Bearing arrangement with integrated electrical insulation for electric motor or machine

Abstract

The invention relates to a bearing arrangement with integrated electrical insulation. The bearing arrangement comprises a bearing (10) provided with a first ring (12) and a second ring (14) rotatable relative to each other. The device comprises at least one insulating sleeve (26) mounted on the second ring of the bearing and provided with a bushing (28) and an insulating liner (30) interposed radially between the second ring and the bushing and made of an electrically insulating material. The liner includes an outer surface (28a) and an inner surface (28b) defining a radial thickness of the liner. An insulating liner is overmolded on the second ring of the bearing and overmolded on at least one of the outer and inner surfaces of the bushing. The bushing is made of at least two first (32) and second (34) parts, each part comprising an axial portion (32a, 34a) and a radial collar (32b, 34b) extending radially inward from the axial portion.

Description

Technical Field

[0001] This invention relates to the field of bearings, and particularly to bearings for electric motors, electric machines and related equipment. Background Technology

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

[0003] During operation, as the shaft rotates, a potential difference may occur between the shaft and the housing of an electric motor or electric machine, which generates a current between the inner ring (fixed to the shaft) and the outer ring (fixed to the housing) of the rolling bearing.

[0004] Current flowing through the components of a rolling bearing can damage these components, particularly the rolling elements and the raceways formed on the inner and outer rings. Discharge can also generate vibration.

[0005] To overcome these shortcomings, it is known to replace the rolling elements of the bearing, which are made of the same steel as the inner and outer rings, with rolling elements made of ceramic. This is usually called a hybrid rolling bearing.

[0006] However, these hybrid rolling bearings are relatively expensive.

[0007] To overcome the aforementioned drawbacks, it is also known to provide an insulating sleeve for the outer ring of a rolling bearing, the insulating sleeve having a bushing and an insulating lining made of an electrically insulating material and located radially between the outer ring and the bushing.

[0008] To achieve the fixation of the insulating liner on the outer ring and bushing without the need for additional components or specific machining of the outer ring, an overmolded insulating liner can be used.

[0009] However, with this solution, detachment relative to the insulating liner and bushing may occur during operation.

[0010] Therefore, the present invention aims to remedy the aforementioned disadvantages by proposing a bearing device that is simple in design and economical. Summary of the Invention

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

[0012] The device further includes at least one insulating sleeve mounted on the second ring of the bearing. The insulating sleeve has a bushing and an insulating lining, the insulating lining being radially positioned between the second ring of the bearing and the bushing. The insulating lining is made of an electrically insulating material.

[0013] The bushing includes an outer surface defining the radial thickness of the bushing and an inner surface opposite the outer surface.

[0014] The second ring includes an outer surface defining the radial thickness of the second ring and an inner surface opposite the outer surface, as well as a first front face and a second front face defining the axial length of the second ring.

[0015] The insulating lining covers at least one of the outer and inner surfaces of the second ring of the bearing and at least one of the outer and inner surfaces of the bushing.

[0016] According to a general feature, the bushing is made of at least two separate first and second parts, each part including an axial portion and a radial collar extending from the axial portion at least radially toward the inside.

[0017] According to another general feature, the axial portions of the first component and the axial portions of the second component at least partially define the surface of the bushing on which the insulating lining is formed.

[0018] According to another general feature, at least the radial collar of the first component of the bushing extends radially beyond the second turn and covers the outer or inner surface of the insulating lining thereon, and the radial collar is provided with a plurality of through-holes spaced apart from each other in the circumferential direction.

[0019] According to another general feature, the insulating liner is also overmolded on the inner face of the radial collar of each of the first and second components of the bushing, and at least partially overmolded on the first and second front faces of the second ring.

[0020] According to another general feature, the insulating liner includes a set of blind holes, each blind hole extending axially inside one of the through holes in the radial collar of the first component of the bushing, and maintaining a distance axially from the first face of the second ring.

[0021] Producing a bushing with radial collars using these two components allows for effective fixation to the insulating liner. This avoids the risk of relative displacement between the insulating liner and the bushing in the axial direction, especially under temperature variations.

[0022] "Axial direction" should be understood as the direction parallel to the axis of the bearing assembly.

