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

Abstract

[Bearing system with integrated electrical insulation, particularly for electric motors or machines] The bearing system comprises a bearing 10 having a first ring 12 and a second ring 14 capable of rotating relative to each other. The system includes at least one insulating sleeve 26 mounted on the second ring and having a bushing 28 and an insulating lining 30 made of electrically insulating material. The insulating lining 30 is fixed to the second ring 14 and to at least one of the outer and inner surfaces of the bushing. The system further comprises at least one first sealing device 32 mounted on the insulating lining 30 and forming a first dynamic annular seal with the first ring 12, the insulating lining 30 comprising at least first axial retaining hooks 44 of the first sealing device spaced circumferentially apart. Reference: Figure 4

Description

Title of the invention: Bearing system 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 some applications, surrounding pollution can reduce the bearing life.

[0009] The present invention therefore aims to remedy this drawback by proposing a bearing system of simple and economical design. Summary of the invention

[0010] The invention relates to a bearing system comprising a bearing provided with a first ring and a second ring capable of rotating relative to each other.

[0011] The system further comprises at least one insulating sleeve mounted on the second bearing ring. The insulating sleeve is provided with a socket and a An insulating gasket is radially interposed between the second bearing ring and the bushing. The insulating gasket is made of electrically insulating material.

[0012] The sleeve comprises an outer surface and an inner surface opposite to the outer surface and which delimit the radial thickness of said sleeve.

[0013] The insulation lining is fixed to the second ring of the bearing and at least to one of the outer and inner surfaces of the bushing.

[0014] According to a general characteristic, the system further comprises at least one first sealing device mounted on the insulation lining and forming a first dynamic annular seal with the first ring.

[0015] According to another general feature, the insulation lining includes at least the first axial retaining hooks of the first sealing device spaced from each other in the circumferential direction.

[0016] By "dynamic sealing," we mean a seal between two parts that can have relative movement. In contrast to a dynamic seal, we mean a seal between two parts that cannot have relative movement.

[0017] The first dynamic annular seal formed jointly by the first sealing device and by the first ring can be obtained by narrow passage(s) and / or by friction.

[0018] The first sealing device forms a barrier stopping polluting particles that can move towards the inside of the bearing.

[0019] Preferably, the insulation lining includes at least one first axial heel extending axially outwards and supporting the first axial retaining hooks.

[0020] The second ring may include 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, the insulation lining being fixed at least on one of the outer and inner surfaces of the second ring.

[0021] According to an advantageous design, the insulation lining comprises at least a first radial heel extending radially and covering at least part of the first front face of the second ring and against which the first sealing device is axially supported by the first axial retaining hooks.

[0022] Alternatively, it remains possible to provide that the first axial retaining hooks axially support the first sealing device against the second ring.

[0023] Preferably, the first axial retaining hooks are made as one piece with the insulation lining. Alternatively, the first axial retaining hooks could be attached to the insulation lining.

[0024] Advantageously, the insulating gasket is overmolded onto the second bearing ring and at least onto said bushing surface. Alternatively, the insulating gasket can be fixed by any other suitable means, for example by bonding.

[0025] Preferably, the first axial retaining hooks of the insulation lining extend radially from the side of the first ring.

[0026] According to a particular design, the first sealing device includes a fixing part fixed in the first annular mounting groove of the insulation trim and made of rigid material, the insulation trim being made of flexible electrical insulating material.

[0027] The first sealing device may include a sealing flange. Alternatively, the first sealing device may include a sealing gasket.

[0028] Advantageously, the system may further include at least one second sealing device mounted on the insulation lining and forming with the first ring a second dynamic annular seal.

[0029] The second dynamic annular seal formed jointly by the second sealing device and by the first ring can be obtained by narrow passage(s) and / or by friction.

[0030] The insulating gasket includes at least two axial retaining hooks of the second sealing device spaced circumferentially apart. The first and second sealing devices are arranged axially on either side of the second ring.

[0031] The first ring may include first and second front faces delimiting the axial length of said second ring.

[0032] The first front face of the second ring and the first front face of the first ring are located axially on one side with respect to a median radial plane of the system. The second front face of the second ring and the second front face of the first ring are located axially on a second side with respect to said median radial plane.

[0033] Advantageously, the first front face of the second ring is axially offset inwards relative to the first front face of the first ring, and the first sealing device is located axially between said first front faces.

