Bearing

Abstract

Rolling bearing having an open side 60a permitting supply of lubricant to the rolling elements 68 and a closed side 60b sealed by a bearing shield 74 to prevent passage of lubricant or debris. The bearing shield 74 may be an annular, metal alloy or steel alloy, seal for sealingly engaging the inner race. The bearing shield may be installed and received within a circumferential groove recess channel 76 around the outer race 60. A clearance c less than 400 microns may be formed between the bearing shield and the inner race 66. Circlips may engage the bearing with surrounding components on the open side 60a, the circlips defining an annular opening 60a in between to permit lubricant flow. Bearing may be dry bearing, lubricant free during installation. Bearing may be for electric machine and / or transmission of a vehicle.

Description

TECHNICAL FIELD The present disclosure relates to a bearing for rotatably support a shaft of an electric drive unit (EDU) assembly, an EDU assembly for a vehicle, and a vehicle comprising an EDU assembly. BACKGROUND Driven by environmental, economic and technological factors, vehicles, for example automotive vehicles, are transitioning from diesel and petrol internal combustion engines (ICEs) towards more sustainable alternatives, such as battery electric vehicles (BEV) or hybrid electric vehicles (HEV). Such vehicles include an electric drive unit (EDU) assembly for providing tractive power to the wheels of the vehicle. The EDU assembly may include one or moving components, for example gears of the transmission and bearings. Different parts of the EDU assembly may have different lubrication and / or cleanliness requirements. For example, the electric machine cavity of the EDU assembly may typically be “clean” and have specific requirements regarding the allowable levels of lubricant and migration of particulate matter into the electric machine cavity. It is possible for components of the transmission, for example gears, bearings and splines, to wear in use, and for lubricant to become contaminated with debris, for example metallic particles. If such debris builds up on the electric machine on the EDU assembly, this can result in short circuiting of the electric machine. In particular, debris can build up or become stacked up in the airgap defined between a rotor and stator of the electric machine, which can have an adverse effect on operation of the electric machine. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a bearing, an electric drive unit (EDU) assembly and a vehicle, as claimed in the appended claims. According to an aspect of the present teachings there is provided a bearing for rotatably supporting a shaft of an electric drive unit (EDU) assembly, the bearing comprising: a fixed outer race; a rotary inner race located radially inward of the outer race and configured to rotate relative to the outer race, in use; a plurality of rotating elements located between the inner race and the outer race; the bearing having an open side configured to permit a supply of lubricant to lubricate the plurality of rotating elements, and a closed side opposing the open side; the closed side being defined by a bearing shield extending between the outer race and the inner race, wherein the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the open side to the closed side. According to another aspect of the present teachings there is provided a bearing for rotatably supporting a shaft of an electric drive unit (EDU) assembly, wherein the bearing is located, in use, between a transmission cavity side of the EDU assembly and an electric machine cavity side of the EDU assembly, the bearing comprising: a fixed outer race; a rotary inner race located radially inward of the outer race and configured to rotate relative to the outer race, in use; a plurality of rotating elements located between the inner race and the outer race; the bearing having an open side configured to permit a supply of lubricant from the transmission cavity side or the electric machine cavity side to lubricate the plurality of rotating elements, and a closed side opposing the open side; the closed side being defined by a bearing shield extending between the outer race and the inner race, wherein the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the open side to the closed side. In EDU assemblies, the transmission cavity typically requires the circulation of a significant amount of lubricant therein. Due to wear over time of the transmission components, the lubricant can become mixed with fine particulate matter and thus be considered “dirty”, in use. The electric machine cavity side also receives a supply of lubricant and it is advantageous that the electric machine cavity side remains free of particulate matter or “clean”. In use, components of the transmission, for example gears, bearings, splines etc., may wear and the lubricant in the transmission cavity may become contaminated with debris, for example metallic particles. If such debris migrates from the transmission cavity and contaminates the electric machine cavity, the debris may build up on the electric machine and result in short circuiting of the electric machine. In particular, debris can build up or become stacked up in an air gap defined between a rotor and a stator of the electric machine, which