Concentric assembly of parts using radial keys

Abstract

An assembly comprising at least one first part (1) and a second part (11) concentric and extending about a common axis (X). At least the first part (1) comprises first radial holes (1.1) having two through ends, and the second part (11) comprises second radial holes (11.1), each second radial hole (11.1) extending in line with one of the first radial holes (1.1) and having one through end opposite one of the through ends of said first radial hole (1.1) to form a pair of aligned holes. A key (2) extends through each pair of aligned holes to bind the concentric parts (1, 11) to each other in rotation and translation about the common axis. (Figure from the summary: Fig. 4)

Description

Title of the invention: Assembly of concentric parts by radial keys

[0001] The present invention relates to the field of mechanical assemblies and more precisely to assemblies of at least two concentric elements.

[0002] BACKGROUND OF THE INVENTION

[0003] It is known to have parts comprising concentric parts such as a hub part surrounded by a disc part. These parts are for example produced by machining, casting, forging or a combination of these manufacturing methods. In such parts, both parts are made of the same material.

[0004] Assemblies of concentric parts are also known which are assembled to each other by welding, or gluing... for a non-dismountable assembly; or by screwing, bolting, or clamping... for a removable assembly. The removable assemblies obtained are often relatively bulky and heavy, or require the production of complex geometric shapes. This is even more true in the presence of more than two concentric parts, or with relatively thin parts (for example flat parts such as discs), or having to fit into a restricted volume, or being subjected to torques, or subjected to temperature variations which can lead to differential thermal expansions.

[0005] SUBJECT OF THE INVENTION

[0006] The invention aims in particular to remedy at least in part the aforementioned drawbacks. Summary of the invention

[0007] To this end, according to the invention, an assembly is provided comprising at least a first part and a second concentric part extending around a common axis. According to the invention, at least the first part comprises first radial bores having two emerging ends and the second part comprises second radial bores, each second radial bore extending in the extension of one of the first radial bores and having one emerging end opposite one of the emerging ends of said first radial bore to form a pair of aligned bores, and in that a key extends in each pair of aligned bores to connect the concentric parts to each other in rotation and in translation along the common axis.

[0008] Thus, the keys serve to connect the concentric parts to each other in rotation and in translation along the common axis. The keys therefore ensure the transmission of torque from one part to another. The keys can also be accommodated within the thickness of the parts and therefore do not take up space outside the parts. The keys can be sized to allow clearance adapted to the application in question and differential expansion. The different parts of the assembly can be made of different materials and thus perform different functions and / or be subject to different stresses.

[0009] According to additional characteristics, considered independently of each other or all or part in combination: - each second radial bore has one end opening opposite the first radial bore of the pair of aligned bores; - the assembly comprises an element for immobilizing each key in a radial direction of the concentric parts; - the immobilizing element of each key preferably then extends in an axial direction and passes through a part of one of the concentric parts to be in contact with the key; - the immobilizing element of each key is for example a screw; - the screw also passes through the key and has a screwed-in free end section in the said room; - the concentric parts are made of different materials; - one of the concentric parts is a brake disc; - one of the concentric parts is a flywheel.

[0010] The invention also relates to an aircraft comprising such an assembly.

[0011] The invention allows for simple, effective and compact fixing of concentric parts. The assembly produced uses a reduced number of elements. The parts of the assembly cannot rotate around each other and disengage from each other. The assembly according to the invention also makes it possible to take into account the behavior of different materials, particularly under the effect of temperature (thermal expansion).

[0012] Other characteristics and advantages of the invention will emerge from reading the following description of a particular and non-limiting embodiment of the invention. Brief description of the drawings

[0013] Reference will be made to the accompanying drawings, among which:

[0014] [Fig-1] [Fig.l] is a partial schematic front view of an aircraft comprising wheels equipped with a magnetic braking device comprising an assembly according to the invention;

[0015] [Fig.2] [Fig.2] is a partial schematic view of one of these wheels, in half- axial section;

[0016] [Fig.3] [Fig.3] is a perspective view of the assembly according to the invention;

[0017] [Fig.4] [Fig.4] is an exploded perspective view of this assembly. DETAILED DESCRIPTION OF THE INVENTION

[0018] With reference to Figures 1 and 2, the assembly according to the invention is described in application to a braking system carried by an aircraft 100 comprising landing gear 101. Each landing gear 101 comprises a leg having one end provided with two coaxial shafts 102 on each of which a wheel 103 is mounted to pivot, each shaft 102 having a central axis defining an axis X of rotation of the wheel 103 which it carries. Each wheel 103 comprises, in a manner known per se, a hub 104 mounted to pivot on the shaft 102 and a rim 105 connected to the hub 104 by a web 106. The rim 105 and the hub 104 define between them an annular space 107 having one end closed by the web 106 and one end open towards the outside of the wheel 103 forming an entrance to the annular space 107. The rim 105 is surrounded by a tire, not shown, received between two lips of the rim 105.

[0019] According to the invention, the wheels 103 are equipped with a magnetic braking device generally designated 200, which here extends to the entrance of the annular space 107.