[0034] Thus, the overall axial dimensions of the system are not increased due to the presence of the first sealing device. The overall weight of the system taking into account the reduced axial length of the second ring compared to that of the first ring.

[0035] Advantageously, the second front face of the second ring is axially offset inwards relative to the second front face of the first ring. When the system is equipped with a second sealing device, this device can advantageously be located axially between said second front faces.

[0036] If the insulation lining is made of synthetic material or elastomer material, it makes the system less sensitive to temperature variations.

[0037] In a particular embodiment, the bushing is made of metallic material. The bushing can thus be easily machined to a predetermined radial tolerance. Advantageously, the bushing is obtained from a sheet metal blank by cutting, stamping, and rolling.

[0038] 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.

[0039] According to a first conception, the sleeve delimits the outer surface of said system. In this case, the second ring is the outer ring of the bearing.

[0040] According to a second alternative design, the sleeve delimits the inner surface of said system. In this case, the second ring is the inner ring of the bearing.

[0041] 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.

[0042] The invention also relates to an electric motor comprising a housing, a shaft and at least one bearing system as defined above and mounted radially between the housing and the shaft. Brief description of the figures

[0043] The present invention will be better understood upon study of the detailed description of embodiments, taken by way of non-limiting examples and illustrated by the accompanying drawings, in which:

[0044] [Fig-1] is a perspective view of a bearing system according to a first embodiment of the invention,

[0045] [Fig.2] is a perspective view of the bearing system of [Fig.1] in which one of the sealing flanges is not shown,

[0046] [Fig.3] is a perspective view of one of the sealing flanges of the bearing system of [Fig.1],

[0047] [Fig.4] is a half axial cross-sectional view of the bearing system of [Fig.1],

[0048] [Fig.5] is a half axial cross-sectional view of the bearing system of [Fig.1] on which the sealing flanges are not shown,

[0049] [Fig.6] is a half axial cross-sectional view of a bearing system according to a second embodiment of the invention,

[0050] [Fig.7] is a half axial cross-sectional view of a bearing system according to a third embodiment of the invention,

[0051] [Fig.8] is a half axial cross-sectional view of a bearing system according to a fourth embodiment of the invention,

[0052] [Fig.9] is a perspective view of the bearing system of [Fig.8], and

[0053] [Fig. 10] is a perspective view of the bearing system of Figures 8 and 9 in which an inner ring, rolling elements and a cage are not shown. Detailed description of the invention

[0054] The bearing system illustrated in Figures 1 to 5 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.

[0055] The bearing system is designed so as not to conduct electric currents. The bearing system has integrated electrical insulation.

[0056] 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.

[0057] In the illustrated embodiment, the bearing 10 also includes a row of rolling elements 16, here balls, interposed radially between the inner ring 12 and the outer ring 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.

[0058] The inner ring 12 comprises a cylindrical bore 12a, an axial cylindrical outer surface 12b radially opposed to the bore, and opposing radial first and second 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.

[0059] 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.

[0060] 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 faces 14c, 14d axially delimiting the bore 14b 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.

[0061] 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.

[0062] The bearing system 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.

[0063] The insulation sleeve 26 includes a sleeve 28 and an insulation packing 30 interposed radially between the outer ring 14 and the sleeve 28. The insulation packing 30 is here overmolded on the outer ring 14 and on the sleeve 28.

[0064] As will be described in more detail later, the bearing system further includes first and second sealing flanges 32, 34 fixed to the insulation lining 30.

[0065] The bushing 28 is annular in shape. The bushing 28 is made from a single piece. The bushing 28 is here made in one piece. Preferably, the bushing 28 is made of steel. The bushing 28 can advantageously be obtained from a tube or from forged and / or rolled blanks, or even from stamping.

[0066] The sleeve 28 comprises an axial annular cylindrical outer surface 28a, and an axial annular cylindrical bore 28b radially opposed to the outer surface 28a. 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 axis 25 of the bore 28b is coaxial with the X-X' axis. The bore 28b remains radially recessed from the outer surface 14a of the outer ring.

[0067] 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 system 10. In other words, the outer surface 28a defines the outer diameter of the bearing system 10.

[0068] The sleeve 28 also includes opposing radial first and second front faces 28c, 28d axially delimiting the bore and the outer surface. The front faces 28c, 28d define the axial length of the sleeve.