can have an adverse effect on operation of the electric machine. It shall be appreciated that some transmission of lubricant from the transmission cavity to the electric machine cavity may be allowable, however it is advantageous that such lubricant is free of debris. Additionally, providing an open side in communication with the lubricant supply and a closed side negates the need for a self-contained lubricant supply, thereby reducing the number of shields or seals. This helps to reduce rotational losses across the bearing, thereby increasing the efficiency of the bearing whilst reducing the space occupied by the bearing in an axial direction. The bearing shield may be substantially annular. Advantageously, the substantially annular bearing shield is simple to manufacture and assemble, and helps to inhibit passage of lubricant and / or debris across the bearing around an annulus of the bearing. A clearance may be defined between the bearing shield and the inner race. Advantageously, the clearance helps to inhibit the passage of debris across the bearing because particle sizes bigger than the size of the clearance cannot pass therethrough. Additionally, the clearance helps to reduce rotational losses between the bearing shield and the inner race because the bearing shield does not contact the inner race. This increases the efficiency of the bearing. The clearance may be less than 400 microns. The clearance may be less than 200 microns. Advantageously, clearances within these ranges have been found to inhibit the passage of debris across the bearing, particularly metallic particles. Additionally, the clearance helps to reduce rotational losses between the bearing shield and the inner race. The bearing shield may be at least partially formed from a metal alloy. The bearing shield may be formed from a steel alloy. The bearing shield may be formed from a low carbon steel alloy. Advantageously, bearing shields formed from metal alloys have increased durability and temperature resistance and are compatible with a range of different lubricants. Additionally, metal bearing shields are impact resistant, thereby reducing damage to the bearing. The bearing shield may be a seal. The seal may be at least partially formed from a polymer material. The seal may include a metallic body at least partially covered with a polymer coating. Advantageously, seals (particularly polymer seals) are flexible and elastic, thereby allowing for sealing even when there is some level of misalignment or movement caused by dynamic operating conditions. The seal may be configured to sealingly engage the inner race. Advantageously, sealing the inner race helps to inhibit passage of lubricant and / or debris from the open side to the closed side of the bearing. The bearing shield may be fixedly mounted to the outer race and may be located between the outer race and the inner race with respect to a radial direction. Advantageously, fixing the bearing shield to the outer race means that the bearing shield can be fixedly mount to the bearing, in use. Additionally, it is a simple way of mounting the bearing shield to the bearing, thereby improving ease of assembly. The outer race may comprise a recess, groove or channel. The bearing shield may be received within the recess, groove or channel, in use. The recess, groove or channel may extend circumferentially around the outer race. Advantageously, the recess, groove or channel is simple to manufacture and assemble and minimises an axial length of the bearing. The bearing may comprise an inner circlip configured to engage with the shaft. The bearing may comprise an outer circlip configured to engage with a housing of the EDU assembly. The outer and / or inner circlip may be located on the open side. Advantageously, the inner and outer circlip help to mount the bearing to both the shaft and the housing, whilst enabling the supply of lubricant from the transmission cavity side or the electric machine cavity side. The outer circlip may be located radially outward of the inner circlip to define an annular opening therebetween. The annular opening may be configured to permit the supply of lubricant from the transmission cavity side or the electric machine cavity side to lubricate the plurality of rotating elements. Advantageously, the annular opening helps to permit an even distribution of lubricant to the plurality of rotating elements. The bearing may be a dry bearing that is lubricant free upon installation. Advantageously, as the open side receives a supply of lubricant from the transmission cavity side orthe electric machine cavity side, there is not a need for a self-contained supply of lubricant. This allows the bearing to be lubricated by cooled “fresh” lubricant delivered at a rate according to the heat dissipation requirements in the bearing. This allows the bearing to operate at high speeds and loads. Additionally, providing a bearing that is lubricant free on installation helps to reduce the level of maintenance to the lubricant supply throughout the lifespan of the bearing. According to another aspect of the present teachings there is provided an electric drive unit (EDU) assembly for a vehicle, the EDU assembly comprising: an EDU housing comprising a first cavity and a second cavity and defining a first cavity side and a second cavity side; a rotatable