Motor vehicle wheel assembly

Abstract

A motor vehicle drive wheel assembly (10) includes a fixed subassembly (12) including two outer raceways (22, 24); a rotating subassembly (14) including a hub (30), two inner raceways (56, 62) and two rows of roller bodies (16, 18), the two rows of roller bodies (16, 18) being arranged in two pitch planes (PP1, PP2). One of the inner raceways is formed on a rolling bearing ring (36), which bears against a transmission bowl at an annular contact interface located between the two pitch planes (PP1, PP2).

Description

Technical Field

[0001] The present invention relates to a motor vehicle wheel assembly. Background Art

[0002] Once mounted on a vehicle, a motor vehicle drive wheel assembly generally comprises: a fixed subassembly intended to be fastened to a suspension element of the vehicle and comprising a first outer raceway and a second outer raceway defining an axis of rotation; a rotating subassembly capable of rotating relative to the fixed member about the axis of rotation and comprising a wheel hub, a transmission bowl, a first inner raceway positioned opposite the first outer raceway, a second inner raceway positioned opposite the second outer raceway; and rolling elements forming a first row of rolling elements between the first outer raceway and the first inner raceway, and a second row of rolling elements between the second outer raceway and the second inner raceway. The wheel hub has an attachment interface for the wheel rim and the brake disc. Consequently, the assembly typically has a stack of technical functions arranged along the axis of rotation from the interior to the exterior of the vehicle: torque transmission, attachment to the vehicle's suspension, rotational guidance, braking, and rolling, which requires large dimensions in the axial direction (i.e., transversely to the vehicle's coordinate system).

[0003] Document FR 3,052,104 has already proposed shrinking the inner rolling bearing ring for the second inner raceway onto the transmission bowl. This makes it possible to reduce the axial dimension for a given distance between the two rows of rolling elements while increasing the pitch diameter of the row of rolling elements located on the inside of the vehicle. This configuration offers a solution for reconciling reduced axial bulk with good performance in terms of payload and camber stiffness, with payload and camber stiffness increasing as a function of the distance between the two rows of rolling elements and increasing as a function of the pitch diameter of the two rows of rolling elements.

[0004] Electric and hybrid vehicle powertrains are often more cumbersome at the drive wheels in the vehicle width direction than combustion engine powertrains, which leads to shortening of the transverse drive shafts. This shortening is undesirable because it results in larger angles in the transmission joints. Against this backdrop, any measure that makes it possible to even slightly increase the space available for these transverse drive shafts is desirable. Consequently, there is an increasing demand for axially compact drive wheel assemblies, without sacrificing performance, particularly in terms of payload and rigidity. Summary of the Invention

[0005] The object of the present invention is to provide a motor vehicle drive wheel assembly which combines axial compactness, a high payload and a good level of camber stiffness.

[0006] To this end, according to a first aspect of the present invention, a motor vehicle drive wheel assembly is proposed, the motor vehicle drive wheel assembly comprising:

[0007] - a stator assembly comprising a first annular outer raceway and a second annular outer raceway centered about a common axis of rotation;

[0008] - a rotating subassembly, which is rotatable relative to the fixed subassembly around the rotation axis, and comprises a wheel hub, a transmission bowl and at least one inner rolling bearing ring, the wheel hub comprising a flange, the flange being provided with an interface for attaching a wheel rim or a brake disc, the attachment flange forming a mounting surface of the wheel rim or the brake disc, the mounting surface facing axially in a disassembly direction of the wheel rim or the brake disc, the disassembly direction being parallel to the rotation axis, the mounting surface being tangent to an assembly reference surface perpendicular to the rotation axis, the inner rolling bearing ring shrinking over a shrink fit bearing of the wheel hub, the inner rolling bearing ring bearing against the transmission bowl at an annular contact interface extending at least in a radial direction relative to the rotation axis, the rotating subassembly further comprising a first inner raceway positioned opposite the first outer raceway and a second inner raceway positioned opposite the second outer raceway and formed on the inner rolling bearing ring; and

[0009] - rolling elements, forming a first row of rolling elements capable of rolling on the first outer raceway and the first inner raceway, and a second row of rolling elements capable of rolling on the second outer raceway and the second inner raceway, wherein a first nodal plane containing the centers of the rolling elements of the first row of rolling elements is located at a non-zero distance L from a second nodal plane containing the centers of the rolling elements of the second row of rolling elements in the disassembly direction, and the first row of rolling elements and the second row of rolling elements are located on the same outer side of a limiting plane of the drive wheel assembly, which is tangential to the rolling elements of the second row of rolling elements and perpendicular to the axis of rotation;

[0010] According to the invention, the annular contact interface between the inner rolling bearing ring and the annular bearing surface of the transmission bowl is at least partially positioned between the first nodal surface and the limit plane, and preferably completely between the first nodal surface and the limit plane, and has a maximum contact diameter DA, which is greater than the diameter DF of the shrink fit bearing and smaller than the raceway bottom diameter DI2 of the second inner raceway.

[0011] In this context, the maximum contact diameter DA is understood to mean the maximum diameter observed at the effective contact between the drive bowl and the inner rolling bearing ring and measured in a plane perpendicular to the axis of rotation.

