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 gasket 30 made of electrically insulating material. The insulating gasket 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 includes at least one first sealing device 32 fixed in a first annular mounting groove 36 for the insulating gasket 30 and forming a first dynamic annular seal with the first ring 12. 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 fixed in a first annular mounting groove of the insulation lining and forming a first dynamic annular seal with the first ring.

[0015] 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.

[0016] 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.

[0017] By "annular groove" is meant a groove that extends over 360°. The bottom of the groove may be continuous, or alternatively discontinuous, in the circumferential direction. In this second case, the bottom of the annular groove consists of a plurality of continuous surfaces that are spaced from one another in the circumferential direction.

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

[0019] Preferably, the first annular groove of the insulation lining is oriented radially towards the side of the first ring.

[0020] 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.

[0021] In the design in which the insulation lining is obtained by overmolding, the latter may include at least one first demolding groove offset radially from the side of the sleeve relative to the first mounting groove and formed on a first front face of said lining, at least one first heel remaining radially between the first mounting and demolding grooves.

[0022] This facilitates axial demolding of the first mounting groove during the manufacture of the system.

[0023] Preferably, said first heel of the insulation lining is provided with a frustoconical surface extending from the first front face obliquely towards the second ring and located radially on the side of the first mounting.

[0024] This facilitates the mounting of the first sealing device inside the first annular mounting groove of the insulation trim.

[0025] 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.

[0026] The first sealing device may include a sealing flange. Alternatively, the first sealing device may include a sealing gasket.

[0027] Advantageously, the system further comprises at least one second sealing device fixed in a second annular mounting groove of the insulation lining and forming with the first ring a second dynamic annular seal, the first and second sealing devices being arranged axially on either side of the second ring.

[0028] 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.

[0029] 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.

[0030] The first ring may include first and second front faces delimiting the axial length of said second ring.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] If the insulation lining is made of synthetic material or elastomeric material, it makes the system less sensitive to temperature variations.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] According to a second alternative design, the sleeve defines the inner surface of said system. In this case, the second ring is the inner ring of the bearing.

[0040] 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.

[0041] 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

[0042] 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:

[0043] [Fig-1] is a perspective view of a bearing system according to a first embodiment of the invention,

[0044] [Fig.2] is a perspective view of the bearing system of [Fig.1] in which one of the sealing flanges is not shown,

[0045] [Fig.3] is a perspective view of one of the sealing flanges of the bearing system of [Fig.1],

[0046] [Fig.4] is a half axial cross-sectional view of the bearing system of [Fig.1],

[0047] [Fig.5] is a half axial cross-sectional view of the bearing system of [Fig.1] on which the sealing flanges are not shown,

[0048] [Fig.6] is a half axial cross-sectional view of a bearing system according to a second embodiment of the invention,

[0049] [Fig.7] is a half axial cross-sectional view of a bearing system according to a third embodiment of the invention,

[0050] [Fig. 8] is a half axial cross-sectional view of a bearing system according to a fourth embodiment of the invention, and a detailed description of the invention

[0051] 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.

[0052] The bearing system is designed so as not to conduct electric currents. The bearing system has integrated electrical insulation.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The outer ring 14 comprises an axial cylindrical outer surface 14a, a cylindrical bore 14b radially opposed to the outer surface 14a, and first and second radial opposing front 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.

[0058] The outer ring 14 further includes an external raceway 20 for the rolling elements 16 which is formed on the bore 14b. The raceway 20 is directed radially inwards.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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 30b bore has a stepped shape.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] As more clearly illustrated in [Fig. 5], the insulating gasket 30 comprises first and second annular grooves 36, 38 formed on the bore 30b and extending radially outwards. Each groove 36, 38 is oriented radially towards the inner ring 12, i.e., radially inwards. Each groove 36, 38 extends over 360°. The bottom of each groove 36, 38 forms a continuous surface in the circumferential direction.

[0077] The sealing flanges 32, 34 are respectively fixed in the grooves 36, 38 of the insulation lining. The grooves 36, 38 allow the sealing flanges 32, 34 to be mounted on the insulation lining.

[0078] The groove 36 is formed on the bore 30b of the insulating lining by being axially offset on the inner side of the system relative to the front face 30c and by being axially offset on the outer side of the system relative to the front face 14c of the outer ring. The groove 36 is axially offset on the inner side of the system relative to the front face 12c of the inner ring.

[0079] Similarly, the groove 38 is formed on the bore 30b of the insulating gasket by being axially offset on the inner side of the system relative to the front face 30d and by being axially offset on the outer side of the system relative to the front face 14d of the outer ring. The groove 38 is axially offset on the inner side of the system relative to the front face 12d of the inner ring.

