Device for connecting an aircraft wheel pneumatic tire to the aircraft's central pneumatic system

CA 02641979 2008-10-20 1 Device for connecting an aircraft wheel tire to a pneumatic unit of the aircraft.

The invention relates to a device for connecting an aircraft wheel tire to a pneumatic unit of the aircraft.

BACKGROUND OF THE INVENTION Aircraft are known comprising devices for connecting the tires of the wheels to an on-board pneumatic unit.

The unit can be an air compressor, a nitrogen generator, or any other system making it possible to supply a pressurized gas capable of inflating the tires.

Depending on whether the pressure proposed by the pneumatic unit is higher or lower than that prevailing in the tire, the tire inflates or deflates.

When the aircraft is on the ground, the pneumatic unit can be connected to an external pressure source.

Document GB1031726 illustrates such a device, certain elements of which are external to the axle.

In particular, the wheel is fitted with a protective cover which covers the end of the axle and which receives a tire isolation valve.

This arrangement of the valve makes it sensitive to external shocks.

Furthermore, this valve is actuated by a needle movable in an axial orifice of the axle.

This type of device is not suitable for modern aircraft most of the time having hollow axles.

In addition, it has several separately removable parts (the needle in the axle, the valve in the wheel cover), which does not facilitate its maintenance.

Also known from documents US 2107405 and US2685906 are other devices, more particularly suitable for land vehicles.

In particular, the device illustrated in document US2685906, in accordance with the preamble of claim 1, proves to be advantageous in that it is entirely modular and can be dismantled CA 02641979 2008-10-20 2 as a whole, on condition of course of disconnect it from the gas inlets.

However, this device protrudes from the wheel and is therefore exposed to shocks.

OBJECT OF THE INVENTION The object of the invention is a device for adjusting the pressure in a tire fitted to an aircraft wheel, inspired by that of document US2685906, but better protected.

BRIEF DESCRIPTION OF THE INVENTION According to the invention, there is provided a device for selectively connecting to a pneumatic unit of an aircraft a tire of a wheel of the aircraft mounted to rotate on a hollow axle of the aircraft, the device comprising .

a stator and a rotor which is mounted to rotate on the stator along an axis which in service coincides with an axis of rotation of the wheel, and which comprises means for its rotational drive by the wheel;

- a seal which extends between the stator and the rotor to close a first chamber extending between the rotor and the stator and into which opens a first pneumatic port carried by the stator for the connection of the device with the central unit pneumatic;

the rotor defining a second chamber into which opens a second pneumatic port for connecting the device with the tire;

the rotor carrying a valve extending through a wall of the rotor separating the first and the second chamber to selectively put the two chambers in pneumatic communication when the valve is open;

the stator carrying an actuator acting selectively on the valve to switch the latter from a stable closed state to an open state.

CA 02641979 2008-10-20 3 According to the invention, the stator is bell-shaped which is intended to be received with adjustment in the axle and which comprises a bottom wall which carries the first pneumatic port for its connection to the axle. pneumatic unit by a pipe running through the axle, the rotor extending substantially inside the stator.

Thus, the entire device is housed in the axle and is there protected from shocks.

What is more, the arrangement of the first port on the back wall facilitates the connection of the device to the power plant via a pipe running through the axle.

Preferably, the actuator is of the electro-mechanical type.

Thus, the use of an electromechanical actuator makes it possible to include it entirely in the first chamber, without it being necessary to provide an actuating chamber in the stator or an additional pneumatic port for the activation of the actuator. 'actuator.

The pressurized gas from the pneumatic unit can flow from the first port to the valve or green through the electromechanical actuator.

However, the gas will only reach the tire if the valve is open, and therefore only if the actuator is activated.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood in the light of the description which follows with reference to the figures of the appended drawings, among which:

- Figure 1 is a sectional view of a wheel mounted on an aircraft axle equipped with a device according to a particular embodiment of the invention;

- Figure 2 is an enlarged sectional view of the device illustrated in Figure 1.

DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. 1, the device of the invention is here illustrated in place on an aircraft equipped with a pneumatic generation, for example a presser com CA 02641979 2008-10-20 4 which receives pressure. nitrogen from an air separation system which sends oxygen from the air to an aircraft oxygen circuit, and nitrogen from the air to the compressor. The aircraft comprises at least one wheel 1 comprising a rim 2 which carries a tire 3 and which is received in rotation about an axis of rotation X on a hollow axle 4, by means of bearings 5.

The device 10 of the invention is arranged in the axle 4 at the end of the latter and comprises a stator 11 inserted to fit into the axle 4 and fixed to the latter by fixing means not shown.

The device 10 further comprises a rotor 12 mounted to rotate in the stator 11.

The device 10 will be detailed below in relation to FIG. 2.

It suffices here to note that the rotor 12 is driven in rotation with the wheel by means of a finger 13 which extends to cooperate with a protective cover 14 integral with the wheel 1.

Turning now to Figure 2, we see that the stator 11 is generally bell-shaped which is intended to be inserted to fit into the axle shown here in dotted lines, almost entirely apart from an end flange abutting on the end of the axle.

The stator 11 has a bottom wall 19 which carries a first pneumatic port 15 for connecting the device to the pneumatic unit of the aircraft, by means of a pipe 16 running through the axle 4.

