FR3147790A1 - Landing gear with rotation speed measuring device - Google Patents

Abstract

Landing gear (101) comprising at least: - a shaft (102), - at least one wheel (103) rotatably mounted on the shaft, - at least one braking device (1) for the wheel, - at least one measuring device (10) arranged to measure a rotational speed of the wheel, the landing gear being configured in that the measuring device is arranged between the friction member and the shaft, the measuring device comprising at least one target (11) rotatably connected to the wheel and at least one support (12) connected to the shaft, the support carrying at least one sensitive component (13) arranged opposite a rotational trajectory of the target and capable of cooperating with the target to generate at least one signal representative of the rotational speed of the wheel. Corresponding aircraft. FIGURE OF THE ABSTRACT: Fig. 2

Description

Landing gear with rotation speed measuring device

The invention relates to a landing gear equipped with a wheel and a device for measuring the rotation speed of said wheel.

The invention also relates to an aircraft equipped with such a landing gear.

BACKGROUND OF THE INVENTION

Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those in circulation requiring the implementation of technological solutions in order to make them compliant with the regulations in force. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change. Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

Consequently, the Applicant is constantly working to reduce its negative climate impact through the use of methods and the exploitation of processes.

virtuous development and manufacturing and minimizing greenhouse gas emissions to the minimum possible to reduce the environmental footprint of its activity.

This sustained research and development work covers new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and the lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

An aircraft wheel typically consists of a rim surrounded by a tire and connected by a web to a hub mounted to rotate on a wheel support shaft (axle or spindle).

Friction braking devices are known comprising a stack of brake disks which is housed in an annular space extending between the rim and the hub and which comprises an alternation of rotor disks linked in rotation with the wheel and stator disks fixed relative to the wheel support shaft. The braking device also comprises hydraulic or electromechanical actuators mounted on an actuator holder and arranged to apply a pressing force on the stack of disks so as to generate a braking torque to brake the rotation of the wheel.

Typically the braking device cooperates with a monitoring system that measures and monitors certain parameters of the braking device.

The monitoring system thus conventionally comprises a temperature measuring device which measures the temperature of the disk stack, a speed measuring device which measures the rotation speed of the wheel, and a pressure measuring device which measures the pressure

prevailing in the wheel tire. Commonly, speed measuring devices are arranged inside the shaft at one of its ends.

Application FR 1 908 422 of the present Applicant proposes for example such a monitoring system with the integration of the speed measuring device inside the shaft.

Although this placement is clever, it poses a problem when you also want to motorize the wheel for the ground taxiing phases. Indeed, the integration of an actuator in the shaft no longer leaves the necessary volume to also fix the speed measuring device in the same place.

SUBJECT OF THE INVENTION

The invention aims in particular to propose a landing gear which at least partially overcomes the aforementioned drawback.

For this purpose, a landing gear is provided comprising:

- a tree,

- at least one wheel mounted rotating on the shaft,

- at least one wheel braking device, the braking device comprising at least one friction member, an actuator support, and at least one braking actuator carried by the actuator support and arranged to selectively exert a braking force on the friction member,

- at least one measuring device arranged to measure a rotation speed of the wheel.

According to the invention, the measuring device is arranged between the friction member and the shaft, the measuring device comprising at least one target linked in rotation to the wheel and at least one support linked to the shaft, the support carrying at least one sensitive component arranged opposite a rotating trajectory of the target and capable of cooperating with the target to generate at least one signal representative of the rotation speed of the wheel.

Thus, the wheel rotation speed measuring device is cleverly arranged at the level of the wheel braking device. At this level there is less constraint linked to the integration of a ground rolling device.

In addition, it is thus possible to free up the internal volume of the shaft which can therefore be equipped (if desired) with a ground rolling device.

The invention thus makes it possible to equip the landing gear with both a ground taxiing device and a device for measuring the wheel rotation speed.

Advantageously, the measuring device previously described can be added to a landing gear without it being necessary to touch a braking device of the prior art already in place in the landing gear.

The same existing braking device can therefore be equipped with the measuring device described above as well as a measuring device of the prior art.

