SYSTEM FOR CONTROLLING THE OPENING SPEED OF A SLIDING DOOR AND AIRCRAFT EQUIPPED WITH IT

Description

Technical field of the invention

[0001] The invention relates to aircraft sliding door opening systems, and more particularly to systems for controlling the speed of movement of aircraft sliding doors and to aircraft equipped with at least one such system. Prior art

[0002] Generally, an aircraft includes a sliding side door designed to open during flight, for example during a parachute drop or during a helicopter hoist, when the aircraft is a helicopter.

[0003] When it is opened, the sliding door is subjected to aerodynamic forces that can generate significant opening speeds of the door.

[0004] The aerodynamic forces applied to the sliding door are proportional to the square of the aircraft's flight speed.

[0005] Generally, a helicopter is equipped with end-of-stroke shock absorbers to cushion the shock generated by the sliding door reaching its stop, thus preserving the helicopter's structure.

[0006] However, such actuators do not allow control of the speed of the sliding door during its travel, especially at the high flight speeds of the helicopter.

[0007] Document FR3072707 discloses a winder for slowing the closing of a sliding door comprising a drum and a rewinding means connected to the drum.

[0008] The roller also includes a strap connected to the sliding door and a centrifugal brake with mechanical components.

[0009] The centrifugal brake consists of weights that move radially on the drum by means of springs and rub against a metallic surface.

[0010] The braking torque generated by the winder follows a law proportional to the square of the speed, so it is not possible to implement a variable law to modulate the damping according to the speed of the door.

[0011] In addition, the speed of the sliding door is slowed down even at low speeds.

[0012] Furthermore, the implementation of mechanical components rubbing against each other leads to wear on said components.

[0013] Mechanical components are also sensitive to environmental variables, such as temperature, humidity, and vibration, so the value of the braking torque fluctuates according to the wear state of the components and environmental variables.

[0014] Reference can also be made to document EP3747760 which discloses a control device to control the opening speed of a sliding door when the door has reached a predetermined door opening speed.

[0015] The device includes a winding shaft connected to a belt and an electromagnetic eddy current brake to reduce the rotational speed of the winding shaft.

[0016] The electromagnetic eddy current brake comprises a stator and a rotor which describes a rotational movement around its axis.

[0017] The stator comprises a copper ring and a pack of magnetic laminations, and the rotor comprises a magnetic hub with permanent magnets arranged so that a north pole follows a south pole. The copper ring is subjected to a varying magnetic field generated by the permanent magnets, the frequency of which is proportional to the rotor's rotational speed.

[0018] The magnetic field is looped back through the stator laminations. This phenomenon induces eddy currents in the copper ring, which generate a stator magnetic field.

[0019] The stator magnetic field opposes the rotor magnetic field generated by the permanent magnets, creating an electromagnetic torque. This torque is proportional to the frequency of the varying magnetic field and therefore to the rotor's rotational speed. The magnetic damping generated by the electromagnetic brake, defined as the ratio of the electromagnetic torque to the rotational speed, remains constant regardless of the rotor's rotational speed.

[0020] According to another embodiment, the electromagnetic eddy current brake includes a winding replacing the copper ring allowing the damping coefficient to be varied.

[0021] However, the use of an electromagnet requires the control device to be powered by an external power source, complicating the installation of the device in the aircraft.

[0022] The aim of the invention is to overcome all or part of these drawbacks. Description of the invention

[0023] In view of the foregoing, the invention relates to a system for controlling the speed of movement of a sliding aircraft door comprising an electromagnetic braking device for the door having a transmission shaft and electromagnetic resistive means, and connecting means intended to be connected to the sliding door and cooperating with the transmission shaft so that when the sliding door moves in a predetermined direction, the connecting means drive the transmission shaft and the electromagnetic resistive means apply a resistive torque on the transmission shaft to control the speed of movement of the door.

[0024] The resistive means are autonomous and include a control law linking a first damping value to a first speed threshold of door movement speed, a second damping value to a second speed threshold of door movement speed greater than the first speed threshold, the resistive means applying on the transmission shaft the resistive torque equal to a first torque equal to the first damping value multiplied by the difference between the door movement speed and the first speed threshold when the movement speed is greater than the first speed threshold, and applying the resistive torque equal to the sum of the first torque and a second torque equal to the second damping value multiplied by the difference between the door movement speed and the second speed threshold when the movement speed is greater than the second speed threshold.

