Connecting device of a tire of an aircraft to a central inflation system

(54) Title: DEVICE FOR SELECTIVELY CONNECTING A TIRE TO AN AIRCRAFT PNEUMATIC UNIT (30) Unionist Priority: 10/23/2007 fr 0707429 (73) Owner (s): Messier-Bugatti (72) Inventor (s): Bartrand Maes, Jean-Clair Pradier, Olivier Collet (57) Summary: device to connect

SELECTIVELY A TIRE TO A PNEUMATIC UNIT OF AN AIRCRAFT. The invention relates to a device for selectively connecting a tire to an aircraft pneumatic unit, the tire forming part of a wheel mounted to rotate on a hollow axis of the aircraft, the device comprising a stator (11) and a rotor (12 ) that is mounted to rotate in relation to the stator and that includes means (13) that enables it to rotate by the wheel. According to the invention, the stator is bell-shaped and is designed to be received as a pressure fitting on the shaft, and includes an end wall (19) that takes a first pneumatic hole for connection to the pneumatic unit by means of a tube that is arranged along the inner part of the shaft, the rotor extending substantially within the stator.

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HWHM643-3 “DEVICE FOR SELECTIVELY CONNECTING A TIRE TO AN AIRCRAFT PNEUMATIC UNIT”

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

BACKGROUND OF THE INVENTION

Aircraft are known to include devices for connecting wheel tires to a pneumatic unit on board. The unit can be a tire compressor, a nitrogen generator, or any other system that allows gas to be delivered at an adequate pressure to inflate the tires. Depending on whether the pressure provided by the pneumatic unit is higher or lower than the pressure on the tire, the tire will inflate or deflate. When the aircraft is on the ground, the pneumatic unit can be connected to an external pressure source.

GB 1 031 726 illustrates such a device, which has some of its elements off-axis. In particular, the wheel is equipped with a protective cover that covers the end of the axle and which receives a tire isolation valve. This valve arrangement makes it sensitive to external impacts. In addition, the valve is actuated by a needle that is movable in an axial hole in the shaft. This type of device is not suitable for modern aircraft that normally have hollow shafts. Furthermore, it includes a plurality of parts that are separately removable (the needle on the axle, the valve on the wheel cover), which do not facilitate its maintenance.

US 2. 107 405 and US 2 685 960 disclose other devices, more particularly adapted for land vehicles. In particular, the device shown in US 2 685 906, which is in accordance with the introductory part of claim 1, is considered to be advantageous in that it is completely modular and can be removed as a whole, naturally provided that the gas connections are disconnected. However, this device protrudes from the wheel and is therefore exposed to impacts.

OBJECTIVE OF THE INVENTION

An object of the invention is to provide a device for adjusting the pressure in a part that forms the tire of an aircraft wheel, based on the device of document US 2685 906, to better protect. BRIEF DESCRIPTION OF THE INVENTION

According to the invention, a device is provided to selectively connect a tire to an aircraft pneumatic unit, the tire-forming part of a wheel mounted to rotate on a hollow axis of the aircraft, the device comprising:

- a stator and a rotor mounted to rotate in relation to the stator around a geometric axis which, in operation, coincides with the geometric axis of rotation of the wheel, and including devices to enable the wheel to put it in rotation;

- a seal that extends between the rotor and the stator to close a first chamber that extends between the rotor and the stator and within which a first pneumatic orifice opens, the orifice being loaded by the stator to connect the device to the pneumatic unit;

- the rotor defining a second chamber in which a second pneumatic orifice opens to connect the device to the tire;

- the rotor carrying a valve that extends through a wall of the rotor that separates the first and second chambers, thus enabling the two chambers to be selectively in pneumatic communication by opening the valve; and

- the stator carrying an actuator that acts selectively on the valve in order to switch between a stable closed state and an open state.

According to the invention, the stator is bell shaped, being designed to be received as a pressure fitting on the shaft and having an end wall that takes the first pneumatic hole for connection in the pneumatic unit through a tube that passes inside the axis, the rotor extending substantially inside the stator.

Thus, the entire device is housed on the axis where it is protected from impacts. In addition, the arrangement of the first hole in the end wall makes it easier to connect the device to the pneumatic unit by means of a tube that runs along the inside of the shaft.

Preferably, the actuator is of the electromechanical type. Thus, the use of an electromechanical actuator allows the actuator to be incorporated completely into the first chamber, without any need to provide an actuator chamber in the stator, or an additional pneumatic hole to activate the actuator. The gas under pressure from the pneumatic unit can flow from the first orifice towards the open valve, passing through the electromechanical actuator. However, the gas will reach the tire only if the valve is open, that is, only if the actuator is activated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood in the light of the following description with reference to the figures in the accompanying drawings, in which:

Figure 1 is a sectional view of a wheel mounted on an aircraft axle that is equipped with a device that constitutes a particular embodiment of the invention; and

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

DETAILED DESCRIPTION OF THE INVENTION

With reference to figure 1, the device of the invention is shown in place of an aircraft equipped with a tire generator, for example, a compressor, which receives nitrogen from an air separator system that takes oxygen from the air into an oxygen circuit of the aircraft and nitrogen from the air to the compressor. The aircraft has at least one wheel 1 comprising a rim 2 which carries a tire 3 and which is received to rotate around a geometric axis of rotation X on a hollow axis 4, by means of ball bearings 5. Device 10 of the The invention is placed on the shaft 4 at its end and comprises a stator 11 snapped onto the shaft 4 and secured to it by fixing means (not shown). The device 10 additionally comprises a rotor 12 rotatably mounted on the stator 11.0 Device 10 is described in more detail below with reference to figure 2. At this point, it is sufficient to observe that the rotor 12 is forced to rotate together with the wheel by means of of a finger 13 extending to cooperate with a protective cap 14 attached to the wheel 1.

