Aircraft landing gear equipped with at least one wheel and a wheel steering device

Abstract

Aircraft landing gear (2), comprising: a box (4) having one end intended to be articulated on a structure of an aircraft (1); a sliding rod (5) mounted to slide in the box along a longitudinal axis (X) of said sliding rod and having one end provided with an axle (6) carrying a wheel (7); and a wheel orientation device (10, 10', 10'', 10''') arranged to control a pivoting of the sliding rod about its longitudinal axis, the orientation device comprising: a rotating member (11, 12) mounted to rotate freely about said longitudinal axis, the rotating member being rotationally fixed to the sliding rod and comprising a toothed sector (12); a drive shaft (13) comprising a section provided with a helical groove (13.1) which forms a worm gear meshing with the toothed sector; and a motor (15, 19") rotating the drive shaft. Figure from the summary: Fig. 2

Description

Title of the invention: Aircraft landing gear equipped with at least one wheel and a wheel steering device

[0001] The present invention relates to the ground movement of an aircraft, and in particular an aircraft landing gear comprising a steerable lower part provided with at least one wheel, and a steering device adapted to rotate the lower part in response to a steering command.

[0002] The invention also relates to an aircraft equipped with such a lander.

[0003] BACKGROUND OF THE INVENTION

[0004] Auxiliary aircraft landing gear generally comprises a box hinged to an aircraft structure, the box receiving a sliding rod having an axle with wheels at its lower end. It is known to equip auxiliary landing gear with a wheel steering device to facilitate the aircraft's movement on the ground and enable it to make turns. The steering device generally comprises a rotating member mounted on the box (such as a collar or a rotating tube) and connected to the sliding rod by a compass that allows the rod to slide freely, but locks the sliding rod to the rotating member. The angular position of the latter relative to the box is controlled by a steering actuator.

[0005] Orientation actuators are known, comprising a rack mounted to slide within cylinders extending on either side of the housing. The rack meshes with a toothed portion of the rotating member forming a pinion and is moved hydraulically or pneumatically.

[0006] Nevertheless, more and more aircraft are moving towards electrical equipment, particularly for reasons of reliability and weight. Furthermore, the size of such a steering actuator is significant due to the rack's translation, which complicates its integration into an already constrained environment.

[0007] Orientation actuators comprising an electric motor driving the rotating part via a parallel-axis reducer are also known. Such a reducer generally has a limited reduction ratio, so that orienting the wheels requires a high-power electric motor which, by definition, has a significant mass and size.

[0008] SUBJECT OF THE INVENTION

[0009] The invention therefore aims to provide an aircraft landing gear equipped with at least one wheel and a wheel orientation device which at least partially overcomes the aforementioned disadvantages. Summary of the invention

[0010] To this end, an aircraft landing gear is proposed, comprising: • a box having one end intended to be hinged to a structure of an aircraft; • a sliding rod mounted to slide within the casing along a longitudinal axis of said sliding rod and having one end provided with an axle carrying at least one wheel; and • a wheel orientation device, arranged to control a pivoting of the sliding rod around its longitudinal axis.

[0011] According to the invention, the orientation device comprises: • a rotating member extending coaxially to the longitudinal X axis of the sliding rod, between the casing and said sliding rod, and mounted to rotate freely about said longitudinal axis, the rotating member being rotationally fixed to the sliding rod and comprising a toothed sector; • a drive shaft comprising a section provided with a helical groove that forms a worm gear meshing with the toothed sector; and • at least one motor driving the drive shaft in rotation.

[0012] Due to its rotary operation, the overall size of the orientation device is limited, particularly compared to a rack and pinion orientation device. Furthermore, the reduction gear formed by the toothed ring and the worm gear can be arranged to provide a high transmission ratio and thus allow the use of a low-power electric motor.

[0013] According to a particular feature, the section of the drive shaft and the toothed sector together form a reversible gear, which makes it possible to control the orientation of the wheel even in the event of a motor failure.

[0014] According to another particular characteristic, the motor is an electric motor.