For the present application, when it is indicated that a part A is fixed to a part B, this means that part A is either fixed directly to part B or fixed by means of any intermediate part, itself fixed directly to part B (the intermediate part being for example a heat shield, a part dedicated to the fixing of part A, etc.).

Preferably, the support carries at least one first sensitive component arranged opposite the rotating trajectory of the target, and capable of cooperating with the target to generate at least one first signal representative of the rotation speed of the wheel, and at least one second sensitive component arranged opposite the rotating trajectory of the target, and capable of cooperating with the target to generate at least one second signal representative of the rotation speed of the wheel.

This helps improve the reliability of the measuring device.

The fact that the number of sensitive components is greater can also be used to increase the refresh rate of the wheel rotation speed estimate.

Preferably, the first sensitive component and the second sensitive component are circumferentially offset from each other.

By studying the two signals emitted by the two sensitive components offset from each other, it is thus possible to estimate the direction of rotation of the wheel.

This is particularly interesting in the case where the shaft is also equipped with a ground taxiing device. Indeed, it is then appropriate to be able to control a reverse gear of the aircraft equipped with such a ground taxiing device. It is thus possible to ensure a safety function for measuring the rotation speed during reverse gear.

The number of targets and/or patterns carried by the target can also be reduced (by increasing the size of each of the targets and/or patterns) to increase the distance between the sensitive components and the target(s).

For the present application, by “circumferentially offset” is meant that the two sensitive components extend on the same periphery of a given element and at different zones of said periphery so that two successive components define an angular segment of the given element.

Optionally, the target is also carried by the stand.

Optionally, the support is shaped into a box.

Optionally, the target and/or sensitive component is entirely arranged in the housing.

Optionally, part of the case is a heat shield.

Optionally, the support is attached to a torque tube of the lander.

Optionally, the bracket is attached to a tree guard.

Optionally, the target and/or support extend coaxially to the shaft.

Optionally, the landing gear further includes a ground taxiing device arranged inside the shaft.

Optionally, the support includes an internal collar supporting the sensitive component.

Optionally, the sensitive component is a detector capable of generating an electrical signal. The invention also relates to an aircraft equipped with such a landing gear.

Other characteristics and advantages of the invention will emerge from reading the following description of particular and non-limiting embodiments of the invention.

Reference will be made to the attached drawings, including:

there is a partial schematic front view of an aircraft equipped with landing gear according to the invention;

there is a partial schematic view of a landing gear according to a first embodiment of the invention, in axial half-section;

there is an enlarged view of part of the lander shown in ;

there is a diagram of the signals of sensitive components of the lander shown in ,

there is a partial schematic view of a landing gear according to a second embodiment of the invention, in axial half-section.

DETAILED DESCRIPTION OF THE INVENTION

There represents an aircraft 100 comprising landing gears 101.

At least one of the landers 101 comprises a leg having one end provided here with two coaxial shafts 102 on each of which is mounted to pivot at least one wheel 103, each shaft 102 having a central axis defining an axis X of rotation of the wheel 103 which it carries.

With reference to Figures 2 to 4, a first embodiment of the invention will now be described.

At least one of the wheels 103 comprises a hub 104 mounted to pivot on the shaft 102 and a rim 105 connected to the hub 104 by a web 106. The rim 105 is surrounded by a tire 109 received between two lips 108 of the rim 105.

Said wheel is furthermore associated with a friction brake 1 intended to brake said wheel 103.

The brake 1 comprises an actuator support, which is here a braking crown 2 mounted coaxially to the axis X. The braking crown 2 carries at least one braking actuator, and preferably a plurality of braking actuators 3. In a manner known per se, the braking crown 2 comprises a plurality of casings 4 of generally cylindrical external shape. Each casing 4 defines a cavity 5 which opens on the side of the wheel 103 and which forms a piston housing 6. Each braking actuator 3 comprises a cylindrical sleeve 7 in which one of the pistons 6 is mounted, arranged to slide parallel to the axis X. The sleeve 7 is received in a sealed manner in the piston housing 6.