[0023] Furthermore, compared to the one-piece production of bushings with collars, producing bushings in at least two separate parts facilitates placing the second ring inside the mold that provides the mold for overlaying the molded insulating lining.

[0024] Furthermore, considering the dimensions of the radial collar of the first component of the bushing, when a significant axial load is applied to a device with this collar (which supports the shoulder of the housing) mounted inside the associated motor or electric machine, the portion of the insulating liner located axially between the second ring and the radial collar is not subjected to shear stress. More specifically, in this case, compressive stress is applied to this portion of the insulating liner. This increases the reliability of the device.

[0025] Each blind hole in the insulating liner corresponds to the footprint of the syringe used during the overmolding of the insulating liner during the manufacture of the bearing assembly. Injecting material through the through-hole of the radial collar of the first component of the bushing allows for an increase in the radial dimension of the radial collar and the support surface of the associated electric machine or motor mount. This also allows for a reduction in the material volume of the insulating liner, which is more expensive than the bushing material.

[0026] According to a particular design, the insulating liner covers the bore of each of the plurality of through-holes in the radial collar of the first component of the bushing. Alternatively, the insulating liner may cover only some of the through-holes.

[0027] Preferably, the radial collar of the second component of the bushing extends radially beyond the outer or inner surface of the second ring that is overly molded with the insulating lining. Alternatively, it may be proposed that the radial collar of the second component of the bushing remain radially retracted from the outer or inner surface of the second ring that is overly molded with the insulating lining.

[0028] Advantageously, the radial collar of the second component of the bushing is provided with a plurality of through holes spaced apart from each other in the circumferential direction. In this case, the insulating liner may include a set of through holes, each through hole extending axially inside one of the through holes and leading into the second front face of the second ring.

[0029] Each through-hole in the insulating liner corresponds to the positioning of the pin, thereby allowing the centering of the second component of the bushing and the transmission of closing forces of the mold used during the overmolding of the insulating liner.

[0030] The locating pin, via the through-hole of the radial collar of the second component of the bushing, allows for an increase in the radial dimension of the radial collar and the support surface of the associated electric machine or motor mount. Furthermore, this allows for a reduction in the volume of material in the insulating liner.

[0031] According to a particular design, the insulating liner covers the bore of each of the plurality of through-holes in the radial collar of the second component of the bushing. Alternatively, the insulating liner may cover only some of the through-holes in the plurality of through-holes in the radial collar of the second component of the bushing.

[0032] According to a particular design, the insulating liner may include at least one stud between two consecutive through-holes in the circumferential direction, the at least one stud extending inside one of the through-holes in the radial collar of the second component of the bushing. Alternatively, the studs may be distributed differently. In another variation, the insulating liner may not have studs if a centering pin is provided to be received in each through-hole of the radial collar of the second component of the bushing.

[0033] In one embodiment, the first and second components of the bushing are symmetrical with respect to the radial median plane of the device. This allows for a reduction in the cost of manufacturing the device.

[0034] According to a particular design, the axial portions of the first component and the axial portions of the second component of the bushing are in axial contact with each other and together define the entire surface of the bushing on which the insulating lining is formed.

[0035] According to another design, the axial portions of the first component and the second component of the bushing are axially spaced apart from each other. In this case, the bushing may further include an additional ring axially positioned between the axial portions of the first and second components, and together with the axial portions of the first and second components of the bushing, defining the surface of the bushing on which the insulating lining is formed.

[0036] According to a particular design, the surface of the bushing is provided with at least one groove extending in the circumferential direction, and an engagement rib of the insulating liner having a complementary shape extends in the groove.

[0037] Therefore, the axial engagement between the insulating liner and the bushing was increased.

[0038] "Circumferential direction" should be understood as the direction perpendicular to the axial direction and perpendicular to the radius of the bearing assembly; in other words, it is tangent to the circle centered on the axis of the bearing assembly.

[0039] Each axial portion of the first and second components of the bushing may be provided with at least one groove extending in the circumferential direction, in which an engagement rib of the insulating liner with a complementary shape extends.

[0040] If the insulating liner is made of synthetic or elastomeric materials, this makes the device insensitive to temperature changes.

[0041] In one particular embodiment, the first and second components of the bushing are made of metallic material. Therefore, the bushing can be easily machined to a predetermined radial tolerance.

