Braked wheel equipped with a drive device

Abstract

A vehicle wheel (1), rotatably mounted on an axle (E), comprising a wheel-braking device and a wheel-driving device, the braking device comprising a brake disk (11) constrained to rotate with the wheel and a brake caliper (14) straddling the disk in order to exert friction forces on the disk by means of a brake actuator mounted on the caliper, and the drive device comprising a gear motor (23) driving in rotation a pinion which is arranged to mesh with a ring gear (21) constrained to rotate with the disk.

Description

[0001]BRAKED WHEEL EQUIPPED WITH A DRIVE DEVICE The present invention relates to the movement of a vehicle on the ground, and more particularly to a wheel equipped with a braking device and a drive device. The invention also relates to an aircraft landing gear and an aircraft equipped with such a wheel. BACKGROUND OF THE INVENTION In the field of aviation, it is known to equip aircraft wheels with a brake intended to selectively slow down and stop said aircraft when they are moving on the ground. For aircraft of a certain size, such as helicopters, the brake generally comprises a disc which is integral in rotation with the wheel and which is associated with a caliper which straddles the disc. The caliper comprises two jaws each receiving a brake pad, one of the jaws being mounted movably to be able to clamp the disc between the two pads by means of a braking actuator.To minimize the size of the brake, the caliper is placed astride the disc from the inside of the latter. It is also known to equip aircraft wheels with a device for driving the wheels in rotation to allow the aircraft to move on the ground without using its powertrains. However, the integration of such a drive device proves very difficult in the presence of the brake caliper and its actuator, the available space being limited. OBJECT OF THE INVENTION The invention aims to remedy at least in part the aforementioned drawback. SUMMARY OF THE INVENTION To this end, a vehicle wheel is proposed, rotatably mounted on an axle, comprising a braking device and a wheel drive device.The braking device comprises a brake disc rotatably secured to the wheel and a brake caliper straddling the disc to exert friction forces on the disc by means of a braking actuator mounted on the caliper. The drive device comprises a geared motor rotating a pinion which is arranged to mesh with a toothed crown rotatably secured to the disc. Thus, the disc makes it possible to exert both a braking torque and a rotational drive torque on the wheel. Furthermore, the geared motor can be sized so as to have a sufficient reduction ratio so that, when the geared motor is not electrically powered, the pinion exerts sufficient forces on the toothed crown to lock the disc and therefore the rotating wheel, and thus perform the parking brake function.The geared motor can also be sized so that it can be used as a low-speed brake and thus limit wear on the braking device. In particular, the caliper internally overlaps the disc. In particular, the caliper is mounted on the axle. In particular, the geared motor is mounted on the caliper. In particular, the toothed ring is attached to the disc. In particular, the disc has an external periphery which includes radial peripheral notches defining studs received in axial peripheral notches of the wheel. In particular, the disc is mounted floating on the wheel. In particular, the geared motor and the actuator extend coaxially to the axis (X) of rotation of the wheel. The invention also relates to an aircraft landing gear comprising at least one such 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 non-limiting, and must be read in conjunction with the appended figures, among which: [Fig. 1] Figure 1 is a schematic view of a helicopter comprising wheels equipped with a braking and rotational drive device according to a particular embodiment of the invention; [Fig. 2] Figure 2 is a perspective view of one of the braked / motorized wheels of the aircraft illustrated in Figure 1; [Fig. 3] Figure 3 is an exploded view, from a first angle of view, of the braked / motorized wheel illustrated in Figure 2; [Fig. 4] Figure 4 is an exploded view, from a second angle of view, of the braked / motorized wheel illustrated in Figure 2; [Fig. 5] Figure 5 is a perspective view of the braking and rotational drive device of the wheel illustrated in Figure 2; [Fig.6] Figure 6 is an exploded view of the brake disc of the braking and rotation drive device illustrated in Figure 5. DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, the invention is described in application to a helicopter H but is applicable to other types of aircraft or vehicles such as land vehicles. The helicopter H comprises two main landing gears each comprising a leg having an upper end fixed to a structure of the helicopter H and, opposite, a lower end carrying a wheel 1 rotating about an axis X on a shaft or axle E. The following description relates to one of the wheels 1 of the helicopter H, the wheels 1 being here identical but also being able to be different. The wheel 1 comprises, as illustrated in Figures 2 to 4, an annular rim 2 connected by a web 3 to a hub 4 which is pivotally received on the axle E by means of bearings (not shown).The rim 2 comprises two annular edges or beads 2.1, 2.2 between which a tire (not shown) is mounted. The bead 2.1 comprises a flange extending axially and comprising axial peripheral notches 2.3 which open onto a free edge of the flange and are equally distributed around the axis X. These notches 2.3 define, as will be seen later, mortises. The wheel 1 is said to be "braked", that is to say equipped with a braking device 10 intended to ensure the immobilization of the helicopter H when it is on the ground, in particular when parked. With reference to Figures 2 to 6, the braking device 10 comprises a brake disc 11 having a central axis coaxial with the axis X of rotation of the wheel 1. The disc 11, here made of carbon, is annular in shape and has an external periphery which comprises radial peripheral notches defining studs 11.1 (here seven in number) equally distributed around the axis X. The studs 11.1 are protected by riders 12 fixed to said tenons 11.1 each by two rivets 13 extending parallel to the axis X. The tenons 11.1 are received in the notches 2.3 of the rim bead 2.1 to ensure rotational coupling of the brake disc 11 with the wheel 1 while allowing said disc 11 to move axially with respect to said wheel 1. The disc 11 is thus mounted “floating” and the riders 12 define an interface between the tenons 11.1 of the disc 11 and the notches 2.3 of the rim 2. The braking device 10 also comprises a caliper 14 comprising a body 14.1 fixedly mounted on the axle E by means of a protrusion E1 extending in radial projection from the axle E (figure 