The brake crown 2 is mounted on the shaft 102 here by means of a torque tube 110.

For example, the torque tube 110 comprises an internal collar 111 fixed to an external collar 112 of the shaft 102 (external collar sometimes also called “shaft hand” or “axle hand”). The braking crown 2, and therefore the torque tube 110 are thus fixed relative to the shaft 102. The torque tube 110 is furthermore arranged so as to extend in the rim 105 coaxially with the axis X and therefore with the shaft 102 and the crown 2.

The rim 105 and the torque tube 110 define between them a first annular space 113 having a first end closed by the web 106 and a second end open towards the outside of the wheel 103 forming an entrance to the annular space 113.

Furthermore, the shaft 102 and the torque tube 110 define between them a second annular space 114 having a first end closed by the hub 104 and a second end facing the outside of the wheel 103 and closed by the collars 111, 112. The second annular space 114 is thus arranged between the first annular space 113 and the shaft 102.

The brake 1 also comprises at least one friction member, in this case a stack of carbon discs 8 composed of rotors which are integral in rotation with the rim 105 and stators which are integral in rotation with the torque tube 110. The friction member is housed in the first annular space 113 so as to extend coaxially with the axis X.

The braking actuators 3 are arranged to selectively exert a braking force on the stack of carbon discs 8.

The landing gear 101 also comprises a measuring device 10 arranged to measure a rotation speed of the wheel 103.

The measuring device 10 is arranged between the friction member and the shaft 102 so as to be entirely arranged outside the shaft 102.

More specifically here, the measuring device 10 is housed in the torque tube 110 and optionally is housed in the second annular space 114.

Thus arranged, the measuring device is completely surrounded by the shaft 102 and externally by the torque tube 110.

The measuring device 10 is here arranged coaxially with the shaft 102 and the friction member.

The measuring device 10 comprises at least one target 11.

Target 11 has a generally circular shape and is here a wheel. Target 11 is arranged coaxially to the X axis.

The target 11 is rotationally integral with the wheel 103. The target 11 is positioned near the web 106 and/or the hub 104. The target 11 is for example mounted on the web 106 and/or the hub 104.

Thus positioned, the target 11 is surrounded externally by the friction member (and more particularly here the torsion tube 110) and internally by the shaft 102.

The target 11 is therefore arranged at the first end of the second annular space 114.

The target 11 is for example a first toothed target (in this case a toothed wheel). The target 11 thus comprises an alternation of teeth (or sticks) and hollows. This alternation of teeth and hollows is preferably arranged on one of the two main faces of the target 11.

The teeth are radial teeth, that is to say they extend at a main face of the target 11 in radial directions, and/or axial teeth, that is to say they extend at the circumferential face of the target 11 in axial directions.

Target 11 is for example made of or based on metal.

The measuring device also comprises a support 12 carrying at least one sensitive component.

The support 12 has a generally circular shape and is here a wheel segment or an entire wheel.

The support 12 is arranged coaxially to the X axis.

The support 12 is rotationally integral with the shaft 102. The support 12 is positioned near the second end of the second annular space 114.

The support 12 has for example two end faces. A first end face 12a is opposite a main face 11a of the target 11 (the one carrying the teeth and the hollows for the option where the teeth extend radially). The second end face 12b is opposite the internal collar 111 of the torque tube 110.

The support 12 is here mounted on the torque tube 110.

For example, the support 12 is fixed to the internal collar 111 of the torque tube 110.

Thus positioned, the support 12 is surrounded externally by the friction member (and here also the torsion tube 110) and internally by the shaft 102.

Preferably, the measuring device 10 comprises several sensitive components 13 which are all housed in the support 12.

The sensitive components 13 are fixed to the support 12. For example, the sensitive components 13 are arranged substantially at the level of the first end face 12a of the support 12.

For example, the sensitive components 13 are fixed to an internal collar 14 of the support 12. The internal collar 14 of the support 12 optionally includes clearances 15 to reduce its mass.

The sensitive components 13 are preferably circumferentially offset relative to each other.

