VEHICLE WHEEL HUB INCLUDING A SEAL, WHEEL BEARING ASSEMBLY AND ASSOCIATED MANUFACTURING METHOD

Abstract

Vehicle wheel hub assembly (1), comprising a vehicle wheel mounting flange (2), at least one inner raceway (11), and an intermediate zone between the flange (2) and the raceway, the intermediate zone forming an annular seal seat (3) centered on a reference axis of the wheel hub (4), characterized in that the seal seat (3) comprises at least one frustoconical ground surface (29).

Description

Title of the invention: Vehicle wheel hub comprising a sealing seat, wheel bearing assembly and associated manufacturing method Technical field of the invention

[0001] The invention relates to a vehicle wheel hub comprising a sealing seat, as well as to a wheel bearing incorporating such a hub and to a method of manufacturing such a hub. prior art

[0002] Document JP2022190415 A2 describes a vehicle wheel bearing assembly comprising an outer bearing ring, a one-piece wheel hub forming an inner bearing ring, and a seal fixed to the outer ring and in contact with a seal seat located between a flange and an inner raceway formed on the wheel hub. The function of the seal is to prevent foreign matter, such as muddy water, from entering an internal volume of the bearing. The seal seat has a concave profile in the form of a circular arc in any plane containing the axis of rotation of the bearing assembly.

[0003] With this type of vehicle wheel bearing device, a phenomenon, not explained in the literature, of depressurization of the internal volume of the bearing and / or the internal volume of the seal is observed, which leads to an increase in the contact pressure of the seal on the seal seat and to an uncontrolled drag torque, modifying the initial technical characteristics of the entire bearing device.

[0004] Document WO22059685 Al discloses a vehicle wheel bearing device which differs from the previous one by the addition of a stamped sheet metal ring, pressed onto the wheel hub, to constitute a seat for an added seal on which one or more lips of the sealing gasket fixed to the outer ring of the wheel bearing device slide.

[0005] This type of assembly does not appear to pose the depressurization problem mentioned earlier, but it requires the addition of an extra part, resulting in increased manufacturing and assembly costs. Furthermore, the interface between the flange and the hub also constitutes a potential entry point for contaminants and must itself be protected by the addition of static seals or sealing pastes. Description of the invention

[0006] The invention aims to overcome the drawbacks of the prior art and to propose means of increasing the service life of a bearing device vehicle wheel including a sealing gasket.

[0007] To this end, according to a first aspect of the invention, a vehicle wheel hub is proposed, consisting of a metal part and comprising: - a flange for fixing a vehicle wheel, - at least one raceway defining a reference axis of the wheel hub, the raceway being rotated radially in the opposite direction to the reference axis of the wheel hub, and - an intermediate zone between the flange and the raceway, the intermediate zone forming a seat for an annular seal centered on the reference axis of the wheel hub, the seal seat having at least one ground frustoconical surface.

[0008] The taper of the seal seat allows for better control of its grinding, and results in a surface finish such that there is no longer any suction phenomenon, uncontrolled crushing of the seal against the seat, or increase in drag torque. In particular, it allows grinding to be carried out using a grinding wheel rotating around an axis parallel to a generatrix of the frustoconical ground surface, and having a cylindrical grinding surface centered on its axis of rotation.

[0009] According to one embodiment, the flange has a flange face turned axially towards the rolling path.

[0010] According to one embodiment, the flange has an annular groove opening onto the flange face turned axially towards the rolling path and separating a distal part of the flange face turned axially towards the rolling path from a proximal part of the flange face turned axially towards the rolling path, the proximal part of the flange face turned axially towards the rolling path being located between the annular groove and the seal seat.

[0011] According to one embodiment, the flange face turned axially towards the raceway is connected to the seal seat by a junction portion with a concave profile in any cutting plane containing the reference axis of the wheel hub, and located opposite an annular space delimited by the seal seat and the raceway.

[0012] According to one embodiment, the ground frustoconical surface of the seal seat has a generatrix having one or more of the following dimensional characteristics: - the generatrix has an inclination greater than or equal to 15° with respect to the reference axis of the wheel hub, preferably greater than or equal to 20°; and / or - the generator has an inclination of less than or equal to 50° with respect to the reference axis of the wheel hub, preferably less than or equal to 40°; and / or - the generator has a length greater than 2 mm, preferably 3 mm; and / or - the generator has a length of less than 15 mm, preferably 8 mm.

[0013] The inclination and length of the generatrix of the joint seat then make it possible to position one, and preferably at least two, joint lips, without significantly increasing the axial dimension of the wheel hub, which we seek to minimize.

