FR2813580A1 - Braking device for aircraft wheel comprises complementary friction parts rotating with wheel and wheel support which are pressed against each other by activator part - Google Patents

Abstract

The braking device (14) for an aircraft wheel (10) which rotates on a wheel support (12) comprises complementary friction parts (20,22) which rotate with the wheel and its support. An activator part (34) which presses the complementary friction parts against each other is activated by an activator (24) equipped with an electrical control motor. The activator comprises an automatic device for locking the associated activator part in position in the event of cessation of supply to the electrical motor.

Description

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The present invention relates to a braking device for an airplane wheel rotatably mounted relative to a wheel support, of the type comprising complementary friction members intended to be integral in rotation with the wheel and the wheel support, and at least an actuator equipped with an electric motor for controlling an actuating member adapted to press the complementary friction members against each other.

The wheels of the aircraft are equipped with brakes to slow the aircraft when it lands and during certain taxiing phases on the runways of the airport.

Currently, the brakes include hydraulic actuators making it possible to press the friction members associated with the wheels and the wheel supports against each other.

It is envisaged to replace the hydraulic actuators with electric actuators.

These actuators each comprise an electric motor ensuring the control of an actuating member applied to the friction members ensuring braking. To maintain a pressure force on the friction members, the electric motor should be constantly powered.

In fact, in the absence of power, the mobile elements of the actuator move under the action of the reaction which is applied to them by the compressed fiction organs. The pressure exerted by the actuator then ceases.

Thus, to maintain secure immobilization of the aircraft when it is parked, it is necessary to keep the electric motors of each of the actuators associated with the brakes of the aircraft wheels under tension.

The need to maintain such a power supply to the actuators is not satisfactory.

The object of the invention is to propose a solution to this problem.

To this end, the subject of the invention is a braking device for an airplane wheel rotatably mounted relative to a wheel support, of the aforementioned type, characterized in that at least one actuator comprises a device

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 automatic locking mechanism in position of the associated actuator, in the event of the power supply to the actuator's electric motor ceasing.

According to particular embodiments, the device comprises one or more of the following characteristics - it comprises several actuators each equipped with an electric motor for controlling an actuating member adapted to press the complementary friction members, each countered the others, and only some of the actuators, include an automatic device for locking in position the associated actuating member, in the event of the power supply to the electric motor of the actuator ceasing; - It comprises six actuators each equipped with an electric motor for controlling an actuating member adapted to press the complementary friction members against each other, and only two of the actuators include an automatic device for locking in the position of 'associated actuating member, in the event of the power supply to the electric motor of the actuator ceasing, - the actuators are distributed angularly around the axis of rotation of the wheel, and the actuators comprising an automatic device for locking in position of the associated actuating member, in the event of the power supply to the electric motor of the actuator ceasing, are regularly distributed angularly among all of the actuators; - the actuators comprising an automatic locking device in position of the associated actuating member, in the event of the power supply to the electric motor of the actuator being stopped, are diametrically opposite with respect to the axis of rotation of the wheel ; - The or each automatic device for locking in position the associated actuating member, in the event of the power supply to the electric motor of the actuator including a braking member of said actuating member, which braking member being movable between an active braking position and an inactive braking position, and it comprises elastic means for biasing said braking member towards its active braking position and means with electric return control

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 from said braking member to its inactive braking position against the action of the elastic biasing means; and - said electrically controlled means for returning said braking member to its inactive braking position comprises an electromagnet. The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the drawings, in which - Figure 1 is a cross-sectional view of an airplane wheel equipped with a braking device according to the invention; - Figure 2 is a schematic perspective view of the crown carrying the actuators of the braking device according to the invention; and - Figure 3 is a longitudinal sectional view of an actuator of the braking device according to the invention, this actuator being equipped with a lack of current brake.

In Figure 1 is shown an airplane wheel 10 rotatably mounted around a wheel support 12 constituting a rocket. The wheel 10 is equipped with a braking device 14.

The wheel 12 has a rim 16 on which a tire 18 is mounted.

As known per se, the braking device comprises complementary friction members carried by the wheel support 12 and by the rim 16.

These complementary friction members comprise a set of discs 20 integral in rotation with the rim 16. These discs are arranged so that their axis extends along the axis of rotation of the wheel. They are joined in rotation with the wheel by means of notches made on the rim 16. The discs 20 are free to move in translation along the axis of the wheel over a predefined range of movement.