[0025] The variable control law defined by the different resistive torque values ​​according to the speed of movement of the door allows the speed of movement of the sliding door to be optimized according to ranges of speed of movement of the door.

[0026] Resistive means are not powered by an external power source, so they are self-contained and easy to implement in the aircraft as they do not require electrical connection to aircraft components.

[0027] Preferably, the resistive means include a generator connected to the transmission shaft and configured to apply the resistive torque, and generator control means powered by the generator and comprising the control law.

[0028] Since the resistive means are made by electromechanical components (generator), they are not sensitive to environmental variables, for example temperature, humidity, vibrations, so that the value of the resistive torque does not fluctuate according to environmental variables.

[0029] Advantageously, the control means include dissipation means comprising a first electrical resistive means, a second electrical resistive means, and switching means configured to connect the first resistive means to the generator terminals when the electrical voltage produced by the generator is equal to a first predetermined voltage threshold indicative of the first speed value, and to further connect the second resistive means to the generator terminals when the electrical voltage produced by the generator is equal to a second predetermined voltage threshold indicative of the second speed value. The first resistive means is configured such that when connected to the generator, the generator applies a resistive torque equal to the first torque value to the transmission shaft, and the second resistive means is configured such that when connected to the generator,The generator applies a resistive torque equal to the sum of the first and second torque values ​​to the transmission shaft.

[0030] Advantageously, the switching means include a first switch and first control means configured to close the first switch when the voltage across the first switch is greater than or equal to the first predetermined voltage threshold so as to connect the first resistive means to the generator terminals, and a second switch and second control means configured to close the second switch when the voltage across the second switch is greater than or equal to the second predetermined voltage threshold so as to connect the second resistive means to the generator terminals when the voltage across the second switch is greater than or equal to the second predetermined voltage threshold.

[0031] Advantageously, the first control means or the second control means are further configured to close the switch associated with said means when the voltage across said switch is greater than or equal to a third predetermined voltage threshold, said control means comprising a selection switch configured to control said switch according to the predetermined voltage threshold associated with said first or second means or according to the third voltage threshold.

[0032] Preferably, the generator comprises a brushless rotating electric machine or a brushed rotating electric machine, the braking device further comprises a clutch device connecting the linkage means to the transmission shaft such that the clutch device is engaged when the door moves in the predetermined direction and is disengaged when the door moves in another direction.

[0033] Advantageously, if the generator includes a brushless rotating electrical machine, the control means further include a passive voltage rectifier connecting the brushless rotating electrical machine to the switching means.

[0034] Preferably, if the generator includes a rotating brushed electric machine, the control means further include a diode connecting one terminal of said machine to the switching means so that the rotating electric machine supplies the control means when the door moves in the predetermined direction.

[0035] Advantageously, the linkage means include a strap, the braking device further comprising a return spring configured to wrap the strap around the transmission shaft when the clutch device is disengaged.

[0036] Also proposed is an aircraft with a sliding door and a system as defined above connected to the sliding door. Brief description of the drawings

[0037] 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: [ Fig 1 ] schematically illustrates an aircraft comprising a sliding door according to the invention; [ Fig 2 ] schematically illustrates a partial view of the aircraft comprising a system for controlling the opening speed of the sliding door according to the invention; [ Fig 3 ] schematically illustrates a partial view of the interior of the aircraft cabin according to the invention; [ Fig 4 ] schematically illustrates an example of a system for controlling the opening speed of the sliding door according to the invention; [ Fig 5] schematically illustrates an example of the implementation of a clutch device according to the invention, [ Fig 6 ] schematically illustrates a first example of a control law according to the invention, [ Fig 7 ] schematically illustrates a second example of a control law according to the invention, [ Fig 8 ] schematically illustrates a first embodiment of the resistive means according to the invention, [ Fig 9 ] schematically illustrates a second embodiment of the resistive means according to the invention, [ Fig 10 ] schematically illustrates a first embodiment of the dissipation means according to the invention, [ Fig 11 ] schematically illustrates a method of implementing means of comparison, and [ Fig 12 ] schematically illustrates a third embodiment of the resistive means according to the invention. Detailed description of at least one embodiment

[0038] We refer to the figure 1which schematically illustrates an aircraft 1 comprising a sliding door 2, shown in the closed position, and designed to open in flight, and a system 3 for controlling the speed of movement of the sliding door 2 (not shown).

