Bearing device with integrated electrical insulation, particularly for electric motors or machines

Abstract

[Bearing device with integrated electrical insulation, particularly for electric motors or machines] The bearing device comprises a bearing 10 having a first ring 12 and a second ring 14 capable of rotating relative to each other. The device includes at least one insulating sleeve 26 mounted on the second ring 14 of the bearing and having a bushing 28 and an insulating gasket 30 interposed radially between the second ring 14 and the bushing 28 and made of electrically insulating material. The bushing has an outer surface 28a and an inner surface 28b that define its radial thickness. The insulating gasket 30 is overmolded onto the second ring 14 of the bearing and onto at least one of the outer and inner surfaces of the bushing 28.The bushing 28 is made in at least two first and second parts 32, 34, each part comprising an axial portion 32a, 34a and a radial collar 32b, 34b extending radially inwards from the axial portion. Reference: Figure 1.

Description

Title of the invention: Bearing device with integrated electrical insulation, particularly for electric motors or machines. Technical field of the invention

[0001] The present invention relates to the field of bearings used in particular in electric motors, electrical machines and associated equipment. Prior art

[0002] In an electric motor or machine, at least one roller bearing is mounted between the housing of the motor or electric machine and the rotating shaft in order to support this shaft.

[0003] During operation when the shaft is rotating, an electrical potential difference may appear between it and the housing of the motor or electrical machine, which generates an electric current between the inner ring of the bearing which is attached to the shaft, and the outer ring attached to the housing.

[0004] The electric current passing through the components of the rolling bearing can damage these components, in particular the rolling elements and the raceways formed on the inner and outer rings. Electrical discharges can also generate vibrations.

[0005] To overcome these drawbacks, it is known to replace the bearing's rolling elements, made of the same steel as the inner and outer rings, with rolling elements made of ceramic. This is generally referred to as a hybrid bearing.

[0006] However, such a hybrid bearing is relatively expensive.

[0007] To remedy the aforementioned disadvantages, it is also known to equip the outer ring of the bearing with an insulating sleeve provided with a bushing and an insulating lining made of electrically insulating material and interposed radially between the outer ring and the bushing.

[0008] In order to achieve the fixing of the insulation lining on the outer ring and on the sleeve without additional element or special machining on the outer ring, it is possible to overmold the insulation lining.

[0009] However, with such a solution, a relative separation of the insulation lining and the socket may occur during operation.

[0010] The present invention therefore aims to remedy the aforementioned drawbacks by proposing a bearing device of simple and economical design. Summary of the invention

[0011] The invention relates to a bearing device comprising a bearing provided with a first ring and a second ring capable of rotating relative to each other.

[0012] The device further comprises at least one insulating sleeve mounted on the second bearing ring. The insulating sleeve is provided with a bushing and an insulating gasket interposed radially between the second bearing ring and the bushing. The insulating gasket is made of electrically insulating material.

[0013] The sleeve comprises an outer surface and an inner surface opposite to the outer surface and which delimit the radial thickness of said sleeve.

[0014] The second ring comprises an outer surface and an inner surface opposite to the outer surface and which delimit the radial thickness of said second ring, and first and second front faces delimiting the axial length of said second ring.

[0015] The insulation lining is overmolded at least on one of the outer and inner surfaces of the second bearing ring and at least on one of the outer and inner surfaces of the bushing.

[0016] According to a general characteristic, the sleeve is made in at least two distinct first and second parts, each comprising an axial portion and a radial collar extending at least radially inwards from the axial portion.

[0017] According to another general feature, the axial portions of said first and second parts jointly delimit at least in part said surface of the sleeve on which the insulation lining is overmolded.

[0018] According to another general feature, at least the radial collar of the first part of the sleeve extends radially beyond the outer or inner surface of the second ring on which the insulating lining is overmolded, and is provided with a plurality of through holes which are spaced from each other in the circumferential direction.

