CHEVE, Olivier (11 Chemin de la Bondonnière, Chanceaux S/Choisille, F-37390, FR)
LANDRIEVE, Franck (La Butte, Fondettes, F-37230, FR)
CHEVE, Olivier (11 Chemin de la Bondonnière, Chanceaux S/Choisille, F-37390, FR)
| CLAIMS 1. Sensor unit (4), for a rolling bearing assembly (1) having a rolling bearing (2) equipped with a fixed ring (21), a mobile ring (22) rotatable around a rotation axis (X2-X'2) and a target (5) attached to the mobile ring (22), the sensor unit (4) comprising: at least one sensing element (41 ) adapted to read the target (5), a holding part (42) for holding the sensing element (41), the holding part (42) being arranged to approximately face the mobile ring (22) parallel to the rotation axis (X2-X'2), a securing part (43) intended to secure the sensor unit (4) to the fixed ring (21 ), the securing part (43) being arranged to approximately face the fixed ring (21) parallel to the rotation axis (X2-X'2), wherein the sensor unit (4) further comprises a resilient part (44) attached to the holding part (42) and to the securing part (43), the elasticity of the resilient part (44) allowing a displacement of the holding part (42) relative to the securing part (43), said displacement having a component parallel to the rotation axis (X2- X'2). 2. Sensor unit (4) according to claim 1 , wherein the resilient part (44) is integral with the holding part (42) and/or with the securing part (43). 3. Sensor unit (4) according to claim 1 , wherein the resilient part (44) is distinct from the holding part (42) and from the securing part (43). 4. Sensor unit (4) according to any preceding claim, wherein said displacement only has a component parallel to the rotation axis (X2-X'2), the resilient part (44) having a relatively high stiffness in a direction (Y2-V2) perpendicular to the rotation axis (X2-X'2)- 5. Sensor unit (4) according to any preceding claim, wherein the holding part (42), the securing part (43) and the resilient part (44) respectively are in the general shape of a ring, the resilient part (44) surrounding at least partially the securing part (43), the holding part (42) surrounding at least partially the resilient part (44). 6. Sensor u n it (4 ) accord ing to cla im 5, wherein the resilient part (44) comprises an an nular portion (441 ) and a tu bular portion (442), the annular portion (441 ) having its periphery attached to the holding part (42) and its central region attached to the securing part (43), the tubular portion (442) extending from the central region of the annular portion (441 ) parallel to the rotation axis (X2-X'2) and being attached to the securing part (43). 7. Sensor un it (4) accord ing to any preceding claim, wherein the resilient part (44) is made of a synthetic material, either elastomeric or plastics. 8. Support member (3), for a rolling bearing (2) equipped with a fixed ring (21 ), a mobile ring (22) rotatable around a rotation axis (X2-X'2) and a target (5) attached to the mobile ring (22), the support member (3) comprising: a protruding ring (31 ) for firmly receiving the target (5), the protruding ring (31 ) being arranged to project outwards of the rolling bearing (2), fastening means (35) for fastening the support member (3) in rotation with the mobile ring (22), wherein the su pport mem ber (3) fu rther comprises a seal ing element (36) arranged to cooperate with the fixed ring (21 ) so as to seal the rolling elements (23) of the rolling bearing (2). 9. Support member (3) according to claim 8, wherein the sealing element (36) is a lip seal. 1 0. Su pport member (3) accord ing to any of cla ims 8 to 9, wherein the sealing element (36) is in the general shape of an annulus. 1 1 . Support member (3) accord ing to any of claims 8 to 1 0, wherein the sea l i ng el ement (36) extend s towards the rotation axis (X2-X 2) s o a s to cooperate with the inner ring (21 ) of the rolling bearing (2). 12. Support member (3) according to any of claims 8 to 11 , wherein the sealing element (36) is secured to an annular surface (39) of the support member (3), the annular surface (39) being oriented opposite the protruding ring (31). 13. Support member (3) according to any of claims 8 to 12, wherein the protruding ring (31 ) is in the general shape of a cylinder coaxial with the rotation axis (X2-X'2), the outer surface (33) of which is intended to receive the target (5). 14. Support member (3) according to any of claims 8 to 13, wherein the sealing element (36) is made of a material containing nitrile. 