FR3161661A1 - Mounting bracket for a braked aircraft wheel - Google Patents

Abstract

Aircraft braked wheel (103) comprising: a rim (104) having an inner circumference defining a space for receiving brake rotor discs (107b); at least one bar (10) fixed to the rim by means of a screw (31) for rotationally linking the brake rotor discs to the rim, the screw extending in a radial direction (Y) relative to the rim in a first hole (104.2) provided in the rim and in a second hole (12) provided in the bar; and a shim (20, 20’, 20’’) interposed between the rim and the bar and through which the screw passes, characterized in that a portion of the shim is received by fit in a first counterbore (104.3) formed at an entry of the first hole (104.2) of the rim and/or in a second counterbore formed at an exit of the second hole of the bar. FIGURE OF THE ABBREVIATION: Fig. 4B

Description

Mounting bracket for a braked aircraft wheel

The present invention relates to the field of aeronautics and, more particularly, to the braking of aircraft wheels.

BACKGROUND OF THE INVENTION

Aircraft wheels mounted on landing gear and equipped with a brake are well known. The brake generally comprises stator discs arranged alternately with rotor discs, which are driven in rotation by bars attached to the inner circumference of a wheel rim. The bars are received in peripheral slots on the rotor discs in a direction substantially parallel to an axis of rotation of the wheel. Controlled pressure applied to all the discs generates friction between the opposing discs, and thus a braking torque that slows the wheel's rotation.

With reference to the FIG. 1 Some known bars B are attached to the wheel rim and have at one end a cylindrical shank designed to fit into holes made in a rim face J, and at the opposite end a hole arranged to receive a screw V of a bolt passing through a hole in the rim J. Shims C are interposed between the bars B and the rim J to, on the one hand, position the bars B in a direction parallel to the axis of rotation of the wheel and, on the other hand, help to limit the heat flow between the discs and the rim J which can be detrimental to a tire mounted on said rim J.

As illustrated in the FIG. 1 , the C shims generally have an upper face cooperating with a lower surface of the rim J, and an inferior, substantially flat face cooperating with an upper surface of the bar B.

During braking, the friction between the stator discs and the rotor discs generates braking forces on the bars B which tend to shear the screw V fixing the bar B to the rim J. These braking forces generate a slip of the bar B on the spacer C but also a slip of the spacer C on the rim J, which causes the screw V to bend and may cause it to break.

SUBJECT OF THE INVENTION

The invention aims to provide a fixing wedge for a braked wheel bar of an aircraft, making it possible to overcome at least partially the aforementioned disadvantages.

• une jante ayant un pourtour intérieur délimitant un espace de réception de disques rotors de frein ;
• au moins une barrette fixée à la jante au moyen d’une vis pour lier en rotation les disques rotors de frein à la jante, la vis s’étendant selon une direction radiale vis-à-vis de la jante dans un premier perçage ménagé dans la jante et dans un deuxième perçage ménagé dans la barrette ; et
• une cale interposée entre la jante et la barrette et traversée par la vis.

To this end, the invention proposes a braked aircraft wheel comprising:

• a rim having an inner circumference delimiting a space for receiving brake rotor discs;
• at least one bar fixed to the rim by means of a screw to rotationally link the brake rotor discs to the rim, the screw extending radially from the rim through a first hole in the rim and a second hole in the bar; and
• a shim interposed between the rim and the bar and through which the screw passes.

According to the invention, a portion of the shim is received by fitting into a first counterbore made at an entrance of the first hole in the rim and/or into a second counterbore made at an exit of the second hole in the bar.

The shim cannot therefore slip on the rim during braking, either circumferentially or axially with respect to said rim, so that the bending of the screw is limited.

In particular, the screw is received with a fit in the wedge.

In particular, the wedge is annular in shape.

Depending on a particular characteristic, the wedge cooperates with a bottom of the first counterbore and/or with a bottom of the second counterbore.