[0019] According to yet another general feature, the insulation lining is also overmolded on an inner face of the radial collar of each of said first and second parts of the sleeve and overmolded at least in part on the first and second front faces of the second ring.

[0020] According to another general feature, the insulating packing includes a group of blind holes each extending axially inside one of the through holes in the radial flange of the first part of the sleeve and remaining axially away from the first front face of the second ring.

[0021] The construction of these two parts of the sleeve with radial flanges ensures a secure bond with the insulation lining. The risk of relative movement between the insulation lining and the sleeve in the axial direction is avoided, particularly during temperature variations.

[0022] By "axial direction" is meant the direction parallel to the axis of the bearing device.

[0023] Furthermore, compared to a one-piece embodiment of the socket equipped with collars, the production of which in at least two separate parts facilitates the placement of the second ring inside the mold intended for overmolding the insulation lining.

[0024] Furthermore, given the dimensions of the radial flange of the first part of the sleeve, the portion of the insulating lining located axially between the second ring and this radial flange is not subjected to shear stresses when significant axial loads are applied to the device mounted inside the housing of the motor or electrical machine associated with this flange bearing against a shoulder of the housing. In this case, compressive stresses are applied to this portion of the insulating lining. This increases the reliability of the device.

[0025] Each blind hole in the insulating gasket corresponds to the impression of the injector used during its overmolding during the manufacturing of the bearing assembly. Injecting material through the through holes in the radial flange of the first part of the bushing increases the radial dimension of this flange and the bearing surface with the housing of the associated motor or electrical machine. This also reduces the volume of material required for the insulating gasket, which is more expensive than the material for the bushing.

[0026] According to a particular design, the insulating gasket covers the bore of each hole in said plurality of through holes in the radial flange of the first part of the bushing. Alternatively, the insulating gasket could cover only the bore of some of the holes in said plurality of through holes.

[0027] Preferably, the radial flange of the second part of the sleeve extends radially beyond the outer or inner surface of the second ring onto which the insulating lining is overmolded. Alternatively, it is possible to provide that the radial flange of the second part of the sleeve remains radially recessed from the outer or inner surface of the second ring onto which the insulating lining is overmolded.

[0028] Advantageously, the radial flange of the second part of the sleeve is provided with a plurality of through holes that are spaced circumferentially from one another. In this case, the insulating gasket may comprise a group of through holes, each extending axially inside one of said through holes and opening onto the second front face of the second ring.

[0029] Each through hole in the insulation lining corresponds to the location of a pin allowing the centering of the second part of the sleeve and the transmission of the closing forces of the mold used during the overmolding of the insulation lining.

[0030] Positioning the pins through the through holes in the radial flange of the second part of the sleeve increases the radial dimension of this flange and the bearing surface with the housing of the motor or associated electrical machine. This, in turn, reduces the volume of material in the insulation lining.

[0031] According to a particular design, the insulating gasket covers the bore of each hole in said plurality of through holes in the radial flange of the second part of the bushing. Alternatively, the insulating gasket could cover only the bore of some of the holes in said plurality of through holes in the radial flange of the second part of the bushing.

[0032] According to a particular design, the insulating gasket may include, between two successive circumferential through holes in the gasket, at least one stud extending inside one of the through holes in the radial flange of the second part of the sleeve. Alternatively, the arrangement of the studs may be different. In another embodiment, the insulating gasket may be studless if a centering pin is provided to fit into each through hole in the radial flange of the second part of the sleeve.

[0033] In one embodiment, the first and second parts of the socket are symmetrical with respect to a median radial plane of the device. This reduces the manufacturing cost of the device.

[0034] According to a particular design, the axial portions of said first and second parts of the sleeve are axially in contact with each other and jointly delimit the entirety of said surface of the sleeve on which the insulation lining is overmolded.

