Braking device comprising a hydraulic circuit provided with movable restriction elements, a braked wheel, a landing gear and an aircraft provided with such a device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-29
- Publication Date
- 2026-08-13
Smart Images
Figure EP2026052378_13082026_PF_FP_ABST
Abstract
Description
[0001] BRAKING DEVICE COMPRISING A HYDRAULIC CIRCUIT EQUIPPED WITH MOVABLE RESTRICTION ELEMENTS, BRAKED WHEEL, LANDER AND AIRCRAFT EQUIPPED WITH SUCH A DEVICE.
[0002] The present invention relates to the field of braking of vehicle wheels such as aircraft wheels.
[0003] BACKGROUND OF THE INVENTION
[0004] An aircraft generally includes landing gear having one end connected to the aircraft fuselage and one end fitted with a shaft on which is pivotally mounted a wheel fitted with a braking device.
[0005] The braking device includes at least one stack of discs (including rotor discs rotationally linked to the wheel and stator discs rotationally linked to the shaft), an actuator-carrying ring rotationally linked to the shaft, and actuators mounted in the actuator-carrying ring to exert a pressing force on the stack of discs and thus generate a braking torque on the wheel.
[0006] It is common for the actuators to be linear hydraulic actuators supplied with hydraulic pressure by a power source, usually a pump. These actuators are generally connected in series to the power source by conduits, allowing them to be actuated simultaneously.
[0007] It is known to incorporate fluid passage restrictions in the conduits in order to reduce vibrations in the system during operation.
[0008] It appears that the activation of the braking device nevertheless results in relatively significant vibrations.
[0009] SUBJECT OF THE INVENTION
[0010] The invention aims, in particular, to improve the system mentioned above in order to reduce vibrations during braking. SUMMARY OF THE INVENTION
[0011] For this purpose, the invention provides a braking device for a vehicle wheel, comprising a stack of discs, including at least one rotor disc and one stator disc, and an actuation assembly for exerting a pressing force on the stack of discs, the actuation assembly comprising an actuator-carrying ring coaxial with the stack of discs, hydraulic actuators mounted side-by-side on the actuator-carrying ring, and a hydraulic circuit, having sections having a cylindrical internal surface defining a circular fluid passage cross-section, for connecting the actuators to at least one hydraulic power source, at least one section comprising a restriction element having at least one movable part forming a local restriction of the fluid passage cross-section,the moving part of the restrictor being capable of moving in a direction substantially parallel to the section under the effect of the fluid movement in said section.
[0012] Thus, the invention reduces vibrations generated during operation compared to prior art braking devices by combining the anti-vibration effect of fluid flow restriction and the energy dissipation provided by the movement of the restriction along the conduit. Furthermore, the invention requires no additional energy input, since the movement is initiated by the fluid flow.
[0013] Depending on optional features, used individually or in whole or in part in any technically feasible combination:
[0014] the restricting element has a mechanical link with the section, the mechanical link being arranged to dampen the movement of the moving part; the mechanical link includes at least two springs, each connecting the moving part of the restricting element to the section;
[0015] the moving part of the restriction element is a ring having an outer perimeter adapted to fit the inner surface of the section, an inner perimeter forming a hole through which the fluid passes, and two annular end faces, and in which each spring of the mechanical link extends between one of the annular end faces and an axial stop extending in projection from the inner surface of the section, said springs exerting on the ring an axial elastic return in two opposite directions to return the ring to an equilibrium position;
[0016] the moving part of the restriction device is a deflector core having two ends and a cylindrical surface connecting the two ends and in which springs connect the deflector core to the internal surface of the section so as to elastically maintain the deflector core in an equilibrium position in the vicinity of a central axis of the section to force the fluid to pass between the deflector core and the internal surface of the section;
[0017] The restriction element is an elastic washer having an inner perimeter forming a fluid passage hole and an outer perimeter fixed to the section by conforming to its inner surface, the washer being elastically deformable between two extreme states defining two axial positions of the inner perimeter forming the movable part of the restriction element.