According to another particular characteristic, the wedge includes a shoulder cooperating with an edge of the first counterbore and/or with an edge of the second counterbore.

The invention also relates to a landing gear comprising at least one such braked wheel.

The invention also relates to an aircraft comprising at least one such landing gear.

The invention will be better understood in light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying figures, among which:

FIG. 1 there FIG. 1 is a perspective view of an aircraft braked wheel bar, fitted with a prior art wedge;

FIG. 1 there FIG. 1 is a cross-sectional view of the barrette and wedge illustrated in the FIG. 1 , along a plane perpendicular to the axis of rotation of the wheel;

FIG. 2 there FIG. 2 is a side view of an aircraft including landing gear equipped with braked wheels;

FIG. 3 there FIG. 3 is an axial cross-sectional view of one of the braked wheels of the aircraft illustrated in the FIG. 2 , the rim of which is equipped with bars and shims according to a first embodiment of the invention;

FIG. 4 there FIG. 4 is a perspective view of the barrette and wedge illustrated in the FIG. 3 ;

FIG. 4 there FIG. 4 is a cross-sectional view along plane AA of the bar and wedge illustrated in the FIG. 4 ;

FIG. 5 there FIG. 5 is a view identical to the FIG. 4 illustrating a wedge according to a second embodiment of the invention;

FIG. 5 there FIG. 5 is a perspective view of an early variant of the wedge illustrated in the FIG. 5 ;

FIG. 5 there FIG. 5 is a perspective view of a second variant of the wedge illustrated in the FIG. 5 ;

FIG. 6 there FIG. 6 is a view identical to the FIG. 4 illustrating a wedge according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to Figures 2 and 3, an aircraft 100 according to the invention comprises a structure equipped with landing gear 101. Each landing gear 101 comprises a leg having one end articulated to the structure of the aircraft 100 and an opposite end carrying an axle 102 on which a wheel 103 is mounted to pivot about an axis X.

The wheel 103 comprises two half-wheels, each with an annular rim 104a, 104b connected by a disc 105a, 105b to a half-hub 106a, 106b pivotally mounted on the axle 102. An inner surface of the rim 104a extends opposite an outer surface of the hub 106a and, together with the latter, defines a space for receiving a stack of brake discs. The stack comprises stator discs 107a fixed to rotate relative to the landing gear leg and rotor discs 107b having peripheral notches for receiving bars, generally designated as 10, fixed to the inner surface of the rim 104a. The rotor discs 107b are thus driven in rotation by the rim 104a via the bars 10.

With reference to figures 4A-4B, each bar 10 comprises a body 11 extending along an axis _X11 substantially _parallel to the axis X of rotation of the wheel 103. The body 11 comprises a first end 11a, in the form of a cylindrical tail, which is received in an orifice of the rim 104a extending parallel to the axis X of rotation of the wheel 103, and a second end 11b having a bore 12 which extends in a radial direction Y with respect to the rim 104a and which is traversed by a screw 31 for fixing the bar 10 to an axial extension 104.1 of the rim 104a. The screw 31 comprises a head 31.1 bearing against an internal surface of the body 11 and, opposite, a threaded end portion 31.2 extending through a bore 104.2 formed in the rim extension 104.1 in the radial direction Y. The threaded end portion 31.2 of the screw 31 projects from an external surface of the rim extension 104.1 and receives a nut 32 bearing against the external surface of said extension 104.1 via a washer 33. The screw 31, the nut 32 and the washer 33 form a bolt 30 for fixing the bar 10 to the rim 104a.

The body 11 of the bar 10 also includes two lateral bearing surfaces 13 extending parallel to the _longitudinal axis _X11 of said body 11. The bearing surfaces 13 are designed to cooperate with riders 108 arranged in the peripheral notches of the brake rotor discs 107b. The two bearing surfaces 13 form a non-zero angle α so that, in operation, they extend radially with respect to the rim 104a.