[0042] The first and second components of the bushing can be obtained from sheet metal blanks by cutting, stamping, and rolling.

[0043] In one embodiment, the insulating liner covers the entire surface of the bushing. In this case, the insulating liner completely covers the surface of the bushing in both the axial and circumferential directions.

[0044] According to the first design, the bushing defines the outer surface of the device. In this case, the second ring is the outer ring of the bearing.

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

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

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

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

[0049] - The step of mounting one of the first and second components of the bushing to the bottom of the manufacturing mold.

[0050] - The step of placing the second ring inside the manufacturing mold.

[0051] - The step of installing the first component and the other component of the second component of the bushing inside the manufacturing mold.

[0052] - The step of placing the syringes inside the through-hole of the radial collar of the first component of the bushing, wherein the syringes maintain a certain distance axially from the first front face of the second ring.

[0053] -The step of molding the insulating liner by means of the syringe, and

[0054] - The step of assembling the assembly formed by the second ring, the first and second components of the bushing, and the insulating liner with the first ring of the bearing.

[0055] The method may further include, prior to the overmolding step, placing centering studs inside the through-hole of the radial collar of the second component of the bushing, wherein the studs are axially supported against the second front face of the second ring. Attached Figure Description

[0056] The invention will be more clearly understood by studying the detailed description of the embodiments provided by way of non-limiting example and illustrated in the accompanying drawings, in which:

[0057] Figure 1 This is a front view of a bearing assembly according to an exemplary embodiment of the present invention.

[0058] Figure 2 It is along Figure 1 Half-view of section II-II along axis,

[0059] Figure 3 It is along Figure 1 Half view of section III-III of axis,

[0060] Figure 4 yes Figure 1 A partial exploded perspective view of the bearing assembly, wherein the insulating lining of the assembly is not yet shown, and

[0061] Figure 5 It shows the manufacturing process. Figure 1 A flowchart of a method for assembling a bearing device. Detailed Implementation

[0062] Figure 1 and Figure 2 The illustrated bearing assembly includes a bearing 10, which has a first ring 12 and a second ring 14 that are rotatable relative to each other about the bearing's axis X-X'. In the illustrated exemplary embodiment, the first ring 12 is the inner ring of the bearing, and the second ring 14 is the outer ring.

[0063] The bearing assembly is designed not to conduct current. The bearing assembly has integrated electrical insulation.

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

[0065] In the exemplary embodiment shown, the bearing 10 further includes a row of rolling elements 16 (in this case, balls) radially positioned 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 a uniform circumferential spacing between the rolling elements 16. The bearing 10 may also be provided with sealing gaskets or sealing flanges.

[0066] The inner ring 12 includes a cylindrical bore 12a, a cylindrical axial outer surface 12b radially opposite the bore, and two opposing radial front faces 12c and 12d defining the bore and the outer surface axially. 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 front face 12c and the second front face 12d define the axial length of the inner ring 12.

[0067] The inner ring 12 also includes an inner raceway 18 formed on the outer surface 12b for the rolling element 16. The raceway 18 is oriented radially outward.

[0068] The outer ring 14 includes a cylindrical axial outer surface 14a, a cylindrical hole 14b radially opposite the outer surface 14a, and a first radial face 14c and a second radial face 14d axially defining the hole and the outer surface 14a. The outer surface 14a and the hole 14b define the radial thickness of the outer ring 14. The first face 14c and the second face 14d define the axial length of the outer ring 14.

[0069] The outer ring 14 also includes an outer raceway 20 formed on the bore 14b for the rolling element 16. The raceway 20 is radially oriented inward.

[0070] The bearing assembly also includes an electrically 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 fixed to the outer ring 14.

[0071] The insulating sleeve 26 includes a bushing 28 and an insulating liner 30 radially positioned between the outer ring 14 and the bushing 28. The insulating liner 30 is overmolded onto the outer ring 14 and the bushing 28.