[0035] According to another design, the axial portions of said first and second parts of the sleeve are axially spaced apart from each other. In this case, the sleeve may further comprise an additional ring interposed axially between the axial portions of said first and second parts and jointly delimiting, with said axial portions of said first and second parts of the sleeve, said surface of the sleeve onto which the insulating lining is overmolded.

[0036] According to a particular design, said surface of the socket is provided with at least one groove extending in the circumferential direction and within which extends a rib for attaching the insulation lining of complementary shape.

[0037] Thus, the axial attachment of the insulation lining to the socket is further increased.

[0038] By "circumferential direction" is meant the direction which is perpendicular to both the axial direction and to a radius of the bearing device, in other words, tangent to a circle whose center is on the axis of the bearing device.

[0039] Each axial portion of said first and second parts of the sleeve can be provided with at least one groove extending in the circumferential direction and within which extends a rib for attaching the insulation lining of complementary shape.

[0040] If the insulation lining is made of synthetic material or elastomeric material, it makes the device less sensitive to temperature variations.

[0041] In a particular embodiment, the first and second parts of the sleeve are made of metallic material. The sleeve can thus be easily machined to a predetermined radial tolerance.

[0042] Said first and second parts of the socket can be obtained from a sheet metal blank by cutting, stamping and rolling.

[0043] In one embodiment, said insulating lining covers the entire surface of said socket. In this case, said insulating lining completely covers said surface of the socket in the axial direction and in the circumferential direction.

[0044] According to a first conception, the sleeve delimits the outer surface of said device. In this case, the second ring is the outer ring of the bearing.

[0045] According to a second alternative design, the sleeve defines the inner surface of said device. In this case, the second ring is the inner ring of the bearing.

[0046] In a particular embodiment, the bearing comprises at least one row of rolling elements arranged between raceways of the first and second rings. The rolling elements may be made of metallic material.

[0047] The invention also relates to an electric motor comprising a housing, a shaft and at least one bearing device as defined above and mounted radially between the housing and the shaft.

[0048] The invention also relates to a method for manufacturing a bearing device as defined above, comprising:

[0049] - a step of assembling one of said first and second parts of the socket to base of a manufacturing mold,

[0050] - a step of placing the second ring inside the mold of manufacturing,

[0051] - a step of assembling the other of said first and second parts of the socket inside the manufacturing mold,

[0052] - a step of placing injectors inside the through holes of the radial collar of the first part of the sleeve, the injectors remaining axially at a distance from the first front face of the second ring,

[0053] - a step of overmolding the insulation lining via the injectors, and

[0054] - an assembly step with the first bearing ring of the assembly formed by the second ring, the said first and second parts of the socket and the insulating lining.

[0055] The process may also include, before the overmolding step, a step of placing centering studs inside the through holes of the radial collar of the second part of the bushing, the studs coming axially to bear against the second front face of the second ring. Brief description of the figures

[0056] The present invention will be better understood upon study of the detailed description of an embodiment, taken by way of non-limiting example and illustrated by the accompanying drawings, in which:

[0057] [Fig-1] is a front view of a bearing device according to an exemplary embodiment of the invention,

[0058] [Fig.2] is a half-sectional view along axis II-II of [Fig.1],

[0059] [Fig.3] is a half-sectional view along axis III-III of [Fig.1],

[0060] [Fig.4] is a partial exploded perspective view of the bearing device of [Fig.1] on which an insulating lining of said device has not been shown, and

[0061] [Fig.5] is a flowchart illustrating the manufacturing process of the device level of the [Fig.l]. Detailed description of the invention

[0062] The bearing device illustrated in Figures 1 and 2 comprises a bearing 10 provided with a first ring 12 and a second ring 14 which are able to rotate relative to each other about the axis X-X' of the bearing. In the illustrated embodiment, the first ring 12 is the inner ring of the bearing and the second ring 14 is the outer ring.

[0063] The bearing device is designed so as not to conduct electric currents. The bearing device has integrated electrical insulation.