[0069] The front faces 14c, 28c of the outer ring and the sleeve are located axially on one side with respect to a median radial plane P of the system, 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. The median radial plane P passes here through the center of the rolling elements 16.

[0070] 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.

[0071] 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.

[0072] The insulating gasket 30 is made of electrically insulating material. The insulating gasket 30 may, for example, be made of a synthetic material, such as PEEK or PA46, or of an elastomeric material, for example, rubber. Advantageously, the insulating gasket 30 is made of a flexible electrically insulating material.

[0073] 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.

[0074] 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.

[0075] 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 and with the front faces 14c, 14d of the outer ring. The bore 30b has a stepped shape.

[0076] The front face 14c of the outer ring is axially offset inwards relative to the front face 30c of the insulating gasket. The front face 14d of the outer ring is axially offset inwards relative to the front face 30d of the insulating gasket.

[0077] In the illustrated embodiment, the faces 30c, 28c and 30d, 28d of the insulating gasket and the socket are substantially coplanar, respectively. 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.

[0078] 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.

[0079] As more visibly illustrated in figures 4 and 5, the insulating trim 30 comprises first and second axial annular heels 36, 38 extending axially outwards.

[0080] The tabs 36, 38 are located axially on either side of the insulating lining 30. Tab 36 extends axially outward on one side of the insulating lining, and tab 38 extends axially outward on the other side of the insulating lining. The free end of tab 36 defines the front face 30c of the insulating lining, and the free end of tab 38 defines the front face 30d of the insulating lining. Tabs 36, 38 are symmetrical to each other with respect to the radial median plane P of the system.

[0081] As previously stated, the insulating gasket 30 covers the front faces 14c, 14d of the outer ring. The insulating gasket 30 comprises first and second radial annular lugs 40, 42 extending radially inward and covering these front faces 14c, 14d respectively. The lugs 40, 42 are symmetrical to each other with respect to the radial median plane P of the system. The lug 36 extends axially outward relative to the lug 40. The lug 38 extends axially outward relative to the lug 42.

[0082] The insulation trim 30 includes first hooks 44 and second hooks 46 to respectively ensure the axial retention of the sealing flanges 32, 34 on the trim. The hooks 44, 46 are made in one piece, i.e. from the same material, with the insulation trim 30.

[0083] The hooks 44 are supported by the heel 36 of the insulating lining. The hooks 44 extend radially inwards, i.e., towards the inner ring 12. The hooks 44 are formed on the bore of the heel 36. The hooks 44 are spaced from each other circumferentially, here at regular intervals. Alternatively, the circumferential spacing of the hooks 44 could be irregular. The hooks 44 are here axially recessed from the front face 30c of the insulating lining. The hooks 44 are here identical to each other. Alternatively, the shape and / or circumferential dimensions of the hooks may not be identical. There are ten hooks 44 here. Alternatively, a different number of hooks may be provided.

[0084] The hooks 44 provide axial retention of the sealing flange 32 on the insulating gasket 30 by diametrical interference. The hooks 44 have an inner diameter smaller than the outer diameter of the sealing flange 32. The hooks 44 cooperate with the sealing flange 32 by snapping. Each hook 44 includes an inwardly facing buttress surface (not referenced) bearing axially against the sealing flange 32. The sealing flange 32 is fixed to the insulation gasket, bearing axially on one side against the hooks 44 and on the other side against the heel 40. The hooks 44 hold the sealing flange 32 axially against the heel 40. The sealing flange 32 bears axially against the heel 40 on the side opposite the outer ring 14. The sealing flange 32 bears radially against the bore of the heel 36.

[0085] Axially between each hook 44 and the heel 40, a groove 48 is formed locally, within which the sealing flange 32 is fixed. A plurality of grooves 48 are thus formed on the bore of the heel 36. The grooves 48 are spaced from each other in the circumferential direction. The sealing flange 32 is fixed in the bore of the heel 36.

[0086] Similarly, the hooks 46 are supported by the heel 38 of the insulating gasket. The hooks 46 extend radially inward, i.e., toward the inner ring 12. The hooks 46 are formed on the bore of the heel 38. The hooks 46 are spaced from each other circumferentially, here at regular intervals. Alternatively, the circumferential spacing of the hooks 46 could be irregular. The hooks 46 are here axially recessed from the front face 30d of the insulating gasket. The hooks 46 are here identical to each other. Alternatively, the shape and / or circumferential dimensions of the hooks may not be identical.

