GUIDE CAGE, DEVICE AND ASSOCIATED BEARING BEARING

Abstract

A guide cage (40) is intended to be positioned at least partially between two rings, one of the two rings being a rotating ring capable of rotating relative to the other ring around an axis of revolution, the two rings forming two opposing contact tracks, each having rotational symmetry about the axis of revolution. The guide cage (40) comprises an annular body (62), the annular body (62) forming at least one recess (66) intended to receive a contact rolling body (35), the guide cage (40) being characterized in that it comprises at least one centrifugal disengagement device (68) movable, under the effect of centrifugal force, between a coupling position, intended to be in frictional contact with the rotating ring, below a disengagement angular velocity threshold of the guide cage around the reference axis, and a disengaged position, without contact with the two rings, above the disengagement angular velocity threshold.(Abbreviated figure: 10).

Description

Title of the invention: GUIDE CAGE, DEVICE AND ASSOCIATED BEARING BEARING TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a guide cage intended to be positioned between two rings rotating relative to each other, and for example integrated into a plain or rolling bearing and, in particular, although not exclusively, into a rolling bearing having an additional current-conducting function. PRIOR TECHNOLOGY

[0002] To ensure electrical conduction between a rotating subassembly and a stationary subassembly, it might be tempting to use rolling bearings, whose primary function is to provide relative rotational guidance between the rotating and stationary subassemblies, since the constituent elements of such bearings—raceways and rolling elements—are made of conductive materials. However, it turns out that the lubrication required for the operation of a bearing does not satisfactorily ensure this current flow at high speeds. Indeed, as the rotational speed increases, a lubricant film forms between the rolling elements and the raceways, and its thickness increases with speed. This effect, desirable for the primary mechanical function of the bearing, is not desirable for electrical conduction, because the lubricant behaves as an electrical insulator.Consequently, a potential difference between the raceways generates electrical arcs which rapidly alter the lubricant and the metallic surface of the raceways and rolling elements, causing heating and spalling of the raceways or rolling elements.

[0003] To overcome this problem, it was proposed in document JP 2022118903 to add to a rolling bearing a current-conducting device comprising contact balls rolling on two attached contact tracks, one on the inner ring and the other on the outer ring. The contact balls are made of a flexible and porous conductive material, which has the dual property of absorbing lubricant at the contact between the balls and the contact tracks and of compressing slightly to increase the contact area with the contact tracks as the speed increases. This ensures that the electric current flowing through the rings of the rolling bearing will preferentially pass through the current-conducting device, the impedance of which is significantly lower than that of the rolling bearing.However, this solution is not efficient in terms of friction, especially at low speeds, since contact between the contact tracks and the balls is made regardless of the speed. rotation, whereas at low speeds, the rolling elements of the bearing can very well perform the current-conducting function. Other disadvantages associated with this solution are the technical difficulty of manufacturing conductive porous balls and the risk of increased noise at high speeds due to the presence of surface porosity on the balls, because the intersection of the porosity recesses on the ball surface geometrically creates edges that can locally be considered as flat surfaces. Description of the invention

[0004] The invention aims to remedy at least some of the drawbacks of the prior art mentioned above and to propose a guide cage, for a current-passing device or a plain or rolling bearing, whose behavior is different at low rotational speed and at high rotational speed, so as to limit friction and drag torque at low rotational speed.

[0005] To this end, according to a first aspect of the invention, a guide cage is proposed, intended to be positioned at least partially between two rings, one of the two rings being a rotating ring capable of rotating relative to the other ring around an axis of revolution, the two rings forming two opposing contact tracks, each having a rotational symmetry around the axis of revolution, the guide cage comprising an annular body defining a reference axis intended to coincide with the axis of revolution, the annular body forming at least one recess intended to accommodate a rolling contact body, the guide cage being remarkable in that it comprises at least one centrifugal disengagement device movable, under the effect of centrifugal force, between a so-called coupling position, intended to be a contact position rubbing with the rotating ring,below a certain angular velocity threshold, known as the disengagement threshold, of the guide cage around the reference axis, and above this disengagement angular velocity threshold, a position known as the uncoupled position, intended to be without contact between the two rings.

[0006] The disengagement device keeps the guide cage fixed to the rotating ring below the disengagement angular velocity threshold and releases the cage beyond it. As long as the guide cage and the rotating ring are fixed in rotation, the contact rolling element(s) also remain at rest relative to the rotating ring, thus limiting friction and drag torque.