15. Support member (3) according to any of claims 8 to 14, wherein the support member (3) is made of an aluminum-based material. 16. Rolling bearing assembly (1) having a rolling bearing (2) equipped with a fixed ring (21), a mobile ring (22) rotatable around a rotation axis (X2-X'2) and a target (5) attached to the mobile ring (22), wherein: the rolling bearing assembly (1 ) further comprises a sensor unit (4) according to any of claims 1 to 7, the holding part (42) approximately faces the mobile ring (22) parallel to the rotation axis (X2-X'2), and - the securing part (43) approximately faces the fixed ring (21 ) parallel to the rotation axis (X2-X'2), the securing part (43) is fast in translation with the fixed ring (21 ) parallel to the rotation axis (X2-X'2), the resilient part (44) has a rest position where a clearance (42.22) extends, parallel to the rotation axis (X2-X2), between the holding part (42) and a terminal surface (221) of the mobile ring (22), and a contact position where the holding part (42) contacts the terminal surface (221 ). 1 7. Rol l ing bearing assembly ( 1 ) accord ing to claim 16, wherein the sensing element (41 ) faces the target (5) along a direction (Y2-Y 2) perpendicular to the rotation axis (X2-X'2), 1 8. Roll ing bearing assembly ( 1 ) according to any of claims 1 6 to 1 7, wherein the elasticity of the resilient part (44) is selected so that the force required for putting the resilient part (44) in its contact position is lower than the static load capacity of the rolling bearing (2). 1 9. Roll ing bearing assembly ( 1 ) according to any of claims 1 6 to 1 8, wherein the fixed ring (21 ) is the inner ring and the mobile ring (22) is the outer ring, and wherein the sensor unit (4) is formed according to claim 5. 20. Rol l ing bearing assembly ( 1 ) accord ing to claim 19, wherein the holding part (42) has an outer diameter (D42) larger than the outer diameter (D22) of the outer ring (22), wherein the outer ring (22) defines a sealing surface (222), and wherein the holding part (42) comprises a sealing member (422) arranged to cooperate with the sealing surface (222) so as to seal the clearance (42.22) against exterior contaminants. 21 . Rol l ing bearing assembly ( 1 ) accord ing to claim 20, wherein the sealing surface (222) and the terminal surface (221 ) are defined by a protruding element (220) having a rotational symmetry around the rotation axis (X2-X'2) and a generally "L" cross-section, in a plane comprising the rotation axis (X2-X'2), the seal ing surface (222) extending at a diameter (D222) larger than the outer diameter (D221 ) of the terminal surface (221 ), the sealing surface (222) being longer, parallel to the rotation axis (X2-X'2), than said clearance (42.22), so that the sealing member (422) cooperates with the sealing surface (222) when the resilient part (44) is in its rest position and when the resilient part (44) is in its contact position. 22. Roll ing bearing assembly ( 1 ) according to any of claims 1 6 to 21 , wherein the target (5) is a magnetic encoder washer. 23. Roll ing bearing assembly ( 1 ) according to any of claims 1 6 to 22, wherein the rolling bearing assembly (1 ) further comprises a support member (3) according to any of claims 8 to 15. 24. Method for assembling a rolling bearing assembly (1 ) according to any of claims 1 6 to 23 onto a rotating body having a shaft (7) and a hub (8), like a wheel, wherein the method comprises the steps of: a) securing the fixed ring (21 ) to either one of the shaft (7) and the hub (8); b) fastening the securing part (43) in translation relative to the fixed ring (21 ); c) place the mobile ring (22 ) next to a receiving space (80) defined by the other one of the shaft (7) and the hub (8); d) applying an axial force on the holding part (42) up to putting the resilient part (44) in its contact position; e) applying an axial force on the holding part (42) up to press-fitting the mobile ring (22) to the receiving space (80). |
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sensor unit for a rolling bearing assembly.
Moreover, the present invention relates to a rolling bearing assembly comprising such a sensor unit and/or such a support member. Furthermore, the present invention relates to a method for assembling such a rolling bearing assembly. The present invention also relates to a support member for a rolling bearing assembly. The present invention can be used for example in a wheel of a two- wheels vehicle, such as a motorcycle or a bicycle.
