Wedge for fixing a bar for a braked aircraft wheel

Abstract

The invention relates to a braked aircraft wheel (103) comprising: - a rim (104) having an inner periphery delimiting a space for receiving brake rotor discs (107b); - at least one bar (10) attached to the rim by means of a screw (31) for rotatably connecting the brake rotor discs to the rim, the screw extending in a radial direction (Y) with respect to the rim in a first bore (104.2) provided in the rim and in a second bore (12) provided in the bar; and - a wedge (20, 20', 20'') interposed between the rim and the bar and traversed by the screw, characterized in that a portion of the wedge is received with a fit in a first counterbore (104.3) provided at an inlet of the first bore (104.2) of the rim and / or in a second counterbore provided at an outlet of the second bore of the bar.

Description

[0001]Description Title of the invention: Mounting bracket for a brake bar on an 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 known. The brake generally comprises stator discs arranged alternately with rotor discs, which are driven in rotation by brake bars attached to the inner circumference of a wheel rim. The brake bars are received in peripheral notches on the rotor discs in a direction substantially parallel to an axis of rotation of said wheel. Controlled pressure on all the discs generates friction between the opposing discs and thus a braking torque that slows the rotation of the wheel.Referring to Figure 1A, certain known spacers B are attached to the wheel rim and have, at one end, a cylindrical shank designed to fit into holes in a rim face J, and at the opposite end, a hole designed to receive a screw V of a bolt passing through a hole in the rim J. Shims C are interposed between the spacers B and the rim J to, firstly, position the spacers B parallel to the axis of rotation of the wheel and, secondly, 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 Figure 1B, the shims C generally have an upper face cooperating with a lower surface of the rim J, and a substantially flat lower face cooperating with an upper surface of the spacer B.During braking, friction between the stator and rotor discs generates braking forces on the brake shims B, tending to shear the screw V that secures the shim B to the rim J. These braking forces cause the shim B to slip on the spacer C, and also cause the spacer C to slip on the rim J, resulting in bending of the screw V which can lead to its breakage. OBJECT OF THE INVENTION The invention aims to provide a spacer for securing a brake shim for an aircraft braked wheel, thereby at least partially overcoming the aforementioned drawbacks.SUMMARY OF THE INVENTION To this end, the invention proposes an aircraft braked 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 link the brake rotor discs to the rim in rotation, the screw extending in a radial direction vis-à-vis the rim in a first bore formed in the rim and in a second bore formed in the bar; and ^ a shim, of annular shape, interposed between the rim and the bar and through which the screw passes, a portion of the shim being received by fit in a first counterbore formed at an entrance of the first bore of the rim and / or in a second counterbore formed at an exit of the second bore of 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 by a fit in the wedge. According to a particular feature, the wedge cooperates with a bottom of the first counterbore and / or with a bottom of the second counterbore. According to another particular feature, 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. BRIEF DESCRIPTION OF THE DRAWINGS 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. 1A] Figure 1A is a perspective view of an aircraft braked wheel bar, equipped with a prior art wedge; [Fig.[Fig. 1B] Figure 1B is a cross-sectional view of the bar and shim illustrated in Figure 1A, along a plane perpendicular to the axis of rotation of the wheel; [Fig. 2] Figure 2 is a side view of an aircraft comprising landing gear equipped with braked wheels; [Fig. 3] Figure 3 is an axial cross-sectional view of one of the braked wheels of the aircraft illustrated in Figure 2, the rim of which is equipped with bars and shims according to a first embodiment of the invention; [Fig. 4A] Figure 4A is a perspective view of the bar and shim illustrated in Figure 3; [Fig. 4B] Figure 4B is a cross-sectional view along plane AA of the bar and shim illustrated in Figure 4A; [Fig. [5A] Figure 5A is a view identical to Figure 4A, illustrating a wedge according to a second embodiment of the invention; [Fig. 5B] Figure 5B is a perspective view of a first variant of the wedge illustrated in Figure 5A; [Fig.