[0018] The invention also relates to a braked wheel comprising such a braking device, an aircraft landing gear equipped with such a braked wheel and an aircraft comprising at least one such landing gear.
[0019] Other features and advantages of the invention will become apparent from the following description of particular and non-limiting embodiments of the invention.
[0020] BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Reference will be made to the attached drawings, including:
[0022] [Fig. 1] is an elevational view of an aircraft having landing gear equipped with braked wheels according to the invention;
[0023] [Fig. 2] is a half-sectional view of a braked wheel equipped with a braking device according to the invention;
[0024] [Fig. 3] is a schematic front view of an actuator-carrying ring of this braking device;
[0025] [Fig. 4] is a schematic view of a section of the hydraulic circuit of the braking device according to the invention, equipped with a restriction element according to a first embodiment;
[0026] [Fig. 5] is a schematic view of a section of hydraulic circuit of a braking device according to the invention, equipped with a restriction element according to a second embodiment;
[0027] [Fig. 6] is a schematic view of a section of hydraulic circuit of a braking device according to the invention, equipped with a restriction element according to a third embodiment;
[0028] [Fig. 7] is a view analogous to [Fig. 4] showing a restricting device according to a first variant of the first embodiment;
[0029] [Fig. 8] is a view analogous to [Fig. 4] showing a restricting device according to a second variant of the first embodiment.
[0030] DETAILED DESCRIPTION OF THE INVENTION With reference to Figures 2 and 3, the invention is described in application to an aircraft 100 comprising main landing gear having legs 101 having one end articulated to a structure of the aircraft 100 and opposite a free end provided with an axle 102 on which wheels 103 are pivotally mounted about a main axis X of rotation defined by the axle 102.
[0031] Each wheel 103 comprises a rim 103.1 carrying a tire 103.2, a hub 103.3 extending coaxially to the rim 103.1 defining with it an annular space 103.4, and a disc 103.5 connecting the hub 103.3 to the rim 103.1.
[0032] Each of the 103 wheels is equipped with a braking device generally designated as 1.
[0033] Each braking device 1 comprises a stack of discs 2 housed in the annular space 103.4. The stack of discs 2 comprises alternating rotor discs 2.1 rotationally connected to the rim 103.1 and stator discs 2.2 carried by a torsion tube 3 and rotationally connected to it. The two end discs of the stack of discs 2 are stator discs 2.2. The torsion tube 3, coaxial with the axle 103, extends around the hub 103.3 and has one end fixed to a flange 4 of the axle 102 and an opposite end free, forming a stop for the stack of discs 2.
[0034] The braking device 1 further comprises an actuation assembly 5 including a ring 6 with actuators having an inner circumference pivotally engaged on the torsion tube 3 (or the flange 4 of the axle 102) and further comprising a connecting portion 6.1 which receives a lug 101.1 extending outward from the leg 101 to oppose rotation of the ring 6 around the axle 102 during braking. The actuation assembly 5 also includes actuators 7 mounted on the ring 6 in receiving portions 6.2, and provided with movable pushrods arranged to exert, via a support plate, an axial pressing force on the stack of discs 2 parallel to the X-axis. The ring 6 and the stack of discs 2 are thus both centered on the X-axis.
[0035] The actuators 7 are hydraulic actuators, controllable between two operating states: a first active braking state in which the pushrods are extended and a second inactive braking state in which the pushrods are retracted. These actuators 7 are mounted side-by-side on the ring 6, in a regular circular arrangement around the X-axis.
[0036] A hydraulic circuit 8 is present in the ring 6 in order to connect the actuators 7 to at least one hydraulic power source 9.
[0037] The hydraulic circuit 8 comprises sections 10, some of which connect the hydraulic power source 9 to one of the actuators 7, others connect two actuators 7 together.
[0038] The sections 10 are tubular in shape and have a cylindrical internal surface 10.1 defining a circular fluid passage 10.2 and a cylindrical space 10.3. Each section 10 of the hydraulic circuit 8 is equipped with a restrictor 11. The restrictor 11 comprises a movable part 12 arranged to form a local restriction 13 of the fluid passage 10.2. The movable part 12 of the restrictor 11 is capable of moving in a direction substantially parallel to the section 10 under the effect of the fluid movement in said section 10.
