WO2022219189A1

WO2022219189A1 - Wheel support arm

Info

Publication number: WO2022219189A1
Application number: PCT/EP2022/060182
Authority: WO
Inventors: Alexandre DAULNY; Paul ROBIN; Sébastien Messe; Graeme Klim
Original assignee: Safran Landing Systems
Priority date: 2021-04-16
Filing date: 2022-04-15
Publication date: 2022-10-20
Also published as: FR3121912A1

Abstract

The invention relates to an arm (10) comprising a first end (11) provided with a first bore (12) extending along a first articulation axis (012), and also comprising a second end (13) provided with a first shaft (14) extending along a second articulation axis (014) substantially parallel to the first articulation axis (012), wherein the first bore (12) and the first shaft (14) are connected by a first web (30) and a second web (31) which are separate and extend on either side of a first plane (P1) containing the first axis (012) and the second axis (014). The invention also relates to a landing gear comprising such an arm.

Description

WHEEL SUPPORT ARM

The present invention relates to the field of wheel support arms and more particularly to non-motorized wheel support arms, in particular for landing gear.

BACKGROUND OF THE INVENTION

It is known to produce a wheel support arm using a connecting rod, the first and second ends of which are respectively provided with a first bore and a second bore extending along a first axis of articulation and a second axis of articulation parallel to each other

The first bore generally accommodates bearings for mounting a first shaft integral with a vehicle frame—here an aircraft. The second bore receives a second axle shaft known as a "stub axle" usually mounted in two adjustment bearings. A device for blocking the rotation of the second shaft, such as for example a pin engaged in a radial bore of the second shaft or a stop plate cooperating with a groove of the second shaft, makes it possible to block the rotation of the second shaft relative to the connecting rod. Pin or wafer position securing devices are also provided. The connecting rod body is conventionally made of a thick tube of large diameter.

Such a wheel support arm requires the assembly and manufacture of a large number of mechanical parts whose adjustments must be precise. Each part, and the corresponding assembly, must be calculated, checked and verified. Finally, each mechanical part of the wheel support arm must be checked during maintenance operations. The multiplicity of parts and assembly operations impacts the reliability and the cost of production of such wheel support arms. Finally, maintenance times (checking the adjustment parts and the correct tightening of the various devices) and the stocks of spare parts are costly items on these critical parts.

OBJECT OF THE INVENTION

The object of the invention is in particular to reduce the cost of manufacturing and operating a wheel support arm.

SUMMARY OF THE INVENTION For this purpose, an arm is provided comprising a first end provided with a first bore extending along a first hinge axis. The arm also comprises a second end provided with a first shaft extending along a second axis of articulation substantially parallel to the first axis of articulation. According to the invention, the first bore and the first shaft are connected by a first veil and a second separate veil extending on either side of a first plane containing the first axis and the second axis. This gives an arm that is lighter than the arms of the prior art and which, using less material, is more economical to produce.

The dimensioning of the sails, and thus the weight of the wheel support arm, is further improved when the first and the second sail are connected by a brace.

Within the meaning of the present application, a bracon is a reinforcement structure which connects the first veil and the second veil at points distinct from their ends.

The weight of the wheel support arm is further optimized when the brace and/or the first sail and/or the second sail are perforated.

Advantageously, the first distance measured in a second plane orthogonal to the first axis and which separates a neutral fiber of the brace from the first axis is between one third and two thirds of the distance which separates the first axis of articulation from the second axis of articulation and/or the second distance measured in the second plane and which separates the neutral fiber of the bracon from the second axis is between one third and two thirds of the distance which separates the first axis of articulation from the second axis of articulation. Advantageously, the first veil has a first radius of curvature comprised between one third and two thirds of the distance which separates the first axis of articulation from the second axis of articulation.

This makes it possible to have an arm having interesting mechanical performance while having a relatively simple and light structure.

According to a first embodiment of the second veil, the second veil is rectilinear.

According to a second embodiment of the second web, the second web has a second radius of curvature of between one third and two thirds of the distance which separates the first axis of articulation from the second axis of articulation.

The weight of such a support arm is reduced when the first shaft is hollow.

The thermal stresses undergone by the arm and induced by the braking energy are reduced when the first shaft comprises a channel having an inlet port and an outlet port intended to be connected to a circulation circuit of a heat transfer medium. The performance and service life of the arm and rolling elements are thus improved.

The cooling of the part is particularly effective when the channel extends in a helix around the second axis of articulation. Advantageously, the arm incorporating the first shaft is in one piece.

A wheel support arm is thus obtained consisting of a single piece, which reduces the assemblies and the risk of their failure. The management of the traceability of materials and supplies is simplified. The volume of labor to produce such an arm is also reduced. Finally, the maintenance operations of the arm according to the invention are reduced to checking the integrity of a single part. The combination of these factors results in a wheel support arm which is more economical to operate than known wheel supports.

