Bearing device with integrated electrical insulation, in particular for an electric motor or machine, and associated manufacturing processes

Abstract

[Bearing device with integrated electrical insulation, in particular for an electric motor or machine, and associated manufacturing methods] The bearing device comprises a bearing 10 provided with a first ring 12 and a second ring 14 capable of rotating relative to each other. The device comprises at least one insulating sleeve 26 mounted on the second ring 14 of the bearing and provided with a bushing 28 and an insulating lining 30 interposed radially between the second ring 14 and the bushing 28 and made of electrically insulating material. The insulating lining is overmolded onto the second ring 14 of the bearing and at least onto one of the outer and inner surfaces of the bushing 28 which delimit its radial thickness. The device further comprises at least one first key 32 housed at least partly inside first grooves 34, 40 formed on the bushing and on the insulating lining. Reference: Figure 1

Description

Title of the invention: Bearing device with integrated electrical insulation, in particular for an electric motor or machine, and associated manufacturing methods 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. State of the prior art

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

[0003] In operation when the shaft is rotating, an electrical potential difference may appear between it and the casing of the motor or the electric machine, which generates an electric current between the inner ring of the rolling bearing which is integral with the shaft, and the outer ring integral with the casing.

[0004] Electric current passing through rolling bearing components can damage these components, including rolling elements and raceways on the inner and outer rings. Electrical discharges can also generate vibrations.

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

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

[0007] To overcome the aforementioned drawbacks, it is also known to equip the outer ring of the rolling 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 insulating lining on the outer ring and on the sleeve without additional element or particular machining on the outer ring, it is possible to overmould the insulating lining.

[0009] However, with such a solution, a relative separation of the insulation lining and the sleeve 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 ring of the bearing. The insulating sleeve is provided with a bushing and an insulating lining interposed radially between the second ring of the bearing and the bushing. The insulating lining is made of electrically insulating material.

[0013] The sleeve comprises an outer surface and an inner surface opposite the outer surface and which delimit the radial thickness of said sleeve. The insulating lining is overmolded on the second ring of the bearing and at least on one of the outer and inner surfaces of the sleeve.

[0014] According to a general characteristic, at least one first groove is provided on the socket.

[0015] According to another general characteristic, at least one first groove is provided in the insulating lining. This first groove of the insulating lining is located at least partly in the radial extension of the first groove of the sleeve.

[0016] According to yet another general characteristic, the device further comprises at least one first key housed at least partly inside the first grooves of the sleeve and the insulating lining.

[0017] By "key housed at least partly inside the groove" is meant a key which is housed directly inside said groove, or indirectly inside said groove with the interposition of an intermediate element, for example a part of the insulation lining.

[0018] Thus, a bearing device with integrated electrical insulation is provided which is economical compared to conventional hybrid rolling bearings. In addition, the device is easy to manufacture and assemble in the associated motor or electrical machine.

[0019] Furthermore, the provision of said first key makes it possible to make the sleeve and the insulation lining integral in the circumferential direction. The risk of relative movements between the insulation lining and the sleeve in the circumferential direction is prevented, in particular during temperature variations.

[0020] By "circumferential direction" is meant the direction which is perpendicular to both the axial direction and a radius of the bearing device, in other words, tangent to a circle whose center is on the axis of the bearing device.

[0021] By "axial direction" is meant the direction parallel to the axis of the bearing device.

[0022] By "key" is meant an element allowing the socket and the insulating lining which can have any shape in cross section, for example polygonal such as square, rectangular, or circular, oval, half-moon, etc.

[0023] Said first key may be made of electrically insulating material.

[0024] Alternatively, said first key may be made of electrically conductive material if it is surrounded, at least at one end, by an electrically insulating material.

[0025] According to a particular design, at least one first groove may be provided on the second ring and located in the radial extension of the first groove of the insulation lining.

[0026] In this case, the first key can advantageously be housed at least partly inside the first groove of the second ring. Thus, the sleeve, the insulating lining and the second ring of the bearing are made integral in the circumferential direction. The first groove of the second ring can open onto one of the end faces thereof.

[0027] The sleeve may also comprise two opposite radial front faces which delimit the axial length of said sleeve. The insulating gasket may comprise two opposite radial front faces which delimit the axial length of said gasket.

[0028] The first groove of the socket can be provided on one of the front faces thereof.

[0029] The first groove of the insulation lining can be provided on one of the front faces thereof.