With reference to figure 2, it can be seen that the stator 11 has a general bell shape and is designed to be fitted by pressure on the shaft, which is drawn in dashed lines, being received almost completely in it, except that a collar end that rests on the end of the shaft. Stator 11 has an end wall that takes a first pneumatic orifice 15 for connecting the device to the aircraft's pneumatic unit, through a tube 16 that extends along axis 4. Rotor 12 is completely received inside the stator and it is mounted to rotate inside the stator 11 by means of ball bearings 26. The rotor 12 takes a second pneumatic hole 17 to connect the device to the tire by means of a tube 18 that extends between the rotor 12 and the rim 2 .

The set is particularly compact and is fully incorporated into the shaft, thereby protecting it from any external impact.

Together, stator 11 and rotor 12 define a first chamber that is closed by a ferrule-like seal 21 that is loaded by rotor 12 to cooperate with a cylindrical bearing surface 22 formed by the outer wall of an axial protrusion 28 of stator 11 that extends into the rotor 12. The axial protrusion 28 defines an axial housing 23 that opens to the first chamber 20 and into which an oblong electromechanical actuator 24 is fitted, the actuator being axially limited by a ring 25. The first pneumatic hole 15 opens to the housing 23 and so for the first chamber 20, since the actuator 24 is gas permeable and therefore does not constitute an obstacle to its passage. The actuator 24 extends along the X axis in this embodiment and has a terminal actuator element that is movable along said X axis.

In addition, the rotor 12 defines a second chamber 30 in which the second pneumatic orifice 17 opens. The second chamber 30 is separated from the first chamber 20 by a wall 31 that has a valve 32 that passes through it along the axis of rotation X. The valve is normally closed, thus isolating the two chambers from each other. However, it can be opened by the actuator element of the actuator 14 which pushes the valve stem 32 so as to open the valve and place the two chambers 20, 30 in pneumatic communication with each other.

In order to modify the pressure in the tire, it is appropriate to place the tire in communication with the pneumatic unit. For this purpose, the actuator 24 is actuated in such a way as to open the valve 32 and place the chambers 20 and 30 in communication with each other, whose chambers are connected, respectively, in the pneumatic unit and the tire. Valve 3.2 is then left open for a period of time that is sufficient to allow the desired tire pressure to be established.

These pressure modification operations are normally performed only while the aircraft is in flight, or while the aircraft is parked on the ground. In such conditions, the ferrule seal 21 is subjected to pressure only while the wheel is not turning. This facilitates the ferrule seal 21 to be airtight. However, if a small leak occurs through the ferrule seal 21, it is sufficient that the leakage flow is well below the inflation rate to ensure that the tire is inflated despite this. In a variant, it is possible to use any other type of sealing gasket, which is compatible with the rotation, and which is capable of providing gas tightness, at least while the wheel is not turning.

The use of an electromechanical actuator makes it possible to avoid providing a second pneumatic source to control the actuator, as shown in figure 5 of document US 2 685 906. It would be difficult to arrange two tire tubes on the shaft. In addition, the actuator can be located completely inside the first chamber, as in the first modality shown in figure 4 of this document, however, still allowing the actuator to be controlled separately, and pressure to be raised by the pneumatic unit, which is not possible in the form of figure 4.

The configuration of the device of the invention also facilitates incorporating a wheel rotation sensor, since the rotor 12 is prevented from turning with the wheel. Thus, a tachometer 50 is arranged in the device of the invention, having a stationary part 51 attached to the stator i and a rotating part 52 attached to the rotor 12 and extending in register with the stationary part 51 in order to interact remotely with it by the electromagnetic medium . In a known way, the electromagnetic interaction generates an electric current in the stationary part 51 which is proportional to the rotation speed of the rotor 12 and thus of the wheel. Then, just measure the current that passes through the stationary part 51a in order to determine the speed of rotation of the wheel.

In addition, the configuration of the device of the invention also facilitates incorporating a tire pressure sensor. Thus, a pressure sensor 60 is arranged on the rotor 12 to measure the pressure that exists in the second chamber 30, and thus in the tire, since the second chamber 30 is in pneumatic connection with the tire. The pressure sensor 60 is of the radio frequency type and receives its electrical energy from an antenna 61 placed on the stator 11 in such a way as to be in a position to interact remotely through the electromagnetic medium with the pressure sensor 60, regardless of the angular position of the rotor. 12. Again, the pressure sensor 60 affects the impedance of the antenna 61 depending on the pressure in the chamber 12. Then just measure the current that passes through antenna 60 to determine the pressure in the tire, or measure any other electrical magnitude (voltage, impedance, ...) relative to antenna 60 and that varies with pressure. The pressure sensor arranged in this way replaces the sensor that is normally placed directly on the wheel rim.

The sensors incorporated in the device of the invention are thus particularly well protected from external impacts.

The stationary part 51 of the tachometer 50, the antenna 61 and the actuator 10 are all electrically connected to the aircraft by means of an electrical connector 70 which also extends from the end wall 19 of the stator 11, and by means of an electrical cable 71 which is similarly arranged along axis 4.

The invention is not limited to the description presented, but, on the contrary, it covers any variant that falls within the scope defined by the claims.

In particular, although it is shown a device with a rotor that is completely housed in the stator, it is possible, without evading the invention, to provide a rotor that protrudes a little from the stator, for example, through the second pneumatic orifice that can project from the end of the stator.