[0087] The hooks 46 ensure axial retention of the sealing flange 34 on the insulating gasket 30 by diametrical interference. The hooks 46 have an inner diameter smaller than the outer diameter of the sealing flange 34. The hooks 46 cooperate with the sealing flange 34 by snapping. Each hook 46 includes an inwardly facing buttress surface (not referenced) bearing axially against the sealing flange 34. The sealing flange 34 is fixed to the insulation gasket, bearing axially on one side against the hooks 46 and on the other side against the heel 42. The hooks 46 hold the sealing flange 34 axially against the heel 42. The sealing flange 34 bears axially against the heel 42 on the side opposite the outer ring 14. The sealing flange 34 bears radially against the bore of the heel 38.

[0088] Axially between each hook 46 and the heel 42, a groove (not referenced) is formed locally, within which the sealing flange 34 is fixed. A plurality of grooves are thus formed on the bore of the heel 38. The grooves are spaced from each other in the circumferential direction. The sealing flange 34 is fixed in the bore of the heel 38.

[0089] The sealing flanges 32, 34 are located axially on each side of the insulation lining 30 to close the radial space existing between the latter and the inner ring 12 and within which are housed the outer ring 14, the rolling elements 16 and the cage 17. The sealing flanges 32, 34 are located axially on either side of the outer ring 14. In this embodiment, the sealing flanges 32, 34 are identical to each other and symmetrical with respect to the median P of the system.

[0090] Each sealing flange 32, 34 is arranged radially between the insulation lining 30 and the inner ring 12, and fixed to said insulation lining by being arranged laterally to the outer ring 14.

[0091] Each sealing flange 32, 34 is entirely housed within the radial space defined by the insulating gasket 30 and the inner ring 12. The sealing flange 32, 34 is located axially between the front face 14, 14d of the outer ring and the front face 28, 28d of the sleeve. The sealing flange 32, respectively 34, is axially offset on the inner side of the system relative to the front faces 12c, 28c and 30c, respectively 12d, 28d and 30d, of the inner ring 12, the sleeve 28 and the insulating gasket 30.

[0092] Each sealing flange 32, 34 is made of a rigid material, for example metallic material or thermoplastic material, in particular polyamide.

[0093] Each sealing flange 32, 34 comprises a fastening portion 32a, 34a axially bearing on one side against the hooks 44, 46 and on the other side against the heel 40, 42 of the insulation trim, a sealing portion 32b, 34b which cooperates with the inner ring 12, and a connecting portion 32c, 34c which connects the fixing and sealing portions.

[0094] The fastening portion 32a, 34a of the sealing flange cooperates with the hooks 44, 46 to fix the sealing flange 32, 34 to the insulation gasket 30. In the illustrated embodiment, the fastening portion 32a, 34a of the sealing flange 32, 34 is formed in the form of sectors folded back on themselves. The sectors are spaced circumferentially from one another. In the illustrated embodiment, the circumferential dimension of each hook 44, 46 is such that it cooperates with two successive sectors of the fastening portion 32a, 34a of the associated sealing flange. Alternatively, each hook 44, 46 could cooperate with a different number of sectors. In another variant, the fixing portion 32a, 34a of the sealing flange 32, 34 could be annular.

[0095] The sealing portion 32b, 34b of each sealing flange is in the form of an annular axial portion that radially surrounds the outer surface 12b of the inner ring to form a narrow, labyrinth-like passage with said outer surface. The sealing portion 32b, 34b of each sealing flange forms a dynamic annular seal with the outer surface 12b of the inner ring 12. Alternatively, the sealing portion 32b, 34b of each sealing flange, or of one of the two sealing flanges, could form a dynamic seal with another part of the inner ring 12, for example, the front face 12c, 12d.

[0096] To manufacture the bearing system, the following procedure is used.

[0097] In a first step, the sleeve 28 and the outer ring 14 of the bearing are mounted inside a mold which is intended for overmolding the insulation lining 30.

[0098] Next, in the second step, the insulation lining 30 is overmolded both onto the outer ring 14 and onto the sleeve 28. The hooks 44, 46 are formed during this step.