[0039] The normal direction of movement of the aircraft is represented by a forward-pointing arrow (FWD). The door, however, opens to the rear and is therefore subject to the aerodynamic forces generated during the movement of aircraft 1.

[0040] It is assumed that system 3 controls the opening speed of sliding door 2.

[0041] Alternatively, system 3 controls the closing speed of sliding door 3.

[0042] Aircraft 1 as depicted is a helicopter.

[0043] Of course, aircraft 1 can be any type of aircraft with a sliding door designed to open in flight, for example an airplane with a sliding door.

[0044] There figure 2 illustrates a partial view of aircraft 1, from the outside, with sliding door 2 open.

[0045] The system 3 for controlling the speed of movement of the sliding door 2 (represented by dotted lines) is located in the cabin of the aircraft 1.

[0046] There figure 3 illustrates a partial view of the interior of the cabin of aircraft 1, with the sliding door 2 closed.

[0047] The control system 3 includes an electromagnetic braking device 4 for limiting the speed of movement of the sliding door 2 and mounted on the structure of the aircraft cabin 1, and connecting means comprising a strap 5 wound in the device 4 and attached to a point 6 for fixing the sliding door 2.

[0048] The braking device 4 here limits the opening speed of the sliding door 2.

[0049] Alternatively, the braking device 4 can be mounted on the sliding door 2, and the strap 5 is attached to a fixing point on the aircraft cabin structure 1.

[0050] The system 3 can be mounted on either side of the aircraft 1 relative to a longitudinal axis of symmetry of the aircraft 1, depending on the position of the door.

[0051] When the sliding door 2 opens, the strap 5 unfolds and lengthens under the effect of the translation of the sliding door 2.

[0052] According to another embodiment, the linking means include a rack fixed to the sliding door 2 and the device 4 includes a pinion cooperating with the rack.

[0053] According to yet another embodiment, the linking means comprise a belt connected on one side to the device 4 and, on the other side, to a pulley attached to the sliding door 2.

[0054] There figure 4 illustrates an example of the implementation of system 3.

[0055] We find the braking device 4 and the strap 5.

[0056] The braking device 4 comprises a housing 7 including a centrally mounted transmission shaft 8 held in rotation within the housing 7 by bearings 9, for example ball bearings. Of course, the bearings 9 may be of another type, for example roller bearings or plain bearings.

[0057] The braking device 4 further includes a pulley 10 supporting the strap 5 and held in rotation in the casing 7 by bearings 11.

[0058] The pulley 10 is connected to one end of the transmission shaft 8 via a clutch device 12 and a reducer 13 fixed to the transmission shaft 8.

[0059] The clutch device 12 is engaged when the strap 5 is unwound so that the strap 5 drives the transmission shaft 8, and disengaged when the strap 5 is wound up as the sliding door 2 closes.

[0060] The clutch device 12 includes, for example, a freewheel 14 as shown in the figure 5 .

[0061] The free wheel 12 includes, for example, pawls 15 cooperating with notches 16 so that when the strap 5 is unwound, the pawls 15 are engaged in the notches 16, and so that when the strap 5 is wound around the shaft 8 (closing the door 2), the pawls 15 are no longer engaged in the notches 16.

[0062] The pawls 15 are arranged on a shaft 17 which is attached to an input shaft of the reducer 13.

[0063] Alternatively, the clutch device 12 includes a roller freewheel.

[0064] The reducer 13 includes, for example, an epicyclic reducer and allows the rotational speed of the transmission shaft 8 to be increased.

[0065] The device 4 further includes a return spring 14 driving the pulley 10 to wind the strap 5 around the transmission shaft 8 when the clutch device 12 is disengaged.

[0066] Strap 5 folds up when the sliding door 2 is closed.

[0067] The braking device 4 includes electromagnetic resistive means applying a resistive torque Cr on the transmission shaft 8 to control the speed of movement of the sliding door 2.