[0007] According to one embodiment, the centrifugal disengagement device comprises at least one movable portion connected to the annular body by at least one flexible arm. The movable portion includes a mass distribution which, combined with the controlled deformability of the flexible arm, allows it to move away from the movable ring when the rotational speed of the contact track exceeds the angular velocity threshold of Disengagement. However, to prevent the moving portion from moving excessively radially from its initial position, which could damage the flexible arm and / or bring the moving portion into contact with the other ring, the centrifugal disengagement device includes a stop positioned opposite at least part of the moving portion. This limits the radial movement of the moving portion beyond the disengagement angular velocity threshold. The maximum radial displacement of the moving portion is dimensioned so that, once in contact with the stop, the elastic limit of the cage material is not exceeded in the flexible arm. In practice, the movement between the coupled and disengaged positions is greater than 0.05 mm, preferably greater than 0.10 mm, for example, greater than 0.50 mm. The stop may also serve to stiffen the guide cage.

[0008] According to one embodiment, the moving portion comprises a movable pad intended to be in frictional contact with the rotating ring in the coupling position, i.e., below the disengagement angular velocity threshold. The movable pad is the element configured to adhere by friction to the contact track of the rotating ring when the rotational speed of the rotating ring is below the disengagement angular velocity threshold, while the elasticity of the flexible arm and the mass distribution of the moving portion are determined so as to allow the movable pad to detach from the rotating contact track when the rotational speed of the contact track is above the disengagement angular velocity threshold, by centrifugal force.In other words, the moving portion has a mass distribution configured to cause deformation of the flexible arm, inducing separation of the moving pad from the contact track beyond the disengagement angular velocity threshold.

[0009] According to one embodiment, the lifting of the movable pad is a movement that moves the movable portion away from the reference axis. The cage thus makes it possible to maintain the contact ball, regardless of the operating phase of the current-conducting device, i.e., in rotation or at rest, between the two contact tracks. Preferably, the guide cage comprises three angularly equidistant recesses, so as to be isostatic and balanced.

[0010] According to one embodiment, the recess has dimensions suitable for allowing the contact rolling body radial and / or radial and axial freedom of movement between a first position and a second position further from the reference axis than the first position. Preferably, the recess is oblong with a major axis radial or intersecting the reference axis. In one embodiment, the recess is delimited by at least one axial stop and two opposing guide facets facing each other in an orthoradial direction, the two guide facets preferably being flat or concave. The radial freedom of movement of the rolling body(ies) in the recess(es) allows for their centrifugal movement when the guide cage is driven. at low speed by the rotating ring to which it is attached via the centrifugal disengagement device. This centrifugation of the rolling bodies makes it possible to predict, with contact track shapes adapted for the two rings, that the rolling bodies move from a position, at low rotational speed, in which they are in contact with only one of the two rings, to a position, at medium rotational speed of the cage, in which they are simultaneously in contact with the two opposite contact tracks, this before the angular speed threshold of disengagement is reached and causes the cage to disengage.

[0011] Once a sufficiently high rotational speed is reached of the inner contact track and / or the outer contact track and the contact cage, the centrifugal disengagement device is disengaged from the rotating ring. The contact rolling element(s) then become the driving element of the contact cage, and this speed must be sufficiently high if this state is to be stable.

[0012] By way of example, in the case where the contact cage is intended to be initially driven by the inner contact track via the centrifugal disengagement device, and where the contact rolling bodies are balls, it can be estimated that the centrifugal effect on the contact rolling body(ies) is sufficient as long as the centrifugal force exerted on the balls is greater than the gravitational force on the balls, which can be translated as a first approximation by the inequality: [°OB1>mg

[0014] where m denotes the mass of the ball, fi / denotes the rotational speed of the rotating sub-assembly, DB denotes the diameter of the ball, D a denotes the diameter of the inner contact track and g denotes the acceleration due to gravity. We can thus define an angular velocity of change of behavior O / 0 such that:

[0015] n _ OET - \vb+dci

[0016] As soon as the guide cage reaches the disengagement angular velocity threshold, the cage is released from the rotating ring and driven into rotation by the rolling of the balls on the contact tracks. The cage then rotates at a speed that is lower than the rotational speed of the rotating ring O / , and, considering a non-slip bearing of the contact ball and the inner and outer rings respectively, defined by the following relation:

[0017] o _ o......? »..... - LiIDct+DCE

[0018] where DCi designates the diameter of the contact point between the rotating ring and the contact ball and DCe designates the diameter of the contact point between the fixed ring and the contact ball.