[0015] In particular, the electric motor is radial flux.

[0016] According to another particular feature, a first end of the drive shaft is received in the motor.

[0017] According to another particular feature, the orientation device includes a position sensor of a motor rotor, the position sensor being arranged to deliver a signal representative of an angular position of the rotor.

[0018] According to another particular feature, the toothed sector is formed by a toothed crown.

[0019] According to another particular feature, the orientation device includes a pinion engaging with the helical spline of the drive shaft 13, the rotating member and the pinion extending on either side of the drive shaft to limit any bending of said drive shaft caused by its engagement with said rotating member.

[0020] According to another particular feature, the orientation device includes a second motor in which is received a second end of the drive shaft, opposite to the first end, to drive said drive shaft in rotation.

[0021] The invention further relates to an aircraft comprising at least one such landing gear. Brief description of the drawings

[0022] The invention will be better understood in the light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which:

[0023] [Fig-1] [Fig.1] is a simplified view of an aircraft including a lander auxiliary according to a particular embodiment of the invention;

[0024] [Fig.2] [Fig.2] is a cross-sectional view of the auxiliary lander illustrated in [Fig.1];

[0025] [Fig.3] [Fig.3] is a view identical to [Fig.2] illustrating a first variant of the auxiliary landing gear of the aircraft illustrated in [Fig.1];

[0026] [Fig.4] [Fig.4] is a view identical to [Fig.2] illustrating a second variant of the auxiliary landing gear of the aircraft illustrated in [Fig.1];

[0027] [Fig.5] [Fig.5] is a view identical to [Fig.2] illustrating a combination of the first and second variants illustrated in figures 2 and 3. DETAILED DESCRIPTION OF THE INVENTION

[0028] With reference to figures 1 and 2, the invention is described in application to an aircraft 1 comprising an auxiliary landing gear 2 and two main landing gears 3.

[0029] In a manner known per se, the auxiliary landing gear 2 comprises a box 4 and a sliding rod 5 mounted to slide in the box 4 along a longitudinal axis X of said sliding rod 5. The box 4 has an upper end articulated on a structure of the aircraft 1, and the sliding rod 5 has a lower end fixed to an axle 6 carrying here two wheels 7.

[0030] The auxiliary landing gear 2 also includes a steering device 10 to control a pivoting of the sliding rod 5 around its longitudinal axis X, and therefore the orientation of the wheels 7 carried by the axle 6, so as to facilitate the movement of the aircraft 1 on the ground and to allow it to make turns.

[0031] The orientation device 10 comprises, according to a particular embodiment of the invention, a rotating tube 11 extending coaxially to the longitudinal axis X of the sliding rod 5, between the housing 4 and said sliding rod 5. The rotating tube 11 is mounted to rotate about the axis X and is axially immobilized by means not shown. A compass (not shown) connects the rotating tube 11 to the sliding rod 5 so as to rotationally fix said rotating tube 11 to the sliding rod 5 while allowing free sliding of the sliding rod 5 along its longitudinal axis X.

[0032] The rotating tube 11 is coaxially equipped with a toothed ring 12 extending around said rotating tube 11. The toothed ring 12 forms a toothed sector at 360 degrees and is fixed with respect to the rotating tube 11 so that a rotation of the toothed ring 12 around the axis X causes a rotation of the rotating tube 11 around said axis X: the rotating tube 11 and the toothed ring 12 together form a rotating member.

[0033] The orientation device 10 also includes a drive shaft 13 mounted for rotation in the housing 4 about a longitudinal Y axis of said drive shaft 13 by means of tapered roller bearings 14, said Y axis being orthogonal to the X axis. The drive shaft 13 is substantially axially immobile and has a central section provided externally with a helical spline 13.1 meshing with the toothed ring 12. It is understood that the central section of the drive shaft 13 forms a worm gear and that a rotation of said drive shaft 13 causes a rotation of the toothed ring 12: the toothed ring 12 and the central section of the drive shaft 13 together form a gear.