[0064] The inner ring 12 and outer ring 14 of the bearing are concentric and extend axially along the X-X' axis of the bearing. The inner ring 12 and outer ring 14 are made of steel. The rings are of the solid type.

[0065] In the illustrated embodiment, the bearing 10 also includes a row of rolling elements 16, here balls, interposed radially between the inner rings 12 and outer 14. The rolling elements 16 are made of steel. The bearing 10 also includes a cage 17 for maintaining the regular circumferential spacing of the rolling elements 16. The bearing 10 can also be equipped with seals or sealing flanges.

[0066] The inner ring 12 comprises a cylindrical bore 12a, an axial cylindrical outer surface 12b radially opposed to the bore, and two opposing radial front faces 12c, 12d axially delimiting the bore and the outer surface. The bore 12a and the outer surface 12b define the radial thickness of the inner ring 12. The bore 12a forms the inner surface of the inner ring. The first and second front faces 12c, 12d define the axial length of the inner ring 12.

[0067] The inner ring 12 further includes an inner raceway 18 for the rolling elements 16 which is formed on the outer surface 12b. The raceway 18 is directed radially outwards.

[0068] The outer ring 14 comprises a cylindrical axial outer surface 14a, a cylindrical bore 14b radially opposed to the outer surface 14a, and opposing radial first and second front faces 14c, 14d axially delimiting the bore and the outer surface 14a. The outer surface 14a and the bore 14b define the radial thickness of the outer ring 14. The first and second faces 14c, 14d define the axial length of the outer ring 14.

[0069] The outer ring 14 further includes an outer raceway 20 for the rolling elements 16 which is formed on the bore 14b. The raceway 20 is directed radially inwards.

[0070] The bearing device also includes an electrical insulation sleeve 26 mounted on the outer ring 14. The insulation sleeve 26 is mounted on the outer surface 14a of the outer ring 14. The insulation sleeve 26 is integral with the outer ring 14.

[0071] The insulation sleeve 26 comprises a sleeve 28 and an insulation packing 30 interposed radially between the outer ring 14 and the sleeve 28. The insulation packing 30 is overmolded on the outer ring 14 and on the sleeve 28.

[0072] The bushing 28 is annular in shape. The bushing 28 is made up of two distinct first and second parts 32, 34. These two separate parts 32, 34 form half-flanges which are axially supported against each other. In the illustrated embodiment, the parts 32, 34 of the bushing are identical and symmetrical with respect to a median radial plane P of the device in order to reduce manufacturing costs. The median radial plane P passes through the center of the rolling elements 16. Alternatively, it is of course possible to provide for asymmetrical parts 32, 34. In another variant, it might be possible to provide that the The bushing 28 may consist of more than two parts. Preferably, parts 32 and 34 of the bushing 28 are made of steel. Parts 32 and 34 can advantageously be obtained from a sheet blank by cutting, stamping, and rolling. Alternatively, parts 32 and 34 can be obtained from a tube, from forged and / or rolled blanks, or from sintering and stamping.

[0073] Each portion 32, 34 of the sleeve comprises an annular axial portion 32a, 34a, and an annular radial flange 32b, 34b extending radially inward from the axial portion. The axial portions 32a, 34a are axially supported against each other. The radial flange 32b, 34b extends from the end of the axial portion 32a, 34a located axially on the outer side of the device. In the illustrated embodiment, the radial flanges 32b, 34b are annular.

[0074] The sleeve 28 comprises a cylindrical axial outer surface 28a, and a cylindrical bore 28b radially opposed to the outer surface 28a and whose axis 25 is coaxial with the axis X-X'. The bore 28b forms the inner surface of the sleeve 28. The bore 28b is oriented radially inwards, i.e., towards the outer ring 14 and the insulating gasket 30. The axial portions 32a, 34a of the sleeve parts jointly define the outer surface 28a. Similarly, the axial portions 32a, 34a of the parts jointly define the bore 28b. The outer surface 28a and the bore 28b define the radial thickness of the bushing 28. The outer surface 28a of the bushing forms the outer surface of the bearing device 10. In other words, the outer surface 28a defines the outer diameter of the bearing device 10.