[0012] According to the invention, it is proposed to equip the assembly with an inner rolling bearing ring having a specific geometry, which makes it possible to position the second inner raceway radially outside the first inner raceway and to accommodate a portion of the transmission bowl comprising the annular bearing surface in the recess formed by the inner rolling bearing ring.

[0013] Once the assembly is integrated into a vehicle, the first raceway and the first row of rolling elements are intended to be located further from a longitudinal median vertical plane of the vehicle than the second raceway and the second row of rolling elements.

[0014] Preferably, the annular contact interface between the inner rolling bearing ring and the annular bearing surface of the transmission bowl is located at least partially, and preferably completely, between the first and second pitch surfaces.

[0015] The pitch diameter of the first row of rolling elements is smaller than that of the second row of rolling elements and preferably significantly smaller to increase the volume available to accommodate the transmission bowl. Preferably, the bottom diameter DE1 of the first outer raceway is smaller than the bottom diameter DI2 of the second inner raceway.

[0016] The dimensions of the first rolling bearing, which is composed of the first inner raceway, the first outer raceway and the first row of rolling elements, and the dimensions of the second rolling bearing, which is composed of the second inner raceway, the second outer raceway and the second row of rolling elements, are adapted to the dimensions of the transmission bowl. Thus, according to one embodiment, the transmission bowl has a cavity comprising a plurality of rolling tracks, the rolling tracks having a track bottom diameter DBO, which preferably satisfies one or more of the following conditions:

[0017] - the track bottom diameter DBO is greater than the raceway bottom diameter DI1 of the first inner raceway,

[0018] - the track bottom diameter DBO is smaller than the raceway bottom diameter of the second inner raceway;

[0019] -The rail bottom diameter DBO is greater than the maximum contact diameter DA.

[0020] One or the other of the two rows of rolling elements can consist of conical or cylindrical rollers, which is particularly suitable for highly loaded vehicles.

[0021] However, according to a preferred embodiment aimed at minimizing the torque opposing the rotation of the rotating subassembly, in particular for light vehicles (cars or multi-purpose vehicles), the rolling elements are balls. Preferably, the ball diameter DC1 of the balls forming the first row of rolling elements is less than or equal to the ball diameter DC2 of the balls forming the second row of rolling elements. The increased diameter of the balls of the second row makes it possible to increase the distance between the two rows of balls, which limits the bending of the inner rolling bearing ring and therefore limits the risk of separation between the components of the rotating subassembly. The outer raceways are preferably enclosed in the axial direction in that they each have a raceway bottom which is located in an intermediate axial position between the axial ends of the raceways.

[0022] The rolling bearing ring is preferably a solid metal component, for example made of steel. Shrink-fitting the rolling bearing ring onto the wheel hub requires a shrink-fit bearing that, to optimize the axial compactness of the assembly, extends up to the vicinity of the first inner raceway. Preferably, the inner rolling bearing ring has an end face facing axially in the direction of disassembly, and this end face is located at a distance L1 from the plane containing the point of the annular contact interface between the inner rolling bearing ring and the annular bearing surface of the transmission bowl that is furthest from the axis of rotation, the distance L1 being less than 1.5 times the ball diameter of the balls in the first row of balls.

[0023] According to one embodiment, the maximum contact diameter DA of the annular contact interface is smaller than the sum of twice the diameter DC1 of the rolling elements of the first row of rolling elements and the diameter DF of the shrink-fit bearing.

[0024] In practice, the drive wheel assembly further includes a drive nut and a rolling element guided by rolling tracks formed in a cavity of the drive bowl and on the drive nut. The rolling element and the drive bowl form a drive joint that defines a pitch plane extending through the center of the rolling element when the rotational axes of the drive nut and the drive bowl are aligned. The pitch plane is preferably perpendicular to the rotational axis defined by the stator assembly. A pitch diameter of a pitch circle may also be defined, such that the center of the rolling element is located on the pitch circle when the rotational axes of the drive nut and the drive bowl are aligned.

[0025] Preferably, the maximum contact diameter DA of the annular contact interface is smaller than the pitch diameter DPB of the transmission joint.

[0026] To promote axial compactness of the assembly, the pitch plane of the transmission joint is located at a distance CA from the assembly reference plane, where the distance CA satisfies one or more of the following conditions:

[0027] - The distance CA is less than the pitch diameter of the second row of rolling elements;

[0028] - the distance CA is less than thirteen sevenths of the axial distance measured between the component reference plane and the second nodal surface;

[0029] - the ratio between the distance CA on the one hand and the distance L between the first and second nodal surfaces on the other hand is less than 4.75, preferably less than 4.6;

[0030] The ratio between the difference between the distance CA and the distance L2 between the assembly reference plane and the second pitch plane on the one hand and the pitch diameter of the second row of rolling elements on the other hand is less than 0.45.

[0031] According to one embodiment, the annular contact interface is flat.

[0032] According to another embodiment, the annular contact interface is trumpet-shaped, preferably conical, and preferably has a top angle A that satisfies one or more of the following conditions:

[0033] - the vertex angle A is 100° to 140°;

[0034] The vertex angle A is equal to, within + / - 10°, the vertex angle B of the frustoconical inner surface of the transmission bowl opposite the annular bearing surface.