BACKGROUND ART OF THE INVENTION
A prior art rolling bearing assembly usually has a rolling bearing equipped with a fixed ring, a mobile ring rotatable around a rotation axis and a target attached to the mobile ring. A prior art rolling bearing assembly also has a sensor unit, which comprises a sensor to read the target and which is mounted next to the rolling bearing along a direction parallel to the rotation axis.
A prior art method for assembling such a rolling bearing assembly requires two main steps: A first step consists in securing the rolling bearing to the rotating body, usually by fastening the inner ring to a shaft and by press-fitting, i.e. applying an axial force thereon, the outer ring into a casing, like the hub of a wheel. A second step consists in fastening the sensor unit to the shaft and/or to the casing while accurately placing the sensor unit next to the rolling bearing.
These two main steps are relatively time-consuming, because they require accuracy and successive operations. Besides, the step of press-fitting the outer ring into the casing requires that the overall radial size of the sensor unit be significantly smaller than the outer diameter of the outer ring. Such a requirement induces severe constraints on the design of the sensor unit, in particular for a rolling bearing assembly intended to be mounted in a wheel of a two-wheels vehicle. Moreover, this requirement prevents sealing of the rolling bearing by the sensor unit, thus likely reducing the rolling bearing service life. A prior art rolling bearing assembly also comprises a support member for supporting the target, the support member is secured to the mobile ring so as to accurately position the target which is to be read by the sensor. Besides, the rolling bearing has one or more sealing member(s) extending between the mobile ring and the fixed ring and fastened to one of them. Such a sealing member permits to seal the rolling bearing i.e. to prevent the ingress of exterior contaminants therein or the leakage of lubricant therefrom. However, such an arrangement of two components, i.e. the support member next to the sealing member, is relatively cumbersome and its assembly is relatively time-consuming and difficult.
SUMMARY OF THE INVENTION
One object of the present invention is to overcome the afore-mentioned drawbacks, by providing a sensor unit which allows to apply an axial force on the mobile ring, which provides a clearance between the mobile ring and the sensor unit and which enables a sealing of the rolling bearing.
To achieve this object, a subject-matter of the present invention is a sensor unit, for a rolling bearing assembly having a rolling bearing equipped with a fixed ring, a mobile ring rotatable around a rotation axis and a target attached to the mobile ring, the sensor unit comprising:
at least one sensing element adapted to read the target,
a hold ing part for hold ing the sensing element, the holding part being arranged to approximately face the mobile ring parallel to the rotation axis, a securing part intended to secure the sensor unit to the fixed ring, the securing part being arranged to approximately face the fixed ring parallel to the rotation axis.
The sensor unit further comprises a resilient part attached to the holding part and to the securing part, the elasticity of the resilient part allowing a displacement of the holding part relative to the securing part, said displacement having a component parallel to the rotation axis.
In other words, the resilient part allows to elastically move the holding part parallel to the rotation axis, so that the holding part can contact the mobile ring and apply a force thereon, thus permitting to press-fit the rolling bearing into a casing.
According to advantageous but optional features, considered on their own or in any technically feasible combination:
- The resilient part is integral with the holding part and/or with the securing part.
- The resilient part is distinct from the holding part and from the securing part.
- Said displacement only has a component parallel to the rotation axis, the resilient part having a relatively high stiffness in a direction perpendicular to the rotation axis.
- The holding part, the securing part and the resilient part respectively are in the general shape of a ring , the resilient part surrounding at least partially the securing part, the holding part surrounding at least partially the resilient part.
- The resilient part comprises an annular portion and a tubular portion, the annular portion having its periphery attached to the holding part and its central reg ion attach ed to the secu ri ng pa rt, the tubular portion extending from the central region of the annular portion parallel to the rotation axis and being attached to the securing part.
- The resilient part is made of a synthetic material, either elastomeric or plastics.
Furthermore, another object of the present invention is to provide a support member which has a compact structure and which allows a sealing of the rolling bearing.
To achieve this object, a subject-matter of the present invention is a support member, for a rolling bearing equipped with a fixed ring, a mobile ring rotatable around a rotation axis and a target attached to the mobile ring, the support member comprising:
- a protruding ring for firmly receiving the target, the protruding ring being arranged to project outwards of the rolling bearing,
- fastening means for fastening the support member in rotation with the mobile ring. The support member further comprises a sealing element arranged to cooperate with the fixed ring so as to seal the rolling elements of the rolling bearing.