[0068] The resistive means are autonomous and include a control law linking a first damping value A1 to a first speed threshold V1 of the movement speed Vp of the door 2, a second damping value A2 to a second speed threshold V2 of the movement speed Vp of the door 2, and a third damping value A3 to a third speed threshold V3 of the movement speed Vp of the door 2.

[0069] The second threshold V2 is higher than the first threshold V1 and lower than the third threshold V3.

[0070] The resistive means apply to the transmission shaft 8 the resistive torque Cr equal to a first torque equal to C1 the first damping value A1 multiplied by the difference between the speed of movement Vp of the door 2 and the first speed threshold V1 when the speed of movement Vp is greater than the first speed threshold V1. Cr = C 1 = A 1 ⋅ Vp − V 1 , Vp > V 1

[0071] The resistive means apply to the transmission shaft 8 the resistive torque Cr equal to the sum of the first torque C1 and a second torque C2 equal to the second damping value A2 multiplied by the difference between the movement speed Vp of the gate 2 and the second speed threshold V2 when the movement speed Vp is greater than the second speed threshold V2. Cr = C 1 + C 2 = A 1 ⋅ Vp − V 1 + A 2 ⋅ Vp − V 2 , Vp > V 2

[0072] The resistive means apply to the transmission shaft 8 the resistive torque Cr equal to the sum of the first torque C1, the second torque C2 and a third torque C3 equal to the third damping value A3 multiplied by the difference between the movement speed Vp of the door 2 and the third speed threshold V3 when the movement speed Vp is greater than the third speed threshold V3. Cr = C 1 + C 2 + C 3 = A 1 ⋅ Vp − V 1 + A 2 ⋅ Vp − V 2 + A 3 ⋅ Vp − V 3 , Vp > V 3

[0073] The values ​​of the speed thresholds V1, V2, V3, the first damping value A1, the second damping value A2 and the third damping value A3 are predetermined, for example from tests carried out on aircraft 1.

[0074] For example, we assume that the second depreciation value A2 is greater than the first depreciation value A1 and less than the third depreciation value A3.

[0075] Of course, the depreciation values ​​A1, A2, A3 can be classified differently.

[0076] There figure 6 illustrates a first example of the control law showing the evolution of the resistive torque Cr applied on the transmission shaft 8 according to the value of the displacement speed Vp.

[0077] We assume that the first speed threshold V1 is for example zero so that the device 4 slows down the movement of the sliding door 2 as soon as the door 2 starts to move.

[0078] Device 4 allows the movement of the sliding door 2 to be slowed down until the first speed threshold V1, the speed of movement of the sliding door 2 to be slowed down even further when it exceeds the second speed threshold V2 and even further when it exceeds the third speed threshold V3, so that the sliding door 2 does not exceed a maximum speed permissible by the end-of-stroke shock absorbers of the aircraft 1.

[0079] The first damping value A1 can be zero so as not to affect the operation of the sliding door 2 for travel speeds Vp below the first threshold V1.

[0080] There figure 7 illustrates a second example of the control law showing the evolution of the resistive torque Cr applied to the transmission shaft according to the value of the displacement speed Vp when the first damping value A1 is zero and the first threshold V1 is zero.

[0081] Device 4 slows down the movement of the sliding door 2 when it exceeds the second speed threshold V2 and even more when it exceeds the third speed threshold V3.

[0082] The variable control law defined by different resistive torque values ​​Cr depending on the speed of movement of door 2 allows the speed of movement of sliding door 2 to be optimized according to ranges of speed of movement of door 2 unlike a linear torque-speed evolution.

[0083] The control law allows, for example, the optimization of the speed Vp of the sliding door 2 at low speed (below the second speed threshold V2, the first threshold V1 being zero) by defining a zero resistive torque Cr (corresponding to a first zero damping value A1), a resistive torque Cr whose value is defined by equation (1) when the speed Vp of movement of the sliding door 2 is within an intermediate speed range (between the second speed threshold V2 and the third speed threshold V3) whose value is defined by equation (2), and possibly the optimization of the speed Vp of movement of the sliding door 2 at high speed (above the third speed threshold V3) by defining a resistive torque Cr according to equation (3).