[0030] The first key may be flush with or remain set back from said front face of the socket and said front face of the insulation lining.

[0031] Alternatively, the first key may extend axially projecting relative to said front face of the sleeve and said front face of the insulation lining.

[0032] In this case, the first key may extend inside a groove formed in the housing inside which the bearing device is mounted. The first key forms an anti-rotation means of the device relative to the housing.

[0033] The first key preferably comprises two opposite end faces which delimit the circumferential dimension of said first key. The end faces of the first key may be flat.

[0034] According to a particular design, the device further comprises at least one second key housed at least partly inside the second groove of the sleeve and the insulating lining. The second groove of the insulating lining is located at least partly in the radial extension of the second groove of the sleeve. The second key may be diametrically opposite the first key.

[0035] Said second key can be made of electrically insulating material.

[0036] Alternatively, said second key may be made of electrically conductive material if it is surrounded, at least at one end, by an electrically insulating material.

[0037] According to other designs, the device may comprise only the first key, or at least three keys preferably spaced from each other in the circumferential direction.

[0038] If the insulation lining is made of synthetic material or elastomeric material, it makes the device less sensitive to temperature variations.

[0039] In a particular embodiment, the sleeve is made of metallic material. The sleeve can thus be easily machined to a predetermined radial tolerance.

[0040] In one embodiment, said insulating lining covers the entire surface of said sleeve. In this case, said insulating lining completely covers said surface of the sleeve in the axial direction and in the circumferential direction.

[0041] According to a first design, the sleeve delimits the outer surface of said device. In this case, the second ring is the outer ring of the bearing.

[0042] According to a second alternative design, the sleeve delimits the inner surface of said device. In this case, the second ring is the inner ring of the bearing.

[0043] 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.

[0044] The invention also relates to an electric motor comprising a casing, a shaft and at least one bearing device as defined previously and mounted radially between the casing and the shaft.

[0045] The invention also relates to a method of manufacturing a bearing device as defined above comprising the following successive steps:

[0046] - a step of mounting the socket and at least the second ring inside of a manufacturing mold,

[0047] - a step of overmolding the insulation gasket on the second ring and at less on said surface of the socket,

[0048] - a step of mounting the first key inside the first grooves of the insulation gasket and the socket.

[0049] The method may further comprise, after the step of overmolding the insulation lining and before the step of mounting the first key, a step of machining at least the first groove of the insulation lining. Alternatively, the imprint of at least the first groove could be obtained directly inside the mold.

[0050] The invention also relates to a method of manufacturing a bearing device as defined above comprising the following successive steps:

[0051] - a step of machining at least the first groove of the sleeve,

[0052] - a step of mounting the first key inside the first groove of the socket,

[0053] - a step of mounting the socket equipped with the first key and at least the second ring inside a manufacturing mold, and

[0054] - a step of overmolding the insulation gasket on the second ring and at less on said surface of the socket.

[0055] The invention also relates to a method of manufacturing a bearing device as defined above comprising the following successive steps:

[0056] - a step of machining at least the first groove of the second ring,

[0057] - a step of mounting the first key inside the first groove of the second ring,

[0058] - a step of mounting the socket and at least the second ring equipped with the first key inside a manufacturing mold, and

[0059] - a step of overmolding the insulation gasket on the second ring, at less on said surface of the socket and on the first key. Brief description of the figures

[0060] The present invention will be better understood upon studying the detailed description of embodiments, taken as non-limiting examples and illustrated by the appended drawings in which:

[0061] [Fig-1] is a half-view in axial section of a bearing device according to a first exemplary embodiment of the invention,

[0062] [Fig.2] is a perspective view of the bearing device of [Fig. 1],

[0063] [Fig.3] is a detail view of [Fig.2],

[0064] [Fig.4] is a flowchart illustrating the manufacturing process of the device of level of figures 1 to 3,

[0065] [Fig.5] is a half-view in axial section of a bearing device according to a second example of embodiment of the invention,

[0066] [Fig.6] is a perspective view of the bearing device of [Fig.5],

[0067] [Fig.7] is a half-view in axial section of a bearing device according to a third example of embodiment of the invention,

[0068] [Fig.8] is a perspective view of the bearing device of [Fig.7],

[0069] [Fig.9] is a detail view of [Fig.8],

[0070] [Fig. 10] is a partial exploded perspective view of the bearing device of Figures 7 to 9,