[0014] According to one embodiment, the seal seat comprises at least one additional frustoconical ground surface, having a generatrix with an inclination relative to the reference axis of the wheel hub equal to the inclination of the generatrix of the frustoconical ground surface relative to the reference axis of the wheel hub. This specific arrangement makes it possible to obtain the frustoconical ground surface and the additional frustoconical ground surface in a single grinding operation using a grinding wheel having two cylindrical grinding surfaces.

[0015] According to one embodiment, the joint seat is further from the reference axis of the wheel hub than the inner raceway.

[0016] According to another aspect of the invention, this relates to a vehicle wheel bearing assembly, comprising a vehicle wheel hub according to the previous aspect of the invention and an outer bearing ring carrying a seal which has at least one first seal lip coming into contact with the ground frustoconical surface of the seal seat.

[0017] According to one embodiment, the seal comprises at least a second seal lip coming into contact with the ground frustoconical surface of the seal seat.

[0018] In the event that the seal seat has an additional ground frustoconical surface, an outer bearing ring is provided carrying a seal which has at least a first seal lip coming into contact with the ground frustoconical surface of the seal seat and an additional seal lip coming into contact with the additional ground frustoconical surface of the seal seat.

[0019] Assuming the flange has an annular groove opening onto the flange face oriented axially towards the raceway and separating a distal portion of the flange face oriented axially towards the raceway from a proximal portion of the flange face oriented axially towards the raceway, the seal may advantageously include at least one labyrinth lip penetrating the annular groove, without contacting the wheel hub. The labyrinth provides initial protection against external contaminants upstream of the seal seat.

[0020] According to one embodiment, rolling bodies are arranged so as to roll on at least one external rolling race formed on the outer ring and on an internal rolling race.

[0021] According to another aspect of the invention, it relates to a method for manufacturing a vehicle wheel hub made of a metal part, in particular such as pre- as previously described, the process comprising - a forming of a vehicle wheel hub blank comprising a vehicle wheel mounting flange blank, at least one inner raceway blank defining a reference axis of the hub blank, and an intermediate zone between the flange blank and the raceway blank, and - a grinding step by a grinding wheel having a cylindrical grinding surface around a reference axis of the grinding wheel, the reference axis of the grinding wheel being coplanar with a reference axis of the hub blank and making an angle with the reference axis of the hub blank, the grinding wheel rotating around the reference axis of the grinding wheel and the hub blank rotating around the reference axis of the hub blank, to form, with the cylindrical grinding surface, at the intermediate zone, a joint seat having at least one frustoconical ground surface of which any generatrix has with the reference axis of the hub blank an angle equal to the angle between the reference axis of the grinding wheel and the reference axis of the hub blank.

[0022] The surface finish obtained after grinding with such a grinding wheel is characterized by the absence of grinding marks not perpendicular to the generatrices of the frustoconical ground surface. Any grinding marks present are essentially perpendicular to the generatrices of the frustoconical ground surface, which they intersect. Experience shows that this orientation helps to prevent the appearance of a pressure difference on either side of the joint lip that comes into contact with the frustoconical ground surface.

[0023] According to one embodiment, the grinding wheel has a convex grinding surface in any cutting plane containing the reference axis of the grinding wheel, the grinding step comprising grinding a raceway by the convex grinding surface. Thus, the proposed method makes it possible, in a single grinding step and without changing the orientation of the grinding wheel, to generate both the frustoconical ground surface of the seal seat and the ground surface of the inner raceway.

[0024] According to one embodiment, the angle formed by the reference axis of the hub blank with the reference axis of the grinding wheel is: greater than or equal to 15°, preferably greater than or equal to 20°; and / or less than or equal to 50°, preferably less than or equal to 40°. brief description of the figures

[0025] Other features and advantages of the invention will become apparent from the following description, with reference to the accompanying figures, which illustrate: • [Fig.1] the [Fig.1], a cross-section of a vehicle wheel hub assembly; • [Fig.2] the [Fig.2], manufacturing process of a wheel hub assembly vehicle according to the same cut;

[0026] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. DETAILED description of implementation methods

[0027] Figure 1 illustrates a vehicle wheel bearing assembly, comprising an outer bearing ring 9, a wheel hub 1 forming an inner bearing ring, and rolling elements 12, which may be balls or rollers, coming into contact with at least one outer raceway 10 formed on the outer ring 9 and at least one inner raceway 11 formed directly on the wheel hub 1. The wheel hub consists of a metal part comprising a flange 2 for fixing a vehicle wheel, the raceway 11, and, connecting these two areas, an intermediate area forming a seat for an annular seal 3 centered on a reference axis of the wheel hub 4.