Typically, the sensitive components 13 are all fixed to the same collar 14 while being circumferentially offset from each other. Thus, all the sensitive components 13 extend at the same distance from the X axis and over the same distance from the second end face 12b (or from the first end face 12a) of the support 12. The sensitive components 13 are, on the other hand, arranged on different areas of the external periphery of the internal collar 14 of the support 12.

Furthermore, the sensitive components 13 are arranged so that their measuring axes are all parallel to each other (and here to the X axis).

The sensitive components 13 are all connected to a remote calculation unit (computer type) which may or may not be part of the measuring device 10.

The connection is here of the wired type. Wires 16 are thus connected at one of their ends to the sensitive components 13 to connect the sensitive components 13 to the calculation organ. Alternatively, the connection can be at least partly non-wired.

For example, at least one of the wires 16 connected at one end to one of the sensitive components 13 successively passes through at least the second end face 12b of the support 12, the internal collar 111 of the torque tube 110 and the external collar 112 of the shaft 102 via orifices provided in the support 12, the internal collar 111 of the torque tube 110 and the external collar 112 of the shaft 102 respectively. The wire 16 thus exits the braking device 1 through the central opening of the brake crown 2.

Optionally, the measuring device 10 comprises a thermal screen 17 at least partially surrounding the support 12.

The heat shield 17 thus makes it possible to better protect the sensitive components 13 from the heat generated by the braking device 1 when the wheel brakes.

For example, the heat shield 17 surrounds the entire support 12 with the exception of its second end face 12b in direct contact with the internal collar 111 of the torque tube 110.

The heat shield 17 is for example fixed to said collar 111.

Each sensitive component 13 is here a detector. The detector provides for example a measurement signal (such as an electrical signal) of the “all or nothing” type depending on whether the distance between the detector and the target 11 is greater or not than a predefined threshold. The measurement signal therefore depends on the presence of a tooth or a hollow in front of the detector. This measurement signal thus has a frequency which is proportional to the rotation speed of the target 11 and therefore to the rotation speed of the wheel 103. For example, if the target 11 has one hundred patterns (one hundred teeth), the detector will provide a measurement signal having a frequency one hundred times greater than that of the rotation frequency of the wheel 103.

The various measurement signals are all transmitted to the computing device.

Since each sensitive component 13 delivers a measurement signal, it is possible to cross-reference the different measurement signals provided by the sensitive components 13 to improve the accuracy of the measurement of the rotation speed of the wheel 103.

Furthermore, because the sensitive components 13 are circumferentially offset from each other, it is possible to estimate the direction of rotation of the wheel 103.

There is a diagram representing the evolution of two measurement signals for sensitive components 13 offset from each other so that they target the target 11 with an offset of a quarter of a pattern relative to each other (i.e. a quarter of a tooth here).

We can therefore see that there is a delay between one signal and the other. The relative delay between the signals being positive or negative depending on the direction of rotation of the wheel 103, it is thus possible to deduce the direction of rotation of the wheel 103.

Furthermore, the signals from the various sensitive components 13 are advantageously combined to provide a measurement of the rotation speed of the wheel 103 refreshed more regularly, for example by exploiting the rising and falling edges of the measurement signals. In the case of two sensitive components, offset from each other so that they aim at the target 11 with an offset of a fraction of the pattern relative to each other, it is for example possible to obtain four refreshes of the information on the rotation speed of the wheel 103 during a period of the signal provided by the first sensitive component or by the second sensitive component. Depending on the value of the fraction (1/2 of the pattern, 1/4 of the pattern, etc.), the rising and falling edges of the measurement signals will be more or less close to each other. The value of the fraction thus affects the temporal placement of the refresh times. The number of sensitive components affects the refresh rate of the estimation of the rotation speed of wheel 103.

It is therefore understood that by increasing the number of sensitive components 13, it is possible to also increase the dimensions of the patterns of the target 11 while maintaining the same refresh frequency of the estimation of the rotation speed of the wheel 103.