According to advantageous but optional features, considered on their own or in any technically feasible combination:
- The sealing element is a lip seal.
- The sealing element is in the general shape of an annulus.
- The sealing element extends towards the rotation axis so as to cooperate with the inner ring of the rolling bearing.
- The sealing element is secured to an annular surface of the support member, the annular surface being oriented opposite the protruding ring.
- The protruding ring is in the general shape of a cylinder coaxial with the rotation axis, the outer surface of which is intended to receive the target.
- The sealing element is made of a material containing nitrile.
- The support member is made of an aluminium-based material.
Besides, a subject-matter of the present invention is a rolling bearing assembly having a rolling bearing equipped with a fixed ring, a mobile ring rotatable around a rotation axis and a target attached to the mobile ring, wherein:
- the rolling bearing assembly further comprises a sensor unit according to the present invention,
- the holding part approximately faces the mobile ring parallel to the rotation axis, and
- the securing part approximately faces the fixed ring parallel to the rotation axis,
- the securing part is fast in translation with the fixed ring parallel to the rotation axis,
- the resilient part has a rest position where a clearance extends, parallel to the rotation axis, between the holding part and a terminal surface of the mobile ring, and a contact position where the holding part contacts the terminal surface.
In other words, the support member according to the invention can achieve several functions: supporting the target and sealing the rolling bearing. According to advantageous but optional features, considered on their own or in any technically feasible combination:
- The sensing element faces the target along a direction perpendicular to the rotation axis.
- The elasticity of the resilient part is selected so that the force required for putting the resilient part in its contact position is lower than the static load capacity of the rolling bearing.
- The fixed ring is the inner ring and the mobile ring is the outer ring, and wherein the sensor unit is formed according to the invention.
- The holding part has an outer diameter larger than the outer diameter of the outer ring, wherein the outer ring defines a sealing surface, and wherein the holding part comprises a sealing member arranged to cooperate with the sealing surface so as to seal the clearance against exterior contaminants.
- The sealing surface and the terminal surface are defined by a protruding element having a rotational symmetry around the rotation axis and a generally "L" cross-section, in a plane comprising the rotation axis, the sealing surface extending at a diameter larger than the outer diameter of the terminal surface, the sealing surface being longer, parallel to the rotation axis, than said clearance, so that the sealing member cooperates with the sealing surface when the resilient part is in its rest position and when the resilient part is in its contact position.
- The target is a magnetic encoder washer.
- The rolling bearing assembly further comprises a support member according to the present invention.
Besides, a subject-matter of the present invention is a method for assembling a rolling bearing assembly according to the present invention onto a rotating body having a shaft and a hub, like a wheel, wherein the method comprises the steps of:
a) securing the fixed ring to either one of the shaft and the hub;
b) fastening the securing part in translation relative to the fixed ring;
c) place the mobile ring next to a receiving space defined by the other one of the shaft and the hub; d) applying an axial force on the holding part up to putting the resilient part in its contact position;
e) applying an axial force on the holding part up to press-fitting the mobile ring to the receiving space.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention and its advantages will be well understood on the basis of the following description, which is given as an illustrative example, without restricting the scope of the invention, and in relation with the annexed drawings among which:
- Figure 1 is a perspective view of a hub and a fork of a two-wheels vehicle, the hub comprising a rolling bearing assembly according to the invention, the latter comprising a sensor unit according to the invention and a support member according to the invention;
- Figure 2 is a partial cross-section, at a larger scale and along plane II on figure 1 , of the hub, the fork and the rolling bearing assembly of figure 1 .
- Figure 3 is an exploded perspective view of the rolling bearing assembly of figure 1 ;
- Figure 4 is an exploded perspective view, at an angle different from figure 3, of the rolling bearing assembly of figure 3;
- Figure 5 is a view, at a larger scale, of detail V on figure 2;
- Figure 6 is a view, at a larger scale, of detail VI on figure 5;
- Figure 7 is a perspective view, at a larger scale, of detail VII on figure 6, showing the support member of figure 3;
- Figure 8 is a perspective view of the support member of figure 3; and
- Figure 9 is a view, at a larger scale, of detail IX on figure 5.