[0071] [Fig. 11] is a flowchart illustrating the manufacturing process of the bearing device of Figures 7 to 10,

[0072] [Fig. 12] is a half axial sectional view of a bearing device according to a fourth example of embodiment of the invention,

[0073] [Fig. 13] is a perspective view of the bearing device of [Fig. 12],

[0074] [Fig. 14] is a detail view of [Fig. 13],

[0075] [Fig. 15] is a partial exploded perspective view of the bearing device of FIGS. 12 to 14, and

[0076] [Fig. 16] is a flowchart illustrating the manufacturing process of the bearing device of Figures 12 to 15. Detailed description of the invention

[0077] The bearing device illustrated in [Fig. 1] comprises a bearing 10 provided with a first ring 12 and a second ring 14 which are capable of rotating relative to each other around 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.

[0078] The bearing device is designed so as not to be a conductor of electrical currents. The bearing device has integrated electrical insulation.

[0079] The inner 12 and outer 14 rings of the bearing are concentric and extend axially along the axis X-X' of the bearing. The inner 12 and outer 14 rings are made of steel. The rings are of the solid type.

[0080] In the illustrated embodiment, the bearing 10 also comprises a row of rolling elements 16, here balls, interposed radially between the inner 12 and outer 14 rings. The rolling elements 16 are made of steel. The bearing 10 also comprises a cage 17 for maintaining the regular circumferential spacing of the rolling elements 16. The bearing 10 may also be equipped with seals or sealing flanges.

[0081] The inner ring 12 comprises a cylindrical bore 12a, a cylindrical axial outer surface 12b radially opposite the bore, and two opposite radial end faces (not referenced) axially delimiting the bore and the outer surface. The bore 12a and the outer surface 12b delimit the radial thickness of the inner ring 12. The bore 12a forms the inner surface of the inner ring.

[0082] The inner ring 12 further comprises an inner raceway 18 for the rolling elements 16 which is formed on the outer surface 12b. The raceway 18 is directed radially outwards.

[0083] The outer ring 14 comprises a cylindrical axial outer surface 14a, a cylindrical bore 14b radially opposite the outer surface 14a, and two opposite radial end faces 14c, 14d axially delimiting the bore. The outer surface 14a and the bore 14b delimit the radial thickness of the outer ring 14.

[0084] In the illustrated embodiment, the outer surface 14a of the ring has two distinct diameters. Alternatively, the outer surface 14a could have a single diameter.

[0085] The outer ring 14 further comprises an outer raceway 20 for the rolling elements 16 which is formed on the bore 14b. The raceway 20 is directed radially inwards.

[0086] In the illustrated embodiment, a groove 22 is formed on the front face 14c of the outer ring. The groove 22 is oriented and open axially towards the outside of the outer ring. The groove 22 has a bottom which is offset axially towards the inside of the ring relative to the front face 14c. The bottom of the groove 22 forms a shoulder. The bottom of the groove 22 here extends radially for reasons of simplicity of manufacture. The groove 22 is here annular.

[0087] Similarly, a groove 24 is provided on the front face 14d of the outer ring. The groove 24 is oriented and open axially towards the outside of the outer ring. The groove 24 has a bottom which is axially offset towards the inside of the ring relative to the front face 14d. The bottom of the groove 24 forms a shoulder. The bottom of the groove 24 extends radially here. The groove 24 is annular here. The grooves 22, 24 are symmetrical to each other relative to a median radial plane of the outer ring. The grooves 22, 24 axially delimit the outer surface 14a.

[0088] The bearing device also comprises an electrical insulating sleeve 26 mounted on the outer ring 14. The insulating sleeve 26 is mounted on the outer surface 14a of the outer ring 14. The insulating sleeve 26 is integral with the outer ring 14.

[0089] The insulating sleeve 26 comprises a bushing 28 and an insulating lining 30 interposed radially between the outer ring 14 and the bushing 28. The insulating lining 30 is overmolded onto the outer ring 14 and onto the bushing 28.

[0090] As will be described in more detail later, the bearing device also comprises first and second keys 32, 33 for making the sleeve 28 and insulation lining 30 rotationally integral.

[0091] The sleeve 28 is annular in shape. The sleeve 28 extends axially. The sleeve 28 is made here in a single piece. Alternatively, the sleeve 28 could be made in several pieces bearing against each other, for example two identical pieces. The sleeve 28 comprises a cylindrical annular axial outer surface 28a, and an annular bore 28b radially opposite the outer surface 24a. The bore 28b forms the inner surface of the sleeve 24. The bore 28b is oriented radially inwards, i.e. on the side of the outer ring 14.