[0075] The radial flanges 32b, 34b of the sleeve portions extend radially beyond the outer surface 14a of the outer ring, i.e., radially projecting inward relative to the outer surface 14a. In other words, the free ends of the radial flanges 32b, 34b are offset radially inward relative to the outer surface 14a of the outer ring. The radial flanges 32b, 34b extend to the vicinity of the bore 14b of the outer ring, remaining radially recessed from said bore 14b. The radial flanges 32b, 34b remain axially distant from the outer ring 14.

[0076] Each radial flange 32b, 34b of the portion 32, 34 of the socket is provided with a plurality of through holes 36, 38 which are spaced from each other in the circumferential direction, here regularly. Alternatively, the spacing of the holes 36, 38 could be irregular.

[0077] Holes 36 and 38 are identical here. Alternatively, holes 36 and 38 could not be identical. In the illustrated embodiment, holes 36 and 38 are circular. Alternatively, holes 36 and 38 could have another shape, for example polygonal, such as rectangular, square, oval, etc.

[0078] As previously stated, the holes 36, 38 are through holes. The holes 36, 38 pass axially through the thickness of the associated radial flange 32b, 34b of the sleeve portion 32. The holes 36, 38 open onto the inner and outer faces of the associated flange 32b, 34b. The inner face and the outer face axially opposite the inner face of each radial flange 32b, 34b define the axial thickness of said flange. For each radial flange 32b and 34b, the inner face is oriented axially towards the inside of the device, and the outer face is oriented axially towards the outside of the device.

[0079] In the illustrated embodiment, the holes 36 of the radial flange 32b of the part 32 of the sleeve are axially aligned with the holes 38 of the radial flange 34b of the part 34. Alternatively, the holes 36 could be angularly offset from the holes 38.

[0080] The sleeve 28 also includes two opposing radial front faces 28c, 28d axially delimiting the outer surface 28a. The front faces 28c, 28d define the axial length of the sleeve. The front face 28c is delimited by the radial flange 32b, and the front face 28d is delimited by the radial flange 34b. More precisely, the front face 28c is delimited by the outer face of the radial flange 32b, and the front face 28d is delimited by the outer face of the radial flange 34b.

[0081] The front faces 14c, 28c of the outer ring and the sleeve are located axially on a first side with respect to the median radial plane P of the device, and the front faces 14d, 28d of the outer ring and the sleeve are located axially on a second side with respect to said median radial plane P which is opposite to the first side.

[0082] The front face 14c of the outer ring is axially offset inwards relative to the front face 28c of the sleeve. The front face 14d of the outer ring is axially offset inwards relative to the front face 28d of the sleeve. In other words, the front faces 14c, 14d of the outer ring are axially recessed relative to the front faces 28c, 28d of the sleeve. The axial dimension of the outer ring 14 is smaller than the axial dimension of the sleeve 28.

[0083] The front face 14c of the outer ring is axially offset inwards relative to the front face 12c of the inner ring. The front face 14d of the outer ring is axially offset inwards relative to the front face 12d of the inner ring.

[0084] The insulating gasket 30 is made of electrically insulating material. The insulating gasket 30 can, for example, be made of a synthetic material, such as PEEK or PA46, or be made of an elastomeric material, for example rubber.

[0085] The insulating gasket 30 is radially interposed between the outer surface 14a of the outer ring and the bore 28b of the sleeve. The insulating gasket 30 covers the outer surface 14a of the outer ring. The insulating gasket 30 completely covers the outer surface 14a of the outer ring in both the axial and circumferential directions. The insulating gasket 30 also covers the front faces 14c, 14d of the outer ring.