[0099] Then, in a third successive step, the unit assembly formed by the outer ring 14, the sleeve 28 and the insulating lining 30 is extracted from the mold.

[0100] Next, in a fourth step, the front faces 28c, 28d of the bushing are ground. During this step, the outer surface 28a of the bushing and the raceway 20 of the outer ring can also be ground.

[0101] Finally, in a fifth step, the unit assembly formed by the outer ring 14, the bushing 28 and the insulation lining 30 is assembled with the row of rolling elements 16, the cage 17, the inner ring 12 and the sealing flanges 32, 34.

[0102] The embodiment illustrated in [Fig. 6], in which the identical elements This version, bearing the same references, differs from the first example in that the bushing 28 is made up of two separate parts 50, 52. These two separate parts 50, 52 form half-flanges which are axially supported against each other. In the illustrated embodiment, the parts 50, 52 of the bushing are identical and symmetrical with respect to the radial median plane P of the system in order to reduce manufacturing costs. Alternatively, it is of course possible to provide for asymmetrical parts 50, 52. In another variant, it could be possible to provide for the bushing 28 to be made up of more than two parts. In yet another variant, the bushing 28 could be made as a single piece. Preferably, the parts 50, 52 of the bushing 28 are made of steel. The parts 50, 52 can advantageously be obtained from a sheet metal blank by cutting, stamping, and rolling.

[0103] Each part 50, 52 of the sleeve comprises an annular axial portion 50a, 52a, and an annular radial collar 50b, 52b extending radially inwards from the axial portion.

[0104] The axial portions 50a, 52a are axially supported against each other. The radial flange 50b, 52b extends the end of the axial portion 50a, 52a located axially on the outer side of the system. In the illustrated embodiment, the radial flanges 50b, 52b are annular. Alternatively, at least one of the radial flanges 50b, 52b could be in the form of sectors spaced apart from each other in the circumferential direction. In the illustrated embodiment, the radial flanges 50b, 52b of the sleeve extend radially beyond the outer surface 14a of the outer ring, i.e., radially projecting inward from the outer surface 14a.

[0105] The axial portions 50a, 52a of the sleeve parts jointly define the outer surface 28a of said sleeve. Similarly, the axial portions 50a, 52a jointly define the bore 28b of the sleeve. The front face 28c of the sleeve is defined by the radial flange 50b, and the front face 28d is defined by the radial flange 52b. More precisely, the front face 28c is defined by the outer face of the radial flange 50b, and the front face 28d is defined by the outer face of the radial flange 52b.

[0106] The insulating gasket 30 covers the inner face of each flange 50b, 52b of the sleeve. The inner face and the outer face axially opposite the inner face of each flange 50b, 52b define the axial thickness of said flange. For each flange 50b and 52b, the inner face is oriented axially towards the inside of the system, and the outer face is oriented axially towards the outside of the system. The insulating gasket 30 also covers the free end of each flange 50b, 52b of the sleeve. More specifically, the heel 44, 46 covers the free end of the The flange 50b, 52b of the sleeve. The sealing flange 32, 34 is located axially between the front face 14, 14d of the outer ring and the front face 28c, 28d of the sleeve, delimited by the outer face of the radial flange 50b, 50c of the sleeve. The radial flange 50b, 50c of the sleeve radially surrounds the sealing flange 32, 34.

[0107] The embodiment illustrated in [Fig. 7], in which the identical elements bear the same reference numerals, differs from the second embodiment in that the bore of the axial portion 50a, 52a of each part 50, 52 of the sleeve is provided with a groove 54, 56 which extends circumferentially around the axis 25 of the sleeve bore. Each groove 54, 56 is oriented radially towards the outer ring 14, i.e., radially inwards.

[0108] In the illustrated embodiment, each groove 54, 56 is annular. Alternatively, at least one of the two grooves 54, 56 could not extend over 360°, or could be formed by a succession of turns extending circumferentially and spaced from each other in the circumferential direction.

[0109] Each groove 54, 56 is delimited in the axial direction by two opposing lateral flanks which have a straight profile in axial section and are connected to each other by an axial bottom. Alternatively, other shapes can be provided, for example grooves having in cross-section a shape of an arc of a circle oriented inwards.