[0019] To ensure the balls rotate when the disengagement speed threshold Qç is exceeded, it should preferably be greater than the angular velocity at which behavior changes. This is so that the balls remain, by centrifugal force, in the contact zone with the two contact tracks once the disengagement angular velocity threshold Qç is reached. Therefore, the disengagement device is preferably calibrated such that:

[0020] Qc>^o

[0021] i.e.:

[0022] ... I 2g (Po+Pce) ^F>\I(Dci+Dce)

[0023] Below the disengagement speed threshold Qs, ûc = which leads to preferably defining the angular disengagement speed threshold Qs of the cage such that:

[0024] / 2g {Pq+PcE) ^^^(Dq+PeE) x Pq

[0025] Similar considerations can be made for other configurations.

[0026] According to one embodiment, the guide cage has one or more radially projecting retaining tabs, intended to penetrate a groove in one of the two rings so as to axially maintain the contact cage in its functional position.

[0027] According to one embodiment, the guide cage is made from a single piece of plastic, which minimizes the number of parts and assembly costs. Thus, the guide cage can be manufactured by molding and has a relatively low weight. Such a cage can be made of plastic since it is not intended to be subjected to excessive stresses that could damage it.

[0028] According to another aspect of the invention, it relates to a rotating device comprising: • two rings, one of the two rings being a rotating ring capable of rotating relative to the other ring around an axis of revolution, the two rings forming two opposing contact tracks, each having a rotational symmetry around the axis of revolution, • a guide cage as described above, whose centrifugal disengagement device is in frictional contact with the rotating ring in the coupled position, and is out of contact with both rings in the uncoupled position, and • at least one rolling contact body made of electrically conductive material, housed in at least one cavity of the guide cage, and capable of moving within the cavity of the guide cage by centrifugal force at least between a first contact position, which is a contact position with only one of the two opposing contact tracks and a second contact position which is a simultaneous contact position with both opposing contact tracks.

[0029] The contact tracks thus allow the contact ball axial movement according to the relative rotational speed between the inner and outer rings. Centrifugal force pushes the contact ball away from the reference axis and therefore, by rolling on the outer contact track, moves axially. This axial movement is also permitted by the recess in the guide cage. Thus, when the rotational speed is sufficient, the contact ball is in contact with both contact tracks simultaneously.

[0030] According to one embodiment, the contact roller has a mass such that it moves by centrifugal force between the first contact position and the second contact position at a rotational speed of the guide cage lower than the previously defined angular velocity threshold for disengagement. This ensures proper sequencing of the cage release and its drive by the roller(s).

[0031] Preferably, the guide cage has a guide face located opposite and at a distance of less than 0.5 mm and more than 0.05 mm from a corresponding face of one of the two bearing rings. This ensures radial guidance of the cage in all phases of operation.

[0032] According to another aspect of the invention, a rolling bearing is proposed, comprising: • a rotating device as described above, the two rings being two rolling rings forming two opposite rolling tracks, each having a rotational symmetry about the axis of revolution, located axially at a distance from the two opposite contact tracks, • a bearing cage, separate from the guide cage, and without contact with the guide cage, • rolling guide bodies capable of rolling simultaneously on both rolling paths and held by the rolling cage.

[0033] Such a rolling bearing then benefits from all the advantages of the current-carrying device as described above. The rolling guide elements can be rollers or balls, for example. They can be metallic and smooth, i.e., without porosity.

[0034] According to another aspect of the invention, it relates to a plain bearing remarkable in that it comprises a rotating device as described above, the two rings being two smooth guide rings cooperating with each other by mutual sliding contact or by sliding contact each with an opposite face of an intermediate bearing.

[0035] In such a configuration, the contact tracks and the contact rolling body(ies) are preferably made of electrically conductive material, for example metal, to ensure a current passage function between the two rings, at least when the rotational speed of the cage exceeds the disengagement angular speed threshold. BRIEF DESCRIPTION OF THE FIGURES

[0036] Other features and advantages of the invention will become apparent from the following description, with reference to the attached figures.

[0037] [Fig.1] Fig.1 illustrates, in a cross-sectional view, a rolling bearing comprising a passage device according to a first embodiment.

[0038] [Fig.2] Fig.2 illustrates, in a cross-sectional view, the current passage device only according to the first embodiment.