A shim 20 is interposed between the bar 10 and the rim extension 104.1 to both maintain the bar 10 in a position substantially parallel to the X axis of rotation of the wheel 103, to form a mechanical interface between the bar 10 and the rim 104a, and to form a thermal barrier to the conduction of heat from the bar 10 to the rim 104a. All of this is well known and is mentioned only for information purposes.

According to a first embodiment of the invention, the spacer 20 is generally annular in shape and has in its center a cylindrical hole 21 which extends along the radial direction Y and which receives substantially by adjustment the screw 31 for fixing the bar 10 to the rim extension 104.1.

The shim 20 externally comprises a shoulder 22 defining an upper portion 20a and a lower portion 20b of the shim 20. The upper portion 20a comprises a free end delimiting a first bearing face 20.1, annular and flat, cooperating with an external, flat surface of the body 11 of the bar 10. The lower portion 20b comprises an external perimeter received for fitting in a counterbore 104.3 provided at an entrance of the bore 104.2 of the rim extension 104.1, and has a free end delimiting a second bearing face 20.2, annular and flat, cooperating with a bottom of the counterbore 104.3.

It is understood that the outer perimeter of the upper portion 20b of the wedge 20 cooperates with a lateral face of the counterbore 104.3, which prevents any movement of the wedge 20 in a plane perpendicular to the radial direction Y.

It is also understood that the upper portion 20b of the wedge 20 has a height greater than the height of the counterbore 104.3, so that the clamping forces of the bolt 30 pass through the bottom of the counterbore 104.3.

It should be noted that the lower portion 20a and the upper portion 20b of the wedge 20 include respectively a first recess 23.1 and a second recess 23.2 into which the hole 21 for the passage of the screw 31 opens in order to limit the weight of the wedge 20.

It should also be noted that the annular shape of shim 20 allows it to be manufactured entirely by turning. Its manufacturing cost is thus controlled and limited compared to a shim from the prior art manufactured by milling. This annular shape, known as a shape of revolution, also eliminates the need for positioning the shim 20 with a keying mechanism, resulting in time savings during assembly.

During the braking of the wheel 103, the riders 108 arranged in the peripheral notches of the rotor discs 107b exert on the bars 10 braking forces substantially perpendicular to the radial direction Y tending to shear the screw 31 of fixing the bar 10 to the rim 104a.

By receiving the screw 31 in the hole 21, the shim 20 absorbs the shear forces to which the screw 31 is subjected and transmits them to the rim extension 104.1 via the side wall of the counterbore 104.3, while remaining stationary relative to the rim extension 104.1. The bending of the screw 31 is thus limited, allowing its shear strength to be utilized and preventing its breakage during braking of the wheel 103.

There FIG. 5 illustrates a shim 20' according to a second embodiment of the invention. Similar to the shim 20, the shim 20' externally comprises a shoulder 22' defining a lower portion 20a' and an upper portion 20b' of the shim 20'. The shim 20' differs from the shim 20 in that the height of the upper portion 20b' of the shim 20' is less than the height of the counterbore 104.3 and in that the shoulder 22' forms a bearing surface cooperating with an inner surface of the rim extension 104.1 which extends around the counterbore 104.3. We understand that the 20' wedge is no longer supported against the bottom of the counterbore 104.3 but against an edge of the counterbore 104.3: the tightening forces of the bolt 30 pass through the said edge of the counterbore 104.3 and not the said bottom of the counterbore 104.3.

It should be noted that the shoulder 22’ of the shim 20’ has a greater height than that of the shoulder 22 of the shim 20 so that the bearing surface formed by said shoulder 22’ cooperates sufficiently with the inner surface of the rim extension 104.1 to properly transmit the tightening forces of the bolt 30.

The spacer 20', like spacer 20, absorbs the shear forces to which the screw 31 is subjected and transmits them to the rim extension 104.1 via the lateral wall of the counterbore 104.3, while remaining stationary relative to the rim extension 104.1. The bending of the screw 31 is thus limited, allowing its shear strength to be utilized and preventing its breakage during braking of the wheel 103.