3). The protrusion E1 is received in a receptacle 14.2, of a shape complementary to that of the protrusion E1, of the body 14.1 to ensure both positioning of the caliper 14 on the axle E and the transmission of braking forces. The body 14.1 overlaps an inner periphery of the disc 11 and comprises a first fixed jaw 14.3 which extends axially opposite the disc 3 of the wheel 1 and which carries a first brake pad 15.1 extending parallel opposite a first friction face of the disc 11. The caliper 14 also comprises a second jaw which is mounted axially movable in a first bore of the body 14.1 and which carries a second brake pad 15.2 extending parallel opposite a second friction face of the disc 11, opposite the first friction face. The first pad 15.1 and the second pad 15.2, here made of carbon, are arranged to ensure axial pinching of the disc 11 under the action of a braking actuator 16 attached to the caliper body 14.1, and thus exert friction forces on the disc 11 tending to slow down and / or block the wheel 1 by means of the tenons 11.1 of the disc 11 engaged in the notches 2.3 of the rim 2.The braking actuator 16 is here an electromechanical actuator which comprises an electric motor 16.1 connected to a ball screw 16.3 via a reducer 16.2 to ensure a movement of the second jaw in a direction parallel to the axis X. The ball screw 16.3 is mounted on the caliper body 14.1 and extends, along an axis X16.3 parallel to the axis X, projecting from a front surface 14.4 of said body 14.1 which is turned towards the outside of the wheel 1. The reducer 16.2 extends generally in a plane perpendicular to the axis X and comprises a first end connected to the ball screw 16.3 and, opposite, a second end connected to the electric motor 16.1 which extends along an axis X16.1 parallel to the axis X in the direction of the wheel 1. In order to limit the volume of the size of the braking actuator 16, it will be noted that the motor 16.1 and the ball screw 16.3 do not extend on either side of the reducer 16.2, but on one and the same side of said reducer 16.2.The wheel is also called "motorized", that is to say equipped with a drive device 20 for rotating the wheel 1, intended to ensure movement of the helicopter H without using its powertrains when it is on the ground. The drive device 20 comprises a toothed crown 21 mounted coaxially to fit inside the brake disc 11. The crown 21 comprises an internal periphery provided with a row of teeth 21.1, and an external periphery cooperating with an internal surface 11.2 of the internal periphery of the brake disc 11, the external periphery of the crown 21 having a diameter slightly smaller than that of the internal surface of the brake disc 11. The toothing of the crown (formed by the teeth 21.1) is here straight. The crown 21 is held in position inside the disc 11 by means of keys 22 (here seven in number) extending radially from the inner surface 11.2 of the disc 11 to fit into notches 21.2, of complementary shape, arranged on the external periphery of the crown 21. Each of the keys 22 is received in a corresponding recess 11.3 of the disc 11, the recess 11.3 extending radially to open on one side onto an upper surface of one of the tenons 11.1 and on the other side onto the inner surface 11.2 of the disc 11. The keys 22 are here identical and comprise a flat element comprising: - a first end which extends slightly back from the upper surface of the tenons 11.1 and which comprises two transverse holes 22.1 crossed by the rivets 13 of the corresponding tenon, so that the key 22 is fixed with respect to the disc 11; and − a second end, opposite the first end, which comprises teeth 22.2 (here four in number) received in the conforming notches 21.2 of the crown 21.It is understood that the keys 22 form means for coupling in rotation the toothed crown 21 with the brake disc 11, but also means for coupling in translation along the axis X of said toothed crown 21 with said brake disc 11: the crown 21 is therefore integral with the disc 11. The drive device also comprises a geared motor 23 which is attached to the body 14.1 and which extends along an axis X23 parallel to the axis X, projecting from the front surface 14.4 of the caliper body 14.1. The geared motor 23 comprises an output shaft which extends through a second bore of the body 14.1 and which comprises a free end provided with a pinion 24 meshing with the toothed crown 21 to drive the disc 11 in rotation and thus exert on the brake disc 11 a driving torque tending to drive the wheel 1 in rotation by means of the tenons 11 of the disc 11 engaged in the notches 2.3 of the rim 2.Preferably, the geared motor 23 has a reduction ratio greater than a predetermined ratio so that, when the geared motor 23 is not electrically powered, the pinion 24 exerts sufficient forces on the toothed crown 21 to lock the wheel 1 in rotation. The drive device can then be used as a parking brake. The geared motor 23 can also be sized so that it can be used as a low-speed brake and thus limit the wear of the disc 11 and the brake pads 16.1, 16.2 and therefore increase their service life. 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. Although the disc 11 is here mounted floating, it can also be fixed. The caliper 14 can externally overlap the brake disc 11.Although the brake disc 11 is here rotationally fixed at the rim, it can also be fixed at the disc 3 or the hub 4. Although the caliper 14 is here made of carbon, it can be made of any suitable material, for example steel. Although the first and second pads 16.1, 16.2 are here made of carbon, they can be made of any suitable material. Although the toothed crown 21 is here attached to the center of the disc 11, said crown 21 and said disc 11 can be in one piece and form a single piece. The teeth 21.1 of the crown 21 are for example directly machined in the brake disc 11. Although the braking device 10 here comprises only a single disc 11, it can comprise a plurality of discs 11.Although the braking actuator 16 is here electric, it can be of another nature: hydraulic, pneumatic, etc. The positioning of the caliper 14 on the axle E and the transmission of the braking forces can be achieved other than with the protrusion E1 of the axle E received in the compliant receptacle 14.2 of the caliper body 14.1, for example using one or more pins. The pinion 24 of the drive device can be a roller pinion, for example a roller pinion produced by the company Nexen®. The straight teeth of the pinion 24 can have a domed profile in order to be able to manage small movements and small deformations of the disc / crown assembly 11, 21. The output shaft of the geared motor 23, at the end of which the pinion 24 is fixed, can also be mounted on a spherical bearing. If the application requires it, a clutch system (for example friction) can be incorporated into the geared motor 23.