[0072] Bushing 28 has an annular shape. Bushing 28 is composed of two separate first parts 32 and second parts 34. These two separate parts 32, 34 form half-flanges, which in this case bear against each other axially. In the exemplary embodiment shown, the parts 32, 34 of the bushing are identical and symmetrical with respect to the radial intermediate plane P of the device to reduce manufacturing costs. In this case, the radial intermediate plane P passes through the center of the rolling element 16. Alternatively, asymmetrical parts 32, 34 can certainly be provided. In another variation, it can be provided that bushing 28 is composed of more than two parts. Preferably, the parts 32, 34 of bushing 28 are made of steel. Advantageously, parts 32, 34 can be obtained from sheet metal blanks by cutting, stamping, and rolling. As an alternative, it is advantageous that components 32 and 34 can be obtained from tubes or from forged and / or rolled blanks, or even by sintering and stamping.

[0073] Each component 32, 34 of the bushing includes an annular axial portion 32a, 34a and an annular radial collar 32b, 34b extending radially inward from the axial portion. The axial portions 32a, 34a bear against each other axially. The radial collars 32b, 34b extend from the axial ends of the axial portions 32a, 34a located axially outside the device. In the exemplary embodiment shown, the radial collars 32b, 34b are annular.

[0074] The bushing 28 includes a cylindrical axial outer surface 28a and a cylindrical bore 28b radially opposite the outer surface 28a, the axis 25 of which is coaxial with axis X-X'. The bore 28b forms the inner surface of the bushing 28. The bore 28b is radially oriented inward, i.e., oriented on the side of the outer ring 14 and the insulating liner 30. Axial portions 32a and 34a of the bushing components collectively define the outer surface 28a. Similarly, axial portions 32a and 34a of the components collectively define the bore 28b. The outer surface 28a and the bore 28b define the radial thickness of the bushing 28. The outer surface 28a of the bushing forms the outer surface of the bearing assembly 10. In other words, the outer surface 28a defines the outer diameter of the bearing assembly 10.

[0075] The radial collars 32b and 34b of the bushing parts extend radially beyond the outer surface 14a of the outer ring, i.e., they protrude radially inward relative to the outer surface 14a. In other words, the free ends of the radial collars 32b and 34b are offset radially inward relative to the outer surface 14a of the outer ring. The radial collars 32b and 34b extend up to the vicinity of the hole 14b of the outer ring and remain radially retracted from said hole 14b. The radial collars 32b and 34b maintain a certain distance axially from the outer ring 14.

[0076] Each radial collar 32b, 34b of the bushing components 32, 34 is provided with a plurality of through holes 36, 38 spaced apart from each other in the circumferential direction (in this case, spaced evenly). Alternatively, the spacing of the holes 36, 38 may be non-uniform.

[0077] In this case, holes 36 and 38 are identical. Alternatively, holes 36 and 38 may be different. In the exemplary embodiment shown, holes 36 and 38 are circular. Alternatively, holes 36 and 38 may have different shapes, such as polygons (e.g., rectangles or squares), ellipses, etc.

[0078] As indicated above, holes 36 and 38 are through holes. Holes 36 and 38 axially penetrate the thickness of the associated radial collars 32b and 34b of the bushing component 32. Holes 36 and 38 lead into the internal and external faces of the associated collars 32b and 34b. The internal face and the external face opposite the internal face of each radial collar 32b and 34b define the axial thickness of the collar. For each radial collar 32b and 34b, the internal face is axially oriented towards the inside of the device, and the external face is axially oriented towards the outside of the device.

[0079] In the exemplary embodiment shown, the orifice 36 of the radial collar 32b of the bushing component 32 is axially aligned with the orifice 38 of the radial collar 34b of the component 34. Alternatively, the orifice 36 may be offset at an angle from the orifice 38.

[0080] Bushing 28 also includes two opposing radial faces 28c and 28d that define the outer surface 28a in the axial direction. Faces 28c and 28d define the axial length of the bushing. Face 28c is defined by a radial collar 32b, and face 28d is defined by a radial collar 34b. More specifically, face 28c is defined by the external face of radial collar 32b, and face 28d is defined by the external face of radial collar 34b.

[0081] The front face 14c of the outer ring and the front face 28c of the bushing are axially located on a first side relative to the radial median plane P of the device, and the front face 14d of the outer ring and the front face 28d of the bushing are axially located on a second side opposite to the first side relative to the radial median plane P.