[0020] The magnetic braking device 200 comprises a fixed element, or stator 201, and a mobile element, or rotor 202.

[0021] More precisely here, the stator 201 and the rotor 202 have a disc shape and are coaxial with the wheel 103 and the shaft 102.

[0022] More precisely, the stator 201 preferably comprises an internal part and an external part in the form of two concentric rings of different widths (measured in a radial direction of the rings).

[0023] The internal part is arranged and mounted on a torque tube 108 to slide parallel to the X axis and to be connected to the torque tube 108 in rotation about the X axis (for example by the cooperation of grooves / ribs). The torque tube 108 is fixed to an external collar 102' of the shaft 102 connecting in rotation the torque tube 108 to the shaft 102 or to the leg of the landing gear 101 and carrying actuators 109 here hydraulic or electric.

[0024] The external part is a non-magnetic support provided with a plurality of magnets having free faces opening onto a main face of the stator 201 opposite a main face of the rotor 202 and generating magnetic fields to produce a magnetic flux in the direction of said rotor 202, that is to say an axial magnetic flux parallel to the axis X.

[0025] The rotor 202 has the shape of an annular disc coaxial with the wheel 103 and the shaft 102 and also comprises an internal part and an external part in the form of two concentric rings of different widths (measured in a radial direction rings).

[0026] The internal part is made of copper or any other electrically conductive material.

[0027] The external part is made of any material having mechanical properties suitable for ensure a connection of the rotor 202 to the rim 105. The rotor 202 is fixed to the wheel 103 to be coaxial with the shaft 102 and is therefore linked in rotation to the wheel 103, here to the rim 105 of the wheel 103, and rotates on itself around its central axis relative to the magnets of the stator 201: during this movement of the rotor 202 in a circumferential direction relative to the stator 201, the main face of the rotor 202 remains parallel to the main face of the stator 201.

[0028] The actuators 109 move the stator 201 in an axial direction of the wheel 103 between: - a first position, or maximum braking position of the wheel 103, in which the stator 201 is close to the rotor 202, so that the stator 201 is separated from the rotor 202 by a first predetermined air gap and; - a second position, or free rotation position of the wheel 103, in which the stator 201 is distant from the rotor 202, so that the stator 201 is separated from the rotor 202 by a second predetermined air gap greater than the first predetermined air gap.

[0029] When the rotor 202 pivots opposite the stator 201 at a sufficient speed and with the first air gap, the magnetic flux produced by the magnets is sufficient to generate in the rotor 202 an eddy current and a braking force of the rotor 202. With the second air gap, the magnetic flux produced by the magnets is insufficient to generate in the rotor 202 an eddy current and a braking force of the rotor 202. The operation and control of an eddy current brake are known in themselves and will not be detailed further here.

[0030] The stator 201 and the rotor 202 are therefore both constituted by the assembly of a first part and a second part, namely an internal part and an external part concentric with the internal part.

[0031] The assembly method used is shown in Figures 3 and 4 which relate more particularly to the stator 201 but the principle is identical for the rotor 202.

[0032] The inner part 1 and the outer part 11 have the shape of two rings intended to be concentric with each other once the assembly is carried out. The inner part 1 and the outer part 11 therefore each have an outer periphery and an inner periphery, the outer periphery of the inner part 1 having a diameter slightly smaller than that of the inner periphery of the outer part 11 so that the inner part 1 can be engaged in the outer part 11 along a common axis aligned with the X axis in use. The outer periphery of the inner part 1 then extends opposite the inner periphery of the outer part 11.

[0033] In the embodiment described, the internal part 1 comprises first radial bores 1.1 each having two ends, one opening onto the internal periphery of the internal part 1 and the other onto the external periphery of the internal part 1. The first radial bores 1.1 are here eight in number, are aligned on a median plane of the internal part 1, and are symmetrically distributed around the common axis and equidistant from each other.

[0034] The external part 11 comprises second radial holes 11.1 each having two ends, one opening onto the internal periphery of the external part 11 and the other onto the external periphery of the external part 11. The second radial holes 11.1 are here eight in number, are aligned on a median plane of the external part 11, and are symmetrically distributed around the common axis and equidistant from each other.

[0035] When the internal part 1 is engaged in the external part 11, each second radial bore 11.1 extends in the extension of one of the first radial bores 1.1 and has its end opening onto the internal periphery of the external part 11 opposite the end of said first bore 1.1 opening onto the external periphery of the internal part 1 to form a pair of aligned bores.

[0036] A key 2 extends into each pair of aligned holes to connect the inner part 1 and the outer part 11 both in rotation and in translation along the common axis. Each key 2 here has the shape of a bar having a first section of rectangular section and a second section having an I-shaped section.

[0037] An element is provided for immobilizing each key 2 in a radial direction of the parts, that is to say along the axis of the pair of holes 1.1, 11.1 in which each of them is received. The immobilizing element of each key 2 extends in an axial direction and passes through a portion of the internal part 1 to be in contact with the key 2. More precisely here, the immobilizing element of each key 2 is a screw 3 also passing through the first section of the key 2 and having a free end screwed into the internal part 1. The screw 3 thus ensures the immobilization of the key 2 in the manner of a pin. Alternatively, the screw 3 may be a pressure screw screwed into the internal part 1 so that the free end of the screw is applied against the key 2 and opposes its movement by friction. Alternatively, screw 3 can also be replaced by a pin (e.g. press-fit pin), rivet, glue, etc.It should be noted that the advantage of only fixing the key 2 punctually and to one of the parts is that this leaves it free to expand relative to the part to which it is not fixed.