[0080] The grooves 36, 38 are symmetrical with respect to the median radial plane P of the system.

[0081] The insulation trim 30 includes first and second annular release grooves 40, 42 formed respectively on the front faces 30c, 30d of the insulation trim.

[0082] The groove 40 is radially offset from the side of the sleeve 28, i.e., radially outwards, relative to the groove 36. The groove 40 radially surrounds the groove 36. The groove 40 remains radially distant from the outer surface 30a of the seal of insulation. The groove 40 is oriented and axially open towards the outside of the insulation lining. The groove 40 is formed on the front face 30c of the insulation lining and extends axially inwards. The groove 40 remains axially distant from the front face 14c of the outer ring.

[0083] A first annular heel 44 lies radially between the grooves 36 and 40. The bore of the heel 44 is delimited by the groove 36, and the outer surface of the heel is delimited by the groove 40. The free end of the heel 44 partially delimits the front face 30c of the insulation lining. The heel 44 of the insulation lining is provided with a frustoconical surface 44a extending from the front face 30c towards the outer ring and connecting to the bore of said heel. The frustoconical surface 44a is located radially on the side of the groove 36.

[0084] Similarly, groove 42 is radially offset on the side of the sleeve 28 relative to groove 38. Groove 42 radially surrounds groove 38. Groove 42 remains radially distant from the outer surface 30a of the insulating gasket. Groove 42 is oriented and axially open outwards from the insulating gasket. Groove 42 is formed on the front face 30d of the insulating gasket and extends axially inwards. Groove 42 remains axially distant from the front face 14d of the outer ring. Grooves 40 and 42 are symmetrical to each other with respect to the radial median plane P of the system.

[0085] A second annular heel 46 lies radially between the grooves 38 and 42. The bore of the heel 46 is delimited by the groove 38, and the outer surface of the heel is delimited by the groove 42. The free end of the heel 46 partially delimits the front face 30d of the insulation lining. The heel 46 of the insulation lining is provided with a frustoconical surface 46a extending from the front face 30d towards the outer ring and connecting to the bore of said heel. The frustoconical surface 46a is located radially on the side of the groove 38.

[0086] As previously stated, the sealing flanges 32, 34 are fixed in the grooves 36, 38 of the insulation lining. The sealing flanges 32, 34 are located axially on each side of the insulation lining 30 to close the radial gap between the lining and the inner ring 12, within which the outer ring 14, the rolling elements 16, and the cage 17 are housed. 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.

[0087] 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.

[0088] 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.

[0089] Each sealing flange 32, 34 is made of a rigid material, for example metallic material or thermoplastic material, in particular polyamide.

[0090] The sealing flange 32, 34 includes a fixing portion 32a, 34a fixed in the groove 36, 38 of the insulation lining, 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.

[0091] The fixing portion 32a, 34a of the sealing flange is press-fitted into the groove 36, 38 to fix the sealing flange 32, 34 to the insulation gasket 30. In the illustrated embodiment, the fixing portion 32a, 34a of the sealing flange 32, 34 is formed in the form of sectors folded back on themselves to conform to the shape of the groove 36, 38. The sectors are spaced circumferentially from each other. Alternatively, the fixing portion 32a, 34a of the sealing flange 32, 34 could be annular.

[0092] 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.

[0093] To manufacture the bearing system, the following procedure is used.

[0094] 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.

[0095] Next, in the second step, the insulation lining 30 is overmolded both onto the outer ring 14 and onto the sleeve 28.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] The embodiment illustrated in [Fig. 6], in which the identical elements bear the same reference numerals, differs from the first embodiment 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 median radial plane P of the system in order to reduce manufacturing costs. Alternatively, it is of course possible to provide for non-symmetrical 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.Parts 50, 52 can advantageously be obtained from a sheet metal blank by cutting, stamping and rolling.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] The insulating gasket 30 covers the inner face of each flange 50b, 52b of the socket. 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 socket.

[0104] 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.

[0105] 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.

[0106] 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 inwardly oriented arc of a circle.

[0107] 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.

[0108] The embodiment illustrated in figures 8 and 9, on which the identical elements bear the same references, differs mainly from the third example in that the bearing system includes other sealing devices, replacing the sealing flanges, in this case sealing joints 62, 64 fixed on the insulation lining 30.

[0109] The arrangement of the sealing gaskets 62, 64 in relation to the insulation packing 30, and to the inner 12 and outer 14 rings being identical to that of the sealing flanges of the previous examples, it will not be described again.