[0034] Preferably, this gear is reversible, meaning that the ring gear 12 and the central section of the drive shaft 13 can act as either driving or driven components. It is thus understood that a rotation of the drive shaft 13 causes a rotation of the ring gear 12, but also that a rotation of said ring gear 12 causes a rotation of said drive shaft 13. The ring gear 12 and the drive shaft 13 then form a non-self-locking worm gear reducer. In the event of a failure of the motor 15, it is therefore still possible to orient the wheels 7.

[0035] The drive shaft 13 is driven in rotation by an electric motor 15 connected to a control unit (not shown) which controls the motor 15 in response to a wheel orientation command 7. The motor 15 is a radial flux motor and comprises, in a manner known per se, a fixed element or stator 15.1, and a rotating moving element or rotor 15.2, both received in a housing 16 fixed to the casing 4. The stator 15.1 and the rotor 15.2 have a central axis coinciding with the Y-axis of rotation of the drive shaft 13, the rotor 15.2 extending inside the stator 15.1 and radially with respect to said stator. 15.1. The rotor 15.2 includes a first end having a central hole 15.3 receiving one end of the drive shaft 13. The central hole 15.3 has an internal groove cooperating with an external groove formed on the end of the drive shaft 13 so that a rotation of the rotor 15.2 causes a rotation of the drive shaft 13.

[0036] The orientation device 10 further includes a position sensor 17 of the rotor 15.2 about the Y axis. The position sensor 17 is received in the housing 16 and extends axially opposite a second end of the rotor 15.2, opposite the first end of said rotor 15.2. The position sensor 17 is arranged to deliver a signal representative of an angular position of the rotor 15.2; this signal could, in particular, be used to determine an angular position of the tube rotating 11 about the X axis and thus control or command the orientation of the wheels 7.

[0037] Figure 3 illustrates a 10' orientation device which is none other than a first variant of the orientation device 10 illustrated in [Fig.2].

[0038] The orientation device 10' differs from the device 10 in that it further comprises a pinion 18' mounted to rotate about an axis X[8- substantially parallel to the X-axis and meshing with the helical spline 13.1 of the drive shaft 13. The toothed ring 12 and the pinion 18' extend on either side of the drive shaft 13, the X and X[8' axes defining a plane perpendicular to the Y-axis. The pinion 18' is thus arranged to limit any deflection of the drive shaft 13 caused by the radial loads experienced by the helical spline 13.1 of said drive shaft 13 during its meshing with the toothed ring 12, so as to prevent any separation of said helical spline 13.1 from said toothed ring. 12 and therefore any gear skipping or significant play that could lead to a loss of torque transmission.The 18' pinion can be equipped with an angular position sensor to provide, like the position sensor 17, feedback on the orientation of the wheels 7.

[0039] Figure 4 illustrates a 10” orientation device which is none other than a second variant of the orientation device 10 illustrated in [Fig.2].

[0040] The orientation device 10” differs from the device 10 in that it includes a second electric motor 19” which is substantially identical to the motor 15. The second motor 19” is a radial flux motor and comprises, in a manner known per se, a fixed element or stator 19.1” and a rotating moving element or rotor 19.2”, both housed in a casing 20” attached to the housing 4. The stator 19.1” and the rotor 19.2” have a central axis coinciding with the Y-axis of rotation of the drive shaft 13, the rotor 19.2” extending inside the stator 19.1” and radially opposite said stator 19.1”. The rotor 19.2” comprises a first end having a central hole 19.3” receiving one end of the drive shaft 13, opposite to that received in the rotor 15.2 of the motor 15. The central hole 19.3” has an internal groove cooperating with an external groove formed on the end of the drive shaft 13 so that a rotation of the rotor 19.2” causes a rotation of the drive shaft 13.

[0041] The integration of the second 19” motor allows for: • create a redundancy of the means for rotating the drive shaft 13 formed by the first motor 15; and / or • reduce the power rating of the first motor by controlling the rotation of the drive shaft using both the first motor 13 and the second motor 19” simultaneously; and / or • lower the operating temperature of the first motor by simultaneously using each of the first 13" motor and the second 19" motor at a power lower than their maximum power.