Within the meaning of the present application, an arm is monobloc when it consists of a single continuous piece. Thus, a shaft attached to the shaft by being fitted into a bore of the shaft does not constitute a monobloc piece of this request.

The invention also relates to a landing gear comprising an arm as described above.

Other characteristics and advantages of the invention will become apparent on reading the following description of a particular and non-limiting embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Reference will be made to the attached drawings, among which: [Fig. 1] Figure 1 is a schematic perspective view from a first angle of the wheel support arm according to the invention;

[Fig. 2] Figure 2 is a schematic perspective view from a second angle of the support arm of Figure 1;

[Fig. 3] Figure 3 is a schematic perspective sectional view of the support arm of Figure 1;

[Fig. 4] Figure 4 is a partial schematic sectional view of the support arm of Figure 1; [Fig. 5] Figure 5 is a schematic sectional view along a second plane P2 of the support arm of Figure 1.

DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. 1, the aircraft landing gear of the invention, generally designated 1, comprises a wheel support arm 10 . The first end 11 of the arm 10 is pivotally connected to a yoke 80 secured to an aircraft 81 using a shaft 82

(shown in dotted lines) engaged in a first bore

12 formed in the first end 11. The second end 13 of the arm 10 comprises a first shaft 14 on which is rotatably mounted a wheel 90. In a particular embodiment, the yoke 80 is integral with a first end of a undercarriage leg having a second end connected to an aircraft structure, for example by a joint allowing the undercarriage leg to be moved between a retracted position in a hold of the aircraft and a position extended from the hold of the aircraft .

Referring to Figures 1 to 3, the first bore 12 is made in a first substantially cylindrical portion 15 of the arm 10 and extends along a first axis of articulation O12. The first shaft 14 extends projecting of a second cylindrical portion 16 of the arm 10 and along a second hinge axis O14 substantially parallel to the first axis O12.

As visible in Figures 1, 2 and 4, a second axial bore 17 extends in the first shaft 14 along the second axis of articulation O14 and also passes through the second portion 16.

The first shaft 14 also includes a channel 18 which extends helically around the second bore 17. The channel 18 has an inlet port 19 and an outlet port 20. The channel 18 here has a rectangular cross-section of which the most large width extends parallel to the second axis of articulation O14. The inlet port 19 opens onto a first face 21 of the second portion 16 opposite the second face 22 of the second portion 16 from which the first shaft 14 projects. The inlet port 19 is connected to a first end of a water circulation circuit, not shown. The outlet port 20 opens onto the distal end 23 of the shaft 14 and is connected to a second end of the water circulation circuit. The channel 18 is formed directly in the material of the shaft 14.

The first portion 15 and the second portion 16 are connected by a first veil 30 and a second veil 31 which are distinct and which extend on either side of a first plane P1 containing the first hinge pin O12 and the second hinge pin O14. The first web 30 and the second web 31 are each formed by a first flat beam and a second flat beam which each have two main faces substantially parallel to each other: one of the main faces of the first beam plate extending opposite one of the main faces of the second beam. The first web 30 has a first radius of curvature Rc30 equal to one hundred and seventy-four millimeters and the second web 31 has a second radius of curvature Rc31 equal to three thousand millimeters. The main face of the first veil 30 extending opposite the second veil 31 is therefore concave and the main face of the second veil 31 extending opposite the first veil 30 is here also concave but much more slightly given the fact that the radius of curvature Rc31 is much larger than the radius of curvature Rc30. It will be noted that the first web 30 is provided, in the immediate vicinity of the second portion 16, with a yoke making it possible to articulate a first end of a suspension damper cylinder having a second end articulated to the undercarriage strut. This screed is in one piece with the veil 30 and the portion 16.

A brace 32 connects the first web 30 and the second web 31. The first distance d12-32 measured in a second plane P2 orthogonal to the first axis and which separates the neutral fiber 33 of the brace 32 from the first axis of articulation O12 is, here , equal to one hundred and forty millimetres. The second distance d14-32 measured in the second plane P2 and which separates the neutral fiber 33 from the second axis of articulation O14 is equal to seventy millimeters. Bracon 32 is a reinforcing element extending diagonally relative to sails 30, 31.

As visible in FIG. 3, the first section S30 of the first web 30 considered along a third plane P3 orthogonal to the first plane P1 and parallel to the first hinge axis O12 is substantially rectangular. The second section S31 of the second web 31 considered along the third plane P3 is rectangular just like the third section S32 of the brace 32 considered along the third plane P3 which is also substantially rectangular.

The first veil 30, the second veil 31 and the brace 32 are perforated. More precisely, the first veil 30 and the second veil 31 are each provided with two identical openings, of triangular or teardrop shape, arranged symmetrically along the longitudinal axis of each veil: the top of each opening is oriented towards the first end 11. The brace 32 is connected to the second web 31 between the two openings and to the first web 30 between the second end 13 and the adjacent opening. Bracon 32 is itself provided with an opening. The main interest of the openings is to lighten the structure of the arm.