[0082] The front face 14c of the outer ring is offset axially inward relative to the front face 28c of the bushing. The front face 14d of the outer ring is also offset axially inward relative to the front face 28d of the bushing. In other words, the front faces 14c and 14d of the outer ring are axially retracted relative to the front faces 28c and 28d of the bushing. The axial dimension of the outer ring 14 is smaller than the axial dimension of the bushing 28.

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

[0084] The insulating liner 30 is made of an electrically insulating material. The insulating liner 30 may be made of, for example, a synthetic material (such as PEEK or PA46), or even an elastomeric material (such as rubber).

[0085] The insulating liner 30 is radially positioned between the outer surface 14a of the outer ring and the bore 28b of the bushing. The insulating liner 30 covers the outer surface 14a of the outer ring. In this case, the insulating liner 30 completely covers the outer surface 14a of the outer ring when considering both the axial and circumferential directions. The insulating liner 30 also covers the front surfaces 14c and 14d of the outer ring.

[0086] The insulating liner 30 also covers the bushing bore 28b. In this case, the insulating liner 30 also completely covers the bore 28b when both the axial and circumferential directions are taken into account. The insulating liner 30 covers the bores of the axial portions 32a, 34a of each component 32, 34 of the bushing.

[0087] The insulating liner 30 also covers the inner surface of the radial collars 32b and 34b of each component 32 and 34 of the bushing. The insulating liner 30 also covers the free ends of the radial collars 32b and 34b of each component 32 and 34 of the bushing. The insulating liner 30 also covers the through holes 36 and 38 of the radial collars 32b and 34b of the bushing components 32 and 34.

[0088] The insulating liner 30 has an annular shape. The insulating liner 30 extends axially. The insulating liner 30 includes a cylindrical axial outer surface 30a, a cylindrical bore 30b radially opposite the outer surface 30a, and opposing first radial facets 30c and second radial facets 30d defining the bore and outer surface axially. The radial facets 30c and 30d define the insulating liner 30 axially. The outer surface 30a and the bore 30b define the radial thickness of the insulating liner 30. The outer surface 30a radially contacts the bore 28b of the bushing. The bore 30b radially contacts the outer surface 14a of the outer ring and the facets 14c and 14d of the outer ring.

[0089] The insulating liner 30 includes a set of blind holes 40, each blind hole 40 extending axially within one of the through holes 36 of the radial collar 32b of the bushing component 32. Each blind hole 40 extends axially from the front face 30c in the direction of the outer ring 14, maintaining a distance axially from the front face 14c. In other words, each blind hole 40 has a bottom that is axially oriented outward and offset axially outward relative to the front face 14c.

[0090] Each blind hole 40 corresponds to the positioning of an injector (not shown) that allows overmolding of the insulating liner 30 during the manufacture of the bearing assembly. The shape of the blind hole 40 corresponds to the footprint of the associated injector. In this case, the blind holes 40 are identical to each other. Alternatively, the blind holes 40 may be different when the injectors of the electrically insulating material of the insulating liner 30 have different shapes.

[0091] As indicated above, in the exemplary embodiment shown, the insulating liner 30 covers the bore of the through-hole 36 of the radial collar 32b of the bushing component 32. Therefore, a bead of material exists radially between each blind hole 40 and its associated through-hole 36 of the radial collar 32b. Alternatively, this bead of material may be omitted during the overmolding of the insulating liner 30, provided the syringe is centered relative to the bore of the through-hole 36.

[0092] In the exemplary embodiment shown, the number of blind holes 40 is equal to the number of through holes 36 in the radial collar 32b of the bushing component 32. Alternatively, the number of blind holes 40 may be less than the number of through holes 36, depending on the number of syringes.

[0093] The insulating liner 30 also includes a set of through holes 42, each through hole 42 extending axially inside one of the through holes 38 in the radial collar 34b of the bushing component 34. Each through hole 42 extends axially from the front face 30d in the direction of the outer ring 14 and opens to the front face 14d.

[0094] Each through-hole 42 corresponds to the positioning of a pin (not shown) that allows the bushing components 34 to be aligned and allows the transmission of closing forces from the mold used during the manufacture of the bearing assembly. The shape of the through-hole 42 corresponds to the space occupied by the associated pin. In this case, the through-holes 42 are identical to each other. Alternatively, the through-holes 42 may be different when the pins have different shapes.