DETAILED DESCRIPTION OF SOME EMBODIMENTS
Figure 1 depicts a rolling bearing assembly 1 according to the invention in its assembled and service state. Rolling bearing assembly 1 is mounted into a hub 8 of a not-shown wheel which is held by a fork 9 and which has a shaft 7.
The assembled state of the rolling bearing assembly 1 as illustrated on figure 1 results from the completion of an assembling method according to the invention, which will be described later on.
Figures 2, 3, 4 and 5 depict the rolling bearing assembly 1 , which comprises a ball bearing 2 and a sensor unit 4. Ball bearing 2 has an inner ring 21 and an outer ring 22. Ball bearing 2 includes balls 23 arranged to roll between inner ring 21 and outer ring 22.
Outer ring 22 is fast in rotation with hub 8. Outer ring 22 thus forms a mobile ring of ball bearing 2. Outer ring 22 and hub 8 are intended to rotate around a rotation axis X 2 -X'2 of the ball bearing 2, whereas inner ring 21 and shaft 7 are intended to remain static. Inner ring 21 is secured to shaft 7. Inner ring 21 thus forms a fixed ring of ball bearing 2.
Rolling bearing assembly 1 further comprises a target 5 in the form of an encoder washer. Target 5 has a generally rotational symmetry around axis X2- X' 2 . More accurately, target 5 is in the shape of a cylinder coaxial to axis X 2 -X'2- Target 5 is fastened to a support mem ber 3 accord ing to the invention as hereafter described in relation with figures 8 and 9. Support member 3 belongs to the roll ing bearing assembly 1 , where it is fastened to outer ring 22. Hence, target 5 is fast in rotation with outer ring 22. Target 5 is thus rotatable around axis X 2 -X'2- Sensor un it 4 incl udes a sensing element or sensor 41 . Sen sor 41 is arranged to detect or read target 5 along a rad ial direction, like direction Y2-Y 2 on figu re 2. To read target 5, sensor 41 extends approximately at the same position than target 5 along an axial direction, parallel to axis X 2 -X'2- Sensor 41 extends only partially around axis X 2 -X'2- Sensor 41 hence "faces" a limited area of target 5. Along a rad ial d irection l ike Y2-Y 2, sensor 41 is mounted so that sensor 41 and target 5 are separated by a gap 41 .5, which is less than the maximum sensing distance of sensor 41 .
In the present application, the term "axial" refers to a direction parallel to the rotation axis X 2 -X'2 of bal l bearing 2. The term "rad ial " refers to a direction perpendicular to the rotation axis X2-X'2, l ike radial direction Y2-Y'2 on figure 2. Conversely, a surface is said to be "axial" or "radial" by reference to a direction which is locally or globally perpendicular to that surface. Target 5 can be made of a magnetic material and sensor 41 can perform the magnetic detection of target 5, for instance by detecting the intensity or the variation of the magnetic field generated by target 5.
Figures 5 to 7 illustrate sensor unit 4 with more details. Sensor unit 4 comprises a holding part 42 and a securing part 43. Holding part 42 holds sensor 41 in a position where it can read target 5. Securing part 43 is intended to secure sensor unit 4 to the fixed ring, i.e. to the inner ring 21 in the example of figures 1 to 7.
Holding part 42 is arranged to approximately face the mobile ring, i.e. outer ring 22 in the example of figures 1 to 7, parallel to axis X 2 -X'2- Securing part 43 is arranged to approximately face the fixed earing inner ring 21 parallel to axis X 2 - X' 2 . The adverb "approximately" means that holding part 42 and outer ring 22 have correspond ing positions and extensions along a radial d irection l ike direction Y2-Y 2 on figure 5. Outer ring 22, hence, stands besides or next to the holding part 42.
Securing part 43 is fast in translation along axis X 2 -X'2 with the fixed ring 21 . Indeed, an inner cyl indrical surface of securing part 43 is fitted on the outer cyl indrical surface of shaft 7. Securing part 43 also has a cyl indrical wing 432 fastened to inner ring 21 .