[0039] [Fig.3] Fig.3 illustrates, in an isometric and cross-sectional view, a detail of the rolling according to the first embodiment.

[0040] [Fig.4] Fig.4 illustrates, in an isometric view, a cage of the device current passage according to the first embodiment.

[0041] [Fig. 5] Fig. 5 illustrates a cross-sectional view of the cage according to the first mode of realization.

[0042] [Fig.6] Fig.6 illustrates a geometric detail of the contact track structure of the contact device according to the first embodiment.

[0043] [Fig.7] Fig.7 illustrates a detail of the cage cells.

[0044] [Fig.8] Fig.8 illustrates a detail of a cage disengagement device according to the first mode of implementation.

[0045] [Fig.9] Fig.9 illustrates, in a cross-sectional view, a ball bearing comprising the current passage device according to a second embodiment.

[0046] [Fig. 10] The [Fig. 10] illustrates in a cross-sectional view, the cage of the current passage device according to the second embodiment.

[0047] [Fig. 11] Fig. 11 illustrates in a cross-sectional view the rolling bearing comprising the passage device according to a third embodiment.

[0048] [Fig. 12] Fig. 12 illustrates a detail of the cage disengagement device according to the third embodiment.

[0049] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. DETAILED DESCRIPTION OF IMPLEMENTATION METHODS

[0050] Figures 1 to 10 illustrate a rolling bearing 10 between a fixed sub-assembly 2, for example a housing of a motor vehicle (not shown) defining a reference axis 100, and a rotating sub-assembly 4, for example a shaft, suitable for rotate around the reference axis 100 inside the fixed sub-assembly 2, the bearing comprising an outer metal ring 12 integral with the fixed sub-assembly 2, an inner metal ring 14 integral with the rotating sub-assembly 4, and rolling bodies 16 between the inner ring 14 and the outer ring 12. The bearing 10 further comprises a current-passing device 70 illustrated alone in [Fig.2].

[0051] The inner ring 14 is here a solid, one-piece metallic inner ring comprising an inner annular surface 18 rotated radially opposite the reference axis 100 and extending between a first end face 20 and a second end face 22. On the inner annular surface 18 are formed an inner raceway 24 and an inner contact track 26, which are coaxial and are surfaces of revolution about the reference axis 100. For this purpose, the inner ring 14 may undergo heat treatment and machining, both located at the inner raceway 24 and the inner contact track 26. The inner raceway 24 is positioned near the first end face 20, while the inner contact track 26 is positioned near the second end face 22. The inner contact track 26 forms a first element of the current-conducting device 70.

[0052] The inner raceway 24 comprises two flanks 28 located axially on either side of a raceway bottom 30, and is intended to accommodate the rolling elements 16, which are here balls having a diameter D Br, but could alternatively be rollers, cones, or barrels. The rolling elements 16 are made, preferably constructed, of metal, and are configured to guide and support external radial and / or axial loads.

[0053] The inner contact track 26 is a frustoconical, preferably ground, annular surface with rotational symmetry about the reference axis 100. The inner contact track 26 extends between a first inner end 32, near the second end face 22, and a second inner end 34 near the inner raceway 24. It is configured to accommodate contact rolling elements, and more particularly contact balls 35. The contact balls 35 are made, preferably of metal, and have a diameter DBC. They form an element of the current-conducting device 70. Furthermore, the contact balls 35 are configured to conduct electric current between the fixed outer ring 12 and the rotating inner ring 14, and thus between the fixed subassembly 2 and the rotating subassembly 4.Unlike the rolling elements 16, they are not intended to guide the rotation of the rotating sub-assembly 4. Here, there are 3 of them, positioned 120° apart, but alternatively, there may be more or fewer. The diameter DBC of the contact balls 35 is preferably strictly less than the . length L of the generatrix of the inner contact track 26, in order to allow a movement including an axial component of the contact balls 35 on the inner contact track 26 while reducing the axial bulk of the inner ring 14. Advantageously, the diameter D Bc of the balls should be as small as possible to reduce the bulk of the current passage device 70.

[0054] According to a first embodiment illustrated in Figures 1 to 8, in a section plane including the datum axis 100 (as illustrated in [Fig. 1]), the inner contact track 26 has an inner generatrix 102 forming an angle Al of 17° with the datum axis 100. More generally, this angle Al is greater than 2°, preferably greater than 14°, and less than 47°, preferably less than 42°. The inner generatrix 102 of the inner contact track 26 is such that it moves away from the datum axis 100 as it approaches the inner bearing race 24. The inner bearing race 24 and the inner contact track 26 are separated by an inner separating surface 36.