[0042] Figure 5 illustrates a 10" orientation device which is a combination of the first and second variants of the 10" orientation device shown in Figures 3 and 4. The 10" orientation device thus differs from the 10" device in that it includes both the pinion 18' and the second motor 19'.

[0043] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0044] Although the 15, 19” motors are here radial flow, they can be axial flow.

[0045] The pinion 18' can be replaced by a roller having an external surface bearing against the helical spline 13.1 of the drive shaft 13.

[0046] The steering devices 10, 10', 10”, 10’” may, if necessary, include a gearbox to optimize the efficiency of the motor(s) 15, 19” and / or a clutch system to decouple said motor(s) 15, 19” from the rotating tube 11 and thus allow the wheels 7 to be oriented in the event of a power failure (in particular when the gearing formed by the toothed ring 12 and the central section of the drive shaft 13 is not reversible). The gearbox may, for example, include a planetary or harmonic reducer arranged to increase the torque delivered by the motor(s) 15, 19” to the rotating tube 11.

[0047] The stator(s) 15.1, 19.1” of the motor(s) 15, 19” may be double-wound, or even multi-wound, so as to add additional redundancy of the drive means in rotation of the drive shaft 13 and to ensure said drive means of minimum performance.

[0048] Although the sliding rod 5 here carries two wheels 7, it can also carry only one wheel or a number of wheels greater than or equal to three.

[0049] The toothed ring 12 can be replaced by a toothed sector less than 360 degrees (for example 180 degrees), in particular if the desired amplitude of rotation of the rotating tube 11 is less than 360 degrees.

Claims

Demands

1. Aircraft landing gear (2), comprising: • a box (4) having one end intended to be articulated on a structure of an aircraft (1); • a sliding rod (5) mounted to slide within the box along a longitudinal axis (X) of said sliding rod and having one end provided with an axle (6) carrying at least one wheel (7); and • a wheel steering device (10, 10', 10”, 10”') arranged to control a pivoting of the sliding rod about its longitudinal axis, the steering device comprising: • a rotating member (11, 12) extending coaxially with the longitudinal axis X of the sliding rod, between the box and said sliding rod, and mounted to rotate freely about said longitudinal axis, the rotating member being rotationally fixed to the sliding rod and comprising a toothed sector (12); • a drive shaft (13) comprising a section provided with a helical groove (13.1) which forms a worm gear meshing with the toothed sector; and • at least one motor (15, 19”) driving the drive shaft in rotation.

2. Aircraft landing gear (2) according to claim 1, wherein the drive shaft section (13) and the toothed sector together form a reversible gear.

3. Aircraft landing gear (2) according to any one of the preceding claims, wherein the motor (15, 19”) is an electric motor.

4. Aircraft landing gear (2) according to claim 3, wherein the electric motor (15, 19”) is radial flux.

5. Aircraft landing gear (2) according to any one of the preceding claims, wherein a first end of the drive shaft (13) is received in the engine (15).

6. Aircraft landing gear (2) according to any one of the preceding claims, wherein the orientation device (10, 10', 10', 10”') includes a position sensor (17) of a rotor (15.2) of the motor (15), the position sensor being arranged to deliver a signal representative of an angular position of the rotor.

7. Aircraft landing gear (2) according to any one of the preceding claims, wherein the toothed sector (12) is formed by a toothed ring (12).

8. Aircraft landing gear (2) according to any one of the preceding claims, wherein the steering device (10', 10'”) comprises a pinion (18') meshing with the helical spline (13.1) of the drive shaft (13), the rotating member (11, 12) and the pinion extending on either side of the drive shaft (13) to limit any bending of said drive shaft caused by its meshing with said rotating member.

9. Aircraft landing gear (2) according to any one of the preceding claims, wherein the orientation device (10”, 10”') comprises a second motor (19”) in which is received a second end of the drive shaft (13), opposite to the first end, for rotating said drive shaft.

10. Aircraft (1) comprising at least one landing gear (2) according to any one of the preceding claims.

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