[0035] The radial position of the mounting surface affects the stiffness of the assembly. According to one embodiment, the ratio between the maximum contact diameter DA of the annular contact interface and the pitch diameter DP2 of the second row of rolling elements is less than 0.65.

[0036] According to one embodiment, the transmission bowl comprises a splined end portion which is mounted, fitted or shrunk in a free-standing manner in a splined tubular portion of the hub, thereby forming a splined contact interface, the rotating subassembly preferably comprising at least one axial retaining element which is attached to the transmission bowl and which directly or indirectly bears against an abutment surface of the hub which rotates axially in the direction of disassembly. Preferably, the splined contact interface allows the hub to be disassembled. The axial retaining element may specifically comprise the head of a screw or a nut which is screwed into a threaded hole formed in the transmission bowl parallel to the axis of rotation, the nut being screwed onto a threaded portion formed on the transmission bowl. It may also be that cold deformation of one end of the transmission bowl or of the hub ensures axial interference between the two components. More generally, the end portion of the transmission bowl can have any cylindrical shape having a non-circular base that is freely mounted, fitted or shrunk in a tubular portion of a complementary shape of the hub, thereby forming a contact interface with a non-circular cross-section, the rotating subassembly preferably including at least one axial retaining element that is attached to the transmission bowl and directly or indirectly bears against an abutment surface of the hub that rotates axially in the removal direction.

[0037] For a particularly compact and rigid assembly, one or more of the following arrangements are provided:

[0038] the spline contact interface has a spline pitch diameter DPC, and the annular contact interface is located axially at a distance LAB from the assembly reference plane PA such that the sum of DPC and LAB is less than the pitch diameter DP2 of the second row of rolling elements;

[0039] The distance measured between the end of the spline contact interface closest to the annular contact interface in the axial direction and the assembly reference plane is less than four fifths of the length measured between the assembly reference plane and the second pitch plane.

[0040] According to one embodiment, the wheel hub further includes a centering bearing, which is used to center the brake disc or wheel rim, rotates radially relative to the axis of rotation, and projects axially relative to the mounting surface in the direction of removal. The centering bearing can, for example, be cylindrical or comprise two cylindrical portions with different diameters, the portion closest to the mounting surface preferably having a larger diameter than the portion furthest away, and serves to center the brake disc. Other profiles of the centering bearing are contemplated. The centering bearing can also be discontinuous and can include an annular groove or a groove parallel to the axis of rotation.

[0041] The mounting surface of the flange may be flat or include, for example, radial, annular or spiral striations, splines or grooves.

[0042] According to one embodiment, the rolling elements of the first row of rolling elements have contact points with the first inner raceway and the first outer raceway, the contact points being located on a first contact cone having a first vertex positioned relative to the first row of rolling elements and opposite to the second row of rolling elements, and the rolling elements of the second row of rolling elements have contact points with the second inner raceway and the second outer raceway, the contact points being located on a second contact cone having a second vertex positioned relative to the second row of rolling elements and opposite to the first row of rolling elements.

[0043] In practice, the fixing subassembly may include an attachment clip extending radially relative to the first and second outer raceways. The attachment clip is intended to attach the fixing subassembly to a suspension component of the vehicle. To this end, the attachment clip is preferably equipped with an attachment interface, which may include a hole for attaching the element to the suspension component.

[0044] According to one embodiment, the stator assembly comprises a one-piece solid metal outer ring, which forms the first and second outer raceways and preferably also the attachment clamp. Alternatively, one outer raceway and / or the other outer raceway can be arranged inside a rolling bearing ring, which is contracted into a sleeve forming the attachment clamp.

[0045] According to one embodiment, the first inner raceway is formed on the hub.

[0046] Alternatively, the first inner raceway is formed on a first inner rolling bearing ring, which is at least partially shrunk onto the wheel hub and axially bears against a shoulder of the wheel hub axially facing the second row of rolling elements. The first inner rolling bearing ring has a first axial end axially facing away from the second inner raceway. Preferably, the first inner rolling bearing ring axially bears against a shoulder of the wheel hub axially facing the second row of rolling elements. The shoulder provides axial support for the first inner rolling bearing ring.

[0047] Preferably, the hub is a solid, one-piece metal component, which contributes to greater rigidity of the assembly. Alternatively, the hub may be a solid, one-piece, bi-material component, such as a steel / aluminum or steel / composite combination

[0048] Preferably, the transmission bowl is a solid, one-piece metal component.

[0049] Where appropriate, the rotating subassembly further comprises a brake disc bearing on the mounting surface, a rim bearing on the brake disc and elements for attaching the rim and the brake disc to the attachment flange. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Other features and advantages of the present invention will become apparent from reading the following disclosure with reference to the accompanying drawings.

[0051] [ Figure 1A ] Figure 1A is a longitudinal sectional view of a motor vehicle drive wheel assembly according to a first embodiment of the present invention.

[0052] [ Figure 1B ] Figure 1B and Figure 1A Same, but with the different characteristic dimensions of the wheel assembly already included.

[0053] [ Figure 2 ] Figure 2 is a longitudinal sectional view of a motor vehicle drive wheel assembly according to a second embodiment of the present invention.