This makes it possible to operate with greater target 11 – sensitive component 13 distances for the same resolution. Indeed, since the dimensions of the patterns of the target 11 are greater, this compensates for any loss of performance of the sensitive components 13 linked to the increase in the distance between the sensitive components 13 and the target 11. In order to maintain the same refresh rate for the estimation of the rotation speed of the wheel 103, the number of sensitive components 13 is increased, which in turn compensates for the increase in the dimensions of the patterns of the target 11.

For example, if it is desired to obtain at least one hundred refreshes of the estimation of the rotation speed of the wheel 103 over one revolution of the wheel 103, it is possible according to a first configuration to arrange two sensitive components 13 targeting the target 11 with an offset of 1/2 pattern and with a target 11 having 25 teeth or according to a second configuration to arrange three sensitive components 13 targeting the target 11 with an offset of 1/3 of a pattern and with a target 11 having 17 teeth. The 17 teeth being larger than the 25 teeth, it is then possible to space the sensitive components 13 further away from the target 11 in the second configuration than in the first configuration.

Or increasing the target distance 11 – sensitive components 13 is very interesting because the risk of mechanical interference between the target 11 and the sensitive components 13 decreases accordingly (mechanical interference which may be due to deformations of the wheel 103 during ground taxiing phases for example or even in the event of a particular loading of the aircraft 100). Preferably, the patterns will be widened in the circumferential direction (i.e. there will be fewer patterns around the periphery of the target 11) and will not be widened in the radial direction (i.e. there will be no increase in the radius of the target 11 by widening the patterns).

In reference to the , a second embodiment will now be described.

Apart from the elements indicated below, everything said for the first embodiment is also applicable to the present second embodiment.

While in the first embodiment the target 11 was external to the support 12, in the second embodiment the target 11 is also carried by the support 12 and preferably housed in the support 12.

While the sensitive components 13 are fixed to the support 12 (as in the first embodiment), the target 11 is rotatably mounted in the support 12 so as to be able to be linked in rotation to the wheel 103. For this purpose, the measuring device 10 comprises one or more bearings 18 connecting the target 11 to the support 12, the bearing(s) 18 also being arranged in the support 12.

For example, the sensitive components 13 are fixed to the internal collar 14 of the support 12 and the bearing 18 to another wall 19 of the support 12. The sensitive components 13 and the target 11 are then fixed to reference surfaces internal to the support 12.

The target 11 is arranged at the first end face 12a of the support 12 (the one closest to the hub 104) and the sensitive components 13 between the first end face 12a and the second end face 12b of the support 12.

If the support 12 comprises a heat shield 17, said heat shield 17 is then preferably configured to also at least partially surround the target 11.

Preferably, the landing gear 101 then comprises a clutch system for the rotational connection of the target 11 to the wheel 103 in order to be able to temporarily detach the target 11 from the wheel 103 (for example when the wheel 103 must be removed from the landing gear 101). This makes it possible, for example, to be able to remove the wheel 103 from the landing gear 101 without having to remove the measuring device 10 at the same time.

This facilitates in particular maintenance operations on the wheel 103 and/or the measuring device 10 since the two can be temporarily separated.

For example, the clutch system is a disc or claw clutch. The clutch system is for example a dog clutch with a part 20 fixed to the target 11 and a part 21 (complementary to that 20 fixed to the target 11) fixed to the wheel 103.

The distance between the sensitive components 13 and the target 11 is thus better controlled.

This also simplifies the design of the measuring device 10.

Furthermore, this limits a risk of interference between the target 11 and the sensitive components 13, for example by mechanical elements which would come between the target 11 and the sensitive components 13.

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.

Although here the support is fixed to the torque tube, the support can be fixed to the shaft (and in particular to the external collar of the shaft), or even to the brake crown or even to a braking torque recovery bar or even to a shaft protection or to any other part integral in rotation with the shaft.

The support may carry only one sensitive component. The support will preferably comprise at least two sensitive components and more preferably two sensitive components circumferentially offset from each other. The support may comprise more than one or more than two sensitive components depending on the performance objectives (the response time of the measuring device can indeed be improved with a greater number of sensors), security or availability (by providing redundancy). The support may thus comprise (and in a non-limiting manner) at least three sensitive components). The support may thus comprise (and in a non-limiting manner) between 1 and 8 sensitive components and for example between 1 and 4 sensitive components.