[0038] The materials chosen for the internal part 1, the external part 11 and the keys 2 depend on the function of the parts, the torque to be transmitted from one part to the other via the keys, the importance of the temperature variations (thermal expansions differentials) ... For example: - for the 201 stator, the internal part is made of aluminum and the external part is made of magnetic steel; - for rotor 202, the internal part is made of copper and the external part is made of aluminum; - in both cases, the keys are made of aluminum.

[0039] The number of keys and their adjustment in the holes will be determined according to the stresses, particularly mechanical, involved in the application considered.

[0040] 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.

[0041] In particular, the device may have a structure different from that described.

[0042] The parts may have non-circular shapes, for example polygonal or elliptical. The parts may be provided with a torsion interface at their inner or outer periphery.

[0043] The second holes may be blind opposite the first holes. The inner part may be provided with blind holes and the outer part with radial through holes, or vice versa.

[0044] The number of radial holes may be different from that mentioned.

[0045] The assembly may comprise more than two concentric parts and for example three, namely an internal part and an external part between which an intermediate part extends.

[0046] The keys can be fixed in each of the parts but differential thermal expansions may cause stresses on both the parts and the keys. The keys can be held in the pairs of holes simply by plugging the emerging ends of the pairs of holes.

[0047] The keys can be solid, profiled or hollow bars, or pins; with rectangular, circular, elliptical, polygonal sections, etc. They can have mixed shapes (for example, rectangular at the attachment point and different afterwards). The holes can have any cross-section adapted to that of the keys.

[0048] The braking device may comprise a different number of stators (e.g. more than one) and / or rotors (e.g. more than one).

[0049] Generally speaking, the actuators may be electromechanical or hydraulic actuators, single or double acting. For a single acting actuator, the power supply allows forward movement of the pusher and an elastic element allows the return of the pusher. The number of actuators may be different from that mentioned. Preferably, at least three actuators will be used symmetrically. distributed around the axis of rotation of the wheel to balance the axial forces exerted on the stator.

[0050] A rim part (serving as a support for the tire) can be attached to a wheel part and / or a wheel part can be attached to a hub part. The wheel can have a structure different from that described, be in a single piece or on the contrary in several pieces assembled together. The wheel can thus be a single piece, made in a foundry or by additive manufacturing or from two half-wheels bolted to each other...

[0051] The magnets can be carried by the rotor instead of the stator.

[0052] The magnetic braking device according to the invention may be associated with, or replaced by, a conventional friction braking device which comprises friction members, for example a stack of carbon discs, and a plurality of electromechanical actuators carried by an actuator holder. The rotors and stators may be produced according to an assembly in accordance with the invention. Each stator of the friction braking device may comprise an internal metal part forming a hub for connecting the stator to the torque tube and an external carbon part forming the friction disc. Each rotor of the friction braking device may comprise an external metal part forming a hub for connecting the rotor to the wheel rim and an internal carbon part forming the friction disc. The keys ensure in both cases the transmission of the torque between the friction discs and the hubs.

Claims

Claims

1. Aircraft wheel (103), comprising a braking device comprising an assembly comprising at least a first part (1) and a second part (11) concentric extending around a common axis (X), characterized in that at least the first part (1) comprises first radial bores (1.1) having two emerging ends and the second part (11) comprises second radial bores (11.1), each second radial bore (11.1) extending in the extension of one of the first radial bores (1.1) and having one emerging end opposite one of the emerging ends of said first radial bore (1.1) to form a pair of aligned bores, and in that a key (2) extends in each pair of aligned bores to connect the concentric parts (1, 11) to each other in rotation and in translation along the common axis.

2. Wheel (103) according to claim 1, wherein each second radial bore (11.1) has an end opening opposite the first radial bore (11.1) of the pair of aligned bores.

3. Wheel (103) according to claim 1 or 2, comprising an element for immobilizing each key (2) in a radial direction of the concentric parts (1, 11).

4. Wheel (103) according to claim 3, in which the immobilizing element of each key (2) extends in an axial direction and passes through a part of one of the concentric parts (1, 11) to be in contact with the key (2).

5. Wheel (103) according to claim 3 or 4, wherein the immobilizing element of each key (2) is a screw (3).

6. Wheel (103) according to claim 5, wherein the screw (3) also passes through the key (2) and has a free end section screwed into said part (1).

7. Wheel (103) according to any one of the preceding claims, in which the concentric parts (1, 11) are made of different materials.

8. A wheel (103) according to any preceding claim, wherein one of the concentric parts is a brake disc (201, 202).

9. A wheel (103) according to any preceding claim, wherein one of the concentric parts is a flywheel.

10. Aircraft comprising at least one landing gear provided with a wheel according to any one of the preceding claims.

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