[0086] The insulating gasket 30 still covers the bore 28b of the sleeve. The insulating gasket 30 also completely covers the bore 28b here, considering both the axial and circumferential directions. The insulating gasket 30 covers the bore of the axial portion 32a, 34a of each part 32, 34 of the sleeve.

[0087] The insulating gasket 30 also covers the inner face of the radial flange 32b, 34b of each part 32, 34 of the sleeve. The insulating gasket 30 also covers the free end of the radial flange 32b, 34b of each part 32, 34 of the sleeve. The insulating gasket 30 further covers the bore of the through holes 36, 38 of the radial flanges 32b, 34b of the parts 32, 34 of the sleeve.

[0088] The insulating gasket 30 is annular in shape. The insulating gasket 30 extends axially. The insulating gasket 30 comprises a cylindrical axial outer surface 30a, a cylindrical bore 30b radially opposed to the outer surface 30a, and opposing radial first and second front faces 30c, 30d axially delimiting the bore and the outer surface. The radial front faces 30c, 30d axially delimit the insulating gasket 30. The outer surface 30a and the bore 30b define the radial thickness of the insulating gasket 30. The outer surface 30a is in radial contact with the bore 28b of the sleeve. The bore 30b is in radial contact with the outer surface 14a of the outer ring and with the front faces 14c, 14d of the outer ring.

[0089] The insulating gasket 30 comprises a group of blind holes 40, each extending axially inside one of the through holes 36 in the radial flange 32b of the sleeve portion 32. Each blind hole 40 extends axially from the front face 30c towards the outer ring 14, remaining axially distant from the front face 14c. In other words, each blind hole 40 has a bottom that is oriented axially outwards and is offset axially outwards relative to the front face 14c.

[0090] Each blind hole 40 corresponds to the location of an injector (not shown) that allows the insulating packing 30 to be overmolded during the manufacture of the bearing device. The shape of the blind hole 40 corresponds to the imprint of the associated injector. The blind holes 40 are identical here. Alternatively, the blind holes 40 may not be identical when the injectors of the electrical insulating material of the insulating packing 30 are of different shapes.

[0091] As previously stated, in the illustrated embodiment, the insulating gasket 30 covers the bore of the through holes 36 in the radial flange 32b of the sleeve portion 32. A radial bead of material therefore remains between each blind hole 40 and the associated through hole 36 in the radial flange 32b. Alternatively, it might be possible to eliminate this bead of material if the injector is centered against the bore of the through hole 36 during the overmolding of the insulating gasket 30.

[0092] In the illustrated embodiment, the number of blind holes 40 is equal to the number of through holes 36 in the radial flange 32b of the sleeve portion 32. Alternatively, depending on the number of injectors, the number of blind holes 40 could be less than the number of through holes 36.

[0093] The insulating gasket 30 also includes a group of through holes 42, each extending axially inside one of the through holes 38 in the radial flange 34b of the sleeve portion 34. Each through hole 42 extends axially from the front face 30d towards the outer ring 14 and opens onto the front face 14d.

[0094] Each through hole 42 corresponds to the location of a pin (not shown) which allows the centering of the bushing portion 34 and the transmission of the closing forces of the mold used during the manufacture of the bearing device. The shape of the through hole 42 corresponds to the imprint of the associated pin. The through holes 42 are identical here. Alternatively, the through holes 42 may not be identical when the pins are of different shapes.

[0095] As previously stated, in the illustrated embodiment, the insulating gasket 30 covers the bore of the through holes 38 in the radial flange 34b of the sleeve portion 34. A radial bead of material therefore remains between each through hole 42 and the associated through hole 38 in the radial flange 34b. Alternatively, it might be possible to eliminate this bead of material if the pin is centered against the bore of the through hole 38 during the overmolding of the insulating gasket 30.