[0084] As in this example the first damping value A1 is zero, device 4 does not slow down the speed of movement Vp of door 2 so that if friction acting on door 2 increases in such a way as to slow down the speed of movement Vp of door 2, it is not necessary to disconnect the strap from door 2 to obtain a satisfactory speed of movement of door 2.

[0085] The second speed threshold V2 is for example between 0.5 and 0.7 m / s when the first speed threshold V1 is zero.

[0086] In what follows, we assume that the first threshold V1 is zero and that the first damping value A1 is zero.

[0087] Alternatively, the control law can define more than three pairs associating a damping value with a speed threshold.

[0088] By referring to the figure 4, the resistive means include a generator 18 connected to the transmission shaft 8 to apply the resistive torque Cr on said shaft, and control means 19 of the generator 18 supplied by the generator and comprising the control law.

[0089] The control means 19 are made from semiconductors as detailed below and are fixed to the housing 7.

[0090] The generator 18 comprises a brushless rotating electric machine or a brushed rotating electric machine, operating in eddy current damping, and includes a rotor 20 attached to the transmission shaft 8 and a stator 21 attached to the casing 7.

[0091] The stator 21 includes a magnetic circuit comprising a stack of magnetic laminations, and the rotor 20 includes permanent magnets arranged so that a north pole follows a south pole.

[0092] The stack of sheets is subjected to a variable magnetic field generated by permanent magnets whose frequency is proportional to the rotational speed of the rotor.

[0093] The magnetic field is looped back through the stator laminations, inducing the appearance of eddy currents in the magnetic circuit which generates a stator magnetic field.

[0094] The stator magnetic field opposes the rotor magnetic field generated by the permanent magnets and creates an electromagnetic torque equal to the resistive torque Cr.

[0095] The resistive torque Cr is proportional to the frequency of the varying magnetic field and therefore to the rotational speed of the rotor.

[0096] There figure 8 schematically illustrates a first method of implementing resistive means.

[0097] The generator 18 includes a brushless rotating electrical machine, for example of the three-phase synchronous type.

[0098] The control means 19 include a voltage rectifier 22 connected to the brushless rotating electric machine to rectify the voltage generated by said machine when driven by the transmission shaft 8, and dissipation means 23.

[0099] The rectifier 22 is of the passive type and includes, for example, a diode bridge with three identical branches 24, 25, 26.

[0100] Each branch 24, 25, 26 includes two diodes 27, 28.

[0101] The cathode of a first diode 27 is connected to a first terminal 29 of the dissipation means 23, the anode of the first diode 27 is connected to the cathode of the second diode 28.

[0102] The anode of the second diode 28 is connected to a second terminal 30 of the dissipation means 23.

[0103] The anode of the first diode 27 is further connected to a phase of the three-phase rotating electrical machine so that each branch 23, 24, 25 is connected to a different phase of said machine.

[0104] Alternatively, the rotating electrical machine may comprise more or less three phases, each phase being connected to a different branch of the passive rectifier 22.

[0105] There figure 9 schematically illustrates a second embodiment of the resistive means.

[0106] Generator 18 includes a brushed electric machine.

[0107] The control means 19 include the dissipation means 23.

[0108] A positive terminal 31 of the brushed electric machine is connected to the first terminal 29 of the dissipation means 23 and a negative terminal 32 of the brushed electric machine is connected to the second terminal 30 of the dissipation means 23.

[0109] There Figure 10schematically illustrates a first method of implementing the means of dissipation 23.

[0110] The dissipation means 23 include a first electrical resistive means and a second electrical resistive means formed by the coils of the generator 18, and for example by a first resistance 33 and a second resistance 34.

[0111] The dissipation means 23 further include switching means 35.

[0112] The switching means 35 connect the first resistive means to the terminals of the generator 18 when the electrical voltage Vgen produced by the generator 18 is equal to a first predetermined voltage threshold S1 indicative of the second speed value V2.

[0113] The switching means 35 further connect the second resistive means to the terminals of the generator 18 when the electrical voltage Vgen produced by the generator is equal to a second predetermined voltage threshold S2 indicative of the third speed value V3.