The rotor 12 is here received entirely in the stator and is mounted so as to rotate in the stator 11 by means of bearings 26.

The rotor 12 carries a second pneumatic port 17 for connecting the device with the tire, via a pipe 18 extending between the rotor 12 and the rim 2.

The assembly is particularly compact and is fully integrated into the axle, which protects it from any external impact.

CA 02641979 2008-10-20 The stator 11 and the rotor 12 together define a first chamber 20 which is closed here by a lip seal 21 which is carried by the rotor 12 to cooperate with a cylindrical bearing surface 22 formed by the outer wall 5 an axial protrusion 28 of the stator 11 extending into the rotor 12.

The axial protrusion 28 defines an axial housing 23 which opens into the first chamber 20 and in which an elongated electromechanical actuator 24 is engaged, the latter being stopped axially by a ring 25.

The first pneumatic port 15 opens into the housing 23, and therefore into the first chamber 20, it being understood that the actuator 24 is permeable to gases and therefore does not form an obstacle to the passage of the latter. The actuator 24 here extends along the X axis and has a terminal actuator member movable along said X axis.

Furthermore, the rotor 12 defines a second chamber 30 into which the second pneumatic port 17 opens.

The second chamber 30 is separated from the first chamber 20 by a wall 31 which is crossed by a valve 32 extending along the axis of rotation X.

The valve is normally closed, which isolates the two chambers, but can be opened by the actuator of the actuator 24 which pushes the valve stem 32 to open the latter and put the two chambers 20, 30 in pneumatic communication.

To modify the pressure in the tire, it is necessary to put the latter in communication with the pneumatic unit.

To do this, the actuator 24 is activated so that the latter opens the valve 32 to put the chambers 20 and 30, connected respectively to the pneumatic unit and to the tire, into communication.

The valve 32 is then left open for a sufficient time for the desired pressure to be established in the tire.

These pressure modification operations are normally carried out only when the aircraft is in flight or when the aircraft is stationary on the ground.

Under these conditions, the lip seal 21 is only put under pressure when the wheel is not turning. The sealing of the lip seal 21 is then more easily achieved.

However, if a slight leak appears at the level of the lip seal 21, it will suffice for the leakage rate to be appreciably less than the inflation rate to nevertheless ensure the inflation of the tire.

As a variant, it is possible to use any other type of seal, compatible with a rotational movement, and which is capable of ensuring gas-tightness at least when the wheel is not rotating.

The use of an electromechanical actuator makes it possible to avoid the supply of a second pneumatic source to control the actuator, as in the embodiment illustrated in FIG. 5 of document US2685906.

Indeed, it would be difficult to route a second pneumatic pipe through the axle.

In addition, the actuator can be disposed entirely in the first chamber as in the first embodiment illustrated in FIG. 4 of the same document, but while allowing separate control of the actuator and of the pressurization by the central unit. pneumatic, which is not possible in the embodiment of FIG. 4.

The configuration of the device of the invention also makes it possible to easily integrate a wheel rotation sensor, since the rotor 12 is driven in rotation with the wheel.

Thus, a tachometer 50 is arranged in the device of the invention, with a fixed part 51 integral with the stator 11 and a rotating part 52 so1i.daire of the rotor 12 which extends opposite the fixed part 51 to interact. electromagnetic remote with it.

In a manner known per se, CA 02641979 2008-10-20 7 the electromagnetic interaction generates in the fixed part 51 a current proportional to the speed of rotation of the rotor 12, and therefore of the wheel.

It is then sufficient to measure the current which circulates in the fixed part 51 in order to know the speed of rotation of the wheel.

Furthermore, the configuration of the device of the invention also makes it possible to easily integrate a tire pressure sensor.

Thus, a pressure sensor 60 is placed on the rotor 12 to measure the pressure prevailing in the second chamber 30, and therefore in the tire, since the second chamber 30 is in pneumatic relation with the tire.

Here, the pressure sensor 60 is of the radiofrequency type and receives its electrical energy from an antenna 61 arranged on the stator 11 to be in remote electromagnetic interaction with the pressure sensor 60, whatever the angular position of the rotor 12.

In return, the pressure sensor 60 influences the impedance of the antenna 61 as a function of the pressure prevailing in the chamber 12.

It is then sufficient to measure the current which circulates in the antenna 60 in order to know the pressure in the tire or any other electrical quantity (voltage, impedance, etc.) relating to the antenna 60 varying with the pressure.

The pressure sensor thus arranged replaces the sensor which is usually placed directly on the rim of the wheel.

The sensors integrated in the device of the invention are therefore particularly protected from external shocks.

The fixed part 51 of the tachometer 50, the antenna 61, and the actuator 24 are all electrically connected to the aircraft by means of an electrical connector 70 also extending on the bottom wall 19 of the stator 1.1, by means an electric cable 71 also running in the axle 4.

CA 02641979 2008-10-20 8 The invention is not limited to what has just been described, but on the contrary encompasses any variant coming within the scope defined by the claims.

In particular, although a device has been illustrated here with a rotor fully housed in the stator, it is possible, without departing from the invention, to provide a rotor which protrudes slightly from the stator, for example via the second pneumatic port which can protrude from the end of the stator.