[0039] With reference to Figure 4 and according to the first embodiment, the moving part 12 of the restrictor 11 is a ring having an outer circumference 12.1, an inner circumference 12.2, and two annular end faces 12.3 opposite each other. The outer circumference 12.1 of the moving part 12 and the circular passage section 10.2 formed by the inner surface 10.1 of the section each have a diameter close to each other, allowing the moving part 12 to be guided in translation along the section 10. The diameter of the outer circumference 12.1 is slightly smaller than that of the passage section 10.2, so that the outer circumference 12.1 of the moving part 12 fits snugly against the inner surface 10.1 of the section 10.
[0040] The movable part 12 is thus mounted to slide in the cylindrical space 10.3, and is movable between an equilibrium position and two extreme translation positions in two opposite directions.
[0041] The inner perimeter 12.2 of the movable part 12 forms a circular hole through which the fluid passes, this hole then defining a restriction 13 in the flow of the fluid.
[0042] The moving part 12 has a mechanical connection 14 with the section 10. In this first embodiment, the mechanical connection comprises helical compression springs 14.1, and two annular axial stops 14.2 which extend radially from the internal surface 10.1 of the section 10 inwards and which are positioned on either side of the moving element 12. The springs 14.1 are positioned antagonistically: each spring 14.1 has a first end in contact with one of the end faces 12.3 of the moving part 12 and a second end in contact with one of the axial stops 14.2 facing said end face 12.3.
[0043] The springs 14.1 apply two elastic return forces to the moving element 12 along the direction of the section, but in two opposite directions, to allow the moving element 12 to move in translation between two extreme positions and to be returned to an equilibrium position between the two extreme positions. The presence of the springs 14.1 in the mechanical linkage 14 dampens the displacement of the moving part 12. On the one hand, the passage restriction 13 formed by the restrictor 11 causes pressure losses in the fluid flow, which have the effect of dampening the vibrations of the device.
[0044] On the other hand, the moving part 12 of the restrictor 11 moves with the fluid displacement and acts on the device 1 as a tuned dynamic damper (ADA) or harmonic damper. The moving part 12, through its displacement, absorbs some of the energy that causes the vibration, thus reducing it.
[0045] Device 1 therefore makes it possible to combine these two operating principles, taking advantage of each of their anti-vibrational effects, without input of energy.
[0046] According to the first variant of the first embodiment, illustrated in Figure 7, the outer rim 12.1 of the moving part 12 has a diameter smaller than that of the passage section 10.2 in order to accommodate, between the inner surface 10.1 of the section and the outer rim 12.1, an elastic element 15 that is fixed relative to the section 10 and that rubs against the surface defining the outer rim 12.1 of the moving part 12. The surface defining the outer rim 12.1 of the moving part 12 is a right cylindrical shape with a circular cross-section. The elastic element 15 is in the form of a ring having a small V-shaped cross-section, the apex of which defines the inner contour of the elastic element 15 and is elastically pressed against the surface defining the outer rim 12.1, with the free ends of its arms bearing against the inner surface 10.1.Other shapes are obviously conceivable, including non-annular shapes (one can have several elastic elements separated from each other and distributed angularly over a perimeter of the passage section 10.2.
[0047] The apex of the V of the elastic element 15 rubs against the outer rim 12.1 when the moving part 12 moves axially within the section 10. This friction induces nonlinear behavior in the damper formed by the moving part 12 and the springs 14.1. The damper acts as a nonlinear energy sink (or NES). This broadens the damper's effective range in terms of frequency band and facilitates the determination of the spring stiffnesses and the damper's mass. The improvement, resulting from the introduction of friction, makes the damper in the first embodiment more robust and easier to implement.