[0114] The relationship between the voltage produced by the generator 18 and the speed of movement of the sliding door 2 is determined from the characteristics of the reducer 13, the generator 18, and the connecting means.

[0115] The first resistive means is dimensioned so that when connected to generator 18, generator 18 applies the resistive torque Cr as defined by equation (2) on the transmission shaft 8.

[0116] The second resistive means is dimensioned so that when connected to the generator, the generator applies the resistive torque Cr as defined by equation (3) on the transmission shaft 8.

[0117] The sizing of the first resistive means and second resistive means takes into account the resistance of the coils of generator 18.

[0118] The switching means 35 include for example a first switch 36, a second switch 37, first control means 38 of the first switch 36, and second control means 39 of the second switch 37.

[0119] The first switch 36 and the second switch 37 each include, for example, a field-effect transistor or a transistor of another type.

[0120] Alternatively, the first switch 36 and the second switch 37 each include a set of transistors, for example connected in a Darlington scheme, if the electrical power passing through a transistor is likely to damage or destroy said transistor.

[0121] The drains of the transistors of the first switch 36 and second switch 37 are connected to the first terminal 29.

[0122] The source of the transistor of the first switch 36 is connected to a first end of the resistance 33 of the first resistive element, and the gate of said transistor is connected to the first control means 38.

[0123] The source of the transistor of the second switch 37 is connected to one end of the resistance 34 of the second resistive element, and the gate of said transistor is connected to the second control means 39.

[0124] The second end of the first and second control resistors 40, 41 is connected to the second terminal 30.

[0125] When the voltage Vgen produced by the generator 18 is equal to or greater than the first threshold S1, the transistor of the first switch 36 is conducting and connects the resistor 33 to the first and second terminals 29, 30.

[0126] When the voltage Vgen produced by the generator 18 is equal to or greater than the second threshold S2, the transistor of the second switch 37 is conducting and connects the resistor 34 to the first and second terminals 29, 30.

[0127] As soon as the voltage Vgen produced by the generator 18 is less than the second threshold S2, the transistor of the second switch 37 is open so that the resistor 34 is no longer connected to the first and second terminals 29, 30.

[0128] As soon as the voltage Vgen produced by the generator 18 is less than the first threshold S1, the transistor of the first switch 36 is open so that the resistor 33 is no longer connected to the first and second terminals 29, 30.

[0129] The first control means 38 close the first switch 36 when the voltage across the first switch 36 is greater than or equal to the first voltage threshold S1.

[0130] The second control means 39 close the second switch 37 when the voltage across the first switch 37 is greater than or equal to the second voltage threshold S2.

[0131] The first control means 38 include voltage comparison means comprising for example a first Zener diode 40 having a threshold voltage equal to the first threshold S1 of voltage and a first control resistor 41, and the second control means 39 include voltage comparison means comprising for example a second Zener diode 42 having a threshold voltage equal to the second threshold S2 of voltage and a second control resistor 43.

[0132] The cathode of the first and second Zener diodes 40, 42 is connected to the first terminal 29.

[0133] The anode of the first Zener diode 40 is connected to the gate of the transistor of the first switch 36 and to one end of the first control resistor 41.

[0134] The second end of the first control resistor 41 is connected to the source of the transistor of the first switch 36.

[0135] The anode of the second Zener diode 42 is connected to the gate of the transistor of the second switch 37 and to one end of the second control resistor 43.

[0136] The second end of the second control resistor 43 is connected to the source of the transistor of the second switch 37.

[0137] Zener diodes 38, 39 compare the voltage Vgen produced by generator 18 to the threshold voltages S1, S2.

[0138] Alternatively, the first and second electrical resistive means are formed by the coils of generator 18 and one of the first and second resistors.

[0139] According to yet another variant, the first and second electrical resistive means are formed by the coils of the generator 18, the dissipation means 23 not having first and second resistances (generator 18 short-circuited), the control law being a simple linear law having a trigger threshold equal to the value of the first threshold V1 if the first threshold V1 has a non-zero value, and having no trigger threshold otherwise.

[0140] Alternatively, a resistor is connected between terminals 29, 30 to create a permanent resistive torque applied to the transmission shaft 8 as soon as the door 2 is opened.