[0110] The insulation packing 30 also includes two ribs 58, 60 extending radially outwards from the outer surface 30a and each housed within one of the grooves 54, 56 of the sleeve. The rib 58, 60 is complementary in shape to the associated groove 54, 56. Each rib 58, 60 projects beyond the outer surface 30a of the insulation packing. Each rib 58, 60 is formed on the outer surface 30a during the overmolding of the insulation packing 30.

[0111] The embodiment illustrated in Figures 8 to 10, in which the identical elements bear the same reference numerals, differs from the previous example, notably in the axial arrangement of the sealing flanges 32, 34. The sealing flange 32, 34 is located here axially between the front face 14, 14d of the outer ring and the inner face of the radial flange 50b, 50c of the sleeve. The sealing flange 32, 34 is axially offset inwards relative to the inner face of the radial flange 50b, 50c of the sleeve.

[0112] This makes it possible to locally increase the radial dimension of the radial collars 50b, 50c of the sleeve, each of which here has a crenulated shape in the circumferential direction at its free edge. With a local radial dimension The larger radial collars 50b, 50c of the bushing increase the bearing surface between the system and the housing of the associated electric motor.

[0113] In the illustrated embodiments, the bearing system includes sealing flanges. Alternatively, the bearing system could include other sealing devices, instead of sealing flanges, for example sealing gaskets.

[0114] 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.

[0115] Alternatively, an inverted arrangement may be provided in which the second ring 14, to which the insulating sleeve 30 is attached, 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 interposed radially between the bore 12a of the inner ring and the outer surface of the bushing. The insulating sleeve is fixed at least on the inner surface of the inner ring and at least on the outer surface of the bushing. The bore of the bushing defines the bore of the bearing system. The sealing device(s) are fixed to the outer surface of the insulating sleeve.

[0116] In the described embodiments, the system bearing 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

Demands

1. A bearing system 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 defining the radial thickness of said bushing, the insulating gasket (30) being fixed to the second ring (14) of the bearing and to at least one of the outer and inner surfaces of the bushing (28), characterized in that the system further comprises at least one first sealing device (32) mounted on the insulating gasket (30) and forming a first dynamic annular seal with the first ring (12),the insulation lining (30) comprising at least the first axial retaining hooks (44) of the first sealing device spaced from each other in the circumferential direction.

2. System according to claim 1, wherein the insulation lining (30) comprises at least one first axial heel (36) extending axially outwards and supporting the first axial retaining hooks (44).

3. System according to claim 1 or 2, wherein the second ring (14) comprises an outer surface (14a) and an inner surface (14b) opposite the outer surface and which delimit the radial thickness of said second ring, and first and second front faces (14c, 14d) delimiting the axial length of said second ring, the insulating packing (30) being fixed at least on one of the outer and inner surfaces of the second ring (14).

4. System according to claim 3, wherein the insulation lining (30) comprises at least a first radial heel (40) extending radially and covering at least part of the first front face (14c) of the second ring and against which the first sealing device (32) is axially supported by the first axial retaining hooks (44).

5. System according to claim 3 or 4, wherein the first ring (12) comprises first and second front faces (12c, 12d) delimiting the axial length of said second ring, the first front face (14c) of the second ring and the first front face (12c) of the first ring being located axially on a first side with respect to a median radial plane (P) of the system, the first front face (14c) of the second ring being axially offset inwards with respect to the first front face (12c) of the first ring, the first sealing device (32) being located axially between said first front faces (14c, 12c).

6. System according to any one of the preceding claims, wherein the first axial retaining hooks (44) are made as one piece with the insulation lining (30).

7. System according to any one of the preceding claims, wherein the first axial retaining hooks (44) of the insulation lining extend radially from the side of the first ring (12).

8. System according to any one of the preceding claims, wherein the first sealing device (32) comprises a sealing flange or a sealing gasket.

9. A system according to any one of the preceding claims, wherein the system further comprises at least one second sealing device (34) mounted on the insulation lining (30) and forming with the first ring (12) a second dynamic annular seal, the insulation lining (30) comprising at least second axial retaining hooks (46) of the second sealing device spaced from each other in the circumferential direction, the first and second sealing devices (32, 34) being arranged axially on either side of the second ring (14).

10. Electric motor comprising a housing, a shaft and at least one bearing system according to any one of claims 1 to 9 mounted radially between the housing and the shaft.

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