[0092] The sleeve 28 also comprises two opposite radial end faces 28c, 28d axially delimiting the bore and the outer surface. The end faces 28c, 28d delimit the axial length of the sleeve. The outer surface 28a and the bore 28b delimit the radial thickness of the sleeve 24. The outer surface 28a of the sleeve delimits the outer surface of the bearing device 10. In other words, the outer surface 28a defines the outer diameter of the bearing device 10.

[0093] In the illustrated embodiment, the front faces 28c, 28d of the sleeve are respectively coplanar with the front faces 14c, 14d of the outer ring. Alternatively, it could be possible to provide other arrangements. For example, the sleeve 28 could have a smaller, or larger, axial dimension and remain axially set back from the faces 14c, 14d of the outer ring, or project from said faces.

[0094] Referring to [Fig. 3], a first groove 34 is formed on the sleeve. The first groove 34 is formed on the front face 28d of the sleeve. The groove 34 is oriented and open axially outward. The groove 34 opens radially into the bore 28b of the sleeve. In the illustrated embodiment, the groove 34 also opens radially onto the outer surface 28a of the sleeve.

[0095] The groove 34 is delimited in the circumferential direction by two lateral flanks 34a, 34b facing each other which are connected to each other by a radial bottom 34c. The flanks 34a, 34b are here rectilinear and extend radially. The bottom 34c also extends radially and is oriented axially outwards. Alternatively, the groove 34 could be devoid of a bottom, the flanks 34a, 34b then connecting directly.

[0096] In the illustrated embodiment, a first groove 36 is formed on the outer ring. The groove 36 is formed on the outer surface of the groove 22 of the outer ring and opens onto the front face 14d. The groove 36 is open axially outward. The groove 36 is oriented and open radially outward.

[0097] The groove 36 is delimited in the circumferential direction by two lateral flanks 36a, 36b facing each other which are connected to each other by a radial bottom (not visible). The groove 36 also comprises an axial bottom 36c which connects to the flanks 36a, 36b and to the radial bottom. The flanks 36a, 36b are here rectilinear and extend radially. The radial bottom also extends radially and is oriented axially outwards. Alternatively, the groove 36 could be without a bottom, the flanks 36a, 36b then connecting directly.

[0098] The insulating lining 30 is made of electrically insulating material. The insulating lining 30 may for example be made of synthetic material, such as PEEK or PA46, or may be made of elastomeric material, for example rubber.

[0099] Referring to Figures 1 to 3, the insulating lining 30 is interposed radially between the outer surface 14a of the outer ring and the bore 28b of the sleeve. The insulating lining 30 covers the outer surface 14a of the outer ring. The insulating lining 30 here completely covers the outer surface 14a in considering the axial and circumferential directions. The insulating lining 30 also covers the grooves 22, 24 of the outer ring. The insulating lining 30 also covers the groove 36 of the outer ring. The insulating lining 30 covers the flanks 36a, 36b, and the axial bottom 36c and the radial bottom of the groove 36.

[0100] The insulating lining 30 further covers the bore 28b of the sleeve. The insulating lining 30 also here completely covers the bore 28b considering the axial and circumferential directions. The insulating lining 30 also covers the groove 34 of the sleeve. The insulating lining 30 covers the flanks 34a, 34b, and the bottom 34c of the groove.

[0101] The insulating lining 30 is annular in shape. The insulating lining 30 extends axially. The insulating lining 30 comprises a cylindrical axial outer surface 30a, a cylindrical bore 30b radially opposite the outer surface 30a, and two opposite radial end faces 30c, 30d axially delimiting the bore and the outer surface. The radial end faces 30c, 30d delimit the axial length of the insulating lining 30. The outer surface 30a is in radial contact with the bore 28b of the sleeve. The portion of the insulating lining 30 which covers the groove 34 forms a protrusion which extends radially outward. The bore 30b is in radial contact with the outer surface 14a of the outer ring, with the grooves 22, 24 and with the axial bottom 38c of the groove 38. The bore 30b has a stepped shape.The portion of the insulating lining 30 which covers the groove 36 forms a protrusion which extends radially inwards.

[0102] In the illustrated embodiment, the faces 14c, 30c, 28c and 14d, 30d, 28d of the outer ring, the insulating lining and the sleeve are respectively coplanar.