[0055] On the inner annular surface 18, a receiving portion 38 is further formed, configured to receive on the inner ring 14 a guide cage 40 described later in this application. The receiving portion 38 is positioned between the second end face 22 and the inner contact track 26. As it approaches the second end face 22, it comprises a circularly cylindrical receiving face 42, an annular groove 44, and a chamfer 46 opening onto the second end face 22.

[0056] The fixed outer ring 12 is here a solid, one-piece metal ring comprising an outer annular surface 48 oriented radially towards the reference axis 100 and extending between a first outer end 50 and a second outer end 52. On the outer annular surface 48 are formed an outer raceway 54 and an outer contact track 56 coaxial, defining the reference axis 100. For this purpose, the outer ring 12 may undergo heat treatment and machining, both located at the outer raceway 54 and the outer contact track 56. The outer contact track 56 forms a second element of the current-conducting device 70.

[0057] The outer raceway 54 comprises two flanks 28' located axially on either side of a raceway bottom 30'. The outer raceway 54 is located opposite the raceway 24 and is intended to accommodate the rolling bodies 16.

[0058] The outer contact track 56 has an annular frustoconical surface, preferably ground, and exhibits rotational symmetry about the datum axis 100. The outer contact track 56 is located opposite and at a distance from the inner contact track 26 and is configured to accommodate the contact balls 35. In a section plane containing the datum axis 100 (as illustrated in [Fig. 1]), the track of The external contact 56 has an external generatrix 104 forming, with the reference axis 100, an angle A2 of 15°. More generally, the angle A2 is greater than 1.5°, preferably greater than 12°, and less than 45°, preferably less than 40°. The outer generatrix 104 of the outer contact track 56 is such that it moves away from the reference axis 100 as it approaches the outer raceway 54. Furthermore, as it approaches the outer raceway 54, it moves away from the reference axis 100 less rapidly than the inner generatrix 102 of the inner contact track 26. The outer contact track 56 more generally has, in any cutting plane including the reference axis 100, a generatrix forming, with the generatrix of the inner contact track 26, an angle greater than 0.5°, preferably greater than 1°, and less than 30°, preferably less than 15°.The outer rolling track 54 and the outer contact track 56 are separated by an outer separating surface 58.

[0059] The ball bearing 10 further comprises a bearing cage 60, configured to space and maintain the rolling elements 16 in predetermined relative positions, and a guide cage 40, independent of the bearing cage 60 and intended to guide the contact balls 35. The guide cage 40, which belongs to the current-carrying device 70, comprises a ring 62 having a guide face intended to be aligned with the seat surface 42. The ring 62 further comprises recesses 66 and at least one disengagement device 68. The guide cage 40 here comprises three recesses 66 angularly offset from each other by an angle of 2ir / 3 so that the current-carrying device 70 is statically balanced. The recesses 66 project axially and radially from the ring 62, so as to fit between the contact tracks without contact.To achieve this, in the cross-sectional plane comprising the reference axis 100 and the center of a contact ball 35 (illustrated in [Fig. 1]), a socket 66 forms, with the reference axis 100, a mean angle greater than 1.5°, preferably greater than 12°, and less than 45°, preferably less than 40°. The sockets 66 are defined by rigid socket elements 64. The sockets 66 are equidistant from each other and have an ovoid shape, i.e., the through hole in the socket element 64 intended to receive the ball has an axial dimension greater than its orthoradial dimension.Thus, the socket element 64 has an axial stop 72 to hold the contact ball 35 between the contact tracks when it moves towards the second end face 22, two orthoradial guide facets 76 to drive the contact ball 35 orthoradially and an axial link 74, opposite the axial stop 72, and linking the two orthoradial guide facets 76 together so as to solidify the structure of the socket 66.