[0048] The first and second variants of the first embodiment illustrated in Figure 8 are identical except that, in the second variant, the surface defining the outer perimeter 12.1 of the moving part 12 is no longer a straight cylinder. Indeed, in the second variant, said outer surface is an annular surface, comprising at least one portion 12.4 curved inwards (i.e., the concavity of the curved portion 12.4 is oriented towards the inner surface 10.1), on which the elastic element 15 rests in such a way that the elastic element 15 is more compressed when it is near the ends of the moving part 12 than when it is in the middle of the moving part 12. Here, the curved portion 10.4 extends from one end to the other of the outer surface of the moving part 12.
[0049] This further improves vibration damping efficiency by introducing more nonlinearities and dissipation. The curvature of the surface defining the outer perimeter 12.1 causes a variation in the compression of the elastic element 15 when the moving part 12 moves axially within the section 10. Thus, the force applied laterally to the moving part 12 will depend on its position. In the extreme left or right position, the dissipative effects are cumulative, which would contribute to the attenuation of brake vibrations.
[0050] According to a third variant, an alternative to the first or second variant, the elastic element 15 is carried by the moving part and rubs against the internal surface 10.1 which is either straight or curved outwards.
[0051] With reference to Figure 5 and according to a second embodiment, the braking device 1 is based on the same principle as that of the first embodiment, but differs from it in that the restriction member 11' has a different moving part 12' and mechanical link 14'.
[0052] Indeed, here the moving part 12' of the restriction element is a deflector core 12', here of substantially ellipsoidal shape, having two ends and a longitudinal surface with closed contour connecting the two ends.
[0053] The deflector core 12' placed in the cylindrical space 10.3 of the section 10 is oriented by aligning its length in the direction of the section 10. The longitudinal surface of the deflector core 12' has a diameter less than the diameter of the circular passage section 10.2 of the section 10. Between the longitudinal surface of the deflector core 12' and the internal surface 10.1 of the section 10 is defined an annular space forming a restriction 13' through which the fluid passes.
[0054] In this second embodiment, the mechanical link 14' comprises two tension springs 14.1': a first spring 14.1' which has a first end connected to a first side of the longitudinal surface of the deflector core 12' and a second end connected to the internal surface of the section 10 opposite said first side; and a second spring 14.1' which has a first end connected to a second side of the longitudinal surface of the deflector core 12' opposite the first side and a second end connected to the internal surface of the section 10 opposite said second side.
[0055] Thus, the springs 14.1' connect the deflector core 12' to the internal surface 10.1 of the section 10 so as to maintain it elastically in an equilibrium position near a central axis of the section 10 in the plane of the springs 14.1'. The deflector core 12' can move along this central axis between two extreme positions located on either side of the equilibrium position. In this second embodiment, the restriction 13' of the fluid passage formed by the restriction element 11' also causes pressure losses in the fluid flow, allowing it to absorb some of the vibrations of the device 1. The moving part, here the deflection core 12' of the restriction element 11', which moves with the fluid displacement, also acts on the device 1 as a tuned dynamic damper that absorbs some of the vibrations.
[0056] With reference to figure 6 and according to a third embodiment, device 1 includes a restricting member 11'' different from the other two embodiments.
[0057] Indeed, the restriction element 11' ' is an elastic washer 11' ' having an external perimeter, an internal perimeter and two main annular faces opposed to each other.
[0058] The washer 11'' and the section 10 have a mechanical connection, in that the outer perimeter of the washer 11'' is fixed to the inner surface 10.1 of said section 10 by conforming to the shape of the latter, for example by gluing or via a tight fit.
[0059] The inner rim of the washer 11'' defines a hole through which the fluid passes, forming the restriction 13''. Under the effect of the fluid displacement in the section 10 and the resulting pressure exerted by the fluid on the main face of the washer 11'', positioned upstream relative to the direction of fluid flow, the elastic washer 11'' deforms, causing the inner rim 12'' to move in the direction of fluid flow. The inner rim 12'' of the washer 11'' thus forms the moving part of the restriction element 11''.
[0060] The elastic washer 11'' then deforms between two extreme states defining two axial positions of the inner perimeter 12''.
[0061] The movement of the inner perimeter 12'' between these two extreme positions has a predominantly axial component and may include a minor radial component.