A yoke extends projecting from the first web 31, in the vicinity of the second end 13 and opposite the second web 31 to allow the articulation of a connecting rod. The brace 32 is connected to the first veil 30, directly above the end of the yoke located on the side of the openings made in the first veil 30.

The arm 10 is here made of titanium by additive manufacturing so as to constitute a one-piece assembly.

Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims. Especially :

- although here the first portion and the second portion of the arm are of substantially cylindrical shape, the invention also applies to other shapes of first and second portions such as for example a square, triangular or any section; - Although here the first channel is connected to a water circulation circuit, the invention also applies to other types of heat transfer medium such as glycol water, freon;

- although here the arm is produced by additive manufacturing to obtain a one-piece titanium assembly, the invention also applies to other manufacturing processes making it possible to obtain a one-piece assembly such as for example molding, forging, welding or machining. The invention also applies to materials other than titanium such as, for example, stainless steel, bronze or aluminum;

- The openings may have a shape other than those described;

- Only one of the first web 30 and the second web 31 can be formed by a flat beam having two main faces substantially parallel to each other;

- The first shaft 14 can be attached to the second end 13 of the arm 10 or be integral with it; - The brace 32 can extend perpendicular to one or the other of the sails 30, 31, or to both;

- the brace, or any reinforcing element between the sails 30, 31, is optional;

- although here the wheel support arm has been described in connection with an aircraft, the invention also applies to other types of vehicles such as for example a vehicle land, in particular rail;

- although here the first radius of curvature is equal to one hundred and seventy-four millimeters, the invention also applies to other values of the first radius of curvature and preferably a value between one third and two thirds of the distance which separates the first axis of articulation from the second axis of articulation;

- although here the second radius of curvature is equal to three thousand millimeters, the invention also applies to other values of the second radius of curvature and preferably a value between one third and two thirds of the distance which separates the first axis of articulation of the second axis of articulation;

- Only one of the sails, for example the first sail, can be curved and the other, for example the second sail, can be straight;

- although here the first distance measured in a second plane orthogonal to the first axis and which separates the neutral fiber of the brace from the first axis of articulation is equal to one hundred and forty millimeters, the invention also applies to other values the first distance and preferably a value between one third and two thirds of the distance which separates the first axis of articulation from the second axis of articulation; - although here the second distance measured in a second plane orthogonal to the first axis and which separates the neutral fiber of the brace from the second axis of articulation is equal to seventy millimeters, the invention also applies to other values of the second distance and preferably a value between one third and two thirds of the distance which separates the first axis of articulation of the second axis of articulation.

Claims

1. Arm (10) comprising a first end (11) provided with a first bore (12) extending along a first hinge axis (O12), the arm (10) also comprising a second end (13) provided of a first shaft (14) extending along a second hinge axis (O14) substantially parallel to the first hinge axis (O12), characterized in that the first bore (12) and the first shaft (14) are connected by a first distinct veil (30) and a second veil (31) extending on either side of a first plane (PI) containing the first axis (O12) and the second axis (O14) and that the first veil (30) has a first radius of curvature (Rc30) comprised between one third and two thirds of the distance which separates the first axis of articulation (O12) from the second axis of articulation (O14).

2. Arm (10) according to claim 1, wherein the first web (30) and the second web (31) are connected by a brace (32).

3. Arm (10) according to claim 2, in which a first distance (d12-32) measured in a second plane (P2) orthogonal to the first axis (O12) and which separates a neutral fiber (33) from the bracon (32) of the first axis (O12) is between one third and two thirds of the distance which separates the first axis of articulation (O12) from the second axis of articulation (O14) and/or in which the second distance (dl4-32) measured in the second plane (P2) and which separates the neutral fiber (33) of the brace (32) from the second axis (O14) is between one third and two thirds of the distance which separates the first axis of articulation (O12) from the second axis of articulation (O14).

4. Arm (10) according to claim 2 or 3, wherein the brace (32) is perforated.

5. Arm (10) according to any one of the preceding claims, wherein the first web (30) and / or the second web (31) is perforated.

6. Arm (10) according to any one of the preceding claims, wherein the second web (31) is rectilinear.

7. Arm (10) according to any one of the claims

1 to 5, in which the second web (31) has a second radius of curvature (Rc31) comprised between one third and two thirds of the distance which separates the first axis of articulation (O12) from the second axis of articulation (O14 ).

8. Arm (10) according to any one of the preceding claims, in which the first shaft (14) is hollow.

9. Arm (10) according to any one of the preceding claims, in which the first shaft (14) comprises a channel (18) having an input port (19) and an output port (20) intended to be connected to a heat transfer medium circulation circuit.

10. Arm (10) according to any one of the preceding claims, wherein the arm (10) incorporating the first shaft (14) is in one piece.

11. Arm (10) according to any one of the preceding claims, wherein the first web (30) and / or the second web 31 are formed by a flat beam having two main faces substantially parallel to each other.

12. Landing gear (1) comprising an arm (10) according to any one of the preceding claims.