[0060] The disengagement devices 68 are also three in number and are equidistant from each other. They are also equidistant from the two adjacent associated recesses 66. Such an arrangement ensures the static balance of the cage and minimizes mechanical stresses, thus maximizing the cage's strength. The disengagement devices 68 are configured to drive the guide cage 40 in rotation with the inner ring 14 at low speed, and to disengage them when the angular speed exceeds a predetermined threshold, called the disengagement angular speed threshold. To achieve this, each of the disengagement devices 68 comprises at least one movable portion 90 connected to a rigid structure 82, formed here by a protrusion, via a flexible arm 84 capable of elastically deforming according to the centrifugal force induced by the rotational speed of the rotating subassembly 4.The moving portion 90 includes a movable pad 78 configured to come into the coupling position, bearing against the inner ring 14, and more particularly the inner annular surface 18, and preferably on at least a portion of the inner contact track 26 when the mechanism is at rest, and more generally below the disengagement angular velocity threshold. Each flexible arm 84, coupled to the moving portion 90 which includes a mass distribution configured to allow tilting, is configured to deform so as to move the moving portion 90 away from the reference axis 100, lifting the associated movable pad 78 from the inner ring 14 as the rotational speed of the rotating subassembly 4 increases until it reaches a disengaged position in which it is no longer in contact with said rotating subassembly 4 as soon as the rotational speed exceeds the disengagement angular velocity threshold.

[0061] The ring 62 also includes radial stops 86, each radial stop 86 being arranged opposite the associated moving portion 90, radially further away from the reference axis 100, so as to limit the centrifugal radial displacement of the moving portion 90.

[0062] The ring 62 further comprises an inner cylindrical annular face 79 facing the reference axis 100. It is intended to be positioned opposite the receiving face 42 of the inner ring 14. The inner annular face 79 comprises at least one retaining tab 80 projecting radially towards the reference axis 100 and intended to penetrate the annular groove 44 of the receiving portion 38. The retaining tab 80 is configured to secure the axial positioning of the guide cage 40 in the ball bearing 10, and is housed without contact in the annular groove 44 of the receiving portion 38. The retaining tabs 80 are preferably flexible, so as to be inserted into the annular groove 44 by elastic deformation.

[0063] The current-passing device 70 comprises, as a reminder, the inner and outer contact tracks as well as the guide cage 40 and the contact balls 35. The The fixed subassembly 2 is radially further from the rotating subassembly 4 at the first inner end 32 than at the second inner end 34. In the cutting plane containing the datum axis 100, any segment S perpendicular to the datum axis 100, and having a first end belonging to the inner contact track 26 and a second end belonging to the outer contact track 56, has: • a center C which, in a direct orthonormal coordinate system having an x-axis coinciding with the reference axis 100 and an ordinate y which passes through the first inner end 32 of the inner contact track 26, has an x-axis equal to x and an ordinate equal to y, defining a function x—>y=f(x) which, when x varies between 0 and the second inner end 34 of the inner contact track 26, is strictly increasing continuously; • a length? defining a function x—> / =g(x) which, when the abscissa x of the center C of the segment S varies between 0 and the second interior endpoint 34, is strictly decreasing continuously, having a maximum value strictly greater than the diameter of the balls D BC, and a minimum value less than or equal to the diameter of the balls D BC.

[0064] When the bearing is stationary, the contact balls 35 position themselves axially between the two contact tracks according to gravity. For example, if the reference axis is horizontal, a contact ball 35 positioned lower than the reference axis will have rolled by gravity along the outer contact track to position itself as close as possible to the raceways 24 and 54. Conversely, a contact ball 35 positioned higher than the reference axis 100 will be driven by gravity along the inner contact track to position itself as far as possible from the raceways 24 and 54. The contact ball is then held between the two contact tracks by the axial stop 72.

[0065] During operation, when the ball bearing 10 is in motion, the rotating sub-assembly 4 drives the guide cage 40 with it via the movable slides 78. The guide cage 40 then drives the contact balls 35 in rotation via one of the two orthoradial surfaces 76 of each socket 66. Under the effect of centrifugal force, these balls move away from the axis of rotation, which coincides with the reference axis 100. The contact balls 35 then roll on the outer contact track, regardless of their initial position. The contact balls roll so as to move as far away as possible from the reference axis 100 under the influence of the centrifugal force. They then move radially and axially towards the point on the inner contact track 26 that is radially furthest from the reference axis 100, here the second inner end 34. This The movement takes place until each contact ball 35 reaches a position in which it is in contact with the inner contact track 26 and the outer contact track 56. Each contact ball 35 is then in an extreme axial position, in contact only with the two contact tracks 26, 56.