Sensor unit 4 further comprises a resilient part 44, which extends between holding part 42 and securing part 43 along a radial direction like direction Y2-Y'2- Resilient part 44 is attached to the holding part 42 and to the securing part 43. Resil ient part 44 has an elasticity wh ich allows a displacement of the holding part 42 relative to the securing part 43.
In the example of figures 1 to 7, this displacement only has a component parallel to axis X2-X'2, because resilient part 44 has a higher stiffness, preferably 10 times higher, in a radial direction like direction Y2-Y'2 than its relatively low stiffn ess along axis X 2 -X'2- I n oth er word s , th e rad i a l com pon ent of th is displacement is not significant with respect to its axial component.
On figures 2, 5 and 6, resil ient part 44 stands in its rest position where a clearance 42.22 extends, parallel to axis X2-X 2, between the holding part 42 and a term inal surface 221 of outer ring 22. Term inal surface 221 is defined by a p rotru d i n g el e m en t 220 wh i ch i s faste n ed to ou te r ring 22. Protruding element 220 has a rotational symmetry around axis X 2 -X'2 and a generally "L" cross-section, in a plane comprising axis X2-X'2, like the plane of figure 6 or 7. Protruding element rests against the axial outer surface of the outer ring 22, and is preferably fastened to it, l ike in the embod iment shown in the figures, for instance by means of laser welding or gluing.
Resil ient part 44 can also stand in a contact position where a contacting face 424 of holding part 42 contacts the terminal surface 221 . In such a contact position, an axial force can be transferred from the holding part 42 to the outer ring 22, as will be hereafter described.
In the example of figures 1 to 9, the resilient part 44 is distinct or different from the holding part 42 and from the securing part 43. For instance, securing part 43 can be made of metal , hold ing part 42 can be made of plastics and resilient part 44 can be made of any resil ient material, for instance a synthetic material like an elastomeric or a plastics material .
Holding part 42, securing part 43 and resilient part 44 respectively are in the general shape of a ring . In the example of figu res 1 to 9, resil ient part 44 completely surrounds securing part 43 and holding part 42 completely surrounds resilient part 44. Thus, resilient part 44 resiliently or elastically connects holding part 42 and securing part 43 on their whole periphery.
Regarding holding part 42, the term "generally" refers to the overall shape, notwithstanding the local exceptions visible on figures 2, 5 to 7. Indeed, holding part 42 also comprises a cable 425, wh ich protrudes outwardly along rad ial direction Y2-Y 2 and towards a not-shown control unit. Cable 425 can transmit electric signals generated by sensor 41 , while reading target 5. Cable 425 and sensor 41 can be overmoulded with holding part 42. Besides, means for remotely transmitting signals like an antenna, can be used instead of cable 425 so as to reduce the overall d imensions of a roll ing bearing assembly accord ing to the invention.
Res i l ient pa rt 44 com prises a n a n n u l a r portion 441 and a tubular portion 442. The periphery of the annular portion 441 is attached to the holding part 42 by means of a peripheral shoulder 443 fitted in a corresponding step 423 of holding part 42. The central region of the annular portion 441 is attached to securing part 43 by means of a central rib 444 fitted into a peripheral groove 434 of securing part 43.
The tubular portion 442 extends from the central region of annular portion 441 parallel to axis X 2 -X'2- The tubular portion 442 is attached to an outer cylindrical surface of securing part 43, for instance by means of shrinking or press-fitting. The tubular portion 442 has a generally hollow frustoconical shape. Alternatively, the tubular portion 442 can have a generally hollow cylindrical shape.
The elasticity of the resilient part 44 is determined so that the force required for putting the resilient part 44 in its contact position with protruding element 220 is lower than the static load capacity of rolling bearing 2. Since the static load capacity of rolling bearing 2 is a given parameter, such a condition can be met by designing resilient part 44 with appropriate dimensions and selecting its material with an appropriate Young's modulus.
Thus, if an operator applies, on sensor unit 4 and towards rolling bearing 2, an axial force that is larger than the static load capacity of rolling bearing 2, the resilient part 44 strains up to its contact position where holding part 42 pushes against the terminal surface 221 . Holding part 42 hence applies on outer ring 22 a force that helps press-fitting the rolling bearing 2 into bore 80. Meanwhile, both securing parts 43 and holding part 42 are in contact respectively with inner ring 21 and outer ring 22, such that there is no load applied on balls 23, hence no risk to damage the rolling bearing 2.