[0103] Alternatively, it is possible to provide other arrangements. For example, the insulating lining 30 could have a reduced axial dimension and remain axially set back from the faces 14c, 14d of the outer ring. Alternatively, the insulating lining 30 could have an increased axial dimension and extend axially projecting from the faces 14c, 14d of the outer ring. In this case, the insulating lining 30 may at least partially cover these faces 14c, 14d. Alternatively, the insulating lining 30 could at least partially cover the faces 28c, 28d of the sleeve.

[0104] In another alternative or in combination, the sleeve 28 could extend axially projecting from the insulation lining 30 relative to the faces 30c and 30d, or remain axially set back from these faces.

[0105] The insulating lining 30 also comprises a first groove 40 which is formed in the portion of the lining which covers the groove 24 of the sleeve and which forms the outer protrusion. The groove 40 extends into the radial thickness of the lining. The groove 40 extends radially inward to the vicinity of the outer surface 30b of the outer ring. The groove 40 is open radially on the outer side. The groove 36 is located in the radial extension of the groove 40. The groove 40 is oriented and open axially outward. The groove 40 opens onto the front face 30d of the insulation lining.

[0106] The groove 40 is delimited in the circumferential direction by two lateral flanks 40a, 40b facing each other which are connected to each other by a radial bottom 40c. The flanks 40a, 40b are here rectilinear and extend radially. The bottom 40c also extends radially and is oriented axially outwards. Alternatively, the groove 40 could be without a bottom, the flanks 40a, 40b then connecting directly. The groove 40 also comprises an axial bottom 40d which connects to the flanks 40a, 40b and to the radial bottom 40c.

[0107] As previously indicated, the bearing device comprises the first key 32. The key 32 is mounted inside the groove 40 of the insulating lining. The key 32 is mounted indirectly inside the groove 34 of the sleeve with the interposition of the part of the insulating lining delimiting the groove 40.

[0108] The key 32 bears in the circumferential direction against the flanks 40b, 40c of the groove 40 of the insulation lining. The key 32 bears axially against the bottom 40c of the groove.

[0109] The key 32 is provided with two lateral faces 32a, 32b which respectively bear in the circumferential direction against the flanks 40b, 40c. The faces 32a, 32b delimit the circumferential dimension of the key 32. The key 32 is here a key of the parallel type. Alternatively, the key 32 could have other shapes, for example the faces 32a, 32b could not be parallel and in particular be of the dovetail type or even have a stepped profile. The key 32 could also have a cylindrical or other shape.

[0110] The key 32 is also provided with a radially inner face 32c bearing against the axial bottom 40c of the groove, and an opposite outer face 32d. The faces 32c, 32d delimit the radial height of the key 32. The outer face 32d is here radially set back from the outer surface 28a of the outer ring. Alternatively, the outer face 32d of the key could be flush with the outer surface 28a.

[0111] The key 32 can be fixed inside the groove 40 by any suitable means, for example by force fitting, by gluing, by adhesive, by overmolding by bi-injection etc. Alternatively, the key 32 can be mounted free inside the groove 40.

[0112] In the illustrated embodiment, the key 32 is flush with the front face 28d of the socket and the front face 30d of the insulation lining. Alternatively, the key 32 could remain set back relative to the front faces 28d, 30d of the sleeve and the insulation lining, or even extend axially projecting relative to these faces as illustrated in the embodiment example of figures 5 and 6.

[0113] As previously indicated, the bearing device also comprises the second key 33. The second key 33 is diametrically opposite to the first key 32 and identical thereto. The mounting of the key 33 on the sleeve 28 and on the insulating lining 30 is identical to that of the first key 32, and will not be described in further detail.

[0114] The first and second keys 32, 33 are made here of electrically insulating material. The keys 32, 33 may for example be made of synthetic material, such as PEEK or PA46, or even be made of elastomeric material, for example rubber. Alternatively, the first and second keys 32, 33 could be made of electrically conductive material and surrounded, at least at one end, by an electrically insulating material.

[0115] To manufacture the bearing device, the procedure is as follows.

[0116] In a first step 50 illustrated in [Fig.4], the groove 34 and the groove (not re The groove 36 and the groove (not referenced) diametrically opposite the outer ring 14 are also machined.