[0028] The mounting flange 2 has a flange face 5, turned axially towards the rolling track 11, and extending radially with respect to the reference axis of the wheel hub 4. The mounting flange 2 is provided, in a known manner, with mounting holes 30 allowing the attachment of a wheel rim (not illustrated) to one side of the flange opposite the flange face 5.

[0029] According to one embodiment, this flask face 5 is separated into two parts by an annular groove 6. The two parts of the flask face 5 being on one side of the annular groove 6, the distal flask face 7, and on the other side of the annular groove 6, located between the annular groove 6 and the joint seat 3, the proximal flask face 8.

[0030] The flange face 5, the outer bearing ring 9, the seal seat 3 and the raceways 10, 11 define an annular space 13. This space is exposed to an environment which can accelerate the wear of the raceways 10, 11 and the rolling elements 12. It is therefore protected by a seal 14 which may comprise a rigid reinforcement 15 and a flexible sealing element 16, for example made of elastomer material, all of which is shrink-fitted onto the outer bearing ring 9.

[0031] According to one embodiment, the sealing element 16 has a labyrinth lip 17 that fits into the annular groove 6 without coming into contact with the surface of this annular groove 6. This arrangement forms a labyrinth 18 which minimizes the entry of external pollutants into the annular space 13.

[0032] According to one embodiment, at the level of the seal seat 3, the sealing element 16 forms a contact lip 19 in sliding contact with the seal seat 3. According to one embodiment, at the level of the seal seat 3, the sealing element 16 forms several contact lips 19 in sliding contact with the seal seat 3.

[0033] The joint seat 3 opens on the one hand onto the proximal flange face 8 by a junction having a concave profile 20 in any cutting plane containing the reference axis of the wheel hub and located opposite the annular space 13, and on the other hand onto the inner rolling race 11 by another junction with a concave profile 20 opposite the annular space 13.

[0034] Remarkably, the seal seat 3 has at least one frustoconical ground surface 29 with respect to the reference axis of the wheel hub 4. This frustoconical ground surface 29 is generated by a generatrix 21 whose inclination with respect to the reference axis of the hub assembly 4 is preferably greater than 15° and less than 50° and preferably measuring at least 2 mm and at most 15 mm. This band width generated by the generatrix 21 allows for one, or preferably two, or even three contact lips 19 depending on the embodiment chosen, without excessively increasing the axial distance between the flange face 5 and the inner raceway 11.

[0035] Remarkably, none of the lips 17,19 of the sealing element 16 is in contact with a surface of the vehicle wheel hub 1 other than the ground frustoconical surface 29.

[0036] According to a variant not illustrated in the figures, the joint seat may have several stepped frustoconical surfaces, which have the same angle a with the reference axis of the wheel hub 4.

[0037] Figure 2 illustrates a manufacturing process for the vehicle wheel hub assembly 1.

[0038] The manufacturing process for a vehicle wheel hub assembly 1 includes forming a wheel hub blank 22 comprising a vehicle wheel mounting flange 2, an inner raceway 11, and an intermediate zone between the flange 2 and the raceway 11.

[0039] Remarkably, this process includes a grinding step using a grinding wheel 23 having at least one first cylindrical grinding surface 24 about a reference axis of the grinding wheel 25, the reference axis of the grinding wheel 25 being coplanar with a reference axis of the hub blank 26 and making a constant angle fi with the reference axis of the hub blank 26. The grinding wheel 23 rotates about the reference axis of the grinding wheel 25 and the wheel hub blank 22 rotates about the reference axis of the hub blank 26, to form the ground frustoconical surface 29 of the ground frustoconical seal seat 3, the generatrices 21 of which make an angle α equal to fi with the reference axis 26. The angle fi is therefore, like the angle α, preferably between 15° and 50°.The equality between the angles a and fi ensures that any striations generated by the grinding wheel at the level of the truncated conical ground surface 29 have an orientation perpendicular to the generatrices of . the rectified frustoconical surface 29 which they intersect.

[0040] The grinding wheel 23 has a second convex grinding surface 27 in any cutting plane containing the reference axis of the grinding wheel 25, and which allows, in the same pass of the grinding wheel during the grinding step, the grinding of the inner raceway 11. The joining areas 20 can be ground in the same grinding step.

[0041] The grinding wheel 23 is preferably made of fine grains and soft grades in order to obtain the best possible grinding of the surface of the seat of the truncated conical joint 3, and is mounted on a grinding machine.