Claims

CLAIMS 1. Vehicle wheel (1), rotatably mounted on an axle (E), comprising a braking device and a wheel drive device, the braking device comprising a brake disc (11) integral in rotation with the wheel and a brake caliper (14) overlapping the disc to exert friction forces on the disc by means of a braking actuator mounted on the caliper, and the drive device comprising a geared motor (23) rotating a pinion which is arranged to mesh with an internal periphery of a toothed crown (21) integral in rotation with the disc.

2. Vehicle wheel (1) according to claim 1, in which the caliper (14) internally overlaps the disc (11).

3. Vehicle wheel (1) according to any one of the preceding claims, in which the caliper (14) is mounted on the axle (E). 4.Vehicle wheel (1) according to any one of the preceding claims, in which the geared motor (23) is mounted on the caliper (14).

5. Vehicle wheel (1) according to any one of the preceding claims, in which the toothed crown (21) is attached to the disc (11).

6. Vehicle wheel (1), any one of the preceding claims, in which the disc (11) has an external periphery which comprises radial peripheral notches defining studs (11.1) received in axial peripheral notches (2.3) of the wheel (1).

7. Vehicle wheel (1), any one of the preceding claims, in which the disc (11) is mounted floating on the wheel (1).

8. Vehicle wheel (1), any one of the preceding claims, in which the geared motor. and the actuator (16) extend coaxially to the axis (X) of rotation of the wheel.

9. Aircraft landing gear comprising at least one wheel (1) according to any one of the preceding claims.

10. Aircraft comprising at least one landing gear according to claim 9.

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