[0054] [ Figure 3 ] Figure 3 is a longitudinal sectional view of a motor vehicle drive wheel assembly according to a third embodiment of the present invention.

[0055] For greater clarity, the same or similar elements are identified by the same reference numerals throughout the drawings. DETAILED DESCRIPTION

[0056] Figure 1A A motor vehicle drive wheel assembly 10 is shown, comprising a stationary subassembly 12 intended to be fastened to a suspension component of a motor vehicle (not shown) and defining an axis of rotation 100; a rotating subassembly 14 rotatable within the stationary subassembly 12 about the axis of rotation 100; and guide rolling bodies 16, 18 between the rotating subassembly 14 and the stationary subassembly 12.

[0057] The stator assembly 12 is here composed of a one-piece solid metal outer ring 20, on which are formed coaxial first and second outer raceways 22, 24, which define an axis of rotation 100. The outer ring further comprises at least one attachment clip 26 extending radially outwards, in which a hole (not shown in this figure) is formed for attaching the attachment clip 26 to a suspension member via an attachment element (not shown).

[0058] The rotating subassembly 14 includes a hub 30 , a drive bowl 32 , a first inner rolling bearing ring 34 , and a second inner rolling bearing ring 36 .

[0059] The hub 30 is a one-piece solid metal component comprising a flange 38 for attaching a drive wheel rim 40 and a brake disc 41. The flange 38 has a face 42 supporting the brake disc 41 and is provided with attachment holes 43 allowing the insertion of attachment elements 143 of the rim 40 and the brake disc 41.

[0060] The wheel hub 30 also has a centering skirt 44 which projects axially relative to the flat bearing surface 42 in the direction of disassembly 200 of the rim 40 and the brake disc 41 and has a centering bearing 45 which is preferably stepped, facing radially outwards and comprises a first cylindrical portion for centering the rim 40 and a second cylindrical portion of equal or greater diameter for centering the brake disc 41 during assembly. The centering bearing 45 is not necessarily intended to remain in contact with the rim 40 and the brake disc 41 after assembly.

[0061] The drive bowl 32 is a solid, one-piece metal component having a solid protruding end portion 46 and a flared middle portion 48 that defines a cavity 50 for the constant velocity joint.

[0062] In this embodiment, the cavity comprises a rolling track 461 positioned opposite a complementary rolling track 321 formed on the transmission joint nut 322, so as to guide the rolling elements 323 along concave paths, for example in the form of circular arcs, each lying in a plane containing the axis of rotation 100. In a known manner, this assembly forms a transmission joint 320 that allows the transmission of motion and torque between the nut 322 fastened to the transmission shaft 324 and the transmission bowl 32 fastened to the hub 30, without the transmission shaft 324 remaining in perfect alignment with the axis of rotation 100 imposed by the outer ring 20, which, as will be recalled, is supported by suspension elements that ensure one or more degrees of freedom of movement of the outer ring 20 relative to the vehicle body.

[0063] The protruding portion 46 of the drive bowl 32 is freely splined, fitted or shrunk into the splined tubular cavity 47 of the hub 30, thereby forming a splined contact interface.

[0064] also, Figure 1A The means for attaching the transmission bowl 32 and the hub 30 are shown, which are realized by a nut 88 screwed onto the threaded end 90 of the projection 46 and bearing against the shoulder 84 of the hub 30 .

[0065] The first inner rolling bearing ring 34 is shrink-fitted on a cylindrical shrink-fit bearing 52 of the hub 30 and bears axially against an annular shoulder 54 formed on the hub 30. A first inner raceway 56 facing the first outer raceway 22 is formed on the first inner rolling bearing ring 34.

[0066] The second inner rolling bearing ring 36 is also shrink-fitted onto the cylindrical shrink-fit bearing 52 of the hub 30, with a transverse end face 57 axially bearing against the first inner rolling bearing ring 34 and an annular transverse abutment face 58 axially facing away from the inner raceway 56 and projecting axially relative to the hub 30, so as to bear against a shoulder 60 formed on the transmission bowl 32. In this embodiment, the annular transverse abutment face 58 and the shoulder 60 are flat. A second inner raceway 62 is formed on the second inner rolling bearing ring 36 opposite the second outer raceway 24. The rolling elements 16, 18 form, on the one hand, a first row of rolling elements 16 that roll on the first outer raceway 22 and the first inner raceway 56, and, on the other hand, a second row of rolling elements 18 that roll on the second outer raceway 24 and the second inner raceway 62.