[0096] In the illustrated embodiment, the insulating gasket 30 comprises, between two successive through holes 42 in the circumferential direction, a stud 44 extending inside the through holes 38 of the radial flange 34b of the sleeve portion 34. The number of through holes 42 is therefore less than the number of through holes 38. Alternatively, the number of through holes 42 could be equal to the number of through holes 38.

[0097] In the illustrated embodiment, the front face 14c of the outer ring is axially offset inwards relative to the front face 30c of the trim insulation. The front face 14d of the outer ring is axially offset inwards relative to the front face 30d of the insulation lining.

[0098] In the illustrated embodiment, the faces 30c, 28c and 30d, 28d of the insulating gasket and the socket are respectively coplanar. Alternatively, other arrangements are possible. For example, the socket 28 could extend axially outward from the insulating gasket 30 relative to the faces 30c and 30d, or remain axially recessed from these faces.

[0099] In the illustrated embodiment, the faces 12c, 28c and 12d, 28d of the inner ring and the sleeve are respectively coplanar. Alternatively, other arrangements are possible. For example, the sleeve 28 could extend axially in projection relative to the faces 12c and 12d of the inner ring, or remain axially recessed from these faces.

[0100] To manufacture the bearing device, the following procedure is used.

[0101] In a first step 50 schematically illustrated in [Fig.5], the second part 34 of the sleeve is mounted inside the mold which is intended for overmolding the insulation lining 30. The mold studs allow the centering of the second part 34.

[0102] In a second successive step 52, the outer ring 14 is placed inside the mold.

[0103] Then, in a third step 54, the first part 32 of the sleeve is mounted inside the mold axially in contact with the first part 32. In this position mounted inside the mold, the first part 32 and the second part 34 of the sleeve are radially at a distance from the outer ring 14.

[0104] Then, in a fourth successive step 56, the insulating lining 30 is overmolded, by means of the mold injectors positioned inside the through holes 36 of the radial flange 32b of the sleeve portion 32. The insulating lining 30 is overmolded both onto the outer ring 14 and onto the first and second portions 32, 34 of the sleeve 28.

[0105] In a fifth successive step 58, the unit assembly formed by the outer ring 14, by the first and second parts 32, 34 the sleeve 28 and by the insulation lining 30 is extracted out of the mold.

[0106] Next, in a subsequent sixth step 60, the front faces 28c, 28d of the sleeve are ground. Given the presence of the sleeve flanges 32b and 34b, the grinding operation is carried out primarily on the sleeve, and not on the insulating lining 30. During this step, the outer surface 28a of the sleeve and the raceway 20 of the outer ring can also be ground.

[0107] Next, in a seventh step 62, the unit assembly formed by the outer ring 14, the first and second parts 32, 34 the bushing 28 and the trim The insulation 30 is assembled with the row of rolling elements 16, the cage 17 and the inner ring 12.

[0108] In the illustrated embodiments, the first ring 12 of the bearing is the inner ring and the second ring 14 on which the insulation packing 30 is overmolded is the outer ring.

[0109] Alternatively, an inverted arrangement may be provided in which the second ring 14, onto which the insulating sleeve 30 is overmolded, is the inner ring. In this case, the insulating sleeve is located in the bore 12a of the inner ring. The insulating sleeve is then radially interposed between the bore 12a of the inner ring and the outer surface of the bushing. The insulating sleeve is overmolded onto the inner ring and at least onto the outer surface of the bushing. The bore of the bushing defines the bore of the bearing device.

[0110] In the described embodiments, the bearing of the device is provided with a single row of rolling elements. Alternatively, the bearing may be provided with several rows of rolling elements. Furthermore, the rolling bearing may include other types of rolling elements than balls, for example, rollers. In another embodiment, the bearing may be a sliding bearing without rolling elements.