shaft extending at least partially through the first cavity and the second cavity; a bearing according to any previous aspect located within the EDU housing and disposed on the shaft for rotationally supporting the shaft; wherein the open side of the bearing is located on one of the first cavity side and the second cavity side, and wherein the bearing shield is configured to inhibit passage of lubricant and / or debris from the open side to the closed side. According to another aspect of the present teachings there is provided an electric drive unit (EDU) assembly fora vehicle, the EDU assembly comprising: an EDU housing comprising a transmission cavity and an electric machine cavity and defining a transmission cavity side and an electric machine cavity side; a rotatable shaft extending at least partially through the transmission cavity and the electric machine cavity; a bearing according to any previous aspect located within the EDU housing and disposed on the shaft for rotationally supporting the shaft; wherein the open side of the bearing is located on one of the transmission cavity side and the electric machine cavity side, and the closed side of the bearing is located on the other of the transmission cavity side and the electric machine cavity side, and wherein the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the open side to the closed side. In EDU assemblies, the transmission cavity typically requires the circulation of a significant amount of lubricant therein. Due to wear over time of the transmission components, the lubricant can become mixed with fine particulate matter and thus be considered “dirty”, in use. The electric machine cavity side also receives a supply of lubricant and it is advantageous that the electric machine cavity side remains free of particulate matter or “clean . In use, components of the transmission, for example gears, bearings, splines etc., may wear and the lubricant in the transmission cavity may become contaminated with debris, for example metallic particles. If such debris migrates from the transmission cavity and contaminates the electric machine cavity, the debris may build up on the electric machine and result in short circuiting of the electric machine. In particular, debris can build up or become stacked up in an air gap defined between a rotor and a stator of the electric machine, which can have an adverse effect on operation of the electric machine. It shall be appreciated that some transmission of lubricant from the transmission cavity to the electric machine cavity may be allowable, however it is advantageous that such lubricant is free of debris. Additionally, providing an open side in communication with the lubricant supply and a closed side negates the need for a self-contained lubricant supply, thereby reducing the number of shields or seals. This helps to reduce rotational losses across the bearing, thereby increasing the efficiency of the bearing whilst reducing the space occupied by the bearing in an axial direction. The open side of the bearing may be located on the transmission cavity side and the closed side of the bearing may be located on the electric cavity side such that the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the transmission cavity side to the electric machine cavity side. Advantageously, providing the open side on the transmission cavity side helps to increase the pressure and / or velocity at which lubricant is supplied to the rotating elements. Providing the closed side on the electric cavity side helps to inhibit passage of debris from both the transmission cavity and from the bearing itself, thereby reducing the likelihood of damage to the electric machine. According to another aspect of the present teachings there is provided: a subassembly for a vehicle, the subassembly comprising: a housing comprising a transmission cavity and an electric machine cavity and defining a transmission cavity side and an electric machine cavity side; a rotatable shaft extending at least partially through the transmission cavity and the electric machine cavity; a bearing according to any previous aspect located within the housing and disposed on the shaft for rotationally supporting the shaft; wherein the open side of the bearing is located on one of the transmission cavity side and the electric machine cavity side, and the closed side of the bearing is located on the other of the transmission cavity side and the electric machine cavity side, and wherein the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the open side to the closed side. According to another aspect of the present teachings there is provided a vehicle comprising an EDU assembly according to a previous aspect. In EDU assemblies, the transmission cavity typically requires the circulation of a significant amount of lubricant therein. Due to wear overtime of the transmission components, the lubricant can become mixed with fine particulate matter and thus be considered “dirty”, in use. The electric machine cavity side also receives a supply of lubricant and it is advantageous that the electric machine cavity side remains free of particulate matter or “clean”. In use, components of the transmission, for example gears, bearings, splines etc., may wear and the lubricant in the transmission cavity may become contaminated with debris, for example