[0117] In a second successive step 52, the bearing 10 and the sleeve 28 are mounted inside a mold which is provided for the overmolding of the insulation lining 30. In this position mounted inside the mold, the sleeve 28 is radially at a distance from the outer ring 14 of the bearing.

[0118] In a third successive step 54, the insulating lining 30 is overmolded both on the outer ring 14 of the bearing and on the sleeve 28.

[0119] Then, in a fourth step 56, the unitary assembly formed by the bearing 10, the sleeve 28 and the insulating lining 30 is extracted from the mold.

[0120] Then, in a fifth successive step 58, the groove 40 and the diametrically opposite groove (not referenced) of the insulation lining are machined. Alternatively, the impressions of these grooves could be obtained directly inside the mold.

[0121] Finally, in a sixth step 59, the first and second keys 32, 33 are mounted inside the grooves of the insulation lining.

[0122] The first and second keys 32, 33 are inserted axially inside the grooves of the insulation lining. Alternatively, the first and second keys 32, 33 could be inserted radially inside the grooves of the insulation lining, for example if the grooves do not open axially on the side of the device.

[0123] The embodiment illustrated in Figures 7 to 10, in which identical elements bear the same references, differs mainly from the first example in that the key 32 is mounted directly inside the groove 34 of the sleeve. Thus, in this example, the key 32 is mounted directly inside the groove 34 of the sleeve and directly inside the groove 40 of the insulation lining. The key 32 is mounted axially bearing against the bottoms of the grooves 34, 40.

[0124] In this example, the radial dimension of the groove 40 of the insulating lining 30 is reduced. The groove 40 is located in the radial extension of the groove 34. The flanks 40a, 40b of the groove 40 respectively extend radially inwards the flanks 34a, 34b of the groove 34. The key 32 bears in the circumferential direction against the flanks 34a, 34b of the groove 34 and the flanks 40b, 40c of the groove 40.

[0125] As for the first embodiment, the mounting of the key 33 is identical to that of the first key 32.

[0126] To manufacture the bearing device, the procedure is as follows.

[0127] In a first step 60 illustrated in [Fig. 11], the groove 34 and the diametrically opposite groove (not referenced) of the sleeve 28, which are provided for mounting the first and second keys 32 and 33, are machined. The groove 36 and the diametrically opposite groove (not referenced) of the outer ring 14 are also machined.

[0128] In a second successive step 62, the keys 32, 33 are mounted in these grooves of the sleeve 28. The sleeve 28 therefore supports the keys 32, 33.

[0129] Then, in a third step 64, the bearing 10 and the sleeve 28 are mounted inside the mold which is provided for the overmolding of the insulation lining 30. In this position mounted inside the mold, the sleeve 28 and the keys 32, 33 are radially spaced from the outer ring 14 of the bearing.

[0130] Then, in a fourth successive step 66, the insulating lining 30 is overmolded both on the outer ring 14 of the bearing, on the sleeve 28 and on the keys 32, 33.

[0131] Finally, in a fifth step 68, the bearing device, which is in the form of a unitary assembly, is extracted from the mold.

[0132] The embodiment illustrated in Figures 11 to 14, in which identical elements bear the same references, differs mainly from the first example in that the key 32 is mounted inside the groove 36 of the outer ring.

[0133] In this example, the groove 36 is located in the radial extension of the groove 40. The flanks 36a, 36b of the groove 36 extend respectively radially towards inside the flanks 40a, 40b of the groove 40. The groove 36 opens radially into the bore 14b of the outer ring. The key 32 bears in the circumferential direction against the flanks 36a, 36b of the groove 36 and the flanks 40b, 40c of the groove 40. The key 32 is mounted axially bearing against the bottoms of the grooves 36, 40.

[0134] In this example, the insulating lining 30 covers the upper face of the key 32. The insulating lining 30 also covers the entirety of the groove 40 and is flush with the outer surface 28 of the sleeve.

[0135] As for the first embodiment, the mounting of the key 33 is identical to that of the first key 32.

[0136] To manufacture the bearing device, the procedure is as follows.

[0137] In a first step 70 illustrated in [Fig. 16], the groove 36 and the diametrically opposite groove (not referenced) of the outer ring 14, which are provided for mounting the first and second keys 32 and 33, are machined. The groove 34 and the diametrically opposite groove (not referenced) of the sleeve are also machined.

[0138] In a second successive step 72, the keys 32, 33 are mounted in these grooves of the outer ring 14. The outer ring 14 therefore supports the keys 32, 33 at this stage.