[0141] For high power or thresholds S1, S2 which are not equal to the threshold voltages of the Zener diodes, each Zener diode 40, 42 and the associated control resistor 41, 43 can be replaced by a circuit configured to connect the first resistive means to the terminals of the generator, and to connect the second resistive means to the terminals of the generator when the voltage threshold values ​​S1, S2 are reached.

[0142] There figure 11 schematically illustrates a second embodiment of the control means 38, 39.

[0143] As the architecture of the control means 38, 39 is identical, only the architecture of the first control means 38 is detailed.

[0144] The means for comparing the first control means 38 include a third Zener diode 44 having a threshold voltage equal to the first threshold S1 and a fourth Zener diode 45 having a third threshold voltage equal to a third voltage threshold different from the first threshold S1.

[0145] The anode of each diode 44, 45 is connected to one of the control resistors 41, 43 and the cathode of each of the diodes is connected to a different input 46, 47 of a selection switch 48.

[0146] An output 49 of switch 48 is connected to the first terminal 29.

[0147] The switch 48 allows one or the other of the two diodes 44, 45 to be connected in order to easily modify the voltage threshold of the comparison means by connecting one or the other diode 44, 45 between the first terminal 29 and the control resistor 41, 43.

[0148] The selection switch 48 allows the first switch 36 to be controlled according to the first voltage threshold S1 or according to the third voltage threshold S3.

[0149] Comparison methods allow, for example, easy testing of different voltage thresholds when adjusting the control system 3 mounted in aircraft 1 and connected to the sliding door 2.

[0150] Switch 48 can be controlled manually or by a controller.

[0151] Alternatively, the comparison means may include more than two Zener diodes having different threshold voltages connected in parallel, with switch 48 having as many inputs as there are Zener diodes.

[0152] According to yet another variant, the dissipation means 23 may comprise a mixture of the first and second embodiments of the voltage comparison means Vgen illustrated in Figures 10 and 11 .

[0153] The dissipation means 23 may, for example, include the two diodes 44, 45 in parallel connected to the switch 48 as described in the second embodiment illustrated in the figure 11 to control the first switch 36, and diode 42 to control the second switch 37.

[0154] The clutch device 12 discouples the generator 18 from the pulley 10 so that it does not generate a tension when closing the sliding door 2 which could cause the switching means to switch to apply the resistive torque Cr on the transmission shaft 8.

[0155] There figure 12 schematically illustrates a third embodiment of the resistive means operating with or without the freewheel 12.

[0156] Generator 18 includes the brushed electric machine.

[0157] Since the current generated by the rotating brushed electric machine depends on the direction of rotation of the transmission shaft 8, the control means 19 include the dissipation means 23 and a diode 50 connected to a terminal of said machine and to the switching means so that the rotating brushed electric machine supplies the control means 19 when the sliding door 2 moves in the predetermined direction, here the opening direction of the sliding door 2.

[0158] The positive terminal 31 of the brushed electric machine is connected to the anode of the diode 50, the cathode of the diode 50 is connected to the first terminal 29 of the dissipation means 23, and the negative terminal 32 of the brushed electric machine is connected to the second terminal 30 of the dissipation means 23.

[0159] When the drive shaft 8 drives the rotating brushed electric machine in the direction of opening the sliding door 2, said machine delivers a current on the positive terminal 31 so that the diode 48 is conducting and supplies the dissipation means 23.

[0160] When the drive shaft 8 drives the rotating brushed electric machine in the direction of closing the sliding door 2, said machine delivers a current on the negative terminal 32 so that the diode 48 is not conducting and does not supply the dissipation means 23.

[0161] The resistive means are not powered by an external power source so they are self-contained and easy to implement in aircraft 1 as they do not require to be electrically connected to components of aircraft 1.

[0162] Furthermore, when the generator 18 includes a brushless rotating machine, no part rubs against another so that the resistive means are not likely to wear out, the braking device 4 not requiring any maintenance operation.

[0163] Since the resistive means are made by electromechanical components, they are not sensitive to environmental variables, for example temperature, humidity, vibrations, so that the value of the resistive torque Cr does not fluctuate according to environmental variables.