[0067] For the remainder of this specification, we will focus on Figure 1B There are some notable dimensional characteristics of the components illustrated in , which require some preliminary definitions. Thus, we note that:

[0068] -PP1, the pitch plane on which the pitch circle lies constitutes the locus of the center of the rolling element 16 of the first row of rolling elements;

[0069] -PP2, the pitch plane on which the pitch circle lies constitutes the locus of the center of the rolling element 18 of the second row of rolling elements;

[0070] DP1, the diameter of the pitch circle of the first row of rolling elements 16;

[0071] DP2, the diameter of the pitch circle of the second row of rolling elements 18;

[0072] - DC1, the diameter of the balls 16 constituting the rolling elements of the first row of rolling elements;

[0073] - DC2, the diameter of the balls 18 constituting the rolling elements of the second row of rolling elements;

[0074] PA, a plane perpendicular to the axis of rotation 100 and tangential to the mounting surface 42;

[0075] PB, a plane perpendicular to the axis of rotation 100 and tangential to the axial end face 57 of the second inner ring 36 facing the disassembly direction 200 ;

[0076] PL, a plane perpendicular to the axis of rotation 100 and tangential to the rolling elements 18 of the second row of rolling elements, with both rows of rolling elements 16 , 18 being on the same side of this plane;

[0077] DA, the maximum diameter of the contact interface (ie, the effective contact area) formed between the transverse annular abutment surface 58 on the second inner rolling bearing ring 36 and the annular bearing surface 60 of the transmission bowl 38 ;

[0078] PAB, a plane perpendicular to the axis of rotation 100 and containing the point of the contact interface (in other words, the plane in which a circle of radius DA is drawn), between the annular transverse abutment surface 58 formed on the second inner rolling bearing ring 36 and the annular bearing surface 60 of the transmission bowl 38 that is furthest from the axis of rotation;

[0079] DBO, diameter of the bottom of the track of the rolling track formed in the cavity 50 of the transmission bowl 32; DPB, pitch diameter of the transmission joint 320, which is the diameter of the pitch circle containing the centers of the rolling elements 323 of the transmission joint 320 when the axis of the transmission shaft 324 is aligned with the axis of rotation 100, PPB, plane containing the pitch circle of the transmission joint 320, which plane is perpendicular to the axis of rotation 100 when the axis of the transmission shaft 324 is aligned with the axis of rotation 100,

[0080] DI1, a raceway bottom diameter of the first inner raceway 56, which is defined as the minimum diameter of the raceway 56;

[0081] DI2, a raceway bottom diameter of the second inner raceway 62, which is defined as the minimum diameter of the raceway 62;

[0082] DE1, a raceway bottom diameter of the first outer raceway 22, which is defined as the maximum diameter of the outer raceway 22;

[0083] DF, diameter of the shrink-fit bearing 52 at the second inner rolling bearing ring 36 ;

[0084] - DPC, the spline pitch diameter of the spline contact interface (ie, effective contact area) between the protruding portion 46 of the drive bowl 32 and the splined tubular portion 47 of the hub 30;

[0085] -LPC, the distance measured parallel to the axis of rotation 100, between the assembly reference plane PA on the one hand and the end of the spline contact interface closest to the interface between the transmission bowl 32 and the second inner rolling bearing ring 36 on the other hand, the spline contact interface being between the protruding portion 46 of the transmission bowl 32 and the splined tubular portion 47 of the hub 30.

[0086] The outer raceways 22, 24 formed on the outer rolling bearing ring 20 are axially enclosed, in the sense that each of the outer raceways 22, 24 has a raceway bottom 64, 66 located midway between the axial ends of the respective raceway 22, 24. The rolling elements 16, 18 are balls, and the raceways 22, 24, 56, 62 are arranged to form a rolling bearing having two rows of angular contact balls in a so-called "O" configuration. In other words, the contact point between the first row of rolling elements 16 and the associated raceway 22, 56 lies on a first contact cone having a first apex positioned relative to the first row of rolling elements 16 and opposite to the second row of rolling elements 18, while the contact point between the second row of rolling elements 18 and the associated raceway 24, 62 lies on a second contact cone having a second apex positioned relative to the second row of rolling elements 18 and opposite to the first row of rolling elements 16.

[0087] It is noteworthy that at least the annular bearing surface 60 for the axial support of the transmission bowl 32 on the second inner rolling bearing ring 36 is axially positioned between the pitch surface PP1 of the first row of rolling elements 16 and the stop plane PL, and preferably between the pitch surface PP1 of the first row of rolling elements 16 and the pitch surface PP2 of the second row of rolling elements. The annular bearing surface 60 is radially located between the shrink-fit bearing 52 of the hub 30 and the second inner raceway 62, and preferably between the shrink-fit bearing 52 and the raceway bottom diameter of the first outer raceway 64. In the radial direction, this translates into the fact that the diameter DA is greater than the shrink diameter DF and smaller than the raceway bottom diameter DI2, and preferably smaller than the raceway bottom diameter DE1.

[0088] This positioning gives the assembly 10 great axial compactness and excellent rigidity.

[0089] Preferably, a raceway bottom diameter DE1 of the first outer raceway 22 is smaller than an inner raceway bottom diameter DI2 of the second inner raceway 62 .

[0090] The track bottom diameter BOD of the rolling track 461 formed in the cavity 50 of the transmission bowl 32 satisfies the following conditions:

[0091] - the track bottom diameter DBO is greater than the raceway bottom diameter DI1 of the first inner raceway 56,

[0092] - the track bottom diameter DBO is smaller than the raceway bottom diameter DI2 of the second inner raceway 62;

[0093] The rail bottom diameter DBO is greater than the maximum diameter DA of the annular bearing surface 60 .