[0066] The contact ball 35 rolling on the inner contact track 26 has a rotational speed around the reference axis 100 lower than the rotational speed of the rotating sub-assembly 4. The contact ball 35, housed in the socket 66, drives the guide cage 40 which has separated from the faster rotating inner ring 14 into rotation, the flexible arms 84 deforming elastically so that the movable portions 90 tilt, lifting the movable pads 78 from the inner ring 14 so as not to generate friction.

[0067] Such a current-passing device structure 70, comprising frustoconical contact tracks, has, in a cutting plane including the reference axis, an osculating circle of infinite radius, reducing the contact ellipses between the contact ball 35 and each of the two contact tracks, making it easier to split the lubricant film present in the mechanism, and thus reducing the electrical impedance of the current-passing device 70 at the point of contact, extending the life of the contact tracks as well as the bearing tracks by reducing, and preferably eliminating, electrical arcs.

[0068] According to a second embodiment illustrated in Figures 9 and 10, the inner contact track 26 has an inner generatrix 102 forming an angle A1 of 38° with the reference axis 100, while the outer contact track 56 has an outer generatrix 104 forming an angle A2 of 34° with the reference axis 100. This embodiment is preferred in bearings requiring a smaller axial footprint. The recesses 66 and the disengagement devices 68 then have an angle adapted so as to fit between the two contact tracks.

[0069] Furthermore, according to a third alternative embodiment illustrated in Figures 11 and 12, the outer ring 12 is connected to a rotating subassembly 2, while the inner ring 14 can be connected to a fixed or rotating subassembly. In this scenario, the guide cage 40 is not connected to the inner contact track 26 but to the outer annular surface 48, preferably at least partially to the outer contact track 56. To achieve this, the flexible arm 84 connects the ring 62 to the axially projecting movable portion 90, the movable portion 90 comprising the projecting movable pad 78 of the latter and located in a radial projection of the ring 62. The movable portion 90 has a mass greater than that of the movable pad 78 to which it is connected by a rigid arm 92, understood here as the operating conditions of this part. The movable pad 78 is located radially further from the reference axis 100 than the movable portion 90.In this embodiment, the radial stop 86 is also . Oriented radially towards the reference axis 100, it is positioned opposite the moving portion 90 to limit outward radial displacement of said moving portion 90. During operation, when the rotational speed of the guide cage 40 is sufficiently high, the moving portion 90 moves away from the reference axis 100. This movement is made possible by the flexibility of the flexible arm 84 and achieved by the centrifugal force acting on the mass of said moving portion 90. By lever action, when the moving portion 90 moves away from the reference axis 100, the moving pad 78 is displaced radially in the direction of the reference axis 100, thus lifting it off the outer contact track 56. Furthermore, in this embodiment, the retaining tabs 80 project radially in a centrifugal manner and are housed in an annular groove 44' located on the outer ring 12.

[0070] The examples shown in the figures and discussed above are given for illustrative purposes only. Other embodiments may be considered, in particular by combining the features of the different illustrated embodiments.

[0071] For example, according to an alternative embodiment, the ring 62 can be equipped with a number N, other than three, of pits 6 6 angularly offset from each other by an angle 2ir / N. Independently, the ring 62 can be equipped with a number N', other than three, of disengagement devices 68 angularly offset from each other by an angle 2ir / N'.

[0072] According to another alternative embodiment, the current-conducting device 70 is formed by two rings separate from the two rings forming the raceways. In a variant, the current-conducting device 70 is formed by two separate rings, one of which also forms one of the raceways, the other raceway being formed on a ring separate from the two rings of the current-conducting device. Another feasible variant would be to form the current-conducting device with a ring fixedly mounted on one of the two subassemblies 2, 4 of the rotating device, allowing the assembly and fixing of the guide cage and the provision of one of the two contact tracks, the other contact track being formed directly on the other subassembly 2, 4, which in this hypothesis constitutes the other ring.

[0073] According to another alternative embodiment, the bearing has rolling bodies 16 which are not balls, but cylindrical or conical rollers, or barrel-shaped rollers for example.

[0074] According to another alternative embodiment, the inner contact tracks 26 and outer contact tracks 56 move away from each other as they approach the guideways. The guide cage 40 then comprises recesses and at least one suitable centrifugal disengagement device 68, inserted between the two contact tracks by deformation.

[0075] According to another alternative embodiment, the current passage device 70 is mounted on two rings forming a plain bearing.