As can be seen on figure 5, holding part 42 comprises a cover 421 which faces ba l l beari ng 2 and wh ich has an outer d iameter D42. This outer diameter D42 is larger than the outer diameter D22 of the outer ring 22. In other words, holding part 42 covers and "hides" outer ring 22.
Cover 421 is equipped with a sealing member 422 in the form of a lip seal. The sealing member 422 is fastened to cover 422 and is arranged to cooperate with a sealing surface 222 defined by protruding element 220. The lip of sealing member 422 contacts the sealing surface 222 so as to seal the clearance 42.22 against exterior contaminants. Hence, the sealing member 422 not only seals rolling bearing 2, but also the gap 41 .5 between target 5 and sensor 41 . Like terminal surface 221 , sealing surface 222 is defined by protruding element 220, in particular by an outer cyl indrical part thereof. The terminal surface 221 has a diameter D221 smaller than the outer diameter D222 of the sealing surface 222. In other words, the terminal surface 221 extends closer to axis X 2 -X'2 than the sealing surface 222.
The length L222 of sealing surface 222, when measured parallel to axis X2-X'2, is larger than the axial length L42.22 of clearance 42.22. Thus, the sealing member 422 cooperates with the sealing surface 222 not only when resilient part 44 is in its rest position, but also when resil ient part 44 is in its contact position, i.e. when contacting face 424 touches the terminal surface 221 . The cooperation between sealing member 422 and sealing surface 222 hence, provide an efficient sealing in any service position of resilient part 44.
The assembled state of the rolling bearing assembly 1 , as illustrated on figures 1 , 2 , 5 to 7, resu lts from the completion of an assembling method according to the invention, which will be hereafter described.
Inner ring 21 , outer ring 22 and balls 23 are pre-assembled to form ballbearing 2.
In an initial step, inner ring 21 , i.e. the fixed ring, is secured to shaft 7.
Then, securing part 43 is fastened in translation along X 2 -X'2 relative to inner ring 21 by means of cylindrical wings 432.
Protruding element 220 is secured on the axial, external face of outer ring 22, for instance by laser-welding or gluing.
Thereafter, outer ring 22, i.e. the mobile ring, is placed next to bore 80, which purposely defines a receiving space for the outer ring 22. As from this step, rolling bearing assembly 1 is in its compact state, where sensor unit 4 stands next to the rolling bearing 2.
At a next step, an operator applies an axial force on the holding part 42 towards outer ring 22 and up to putting the resilient part 44 in its contact position with protruding element 220.
Thereafter, the operator applies an axial force on the holding part 42 up to press-fitting outer ring 22 into bore 80. This press-fitting axial force is transmitted by holding part 42 to outer ring 22 via protruding element 220. The completion of an assembl ing method according to the invention results in a rolling bearing assembly 1 according to the invention, as illustrated on figure 5.
Accord ing to a not shown embod iment, the seal ing member can be separated from the sealing surface by a tight clearance. In such an embodiment, the sealing member and the sealing surface are not in contact, unlike sealing member 422 and sealing surface 222. This non-contacting sealing member can include a metallic material and/or be made of a labyrinth seal, so as to provide several ch icanes preventing ingress from exterior contaminants into the clearance 42.22.
According to another not shown embodiment, the sealing surface can be an axial surface in the shape of an annulus coaxial with the rotation axis, instead of sealing surface 222, which is on the shape of a cylinder. This arrangement permits to reduce the overall radial dimensions of the rolling bearing assembly.
According to a further not shown embodiment, the sealing surface can be formed by a surface of the mobile ring, for instance of the outer ring. In such an embodiment, the material constituting the sealing surface should be selected so that the surface roughness complies with the friction against the sealing member, in order to limit the wear thereof. For instance, the mobile ring can be made of a standard steel for bearing such as 1 00Cr6, and the seal ing surface can be obtained by fine grinding or stamping . This embodiment avoids mounting a supplementary separate part on the outer ring, like protruding element 220.