[0094] In this first embodiment, the rolling elements 16, 18 are balls, and the diameter DC1 of the balls forming the first row of rolling elements 16 is smaller than or equal to the diameter DC2 of the balls forming the second row of rolling elements 18. Selecting a relatively small diameter for the first row of balls 16 allows for a sufficient axial thickness of the second inner rolling bearing ring 36 in the shrink-fit region of the hub 30 adjacent the first row of rolling elements 16 and for the pitch surfaces PP1 and PP2 to be brought together. Selecting a larger diameter for the second row of rolling elements 18 ensures good load resistance while maintaining a relatively small distance between the two pitch surfaces PP1 and PP2.

[0095] The axial end plane PB of the second inner rolling bearing ring 36 is located at a distance L1 from the plane PAB, which is less than 1.5 times the ball diameter DC1 of the balls of the first row of rolling elements 16 :

[0096]

[0097] The nodal plane PPB is located at a distance CA from the plane PA, where the distance CA satisfies one or more of the following conditions:

[0098] - the distance CA is less than the pitch diameter DP2 of the second row of rolling elements 18;

[0099] The distance CA is less than thirteen sevenths of the axial distance L2 measured between the tangent plane PA and the pitch plane PP2 of the second row of rolling elements.

[0100] - the ratio between the distance CA and the distance L between the first nodal surface PP1 and the second nodal surface PP2 is less than 4.75, preferably less than 4.6;

[0101] the ratio between the difference between the distance CA and the distance L2 between the plane PA and the second pitch surface PP2 on the one hand and the pitch diameter PD2 of the second row of rolling elements 18 on the other hand is less than 0.45:

[0102]

[0103] The maximum contact diameter DA satisfies one or more of the following conditions:

[0104] The ratio between the diameter DA and the pitch diameter DP2 of the second row of rolling elements 18 is less than 0.65:

[0105]

[0106] The diameter DA is smaller than the sum of the diameter DF of the shrink-fit bearing 52 and the diameter DC1 of the rolling elements 16 of the first row of rolling elements:

[0107] DA<(DF+DC1)

[0108] The pitch diameter DP2 of the second row of rolling elements 18 is greater than the sum of the spline pitch diameter DPC and the distance LAB between the planes PA and PAB:

[0109] DPC+LAB<DP2

[0110] The distance LPC measured between the end of the spline contact interface of the annular contact interface closest in the axial direction to the plane PAB and the assembly reference plane (PA) is less than four fifths of the distance L2 between the plane PA and the pitch plane PP2 of the second row of rolling elements 18:

[0111]

[0112] In practice, the diameter DA is smaller than the pitch diameter DPB of the transmission joint.

[0113] As a variation of this first embodiment, the first raceway 56 may be formed directly on the hub 30 .

[0114] In another variant, the balls 16 , 18 of the two rows of balls may have the same diameter.

[0115] Figure 2 Examples and Figure 1A and Figure 1B The embodiment of differs primarily in that the first inner raceway 56 is formed directly on the hub 30. The second inner raceway 62 is in turn formed on an inner rolling bearing ring 36, which for convenience we will continue to refer to as the "second" inner rolling bearing ring. This second inner rolling bearing ring 36 is shrink-fitted on the shrink-fit bearing 52 and bears axially against the shoulder 86 of the hub 30 and against the shoulder 60 of the transmission bowl 32. This embodiment differs from Figure 1A and Figure 1B The second difference of the embodiment is that the annular abutment surface 58 and the annular support surface 60 are flared, here in the form of a truncated cone. In particular, the positioning and Figure 2 Dimension DA in FIG, corresponds to the largest circle of the contact area between the annular abutment surface 58 and the annular bearing surface 60. The vertex angle A of the annular bearing surface 60 and the annular abutment surface 58 is preferably between 100° and 140°. Furthermore, the vertex angle A is preferably equal to the vertex angle B of the frustoconical inner surface 61 of the transmission bowl 32 opposite the annular bearing surface 60, within + / - 10°.

[0116] The dimensional features presented in the first embodiment also exist in the second embodiment. Specifically, the contact interface created between the annular bearing surface 60 and the annular abutment surface 58 is located axially between the pitch plane PP1 of the first row of rolling elements 16 and the limit plane PL, and preferably between the pitch plane PP1 of the first row of rolling elements 16 and the pitch plane PP2 of the second row of rolling elements 18, and radially between the shrink-fit bearing 52 of the hub 30 and the second inner raceway 62, and preferably between the shrink-fit bearing 52 and the transverse plane containing the diameter of the raceway bottom of the first outer raceway 64.

[0117] Figure 3 An example is Figure 2 A variant of the embodiment of the invention is provided in which the diameters of the balls of the two rows of rolling elements 16, 18 are equal. Compared to the second embodiment, there is a slightly lower axial compactness, but there is a simplification when mounting the rolling bearing, eliminating the risk of incorrect ball selection.

[0118] Figure 3 The means for fastening the connection between the hub 30 and the transmission bowl 32 are shown, which are realized by a screw 76 which engages in a threaded hole 78 of the projection 46 of the transmission bowl 32, and the head 80 of this screw 76 bears against a shoulder 84 of the hub facing away from the transmission bowl 32. These fastening means can be interchanged for all embodiments.