[0110] The sealing gasket 62, 64 comprises a rigid annular insert 66, 68 and a flexible annular sealing gasket 70, 72 fixed to the insert. The insert 66, 68 is made of a rigid material, for example, a metallic material or a thermoplastic material, in particular polyamide. The gasket 70, 72 is overmolded or vulcanized onto the insert 66, 68. The gasket 70, 72 is made of a flexible material, for example, an elastomer such as nitrile rubber or a thermoplastic elastomer.

[0111] The packing 70, 72 of each sealing joint forms two radially external and internal opposing sealing portions exerting respectively a static seal with the insulation packing 30 and a dynamic annular seal with the inner ring 12.

[0112] The outer sealing portion of the gasket 70, 72 of the sealing ring is press-fitted into the groove 36, 38 of the insulation gasket. In the area of ​​the groove 36, 38, the outer sealing portion is form-fitting with said groove to form a fixing portion of the sealing ring 62, 64 on the outer ring 14. The outer sealing portion of the gasket 70, 72 of the sealing ring radially and axially surrounds the large-diameter free edge of the insert 66, 68 so that only the gasket is in contact with the outer ring 14. This promotes good positioning of the sealing ring 62, 64 inside the groove 36, 38 by press-fitting and friction mounting.

[0113] The inner sealing portion of the seal 70, 72 comprises first and second concentric annular inner lips 70a and 70b, 72a and 72b extending axially towards the interior of the bearing. Each lip 70a, 70b and 72a, 72b radially surrounds the outer surface 12b of the inner ring to form a narrow, labyrinth-like passage with said outer surface. Each lip 70a, 70b and 72a, 72b forms a dynamic seal with the outer surface 12b of the inner ring 12. Alternatively, each lip 70a, 70b and 72a, 72b could form a dynamic seal with another part of the inner ring 12, for example, the front face 12c, 12d. In another variant, at least one of the two lips 70a and 70b, 72a and 72b of each inner sealing portion of the gasket 70, 72, or of one of the two sealing portions, could come into frictional contact with the inner ring 12.

[0114] In this embodiment, each heel 44, 46 of the insulation lining is split and consists of a plurality of sectors spaced circumferentially apart. The bottom of each groove 36, 38 forms a discontinuous surface circumferentially, but the groove remains annular, i.e., extends over 360°. The different sectors of the heel 44, 46 are brought close together so that the groove 36, 38 of the insulation lining always has a shape that extends over 360°. The circumferential space between two successive sectors of the heel 44, 46 is for example less than 1.2 mm.

[0115] 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.

[0116] 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 in annular mounting grooves formed on the outer surface of the insulating sleeve.

[0117] 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. 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 which define the radial thickness of said bushing, the insulating gasket (30) being fixed on the second ring (14) of the bearing and at least on 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;62) fixed in a first annular mounting groove (36) of the insulation lining (30) and forming a first dynamic annular seal with the first ring (12).;

2. System according to claim 1, wherein the first annular groove (36) of the insulation lining (30) is oriented radially to the side of the first ring (12).

3. System according to claim 1 or 2, wherein the insulating lining (30) is overmolded onto the second ring (14) of the bearing and at least onto said surface of the bushing (28).

4. System according to claim 3, wherein the insulation lining (30) comprises first and second front faces (30c, 30d) delimiting the axial length of said lining, and at least one first release groove (40) radially offset from the side of the sleeve (28) relative to the first mounting groove (36) and formed on the first front face (30c), at least one first heel (44) remaining radially between the first mounting and release grooves (36, 40).

5. System according to claim 4, wherein said first heel (44) of the insulation lining is provided with a frustoconical surface (44a) extending from the first front face (30c) obliquely in the direction of the second ring (14) and located radially on the side of the first mounting groove (36).

6. A system according to any one of the preceding claims, wherein the first sealing device (32) comprises a part fixing (32a) fixed in the first annular mounting groove (36) of the insulation trim (30) and made of rigid material, the insulation trim (30) being made of flexible electrical insulating material.

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

8. System according to any one of the preceding claims, wherein the system further comprises at least one second sealing device (34; 64) fixed in a second annular mounting groove (38) of the insulation lining (30) and forming with the first ring (12) a second dynamic annular seal, the first and second sealing devices (32, 34; 62, 64) being arranged axially on either side of the second ring (14).

9. A system according to any one of the preceding claims, wherein the second ring (14) comprises an outer surface (14a) and an inner surface (14b) opposite the outer surface and defining 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 packing (30) being fixed at least on one of the outer and inner surfaces of the second ring (14), and wherein the first ring (12) comprises first and second front faces (12c, 12d) defining 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 relative to the first front face (12c) of the first ring, the first sealing device (32; 62) being located axially between said first front faces (14c, 12c).

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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