[0062] In this third embodiment, the restriction 13'' in the fluid flow is formed by the inner perimeter 12'' of the elastic washer 11'' and causes, as in the other two embodiments, pressure losses in the fluid flow allowing to absorb part of the vibrations.
[0063] Upon entering into motion, the inner perimeter 12'' of the elastic washer 11'' acts on the device 1 as a tuned dynamic damper which absorbs part of the vibrations, in a manner similar to other embodiments.
[0064] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.
[0065] In particular, although in the first two embodiments the mechanical linkage is described with two helical springs, it is possible to provide for a different number of springs and / or springs of another type. The mechanical links can include any type of elastic return element such as elastomer buffers. Although in the first embodiment the axial stops are two in number and annular in shape, it is possible for them to be of another shape such as one or more ribs or one or more lugs.
[0066] The springs are optional.
[0067] It is also envisaged that the deflector core could be of any other shape than that described and for example a cylindrical shape.
Claims
DEMANDS Braking device (1) of a vehicle wheel (103), comprising a stack of discs (2) of which at least one rotor disc (2.1) and one stator disc (2.2), and an actuation assembly (5) for exerting a pressing force on the stack of discs (2), the actuation assembly (5) comprising a ring (6) carrying actuators coaxial with the stack of discs (2), hydraulic actuators (7) mounted side-by-side on the ring (6) carrying actuators, and a hydraulic circuit (8), having sections (10) having a cylindrical internal surface (10.1) defining a circular fluid passage section, for connecting the actuators to at least one hydraulic power source (9), characterized in that at least one section (10) comprises a restriction member (11) having at least one movable part (12) forming a local restriction of the fluid passage section, the movable part of the restriction member (11) being arranged to move in a direction substantially parallel to the section (10) under the effect of the movement of the fluid in said section (10) by forming a tuned dynamic damper. Braking device (1) according to claim 1, in which the restriction member (11) has a mechanical link (14) with the section, the mechanical link (14) being arranged to dampen the movement of the moving part (12).
3. Braking device (1) according to claim 2, in which the mechanical linkage (14) comprises at least two springs (14.1), each connecting the movable part (12) of the restrictor member (11) to the section (10).
4. Braking device 1 according to claim 3, wherein the movable part (12) of the restriction member (11) is a ring having an inner circumference (12.2) forming a hole through which the fluid passes, and two annular end faces (13), and wherein each spring (14.1) of the mechanical linkage (14) extends between one of the annular end faces (13) and an axial stop (14.2) projecting out from the inner surface (10.1) of the section (10), said springs (14.1) exerting on the ring an axial elastic return in two opposite directions to return the ring to an equilibrium position.
5. Braking device 1 according to claim 4, in which the movable part (12) of the restriction member has an external contour (12.1) adapted to fit the internal surface (10.1) of the section (10).
6. Braking device 1 according to claim 4, in which a rubbing elastic element (15) is interposed between the outer perimeter (12.1) of the moving part (12) and the inner surface (10.1) of the section (10).
7. Braking device (1) according to claim 3, wherein the movable part (12) of the restriction member (11) is a deflector core (12') having two ends and a cylindrical surface connecting the two ends and wherein the springs (14.1) connect the deflector core (12') to the internal surface (10.1) of the section (10) so as to elastically maintain the deflector core (12') in an equilibrium position in the vicinity of a central axis of the section (10) to force the fluid to pass between the deflector core (12') and the internal surface (10.1) of the section (10).
8. Braking device (1) according to claim 2, wherein the restricting member (11) is a washer (11'')16 elastic having an inner perimeter forming a fluid passage hole and an outer perimeter fixed to the section by conforming to its inner surface (10.1), the washer being elastically deformable between two extreme states defining two axial positions of the inner perimeter forming the movable part (12) of the restriction member.
9. Braked wheel (103) comprising a braking device (1) according to any one of the preceding claims.
10. Aircraft landing gear equipped with a braked wheel (103) according to claim 9.
11. Aircraft (100) comprising at least one landing gear according to claim 10.