[0095] As indicated above, in the exemplary embodiment shown, the insulating liner 30 covers the holes of the through-holes 38 of the radial collar 34b of the bushing component 34. Therefore, a bead of material exists radially between each through-hole 42 and its associated through-hole 38 of the radial collar 34b. Alternatively, this bead of material may be omitted during the overmolding of the insulating liner 30, provided the pins are aligned with the holes of the through-holes 38.

[0096] In the exemplary embodiment shown, the insulating liner 30 includes a stud 44 between two consecutive through-holes 42 in the circumferential direction, the stud 44 extending inside the through-hole 38 of the radial collar 34b of the bushing component 34. Therefore, the number of through-holes 42 is less than the number of through-holes 38. Alternatively, the number of through-holes 42 may be equal to the number of through-holes 38.

[0097] In the exemplary embodiment shown, the front surface 14c of the outer ring is offset axially inward relative to the front surface 30c of the insulating liner. The front surface 14d of the outer ring is offset axially inward relative to the front surface 30d of the insulating liner.

[0098] In the exemplary embodiment shown, the surfaces 30c, 28c and 30d, 28d of the insulating liner and bushing are coplanar. Alternatively, different configurations can be provided. For example, the bushing 28 may extend to protrude axially from the insulating liner 30 relative to surfaces 30c and 30d or remain axially retracted from these surfaces.

[0099] In the exemplary embodiment shown, the inner ring and bushing faces 12c, 28c and 12d, 28d are coplanar. Alternatively, different configurations can be provided. For example, the bushing 28 may extend to protrude axially relative to the inner ring faces 12c and 12d or remain axially retracted from these faces.

[0100] In order to manufacture the bearing assembly, the present invention is carried out in the following manner.

[0101] exist Figure 5 In the first step 50, which is schematically shown, the second component 34 of the bushing is installed inside a mold provided for overmolding the insulating liner 30. The studs of the mold allow for the alignment of the second component 34.

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

[0103] Then, in the third step 54, the first component 32 of the bushing is installed inside the mold, with the mold bearing against the first component 32 in the axial direction. In this position inside the mold, the first component 32 and the second component 34 of the bushing are radially separated from the outer ring 14 by a certain distance.

[0104] Then, in the fourth consecutive step 56, the insulating liner 30 is overmolded using a syringe with a mold positioned inside the through hole 36 of the radial collar 32b of the bushing component 32. The insulating liner 30 is overmolded on the outer ring 14 and overmolded on the first component 32 and the second component 34 of the bushing 28.

[0105] In the fifth consecutive step 58, the unitary assembly formed by the outer ring 14, the first component 32 and the second component 34, the bushing 28 and the insulating liner 30 is removed from the mold.

[0106] Then, in the sixth consecutive step 60, the front surfaces 28c and 28d of the bushing are ground. Considering the presence of the bushing collars 32b and 34b, the grinding operation is primarily performed on the bushing collars 32b and 34b, rather than on the insulating liner 30. During this step, the outer surface 28a of the bushing and the raceway 20 of the outer ring may also be ground.

[0107] Then, in the seventh step 62, the integral assembly formed by the outer ring 14, the first component 32 and the second component 34, the bushing 28 and the insulating liner 30 is assembled with the row of rolling elements 16, the cage 17 and the inner ring 12.

[0108] In the exemplary embodiment shown, the first ring 12 of the bearing is the inner ring, and the second ring 14, on which the insulating liner 30 is overmolded, is the outer ring.

[0109] Alternatively, a reverse arrangement can be provided, in which the second ring 14 overmolded thereon is the inner ring. In this case, the insulating sleeve is located in the bore 12a of the inner ring. Therefore, the insulating liner is radially positioned between the bore 12a of the inner ring and the outer surface of the bushing. The insulating liner is overmolded on the inner ring and at least overmolded on the outer surface of the bushing. The bore of the bushing defines the bore of the bearing assembly.

[0110] In the described exemplary embodiment, the bearing of the device is provided with a single row of rolling elements. In a variation, the bearing may be provided with multiple rows of rolling elements. Moreover, the rolling bearing may include rolling elements of a type other than balls, such as rollers. In another variation, the bearing may be a sliding bearing without rolling elements.