[0139] Then, in a third step 74, the bearing 10 and the sleeve 28 are mounted inside the mold which is provided for the overmolding of the insulation lining 30. In this position mounted inside the mold, the sleeve 28 is radially at a distance from the outer ring 14 of the bearing.

[0140] Then, in a fourth successive step 76, the insulating lining 30 is overmolded both on the outer ring 14 of the bearing, on the sleeve 28 and on the keys 32, 33.

[0141] Finally, in a fifth step 78, the bearing device, which is in the form of a unitary assembly, is extracted from the mold.

[0142] In the illustrated embodiments, the first ring 12 of the bearing is the inner ring and the second ring 14 on which the insulating lining 30 is overmolded is the outer ring.

[0143] Alternatively, it is possible to provide an inverted arrangement in which the second ring 14 on which the insulating lining 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 lining is then interposed radially between the bore 12a of the inner ring and the outer surface of the sleeve. The insulating lining is overmolded on the inner ring and at least on the outer surface of the sleeve. The bore of the sleeve delimits the bore of the bearing device.

[0144] In the described embodiments, the bearing of the device is provided with a single row of rolling elements. The bearing may alternatively be provided with several rows of rolling elements. Furthermore, the rolling bearing may comprise other types of rolling elements than balls, for example rollers. In another variant, the bearing may be a sliding bearing without rolling elements.

Claims

Claims

1. Bearing device comprising a bearing (10) provided with 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 provided with a bushing (28) and an insulating lining (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 delimit the radial thickness of said bushing, the insulating lining (30) being overmolded 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 at least one first groove (34) is provided on the bushing (28) and in that at least one first groove (40) is provided the insulation lining (30),the first groove (40) of the insulating lining is located at least partly in the radial extension of the first groove (34) of the sleeve, the device further comprises at least one first key (32) housed at least partly inside the first grooves (34, 40) of the sleeve and of the insulating lining.,

2. Device according to claim 1, further comprising at least one first groove (36) provided on the second ring (14) and located in the radial extension of the first groove (40) of the insulating lining, the first key (34) being housed at least partly inside the first groove (36) of the second ring.

3. Device according to claim 2, in which the first groove (36) of the second ring opens onto one of the front faces (14d) of said second ring.

4. Device according to any one of the preceding claims, wherein the sleeve (28) comprises two opposite radial front faces (28c, 28d) which delimit the axial length of said sleeve and the insulating lining (30) comprises two opposite radial front faces (30c, 30d) which delimit the axial length of said lining, and wherein the first groove (34) of the sleeve is provided on one of the front faces (28d) of said sleeve and the first groove (40) of the insulating lining is provided on one of the front faces (30d) of said insulating lining.

5. A device according to claim 4, wherein the first key (32) is flush with or remains set back from said front face (28d) of the socket and said front face (30d) of the insulation lining, or extends axially projecting from said front face of the socket and said front face of the insulation lining.

7. A method of manufacturing a bearing device according to any one of claims 1 to 5 comprising the following successive steps: - a step of mounting the sleeve (28) and at least the second ring (14) inside a manufacturing mold, - a step of overmolding the insulating lining (30) on the second ring (14) and at least on said surface of the sleeve (28), and - a step of mounting the first key (32) inside the first grooves (34, 40) of the insulating lining and the sleeve.

8. A method of manufacturing a bearing device according to any one of claims 1 to 5 comprising the following successive steps: - a step of machining at least the first groove (34) of the sleeve, - a step of mounting the first key (32) inside the first groove (34) of the sleeve, - a step of mounting the sleeve (28) equipped with the first key and at least the second ring (14) inside a manufacturing mold, and - a step of overmolding the insulation lining (30) on the second ring (14), at least on said surface of the sleeve (28) and on the first key (32).

9. A method of manufacturing a bearing device according to claim 2 or 3, or claim 4 or 5 dependent on claim 2, comprising the following successive steps: - a step of machining at least the first groove (36) of the second ring, - a step of mounting the first key (32) inside the first groove (36) of the second ring, - a step of mounting the sleeve (28) and at least the second ring (14) equipped with the first key inside a manufacturing mold, and - a step of overmolding the insulation lining (30) on the second ring (14), at least on said surface of the sleeve (28) and on the first key (32).

10. An electric motor comprising a housing, a shaft and at least one bearing device according to any one of claims 1 to 5 mounted radially between the housing and the shaft.

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