[0119] Naturally, the examples shown in the drawings and discussed above are provided for illustrative and non-limiting purposes only.

[0120] As a variant, the fixing subassembly can be provided in multiple parts, wherein in one or more parts there is a clamp 26 which forms the attachment clamp to the suspension element of the vehicle and in which two coaxial outer rolling bearing rings are shrunk.

[0121] One row of rolling elements 16 or the other row of rolling elements 18 of the two rows can be composed of rollers having an axis of rotational symmetry, the center of each rolling element is defined as the center of gravity of the rolling element, and the rolling element diameter is the diameter measured in a plane perpendicular to the axis of rotational symmetry of the rolling element and passing through the center of gravity of the rolling element.

[0122] It is expressly provided that different illustrated embodiments may be combined to provide other embodiments. Figure 1A and Figure 2The mode of attachment between the transmission bowl 32 and the hub 30 illustrated in FIG. 3 is equally applicable to all embodiments of the drive wheel. More generally, the hub 30 can be attached to the transmission bowl 32 by any suitable means, in particular by the method described in application FR 3,003,201. A plurality of pre-machined splines can also be provided on the wall of the tubular cavity 47 of the hub 30 and on the corresponding part of the protruding portion 46 of the transmission bowl 32.

[0123] The transmission joint 320 has been illustrated as a Rzeppa-type constant velocity joint controlled by rolling tracks 461, 321, but may be other variations of constant velocity joints, such as a Rzeppa joint controlled by a joint cage or a cross-track joint. Thus, the rolling tracks 461, 321 do not necessarily have to be circular, or even concave; straight tracks are also possible.

[0124] It should be emphasized that all features as appear to a person skilled in the art from the present description, the drawings and the appended claims, even if they have been specifically described only with respect to other determined features (alone or in any combination), may be combined with other features or groups of features disclosed herein, provided that this is not expressly excluded or technical circumstances make such a combination impossible or meaningless.

[0125] Throughout the text of this application, the term "fixed subassembly" has been used to refer to the subassembly that constitutes the fixed coordinate system for the rotation of the movable subassembly. A person skilled in the art will understand that, depending on the geometry of the suspension interposed between the vehicle body and the fixed subassembly, the subassembly itself needs to move relative to the vehicle body.

Claims

1. A motor vehicle drive wheel assembly (10), comprising: A stator assembly (12) comprising a first annular outer raceway (22) and a second annular outer raceway (24) centered about a common rotation axis (100); A rotating subassembly (14) is rotatable relative to the fixed subassembly (12) about the rotation axis (100), and the rotating subassembly (14) comprises a wheel hub (30), a transmission bowl (32) and at least one inner rolling bearing ring (36), the wheel hub (30) comprising an attachment flange (38), the attachment flange (38) being provided with an interface for attaching a wheel rim (40) or a brake disc (41), the attachment flange (38) forming a mounting surface (42) of the wheel rim (40) or the brake disc (41), the mounting surface (42) axially facing a disassembly direction (200) of the wheel rim (40) or the brake disc (41), the disassembly direction (200) being parallel to the rotation axis ( 100), the mounting surface (42) is tangential to an assembly reference plane (PA) perpendicular to the axis of rotation, the inner rolling bearing ring (36) is shrunk over a shrink fit bearing (52) of the wheel hub, the inner rolling bearing ring (36) bears against the transmission bowl (32) at an annular contact interface, the annular contact interface extending at least in a radial direction relative to the axis of rotation (100), the rotating subassembly (14) further comprising a first inner raceway (56) and a second inner raceway (62), the first inner raceway (56) being positioned opposite the first annular outer raceway (22), the second inner raceway (62) being positioned opposite the second annular outer raceway (24) and being formed on the inner rolling bearing ring (36); and Rolling elements (16, 18), the rolling elements (16, 18) forming a first row of rolling elements (16) capable of rolling on the first annular outer raceway (22) and the first inner raceway (56), and a second row of rolling elements (18) capable of rolling on the second annular outer raceway (24) and the second inner raceway (62), a first nodal plane (PP1) including the center of the rolling element (16) of the first row of rolling elements, the first nodal plane (PP1) being located at a non-zero distance L from the second nodal plane (PP2) in the disassembly direction (200), the second nodal plane (PP2) including the center of the rolling element (18) of the second row of rolling elements, the first row of rolling elements (16) and the second row of rolling elements (18) being located on the same outside of a limiting plane (PL) of the drive wheel assembly (10) that is tangent to the rolling element (18) in the second row of rolling elements (18) and perpendicular to the rotation axis (100); It is characterized in that the annular contact interface between the inner rolling bearing ring (36) and the annular bearing surface (60) of the transmission bowl (32) is at least partially positioned between the first nodal surface (PP1) and the limit plane (PL), and the annular contact interface has a maximum contact diameter DA, which is greater than the diameter DF of the shrink fit bearing and smaller than the raceway bottom diameter DI2 of the second inner raceway (62).

2. The driving wheel assembly (10) according to claim 1, characterized in that The annular contact interface between the inner rolling bearing ring (36) and the annular bearing surface (60) of the transmission bowl (32) is at least partially positioned between the first pitch surface (PP1) and the second pitch surface (PP2).

