit the digital measurement signals to the computer.