metallic particles. If such debris migrates from the transmission cavity and contaminates the electric machine cavity, the debris may build up on the electric machine and result in short circuiting of the electric machine. In particular, debris can build up or become stacked up in an air gap defined between a rotor and a stator of the electric machine, which can have an adverse effect on operation of the electric machine. It shall be appreciated that some transmission of lubricant from the transmission cavity to the electric machine cavity may be allowable, however it is advantageous that such lubricant is free of debris. Additionally, providing an open side in communication with the lubricant supply and a closed side negates the need for a self-contained lubricant supply, thereby reducing the number of shields or seals. This helps to reduce rotational losses across the bearing, thereby increasing the efficiency of the bearing whilst reducing the space occupied by the bearing in an axial direction. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a vehicle in according with an embodiment of the invention; Figure 2 schematically shows the functional units and control system of the vehicle of Figure 1; Figure 3 shows a cross-sectional view of an EDU assembly of the vehicle of Figure 1; and Figure 4 shows a cross-sectional view of a bearing of the EDU assembly of Figure 3. DETAILED DESCRIPTION Figures 1 and 2 show an example of an electric vehicle (EV) 10. The electric vehicle 10 has a battery or battery pack 40. The battery 40 is mounted to and supported by the vehicle body structure 11, in use. The battery 40 may be recharged from an external electrical source. The electric vehicle 10 comprises a pair of front wheels 12 at a front axle 28 and a pair of rear wheels 14 at a rear axle 38. The vehicle has at least one electric drive unit (EDU) assembly 20, 30 by which one or more of the wheels 12, 14 are driven. In the illustrated embodiment, the vehicle 10 comprises two electric drive unit assemblies 20, 30, each associated with one of the pairs of wheels 12, 14. In other embodiments, the vehicle 10 may have a dedicated EDU for each of the front wheels 12 and / or a dedicated EDU for each of the rear wheels 14. In the illustrated embodiment, the front wheels 12 are driven by a first electric drive unit (EDU) assembly 20. The first EDU assembly 20 includes a first electric machine motor 22, a front transmission 24 and power electronics 26. The rear wheels 14 are driven by a second electrical drive unit (EDU) assembly 30. The second EDU assembly 30 includes a second electric machine 32, a rear transmission 34 and power electronics 36. The first EDU assembly 20 and the second EDU assembly 30 each receive a DC supply from battery 40. The 6 first EDU assembly 20 can be considered a first propulsion unit, and the second EDU assembly 30 can be considered a second propulsion unit. As used herein, the term “transmission” may refer to a device with a plurality of gears through which torque can be transmitted from the drive unit to one or more of the wheels. For example, this may refer to a differential, transaxle, and / or a gearbox. In other embodiments, the electric vehicle 10 may include only one EDU assembly 20, 30. For example, the second EDU 30 may be omitted in embodiments where the electric vehicle 10 is a “front-wheel drive” vehicle, or the first EDU assembly 20 may be omitted in embodiments where the electric vehicle is a “rear-wheel drive” vehicle. In further embodiments, one or more of the wheels 12, 14 may be driven individually by a dedicated EDU. For example, the front wheels 12 may each be connected to one of a pair of front EDUs. Referring now to Figure 3, a cross-sectional view of a portion of the first EDU assembly 20 is illustrated. The first EDU assembly 20 will be referred to hereafter as the EDU assembly 20. It shall be appreciated that although the invention is described in relation to the first EDU assembly 20, the invention is also applicable to the second EDU assembly 20, or to any alternative arrangements of first and / or second EDU assembly 20, 20, for example those described above. The EDU assembly 20 includes a housing 50. The housing 50 includes an interior volume for one or more drive components of the EDU assembly 20. In particular, the interior volume houses one or more components of the transmission 24, the electric machine 22 and one or more bearing 60. The housing 50 includes a transmission cavity 54 for housing one or more components of the transmission 24 and an electric machine cavity 56 for housing the electric machine 22. As such, the EDU assembly 20 defines a transmission cavity side 54a and an electric machine cavity side 56a. The transmission cavity 54 is supplied with lubricant circulated throughout the EDU assembly 20. This helps to provide lubrication to the components of the transmission 24. The transmission cavity 54 typically requires the circulation of a significant amount of lubricant therein. Due to wear overtime of the transmission components, the lubricant can become mixed with fine particulate matter and thus be considered “dirty”, in use. The electric machine cavity side 56a also receives a supply of lubricant and it is advantageous that the electric machine cavity side 56a remains free of particulate matter or “clean”. In