[5C] Figure 5C is a perspective view of a second variant of the wedge illustrated in Figure 5A; [Fig. 6] Figure 6 is a view identical to Figure 4A, 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 provided 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 having an annular rim 104a, 104b connected by a flange 105a, 105b to a half-hub 106a, 106b received to pivot 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 in rotation relative to the landing gear leg and rotor discs 107b having peripheral notches that receive 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. Referring 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 includes 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 vis-à-vis the rim 104a and which is crossed 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, form a mechanical interface between the bar 10 and the rim 104a, and form a thermal barrier to heat conduction from the bar 10 to the rim 104a. All of this is well known and is mentioned only for informational 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 rim received for fitting in a counterbore 104.3 formed 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 edge of the upper portion 20b of the shim 20 cooperates with a lateral face of the counterbore 104.3, which prevents any movement of the shim 20 in a plane perpendicular to the radial direction Y. It is also understood that the upper portion 20b of the shim 20 has a height greater than the height of the counterbore 104.3, so that the clamping forces of the bolt 30 are transmitted through the bottom of the counterbore 104.3. It should be noted that the lower portion 20a and the upper portion 20b of the shim 20 each include a first recess 23.1 and a second recess 23.2, respectively, into which the hole 21 for the screw 31 opens, in order to limit the weight of the shim 20. It should also be noted that the annular shape of the shim 20 allows it to be manufactured entirely by turning. Its manufacturing cost is therefore controlled and limited compared to a shim from the prior art manufactured by milling.This annular shape, known as a revolution shape, also eliminates the need for orienting the shim 20, resulting in time savings during assembly. When the wheel 103 is braked, the clips 108, arranged in the peripheral notches of the rotor discs 107b, exert braking forces on the bars 10 that are substantially perpendicular to the radial direction Y, tending to shear the screw 31 that secures the bar 10 to the rim 104a. Upon 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 lateral wall of the counterbore 104.3, while remaining stationary relative to the rim extension 104.1. The bending of the screw 31 is then limited, which makes it possible to exploit the shear strength capabilities of the screw 31 and to avoid any breakage of said screw 31 during the braking of the wheel 103.Figure 5A 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 that 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 correctly transmit the tightening forces of the bolt 30. The shim 20', like the shim 20, takes up the shear forces to which said screw 31 is subjected and transmits them to the rim extension 104.1 via the lateral wall of the counterbore 104.3 while remaining immobile with respect to said rim extension 104.1. The bending of the screw 31 is then limited, which makes it possible to exploit the shear strength capabilities of the screw 31 and to avoid any breakage of said screw 31 during the braking of the wheel 103. Figures 5B and 5C each illustrate a variant of the wedge 20' illustrated in figure 5A.The shim 20' shown in Figure 5B differs from that shown in Figure 5A in that it includes a flat 24' machined at the first bearing surface 20.1' with the body 11 of the bar 10. The shim 20' shown in Figure 5C differs from that shown in Figure 5A in that it includes two bevels 25' extending symmetrically on either side of the first bearing surface 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 locating protrusions 14 extending from the outer surface. of the body 11 of the bar 10 for prior art shims (figures 1A, 4A). Figure 6 illustrates a 20'' shim according to a third embodiment of the invention.The 20" spacer differs from the 20" spacer in that it lacks 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 in either direction. Like the 20" spacer, 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 then limited, which makes it possible to exploit the shear strength capabilities of the screw 31 and to prevent any breakage of said screw 31 during the 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 hole 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 hole 12 of the bar 10. Although the shim is here 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 with the bolt 30, it can also be fixed by screwing with a screw received in a threaded hole in 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

CLAIMS 1. Aircraft braked wheel (103) comprising: - a rim (104a) 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) to link the brake rotor discs to the rim in rotation, the screw extending in a radial direction (Y) vis-à-vis the rim in a first bore (104.2) provided in the rim and in a second bore (12) provided in the bar; and - a spacer (20, 20', 20''), of annular shape, interposed between the rim and the bar and through which the screw passes, a portion of the spacer being received by fit in a first counterbore (104.3) formed at an entrance 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.

2. Wheel (103) braked according to claim 1, in which the screw (31) is received by fit in the spacer (20, 20', 20''). 3.A wheel (103) braked according to claim 1, wherein the wedge (20, 20'') cooperates with a bottom of the first counterbore (104.3) and / or with a bottom of the second counterbore.

4. A wheel (103) braked according to any one of claims 1 to 2, wherein the wedge (20') comprises a shoulder (22') cooperating with an edge of the first counterbore (104.3) and / or with an edge of the second counterbore.

5. Landing gear (101) comprising at least one wheel (103) braked according to any one of the preceding claims.

6. Aircraft (100) comprising at least one landing gear (101) according to claim 5.

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