Claims

Demands

1. Guide cage (40) intended to be positioned at least partially between two rings, one of the two rings being a rotating ring capable of rotating relative to the other ring about an axis of revolution, the two rings forming two opposing contact tracks, each having a rotational symmetry about the axis of revolution, the guide cage (40) comprising an annular body (62) defining a reference axis (100) intended to coincide with the axis of revolution, the annular body (62) forming at least one recess (66) intended to accommodate a rolling contact body (35), the guide cage (40) being characterized in that it comprises at least one centrifugal disengagement device (68) movable, under the effect of centrifugal force, between a coupling position, intended to be a contact position rubbing with the rotating ring, below an angular velocity threshold, called the disengagement angular velocity threshold,of the guide cage around the reference axis, and a decoupled position, intended to be a position without contact between the two rings, beyond the angular velocity threshold.

2. Guide cage (40) according to claim 1, characterized in that the centrifugal disengagement device (68) comprises at least one movable portion (90) connected to the annular body (62) by at least one flexible arm (84).

3. Guide cage (40) according to claim 2, characterized in that the centrifugal disengagement device (68) comprises a stop (86) positioned opposite at least part of the moving portion (90), so as to limit a radial movement of the moving portion (90) beyond the disengagement angular velocity threshold.

4. Guide cage (40) according to claim 2 or 3, characterized in that the movable portion (90) comprises a movable pad (78) intended to be in rubbing contact with the rotating ring threshold angular velocity in the coupling position.

5. Guide cage (40) according to claim 4, characterized in that the movable portion (90) has a mass distribution configured to cause a deformation of the flexible arm (84) inducing a separation of the movable pad (78) from the rotating ring beyond the disengagement angular velocity threshold.

6. Guide cage (40) according to any one of claims 4 to 5, characterized in that the separation of the movable pad (78) is a movement moving the movable portion (90) away from the reference axis (100).

7. Guide cage (40) according to any one of the preceding claims, characterized in that the cavity (66) has a dimension suitable for allowing the contact rolling body a radial and / or axial and radial freedom of movement between a first position and a second position, further away from the reference axis than the first position.

8. Guide cage (40) according to any one of the preceding claims, characterized in that the cavity (66) is oblong with a major axis radial or intersecting with the reference axis.

9. Guide cage (40) according to claim 7 or claim 8, characterized in that the cavity (66) is delimited by at least one axial stop (72) and two opposing guide facets (76) facing each other in an orthoradial direction, the two guide facets (76) preferably being flat or concave.

10. Guide cage (40) according to any one of the preceding claims, characterized in that it comprises one or more radially projecting retaining tabs (80) intended to penetrate into a groove of one of the two rings.

11. Guide cage (40) according to any one of the preceding claims, characterized in that it is made of a piece of plastic material.

12. Rotating device comprising: - two rings, one of the two rings being a rotating ring capable of rotating relative to the other ring about an axis of revolution, the two rings forming two opposing contact tracks, each having rotational symmetry about the axis of revolution, the device being characterized in that it further comprises - a guide cage (40) according to any one of the preceding claims, the centrifugal disengagement device (68) of which is in frictional contact with the rotating ring in the coupled position, and is without contact with the two rings in the uncoupled position, and - at least one rolling contact body made of electrically conductive material, housed in at least one cavity of the guide cage, and capable of moving in the cavity of the guide cage by centrifugal effect at least between a first contact position, which is a contact position with only one of the two opposite contact tracks and a second contact position which is a simultaneous contact position with both opposite contact tracks.

13. Rotating device (10) according to claim 12, characterized in that the contact rolling body has a mass such that it moves by centrifugal effect between the first contact position and the second contact position at a rotation speed of the guide cage lower than the disengagement angular velocity threshold.

14. Rotating device according to any one of claims 12 to 13, characterized in that the guide cage (40) has a guide face located opposite and at a distance of less than 0.5 mm and greater than 0.05 mm from a corresponding face of one of the two bearing rings.

15. Bearing characterized in that it comprises: - a rotating device according to any one of claims 12 to 14, the two rings being two bearing rings forming two opposite rolling races each having a symmetry of revolution about the axis of revolution located axially at a distance from the two opposite contact tracks, - a bearing cage, separate from the guide cage, and without contact with the guide cage, - guide rolling bodies capable of rolling simultaneously on the two rolling races.

16. Plain bearing characterized in that it comprises a rotating device according to any one of claims 12 to 14, the two rings being two smooth guide rings cooperating with each other by mutual sliding contact or by sliding contact each with an opposite face of an intermediate bearing.

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