Claims

1. Demands Bearing device comprising a bearing (10) having a first ring (12) and a second ring (14) capable of rotating relative to each other, and an insulating sleeve (26) mounted on the second ring (14) of the bearing and having a bushing (28) and an insulating gasket (30) interposed radially between the second ring (14) and the bushing (28) and made of electrically insulating material, the bushing comprising an outer surface (28a) and an inner surface (28b) opposite the outer surface and which define the radial thickness of said bushing, the second ring (14) comprising an outer surface (14a) and an inner surface (14b) opposite the outer surface and which define the radial thickness of said second ring, and first and second front faces (14c, 14d) defining the axial length of said second ring,the insulating lining (30) being overmolded at least on one of the outer and inner surfaces of the second ring (14) of the bearing and at least on one of the outer and inner surfaces of the sleeve (28), characterized in that: - the sleeve (28) is made in at least two distinct first and second parts (32, 34) each comprising an axial portion (32a, 34a) and a radial collar (32b, 34b) extending radially inwards from the axial portion, the axial portions (32a, 34a) of said first and second parts jointly delimiting at least in part said surface of the sleeve (28) on which the insulating lining (30) is overmolded, - at least the radial collar (32b) of the first part of the sleeve extending radially beyond the outer (14a) or inner surface of the second ring on which the insulating lining (30) is overmolded, and being provided with a plurality of through holes (36) which are spaced from each other in the circumferential direction, - the insulating lining (30) being further overmolded onto an inner face of the radial collar (32b, 34b) of each of the said first and second parts of the sleeve and overmolded at least in part onto the first and second front faces (14c, 14d) of the second ring, and - the insulation packing (30) comprising a group of blind holes (40) each extending axially inside one of the through holes (36) of the radial collar (32) of the other of the first part of the sleeve and remaining axially at a distance from the first front face (14c) of the second ring.

2. Device according to claim 1, wherein the insulating lining (30) covers the bore of each hole of said plurality of holes (36) through the radial collar (32b) of the first part of the sleeve.

3. Device according to claim 1 or 2, wherein the radial collar (34b) of the second part of the sleeve extends radially beyond the outer (14a) or inner surface of the second ring on which the insulating lining (30) is overmolded,

4. Device according to claim 3, wherein the radial collar (34b) of the second part of the sleeve is provided with a plurality of through holes (38) which are spaced from each other in the circumferential direction, the insulating lining (30) comprising a group of through holes (42) each extending axially inside one of said through holes (38) and opening onto the second front face (14d) of the second ring.

5. Device according to claim 4, wherein the insulating lining (30) covers the bore of each hole of said plurality of holes (38) through the radial collar (34b) of the second part of the socket.

6. Device according to claim 4 or 5, wherein the insulation lining comprises, between two through holes (42) of the insulation lining which are successive in the circumferential direction, at least one stud (44) extending inside one of the through holes (38) of the radial collar (34b) of the second part of the sleeve.

7. Device according to any one of the preceding claims, wherein said first and second parts (32, 34) of the socket are symmetrical with respect to a median radial plane of said device.

8. A device according to any one of the preceding claims, wherein the axial portions (32a, 34a) of said first and second parts of the sleeve are axially in contact with each other against each other and jointly delimit the entire surface of the socket (28) on which the insulation lining (30) is overmolded.

9. A method for manufacturing a bearing device according to any one of claims 1 to 8 comprising: - a step of assembling one of the said first and second parts (32, 34) of the socket at the bottom of a manufacturing mold, - a step of placing the second ring (14) inside the manufacturing mold, - a step of assembling the other of the said first and second parts (32, 34) of the bushing inside the manufacturing mold, - a step of placing injectors inside the through holes (36) of the radial collar (32b) of the first part of the bushing, the injectors remaining axially at a distance from the first front face (14c) of the second ring, - an overmolding step of the insulation lining (30) via the injectors, and - an assembly step with the first ring (12) of the bearing of the assembly formed by the second ring (14), said first and second parts (32, 34) of the bushing and the insulation lining (30).

10. Electric motor comprising a housing, a shaft and at least one bearing device according to any one of claims 1 to 8 mounted radially between the housing and the shaft.

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