In addition, the friction members also include complementary discs 22 interposed between the discs 20. The discs 22 are immobilized in rotation relative to the wheel support 12 and are movable in translation along the axis of rotation of the wheel.

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 The discs 20 and 22 are applied and pressed against each other in the direction of the axis of rotation of the wheel by a set of actuators 24 whose fixed part is integral with the wheel support 12 and whose part mobile is adapted to be applied on the end disc of the stack of discs 20 and 22. The actuators act in a direction parallel to the axis of rotation of the wheel.

The actuators 24 are arranged on a support ring 26 illustrated in FIG. 2. This ring 26 has its axis arranged along the axis of rotation of the wheel.

The actuators 24 are regularly distributed angularly around the axis of rotation of the wheel. In the embodiment illustrated in the figures, the device comprises six actuators.

Among these six actuators, two actuators each include an automatic device 28 for locking in position the actuator control member, in the event of the power supply to the electric motor of the actuator ceasing.

In FIG. 2, these two actuators are designated by the references 24A, the actuators without an automatic locking device being designated by the references 24B.

Automatic blocking devices in the actuator position, in the event of a loss of power to the electric motor, are commonly referred to as "low current brakes".

Advantageously, the actuators 24A equipped with an automatic device for locking in position, in the event of the power supply to the motor ceasing, are regularly distributed angularly around the axis of rotation of the wheel. In the case illustrated in FIG. 2, the two actuators 24A are diametrically opposite.

An actuator 24A with automatic locking device 28 is illustrated in FIG. 3.

Such an actuator comprises a casing 30 intended to be connected to the support crown 26. Inside the casing is arranged an electric motor 32 suitable for controlling an actuating member 34 mounted mobile

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 in translation and adapted to be applied on one of the friction members to ensure their pressurization against each other.

The outlet of the motor 32 is equipped with a pinion 36 engaged with one or more reduction stages 38. The exit of the reduction stages 38 ensures the rotation of a nut 40 of a screw-nut arrangement 42. The screw, denoted 44, of this arrangement is immobilized in rotation and mounted movable in translation relative to the casing 30. It is integral with the actuating member 34.

In addition, a bellows 44 is mounted between the casing 30 and the screw 44. Advantageously, the screw-nut arrangement comprises a ball screw. The automatic device 28 for locking in position the actuating member of the actuator in the event of power supply to the electric motor 32 is disposed at the end of the motor 32. It first ensures a locking in position of the motor axis and therefore a locking in position of the actuator control member.

This device 28 comprises a crown 50 secured to the rotary shaft of the engine, this crown being arranged along the axis of the engine. The crown 50 has on its surface opposite the motor winding a lining formed of a material having a high coefficient of friction.

A washer 52 is mounted movable in translation along the axis of the motor 32. The washer 52 is immobilized in rotation relative to the casing 30 in which it is slidably mounted. The washer 52 is made of a magnetic material.

A spring 54 ensures the permanent stressing of the washer 52 towards the crown 50. In addition, the automatic blocking device 28 comprises an electromagnet 56 disposed at the end along the axis of rotation of the motor 32. This electromagnet 56 is suitable for, when it is supplied, returning the washer 52 against the spring 54. The washer 52 forms a braking member and therefore blocking the crown 50.

Thus, the washer 52 is mounted slidingly movable between an active braking position pressed against the crown 50 under the action of the spring 54 when the electromagnet 56 is not energized and a position

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 active braking, away from the crown 50, when the electromagnet 56 is supplied.

The electromagnet 56 is mounted in series with the motor 32, so that, when the motor 32 is supplied, the electromagnet 56 is also supplied.

When the motor 32 is supplied, the washer 52 is released from the crown 50, thus allowing rotation of the motor 32 and thus displacement of the actuating member 34. Similarly, when the discs forming the friction members complementary to the brake are pressed against each other, the power supply to the motor 32 allows, while the washer 52 is released from the crown 50, to apply a pressure force on the actuating member 34, which force pressure is transmitted to discs 20 and 22.

