FR3049668B1 - BRAKE DISC FOR AN AIRCRAFT - Google Patents

Abstract

The invention relates to a brake (3, 3a, 3b) for an aircraft whose vibration frequency is fixed by a mass-spring system. The brake disk (3, 3a, 3b) comprises two friction faces (4, 6) and a plurality of pairs of projections (9) delimited by a groove (11). Each projecting portion (9) is of substantially parallelepipedal shape and comprises two main faces (10) parallel to the friction faces of the brake disc (3). The brake disk is remarkable in that it comprises at least one elastic device (19) comprising, for at least one pair of projecting parts (9), a pair of flexible blades (21) each disposed on a main face (10). ) a projecting portion (9) of a pair of consecutive projections (9). The brake disc according to the invention is more particularly intended to equip commercial aircraft traveling at low speeds between two airport buildings.

Description

The invention relates to a brake disk for an aircraft and more particularly for an undercarriage of an aircraft.

The document US8479892 describes a landing gear comprising a set of wheels connected by a hub to a landing gear leg and a braking system comprising an assembly of several brake disks. The brake disc assembly comprises rotating brake discs, intended to be in connection with the wheel, alternated with static brake discs, intended to be connected to the hub.

Braking is performed by exerting pressure on the assembly to generate a friction force between the rotating discs and the static discs and thus between the wheel which is rotating and the hub which is fixed.

The brake discs are mounted on the hub and on the wheel rims of the landing gear with a play. During braking, this game creates vibrations in the assembly. Under certain conditions, the vibration frequency of the assembly is identical to the resonant frequency of an avionic equipment or structural element of the aircraft and the braking of the aircraft can generate vibrations around this avionic equipment or structural element of the aircraft. More particularly, when the speed of movement of the aircraft is low, the vibration frequency of the assembly is close to the resonance frequency of the landing gear thus producing a vibration resonance phenomenon (called "Gear Walk" in terminology Anglo-Saxon) which disrupts braking efficiency.

The present invention provides a brake disc overcoming all or part of the disadvantages of the prior art. For this purpose, the object of the invention is a brake disk for an aircraft comprising two friction faces and a plurality of pairs of projecting parts. Each pair of projecting portions is delimited by a groove. Each projecting portion is of substantially parallelepipedal shape and comprising two main faces parallel to the friction faces of the brake disc. The brake disc also comprises at least one resilient device comprising, for at least one pair of projecting portions, a pair of flexible blades each disposed on a major face of a projecting portion of a pair of consecutive projections.

In an alternative embodiment of the brake disc according to the invention, each flexible blade of the brake disc according to the invention comprises a flat portion in contact with the main face and a free portion located in a groove delimiting the two projections.

Advantageously, the free portion is curved and intended in use to be in contact with a force transmission element

In a preferred embodiment, the brake disc according to the invention comprises at least one protective element disposed between at least one elastic device and at least one projecting part.

Advantageously, the brake disc according to the invention comprises a plurality of elastic devices distributed periodically on an outer periphery or on an inner periphery of the brake disc. Other characteristics, details and advantages of the invention will emerge more clearly from the detailed description given below as an indication in relation to drawings in which:

FIG. 1a is an exploded view of a brake disc assembly,

FIGS. 1b and 1c are front views of brake discs used in the assembly of FIG.

FIG. 2a is a sectional view of a brake disc according to a first embodiment of the invention,

FIG. 2b is a sectional view of a brake disk according to a second variant embodiment of the invention,

FIGS. 3a and 3b are sectional views of a brake disc according to the first and second embodiments, in use,

FIG. 4 is a sectional view of a brake disk according to one embodiment of the invention,

FIGS. 5a and 5b are sectional views of a brake disc according to an alternative embodiment of the invention, and

Figures 6a and 6b are front views of a brake disc according to an alternative embodiment of the invention.

FIG. 1a shows an assembly 1 of brake discs 3 of a braking system (not shown) of an aircraft. The assembly 1 consists of an alternation of rotating brake discs 3a (visible in FIG. 1b), connected in rotation with the wheel of the landing gear, and of static brake discs 3b (visible in FIG. , linked in rotation with a hub of a leg of the landing gear.

Each brake disc 3 has two friction faces 4, 6 parallel to each other and intended, in use, to be subjected to a friction force for braking the aircraft. Each brake disk 3 comprises a plurality of pairs of projections 9 spaced by grooves 11 configured to cooperate with a force transmission element 29 (visible in FIGS. 3a and 3b), such as a drive bar on a rim of the wheel or a torque bar present on the hub, ensuring the coupling in rotation between the disk assembly 3 and the wheel or the hub.