Although here all the sensitive components are carried in the same support, the sensitive components may be housed in several supports. Each sensitive component may for example be housed in its own support.

The sensitive component and the target may be different from those presented here. It has indeed been described that the sensitive component was a detector, and that the target was a toothed wheel. This configuration in no way limits the scope of the invention. Whatever the technology used, the sensitive component may be for example a distance sensor or an analog or inductive type. The sensitive component of the analog type may be a Hall Effect sensor. The distance sensor may be a proximity sensor.

The distance or analog type sensor can provide a measurement signal that will produce a measurement signal whose amplitude will depend on the distance of a tooth or a hollow in front of the sensor. The measurement signal will thus have a frequency that will be proportional to the rotation speed of the target and therefore to the rotation speed of the wheel. In addition, it will also be possible to estimate the sensor/target distance. This information can be used to monitor the behavior of the undercarriage (the measuring device, the wheel, etc.) during operation: rotation fault, sensor/target distance problem, etc.

The measurement technology associated with the sensitive/target component may be, for example, inductive technology, magnetic technology, ultrasonic technology, electrical technology or optical technology. Ultrasonic technology and optical technology will allow the measurement to be carried out on non-metallic materials, which will make it possible to use targets made of lighter composite materials.

Of course, the invention will apply equally well to an electric braking device as to a hydraulic braking device.

Although here a heat shield covers the support, the heat shield may be an integral part of the support. The support may also have a cover in place of the heat shield allowing the support to be closed. Preferably, at least the sensitive components will be entirely housed in the support (thus forming a case either by the heat shield or by the cover).

Claims (14)

Landing gear (101) comprising at least:
- a tree (102),
- at least one wheel (103) rotatably mounted on the shaft,
- at least one braking device (1) for the wheel, the braking device comprising at least one friction member, an actuator support, and at least one braking actuator (3) carried by the actuator support and arranged to selectively exert a braking force on the friction member,
- at least one measuring device (10) arranged to measure a rotation speed of the wheel,
the landing gear being configured in that the measuring device is arranged between the friction member and the shaft, the measuring device comprising at least one target (11) linked in rotation to the wheel and at least one support (12) linked to the shaft, the support carrying at least one sensitive component (13) arranged opposite a rotating trajectory of the target and capable of cooperating with the target to generate at least one signal representative of the rotation speed of the wheel. Landing gear (101) according to claim 1, in which the support (12) carries at least one first sensitive component arranged opposite the rotating trajectory of the target (11), and capable of cooperating with the target to generate at least one first signal representative of the rotation speed of the wheel, and at least one second sensitive component arranged opposite the rotating trajectory of the target, and capable of cooperating with the target to generate at least one second signal representative of the rotation speed of the wheel. The landing gear (101) of claim 2, the first sensitive component and the second sensitive component are circumferentially offset from each other. Landing gear (101) according to one of the preceding claims, in which the target (11) is also carried by the support (12). Landing gear according to one of the preceding claims, in which the support (12) is shaped as a housing. Landing gear (101) according to claim 5, wherein the target (11) and/or the sensitive component (13) is entirely arranged in the housing. A landing gear (101) according to claim 5 or claim 6, wherein part of the housing is a heat shield (17). Landing gear (101) according to one of the preceding claims, in which the support (12) is fixed to a torque tube (110) of the landing gear. Landing gear (101) according to one of the preceding claims, in which the support (12) is fixed to a protection of the shaft (102). Landing gear (101) according to one of the preceding claims, wherein the target (11) and/or the support (12) extend coaxially with the shaft. Landing gear (101) according to one of the preceding claims, further comprising a ground taxiing device arranged inside the shaft (102). Landing gear (101) according to one of the preceding claims, in which the support (12) comprises an internal collar (14) supporting the sensitive component (13). Landing gear (101) according to one of the preceding claims, in which the sensitive component (13) is a detector capable of generating an electrical signal. Aircraft (100) equipped with a landing gear according to one of the preceding claims.