On the other hand, when the motor 32 is not supplied, the washer 52 is no longer recalled by the electromagnet 56. Under the action of the spring 54, this washer is applied to the crown 50 and is put in position. taken with it. The washer being angularly fixed relative to the housing, the axis of the motor 32 is then immobilized relative to the casing 30. This immobilization of the axis of the motor 32 ensures a blocking of the actuating member 34 in the position in which it was when the power to the engine was interrupted.

The actuators 24B used in the braking device according to the invention are identical to the actuators illustrated in FIG. 3 but are devoid of the automatic blocking device 28.

The six actuators of the braking device are controlled simultaneously and in a similar manner.

Thus, to ensure braking, the actuating members 34 of the six actuators are moved to press the discs 20 and 22 against each other. A high pressure force is exerted on the discs under the action of the electric motors 32 of each actuator.

During the final stop of the aircraft in a parking area, the supply voltage of the motors 32 is interrupted. The four 24B actuators without automatic blocking device gradually release

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 ment, thus putting an end to the pressure they exerted on the discs 20 and 22. On the contrary, the actuators 24A equipped with automatic blocking devices 28 see their actuating member 34 blocked in the position it occupied before the interruption power supply to the motor 32. Thus, the discs 20 and 22 are kept pressed against each other by the two actuating members 34 blocked. Consequently, even after the power to the electric motors 32 has been cut off, the braking devices can ensure reliable immobilization of the aircraft in its parking area.

The only two actuators equipped with automatic locking devices are sufficient to keep the discs 20 and 22 under pressure. Indeed, in its parking area, the stresses aimed at moving the aircraft are low.

It is understood that only certain actuators being equipped with automatic blocking devices, the cost of the braking device is lower than that of a braking device in which each of the actuators would be equipped with such automatic blocking devices.

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Claims (7)

CLAIMS 1.- Braking device (14) for a wheel (10) of an airplane rotatably mounted with respect to a wheel support (12), of the type comprising complementary friction members (20, 22) intended to be integral in rotation of the wheel (10) and the wheel support (12), and at least one actuator (24A, 24B) equipped with an electric motor (32) for controlling an actuating member (34) suitable for pressing the complementary friction members (20, 22) against each other, characterized in that at least one actuator (24A) comprises an automatic device (28) for locking in position the associated actuating member (34 ), in the event of power supply to the electric motor (32) of the actuator (24A). 2. Braking device according to claim 1, characterized in that it comprises several actuators (24A, 24B) each equipped with an electric motor (32) for controlling an actuating member (34) adapted to press the complementary friction members (20, 22) against each other, and in that some (24A) only of the actuators comprise an automatic device (28) for locking in position the associated actuating member (34 ), in the event of power supply to the electric motor (32) of the actuator (24A). 3. Braking device according to claim 2, characterized in that it comprises six actuators (24A, 24B) each equipped with an electric motor (32) for controlling an actuating member (34) adapted for press the complementary friction members (20, 22) against each other, and in that only two (24A) of the actuators comprise an automatic device (28) for locking in position the associated actuating member ( 34), in the event of power supply to the electric motor (32) of the actuator (24A).  4. Braking device according to claim 2 or 3, characterized in that the actuators (24A, 24B) are distributed angularly around the axis of rotation of the wheel (10), and in that the actuators (24A) comprising an automatic device (28) for locking in position the associated actuating member (34), in the event of power supply to the motor <Desc / Clms Page number 9>  electric actuator (32) of the actuator (24A), are regularly distributed angularly among all of the actuators (24A, 24B). 5. Braking device according to claims 3 and 4, characterized in that the actuators (24A) comprising a device (28) automatic locking in position of the associated actuating member (34), in the event of cessation of the power supply to the electric motor (32) of the actuator (24A), are diametrically opposite with respect to the axis of rotation of the wheel (10). 6. Braking device according to any one of the preceding claims, characterized in that the or each device (28) automatic locking in position of the associated actuating member (34), in the event of cessation of the power supply to the electric motor (32) of the actuator (24A) comprises a braking member (52) of said actuating member (34), which braking member (52) is movable between an active braking position and an inactive position braking, and in that it comprises elastic means (54) for biasing said braking member (52) towards its active braking position and means (56) with electrically controlled return of said braking member (52) its inactive braking position against the action of the elastic biasing means (54). 7. Braking device according to claim 6, characterized in that said means (56) with electrically controlled return of said braking member (52) to its inactive braking position comprise an electromagnet.