According to an alternative embodiment, the projecting portions 9 are located on an outer periphery of the rotating brake discs 3a.

According to an alternative embodiment, the projecting portions 9 are located on an inner periphery, defined by a central orifice, of a static brake disc 3b.

The projections 9 are located in the extension of the disc. Each projecting portion 9 has a substantially parallelepipedal shape and comprises two main faces 10 located in a plane parallel to the friction faces 4, 6 of the brake disc 3 and two contact faces 10 'perpendicular to the brake disc 3 and intended for use in be in contact with the force transmission element 29.

According to the invention, a brake disk 3 is also provided with at least one elastic device 19.

As illustrated in Figures 2a to 3b, the elastic device 19 comprises a pair of flexible blades 21 each disposed on a projecting portion 9 of a pair of protruding portions 9 consecutive. Each flexible blade 21 comprises a flat portion 23 contiguous to a main face 10 of the projecting portion 9. The flat portion 23 is extended by a free portion 25 located in the groove 11 delimiting the two projections 9.

According to a first embodiment, illustrated in Figure 2a, the two flexible blades 21 are located opposite one another.

According to a second variant embodiment, illustrated in FIG. 2b, a first flexible blade 21 is disposed on one of the friction faces 4,6, and the second is disposed on the other friction face 4,6 and so opposed to the first, with respect to a median axis of the groove 11, in order to grip the transmission element.

The fixing of the flexible blades 21 on the brake disc 3 is carried out using rivets 18.

As illustrated in FIGS. 3a and 3b, the flexible blades 21 are arranged on the brake disk 3 in order to be in use in contact with the force transmission element 29. More particularly, in the variant embodiments represented here the free portion 25 is curved and it will be noted that the point of curvature 27 is tangent to the force transmission element 29.

Thus, a brake disk 3 and an elastic device 19 are associated to create a mechanical system, mass-spring type, whose vibration modes are predictable. Knowing the properties of the brake disk 3, the number and the properties (stiffness, dimensions, geometry and material) of the flexible blades 21 are determined so that the frequency of the vibration modes of the assembly 1 equipped with the elastic device 19 is different from the frequencies of the vibration modes of the avionics systems and the structural elements of the aircraft.

Preferably, the elastic device 19 comprises flexible blades 21 having the smallest stiffness so as, in particular, not to generate residual braking.

Of course, the present invention is not limited to the embodiment described above and can be extended to any variant within its spirit.

Thus, the mechanical mass-spring type system can be achieved with an elastic device 19 configured to work in rotation, torsion or traction.

According to an embodiment illustrated in FIG. 4, the brake disc 3 may be equipped with at least one protective device 13 disposed on the protruding parts 9, between the main face 10 and the elastic device 19.

According to an alternative embodiment illustrated in FIGS. 5a and 5b, an elastic device 19 may comprise two pairs of flexible blades 21 arranged on a pair of projecting portions 9.

In general, a brake disc 3 may comprise a plurality of elastic devices 19 distributed periodically over a plurality of pairs of projecting parts 9. By way of example, FIG. 6a shows a rotating brake disc 3a comprising four devices resilient 19 spaced from each other by an angle of 90 ° and Figure 6b has a static brake disc 3b comprising four elastic devices 19 spaced from each other by an angle of 90 °.

Claims (2)

1. Brake disk (3, 3a, 3b) for an aircraft, the brake disk (3, 3a, 3b) comprising two friction faces (4, 6) and a plurality of pairs of projecting portions (9), delimited by a groove (11), each projecting part (9) being of substantially parallelepipedal shape and comprising two main faces (10) parallel to the friction faces (4, 6) of the brake disc (3, 3a, 3b), a device elastic member (19) comprising, for at least one pair of projections (9), a pair of flexible blades (21) each disposed on a main face (10) of a projecting portion (9) of a pair of projecting portions (9) consecutive, each flexible blade (21) comprises a flat portion (23) in contact with the main face (10) and a free portion (25) located in the groove (11), that the free portion (25) is curve and intended in use to be in contact with a force transmission element (29), characterized in that the brake disk comprises at least one ins a protective element (13) disposed between an elastic device (19) and a projection (9). 2. Brake disk (3, 3a, 3b) according to claim 1, characterized in that it comprises a plurality of elastic devices (19) periodically distributed on an outer periphery or on an inner periphery of the brake disk (3, 3a, 3b).