According to another not shown embodiment, the mobile ring can be the inner ring and the fixed ring the outer ring. In such an embodiment, it is the inner ring that is press-fitted onto a shaft thanks to a resilient part of the sensor unit. The sensor unit is fastened to the fixed, outer ring and the clearance extends between the sensor unit and the mobile, inner ring. Hence, the securing part of sensor unit surrounds the resilient part which in turn surrounds the holding part.
The invention has been described with bal ls 23 as rolling elements. However, other rolling elements may be contemplated to implement the present invention, like rollers or needles.
Besides, the target can be discrete instead of symmetric around the rotation axis X 2 -X'2- Instead of a magnetic detection of target 5 by sensor 41 , the rolling bearing assembly can comprise a sensing element performing an optical reading of a purposely designed target. Other kinds of transducers may be contemplated to form the sensing element 41 , e.g. an optoelectronic transducer.
A rolling bearing assembly according to the invention permits to press-fit the roll ing bearing onto a rotating body without damaging the rolling bearing components. Besides, a rolling bearing assembly according the present invention can have a longer service life, when the sensor unit acts as a cover for the rolling bearing. This covering function complies with the requirements of the press-fitting operations thanks to the elasticity of the resilient part.
The support member 3 comprises a protruding ring 31 for firmly receiving the target 5. The protruding ring 31 is arranged to project outwards of the rolling bearing 2, i.e. towards sensor unit 4. Support member 3 has a main body 30 in the form of an annulus extending radially in the region separating inner ring 21 and outer ring 22. The support member 3 also comprises fastening means for fastening the support member 3 in rotation with the outer ring 22, i.e. with the mobile ring. Main body 30 and protruding ring 31 can be made of an aluminium- based material, to form a light and strong support member 3.
The protruding ring 31 is in the general shape of a cylinder, coaxial with axis X 2 -X'2- Protruding cylinder 31 is integral with the main body 30. The support member 3 is equipped with an intermediate ring 32 for receiving target 5. The intermediate ring 32 is said to be "intermediate", because it is placed between protruding ring 31 and target 5.
In other words, intermediate ring 32 is secured to the outer surface 33 of protruding ring 31 , for instance by gluing, press-fitting, overmoulding or shrinking, wh ile target 5 is secu red to the outer surface 34 of intermediate ring 32. Intermediate ring 32 has a rotational symmetry around axis X 2 -X'2- Intermediate ring 32 has an "S" cross-section in a plane comprising axis X2-X'2, like the plane of figure 9. Intermediate ring 32 forms an armature for target 5.
Fastening means comprise an outer wing 35 integral with the main body
30 and having a rotational symmetry around axis X 2 -X'2 and a generally annular shape. The outer wing 35 can be resiliently fastened into a radial groove 225, wh ich forms a step of outer ring 22. The support member 3 is hence fast in rotation with outer ring 22.
Furthermore, support member 3 is equipped with a sealing element 36 in the general shape of an annulus. In the example of figures 5 to 9, the sealing element 36 is a lip seal. The sealing element 36 has a securing portion 37 and a l ip 38. Securing portion 37 is secured to an annular surface 39 of support member 3, for instance by shrinking , overmould ing or gluing. The annular surface 39 is oriented opposite protruding ring 31 .
Lip 38 contacts a radial outer surface of inner ring 21 . Along radial direction Y2-Y 2, lip 38 extends in the inner region, of a smaller diameter, of sealing element 36, whereas securing portion 37 extends in the outer region of larger diameter, of sealing element 36. In order to withstand friction forces, sealing element 36 includes an elastomeric material, in particular its lip 38, for instance a material containing nitrile such as NBR or HNBR, or PTFE or TPU material.
Sealing element 36 extends towards axis X 2 -X'2 up to the inner ring 21 , so as to cooperate with the inner ring 21 , i.e. with the fixed ring, so as to seal balls 23 of rolling bearing 2.
A support member 30 accord ing to the invention has a simple and compact structure, and permits a sealing of the rolling bearing, thus increasing its service life. Such a support member achieves two functions within a sole part, i.e. supporting the target and sealing the rolling bearing.
The structure and arrangement of a sensor unit according to the invention and of a support member according to the invention provide an efficient sealing of the rolling bearing to a rolling bearing assembly according to the invention.