Claims

1. System (3) for controlling the speed of movement of a sliding door (2) for an aircraft (1)) comprising an electromagnetic device (4) for braking the door including a transmission shaft (8) and electromagnetic resistive means (18), and connecting means (5) intended to be connected to the sliding door and cooperating with the transmission shaft so that, when the sliding door moves in a predetermined direction, the connecting means drive the transmission shaft and the electromagnetic resistive means apply a resistive torque (Cr) to the transmission shaft to control the speed of movement of the door, they resistive means not being supplied by an external energy source, characterized in that the resistive means include a control law connecting a first damping value to a first speed threshold (V1) of door movement speed (2), and a second damping value to a second speed threshold (V2) of door movement speed greater than the first speed threshold (V1), the resistive means applying the resistive torque (Cr) to the transmission shaft equal to the first torque equal to the first damping value multiplied by the difference between the speed of movement of the door and the first speed threshold (V1) when the speed of movement is greater than the first speed threshold (V1), and apply the resistive torque equal to the sum of the first torque and a second torque equal to the second damping value multiplied by the difference between the speed of movement of the door and the second speed threshold (V2) when the travel speed is greater than the second speed threshold (V2).

2. The system according to claim 1, wherein the resistive means comprise a generator (18) connected to the transmission shaft (8) and configured to apply the resistive torque (Cr), and means (19) for controlling the generator powered by the generator and including the control law.

3. The system according to claim 2, wherein the control means (19) comprise dissipation means (23) comprising a first electrical resistive means (18, 33), a second electrical resistive means (18, 34), and switching means (35) configured to connect the first resistive means to the terminals of the generator (18) when the electrical voltage produced by the generator is equal to a predetermined first voltage threshold indicative of the first speed value (V1) and also to connect the second resistive means to the terminals of the generator when the electrical voltage produced by the generator is equal to a predetermined second voltage threshold indicative of the second speed value (V2), the first resistive means being configured so that, when it is connected to the generator, the generator applies the resistive torque (Cr) equal to the first torque value (C1) on the transmission shaft (8), and the second resistive means being configured so that, when it is connected to the generator, the generator applies the resistive torque (Cr) on the transmission shaft equal to the sum of the first torque value (C1) and the second torque value (C2).

4. The system according to claim 3, wherein the switching means (35) comprise a first switch (36) and first control means (38) configured to close the first switch when the voltage at the terminals of the first switch is higher than or equal to the predetermined first voltage threshold so as to connect the first resistive means (33) to the terminals of the generator (18), and a second switch (37) and second control means (39) configured to close the second switch when the voltage at the terminals of the second switch is higher than or equal to the predetermined second voltage threshold so as to connect the second resistive means to the terminals of the generator when the voltage at the terminals of the second switch is higher than or equal to the predetermined second voltage threshold.

5. The system according to claim 4, wherein at least the first control means (38) or the second control means (39) are further configured to close the switch (36, 37) associated with said means when the voltage at the terminals of said switch is higher than or equal to a predetermined third voltage threshold, said control means including a selection switch (48) configured to control said switch according to the predetermined voltage threshold associated with said first or second means or according to the third voltage threshold.

6. The system according to any one of claims 2 to 5, wherein the generator (18) comprises a brushless rotating electric machine or a brushed rotating electric machine, the braking device (4) further comprises a clutch device (12) connecting the connecting means to the transmission shaft (8) so that the clutch device is engaged when the door (2) moves in the predetermined direction and is disengaged when the door moves in another direction.

7. The system according to claim 6, wherein if the generator (18) comprises a brushless rotating electric machine, the control means (19) further comprise a passive voltage rectifier (22) connecting the brushless rotating electric machine to the switching means (35).

8. The system according to claim 6, wherein if the generator comprises a brushed rotating electric machine, the control means (19) further comprise a diode (48) connecting a terminal (31) of said machine to the switching means (35) so that the rotating electric machine powers the control means when the door moves in the predetermined direction.

9. The system according to any one of claims 6 to 8, wherein the connecting means comprise a strap (5), the braking device (4) further comprising a return spring (14) configured to wind the strap around the transmission shaft (8) when the clutch device is disengaged.

10. An aircraft (1) comprising a sliding door and a system (3) according to any one of claims 1 to 9 connected to the sliding door (2).