Claims

1. A bearing assembly comprising a bearing (10) and an insulating sleeve (26), the bearing (10) having a first ring (12) and a second ring (14) rotatable relative to each other, the insulating sleeve (26) being mounted on the second ring (14) of the bearing and having a bushing (28) and an insulating liner (30), the insulating liner (30) being radially interposed between the second ring (14) and the bushing (28) and being made of an electrically insulating material, the bushing including an outer surface (28a) defining the radial thickness of the bushing and The inner surface (28b) opposite the outer surface, the second ring (14) includes an outer surface (14a) defining the radial thickness of the second ring and an inner surface (14b) opposite the outer surface, and a first front face (14c) and a second front face (14d) defining the axial length of the second ring, the insulating liner (30) covering at least one of the outer and inner surfaces of the second ring (14) of the bearing and at least one of the outer and inner surfaces of the bushing (28), characterized in that, The bushing (28) is made of at least two separate first parts (32) and second parts (34), each part including an axial portion (32a, 34a) and a radial collar (32b, 34b) extending radially inward from the axial portion, the axial portion (32a) of the first part and the axial portion (34a) of the second part at least partially defining the surface of the bushing (28) on which the insulating lining (30) is formed. - At least the radial collar (32b) of the first component of the bushing extends radially beyond the second turn and covers the outer surface (14a) or inner surface of the insulating lining (30) thereon, and the radial collar (32b) is provided with a plurality of through holes (36) spaced apart from each other in the circumferential direction. The insulating liner (30) also covers the inner surface of the radial collars (32b, 34b) of each of the first and second components of the bushing, and at least partially covers the first front face (14c) and the second front face (14d) of the second ring. - The insulating liner (30) includes a set of blind holes (40), each blind hole (40) extending axially inside one of the through holes (36) in the radial collar (32b) of another first component of the bushing, and maintaining an axial distance from the first front face (14c) of the second ring.

2. The apparatus according to claim 1, characterized in that, The insulating liner (30) covers the hole in each of the plurality of through holes (36) of the radial collar (32b) of the first component of the bushing.

3. The apparatus according to claim 1 or 2, characterized in that, The radial collar (34b) of the second component of the bushing extends radially beyond the second turn and covers the outer surface (14a) or inner surface of the insulating lining (30).

4. The apparatus according to claim 3, characterized in that, The radial collar (34b) of the second component of the bushing is provided with a plurality of through holes (38) spaced apart from each other in the circumferential direction. The insulating liner (30) includes a set of through holes (42), each through hole (42) extending axially inside one of the through holes (38) and opening into the second front face (14d) of the second ring.

5. The apparatus according to claim 4, characterized in that, The insulating liner (30) covers the hole in each of the plurality of through holes (38) of the radial collar (34b) of the second component of the bushing.

6. The apparatus according to claim 4 or 5, characterized in that, The insulating liner includes at least one post (44) between two consecutive through holes (42) in the circumferential direction of the insulating liner, the at least one post (44) extending inside one of the through holes (38) of the radial collar (34b) of the second component of the bushing.

7. The apparatus according to any one of the preceding claims, characterized in that, The first component (32) and the second component (34) of the bushing are symmetrical with respect to the radial midplane of the device.

8. The apparatus according to any one of the preceding claims, characterized in that, The axial portions (32a) of the first component and the axial portions (34a) of the second component of the bushing are in axial contact with each other and together define the entire surface of the bushing (28) on which the insulating lining (30) is formed.

9. A method for manufacturing a bearing device according to any one of claims 1 to 8, comprising: - The step of installing one of the first component (32) and the second component (34) of the bushing at the bottom of the manufacturing mold. - The step of placing the second ring (14) inside the manufacturing mold, - The step of installing another component of the first part (32) and the second part (34) of the bushing inside the manufacturing mold. - The step of placing the syringe inside the through hole (36) of the radial collar (32b) of the first component of the bushing, with the syringe axially at a certain distance from the first front face (14c) of the second ring. -The step of molding the insulating liner (30) by means of the syringe, and - The step of assembling the assembly formed by the second ring (14), the first part (32) and the second part (34) of the bushing and the insulating liner (30) with the first ring (12) of the bearing.

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

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