Figures 5B and 5C each illustrate a variant of the 20' wedge shown in the FIG. 5 .

The 20' wedge illustrated in Figure 5B differs from the one illustrated in the FIG. 5 in that it includes a flat 24' machined at the level of the first bearing face 20.1' with the body 11 of the bar 10.

The 20' wedge illustrated in Figure 5C differs from the one illustrated in the FIG. 5 in that it comprises two bevels 25' extending symmetrically on either side of the first bearing face 20.1 with the body 11 of the bar 10.

The flat 24’ and the bevels 25’ are arranged to allow the shim 20’ to be mounted, respectively in one direction and in two directions, between the rim extension 104.1 and the bar 10 in the presence of keying reliefs 14 extending outward from the outer surface of the body 11 of the bar 10 for prior art shims (figures 1A, 4A).

There FIG. 6 illustrates a 20'' spacer according to a third embodiment of the invention. The 20'' spacer differs from the 20'' spacer in that it is devoid of an external shoulder 22 and has a median plane of symmetry orthogonal to the radial direction Y, so that the 20'' spacer can be mounted between the rim extension 104.1 and the bar 10 indifferently in either direction.

The 20" spacer, like the 20" spacer, absorbs the shear forces to which the screw 31 is subjected and transmits them to the rim extension 104.1 via the side wall of the counterbore 104.3, while remaining stationary relative to the rim extension 104.1. The bending of the screw 31 is thus limited, allowing its shear strength to be utilized and preventing its failure during braking of the wheel 103.

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 the upper portion 20b, 20b’ of the shim 20, 20’ is here received by fit in the counterbore 104.3 made at the entrance of the bore 104.2 of the rim 104a, its lower portion 20a, 20a’ can also be received by fit in a counterbore made at an exit of the bore 12 of the bar 10.

Although the shim here is annular in shape, it can adopt any other shape (oval, square, rectangular, triangular…) which, combined with an appropriate counterbore shape in the rim extension 104.1, prevents any slippage of the shim 20, 20’, 20’’ on the inner surface of the rim 104a during braking.

Although the bar 10 is here fixed to the rim extension 104.1 by bolting using the bolt 30, it can also be fixed by screwing using a screw received in a threaded hole of the rim extension 104.1.

Although the bearing faces 13 of the bar 10 here form a non-zero angle α, they can also be parallel.

Claims (7)

Aircraft braked wheel (103) comprising:
- a rim (104a) having an inner perimeter defining a space for receiving brake rotor discs (107b);
- at least one bar (10) fixed to the rim by means of a screw (31) to rotationally link the brake rotor discs to the rim, the screw extending in a radial direction (Y) vis-à-vis the rim in a first hole (104.2) provided in the rim and in a second hole (12) provided in the bar; and
- a spacer (20, 20', 20'') placed between the rim and the bar and through which the screw passes,
characterized in that a portion of the shim is received by adjustment in a first counterbore (104.3) made at an entry of the first hole (104.2) of the rim and/or in a second counterbore made at an exit of the second hole of the bar. Wheel (103) braked according to claim 1, in which the screw (31) is received to fit in the shim (20, 20’, 20’’). Wheel (103) braked according to any one of the preceding claims, wherein the wedge (20, 20’, 20’’) is annular in shape. Wheel (103) braked according to any one of the preceding claims, wherein the wedge (20, 20’’) cooperates with a bottom of the first counterbore (104.3) and/or with a bottom of the second counterbore. Wheel (103) braked according to any one of claims 1 to 3, wherein the wedge (20’) includes a shoulder (22’) cooperating with an edge of the first counterbore (104.3) and/or with an edge of the second counterbore. Landing gear (101) comprising at least one wheel (103) braked according to any one of the preceding claims. Aircraft (100) comprising at least one landing gear (101) according to claim 6.