3. The driving wheel assembly (10) according to claim 1 or claim 2, characterized in that: The raceway bottom diameter DE1 of the first annular outer raceway (22) is smaller than the raceway bottom diameter DI2 of the second inner raceway (62).

4. The driving wheel assembly (10) according to claim 1 or claim 2, characterized in that: The transmission bowl (32) has a cavity (50) including a rolling track (461), wherein the rolling track (461) has a track bottom diameter DBO, wherein the track bottom diameter DBO satisfies at least one of the following conditions: The track bottom diameter DBO is larger than the raceway bottom diameter DI1 of the first inner raceway (56), The track bottom diameter DBO is smaller than the raceway bottom diameter DI2 of the second inner raceway (62); The track bottom diameter DBO is greater than the maximum contact diameter DA.

5. The driving wheel assembly (10) according to claim 1, characterized in that The rolling elements (16, 18) are balls, and the ball diameter DC1 of the balls forming the first row of rolling elements (16) is smaller than or equal to the ball diameter DC2 of the balls forming the second row of rolling elements (18).

6. The driving wheel assembly (10) according to claim 5, characterized in that The inner rolling bearing ring (36) has an end face (57), which faces axially in the disassembly direction (200) and is located at a distance L1 from a plane (PAB) containing the point of the annular contact interface farthest from the rotation axis, the distance L1 being less than 1.5 times the ball diameter DC1 of the balls (16) in the first row of balls.

7. The driving wheel assembly (10) according to claim 5, characterized in that The maximum contact diameter DA of the annular contact interface is smaller than the sum of twice the diameter DC1 of the rolling element (16) in the first row of rolling elements and the diameter DF of the shrink-fit bearing (52).

8. The driving wheel assembly (10) according to claim 1, characterized in that The drive wheel assembly (10) further comprises a transmission nut (322) and a rolling transmission body (323), wherein the rolling transmission body (323) is guided by rolling tracks (461, 321), wherein the rolling tracks (461, 321) are formed in a cavity (50) of the transmission bowl (32) and on the transmission nut (322), and wherein the transmission nut (322), the rolling transmission body (323) and the transmission bowl (32) form a transmission joint (320) defining a pitch plane (PPB) and a pitch diameter.

9. The driving wheel assembly according to claim 8, characterized in that: The maximum contact diameter DA of the annular contact interface is smaller than the pitch diameter DPB of the transmission joint.

10. The driving wheel assembly according to claim 8, wherein: The pitch plane (PPB) of the transmission joint (320) is located at a distance CA from the assembly reference plane (PA), and the distance CA satisfies multiple of the following conditions: The distance CA is smaller than the pitch diameter DP2 of the second row of rolling elements (18); The distance CA is less than thirteen sevenths of the axial distance L2 measured between the assembly reference plane (PA) and the second nodal surface (PP2); a ratio of the distance CA to the distance L between the first nodal surface (PP1) and the second nodal surface (PP2) being less than 4.75; The ratio of the difference between the distance CA and the distance L2 to the pitch diameter DP2 of the second row of rolling elements (18) is less than 0.45, and the distance L2 is the distance between the assembly reference plane (PA) and the second pitch plane (PP2).

11. The driving wheel assembly (10) according to claim 1 or claim 2, characterized in that: The annular contact interface is flat.

12. The driving wheel assembly (10) according to claim 1 or claim 2, characterized in that: The annular contact interface is conical and has a vertex angle A that satisfies the following conditions: The vertex angle A is 100° to 140°.

13. The driving wheel assembly (10) according to claim 1 or claim 2, characterized in that: The ratio between the maximum contact diameter DA of the annular contact interface and the pitch diameter DP2 of the second row of rolling elements (18) is less than 0.

65.

14. The drive wheel assembly (10) according to claim 1, characterized in that The transmission bowl (32) includes a splined end (46) which is freely mounted, fitted or shrunk in a splined tubular portion (47) of the hub (30) to form a splined contact interface, and the rotating subassembly (14) includes at least one axial retaining element (80, 88) which is attached to the transmission bowl (32) and directly or indirectly abuts against an abutment surface (84) of the hub (30) which rotates axially in the disassembly direction (200).

15. The drive wheel assembly (10) according to claim 14, characterized in that The spline contact interface has a spline pitch diameter DPC, and the annular contact interface is axially located at a distance LAB from the assembly reference plane (PA), so that the sum of the spline pitch diameter DPC and the distance LAB is smaller than the pitch diameter DP2 of the second row of rolling elements.

16. The drive wheel assembly (10) according to claim 14, characterized in that The distance LPC measured between the end of the spline contact interface closest to the annular contact interface in the axial direction and the assembly reference plane (PA) is less than four-fifths of the length L2 measured between the assembly reference plane (PA) and the second pitch plane (PP2).

17. The drive wheel assembly (10) according to claim 1 or claim 2, characterized in that The hub is a solid, one-piece metal component.

18. The drive wheel assembly (10) according to claim 1 or claim 2, characterized in that: The rotating subassembly (14) further comprises a brake disc (41) supported on the mounting surface (42), a rim (40) supported on the brake disc (41), and an element (143) for attaching the rim (40) and the brake disc (41) to the attachment flange (38).

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