Claims

Demands

1. Vehicle wheel hub (1), consisting of a metal part and comprising: - a flange (2) for fixing a vehicle wheel, - at least one inner raceway (11) defining a reference axis of the wheel hub (4), the inner raceway (11) being rotated radially in the opposite direction to the reference axis of the wheel hub (4), and - an intermediate zone between the flange (2) and the inner raceway (11), the intermediate zone forming an annular seal seat (3) centered on the reference axis of the wheel hub (4), characterized in that the seal seat (3) comprises at least one frustoconical ground surface (29).

2. Vehicle wheel hub (1) according to claim 1, characterized in that the flange (2) has a flange face (5) axially turned towards the raceway (11), connected to the seal seat (3) by a concave profile junction portion (20) in any cutting plane containing the reference axis of the wheel hub (4), and located opposite an annular space (13) delimited by the seal seat (3) and the inner raceway (11).

3. Vehicle wheel hub (1) according to any one of the preceding claims, characterized in that the ground frustoconical surface (29) of the seal seat (3) has a generatrix (21) having one or more of the following dimensional characteristics: - the generatrix (21) has an inclination greater than or equal to 15° with respect to the reference axis of the wheel hub (4), preferably greater than or equal to 20°; and / or - the generatrix (21) has an inclination less than or equal to 50° with respect to the reference axis of the wheel hub (4), preferably less than or equal to 40°; and / or - the generatrix (21) has a length greater than 2 mm, preferably 3 mm; and / or - the generatrix (21) has a length less than 15 mm, preferably 8 mm.

4. Vehicle wheel hub (1) according to claim 3, characterized in that the seal seat (3) comprises at least one additional frustoconical ground surface, having a generatrix having an inclination with respect to the reference axis of the wheel hub (4), equal to the inclination of the generatrix (21) of the frustoconical ground surface, with respect to the reference axis of the wheel hub (4).

5. Vehicle wheel hub (1) according to any one of the preceding claims, characterized in that the seal seat (3) is further away from the reference axis of the wheel hub (4) than the inner raceway (11).

6. Vehicle wheel bearing assembly, characterized in that it comprises a vehicle wheel hub (1) according to any one of claims 1 to 5 and an outer bearing ring (9) carrying a seal (14) which has at least one first seal lip (19) coming into contact with the ground frustoconical surface (29) of the seal seat (3).

7. Vehicle wheel bearing assembly according to claim 6, characterized in that the seal (14) comprises at least a second seal lip (19) coming into contact with the ground frustoconical surface (29) of the seal seat (3).

8. Vehicle wheel bearing assembly, characterized in that it comprises a vehicle wheel hub (1) according to claim 4 and an outer bearing ring (9) carrying a seal (14) which has at least a first seal lip (19) coming into contact with the frustoconical ground surface (29) of the seal seat (3) and an additional seal lip coming into contact with the additional frustoconical ground surface of the seal seat.

9. Vehicle wheel bearing assembly according to any one of claims 6 to 8, characterized in that rolling bodies (12) are arranged so as to roll on at least one outer raceway (10) formed on the outer ring (9) and on an inner raceway (11).

10. A method for manufacturing a vehicle wheel hub consisting of a metal part, in particular a hub according to any one of claims 1 to 5, the method comprising: forming a vehicle wheel hub blank (22) comprising a wheel mounting flange blank (2) of vehicle, at least one inner raceway blank (11) defining a reference axis of the hub blank (26), and an intermediate zone between the flange blank (2) and the inner raceway blank (11), characterized in that it comprises a grinding step by a grinding wheel (23) having a cylindrical grinding surface (24) about a reference axis of the grinding wheel (25), the reference axis of the grinding wheel (25) being coplanar with the reference axis of the hub blank (26) and making an angle with the reference axis of the hub blank (26), the grinding wheel (23) rotating about the reference axis of the grinding wheel (25) and the hub blank (22) rotating about the reference axis of the hub blank (26), to form, with the cylindrical grinding surface (24), at the intermediate zone, a joint seat (3) having at least one frustoconical ground surface (29) any generatrix of which has an angle with the reference axis of the hub blank (26) equal to the angle between the reference axis of the grinding wheel (25) and the reference axis of the hub blank (26).

11. Method of manufacturing a vehicle wheel hub assembly (1) according to claim 10, characterized in that the grinding wheel (23) has a convex grinding surface (27) in any cutting plane containing the reference axis of the grinding wheel (25), the grinding step comprising the grinding of an internal raceway (11) by the convex grinding surface (27).

12. A method for manufacturing a vehicle wheel hub assembly according to any one of claims 10 to 11, characterized in that the angle formed by the reference axis of the hub blank (26) with the reference axis of the grinding wheel (25) is: - greater than or equal to 15°, preferably greater than or equal to 20°; and / or - less than or equal to 50°, preferably less than or equal to 40°.

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