use, components of the transmission 24, for example gears, bearings, splines etc., wear and the lubricant in the transmission cavity 54 may become contaminated with debris, for example metallic particles. If such debris migrates from the transmission cavity 54 and contaminates the electric machine cavity 56, the debris may build up on the electric machine 22 and result in short circuiting of the electric machine 22. In particular, debris can build up or become stacked up in an air gap defined between a rotor and a stator of the electric machine 22, which can have an adverse effect on operation of the electric machine 22. It shall be appreciated that some transmission of lubricant from the transmission cavity 54 to the electric machine cavity 56 may be allowable, however it is advantageous that such lubricant is free of debris. The EDU assembly 20 include the bearing 60 for supporting a shaft 62 of the EDU assembly 20. The shaft 62 extends at least partially through the transmission cavity 54 and the electric machine cavity 56. As such, the shaft 62 is driven by the electric machine 22 and transmits drive to the transmission 24 located in the transmission cavity 54. The bearing 60 is located, in use, between the transmission cavity 54 and the electric machine cavity 56. The bearing 60 includes a fixed outer race 64, a rotary inner race 66 located radially inward of the outer race 64 and configured to rotate relative to the outer race 64, and a plurality of rotating elements 68 located between the inner race 66 and the outer race 64. The rotating elements 68 may be ball bearings 68 or roller bearings 68, by way of example. The bearing 60 includes an open side 60a configured to permit and supply of lubricant from the transmission cavity side 54a or the electric machine cavity side 56a to lubricate the plurality of rotating elements 68, and a closed side 60b opposing the open side 60a. The closed side 60b is located on an opposing axial side to the open side 60a. Providing an open side 60a in communication with the lubricant supply and a closed side 60b negates the need for a self-contained lubricant supply within the bearing 60. As such, the bearing 60 may be referred to as a “dry bearing” that is lubricant free on installation. This allows the bearing to be lubricated and cooled by “fresh” lubricant delivered at a rate according to the heat dissipation requirements in the bearing 60, This allows the bearing 60 to operate at high speeds and loads. Additionally, providing a bearing that is lubricant free on installation helps to reduce the level of maintenance to the lubricant supply throughout the lifespan of the bearing 60. Providing a bearing 60 with an open side 60a and a closed side 60b as opposed to bearing with two closed side and a self-contained lubricant supply helps to reduce rotational losses from seals sealingly engaging the rotating shaft 62. In the embodiment illustrated in Figure 3, the open side 60a of the bearing 60 is located on the transmission cavity side 54a and the closed side 60b of the bearing 60 is located on the electric cavity side 56a such that the supply of lubricant is permitted from the transmission cavity side 54a to the plurality of rotating elements 68. Put another way, the open side 60a of the bearing 60 is located closer to the transmission cavity 54 than the closed side 60b is, and the closed side 60b of the bearing 60 is located closer to the electric machine cavity 56 than the open side 60a is. Providing the open side 60a on the transmission cavity side 54a helps to increase the pressure and / or velocity at which lubricant is supplied to the rotating elements 68. Additionally, as significant splash and spray of lubricant occurs on the transmission cavity side 54a, a sufficient supply of lubricant is supplied to the rotating elements 68. In alternative embodiments, the open side 60a of the bearing 60 may be located on the electric machine cavity side 56b and the closed side 60b of the bearing 60 may be located on the transmission cavity side 54a. In such an embodiment, the open side 60a may be configured to permit the supply of lubricant from the electric machine cavity side 56a. The bearing 60 includes an inner circlip 70a configured to engage with the shaft 62. The inner circlip 70a may also be referred to as a retaining ring 70a for the shaft 62. The bearing 60 includes an outer circlip 70b configured to engage with the housing 50 of the EDU assembly 20. The outer circlip 70a may also be referred to as a retaining ring 70a for the housing 50. The inner and outer circlips 70a, 70b help to mount the bearing 60 to both the shaft 62 and the housing 50, whilst enabling a supply of lubricant from the transmission cavity side 54a to the rotating elements 68. The inner circlip 70a is mounted to the shaft 62 such that the inner circlip 7ua rotates with the shaft 62. The shaft 62 includes a recess or groove 78a configured to receive the inner circlip 70a therein, in use. The outer circlip 70b is mounted to the housing 50 such that the outer circlip 70b is fixed to the housing 50 (i.e. the outer circlip 70b does not rotate with the shaft 62. The housing 50 includes a recess or groove 78b configured to receive the outer circlip 70b therein, in use. The inner and outer circlips 70a, 70b are located on the open side 60a. It shall be appreciated that in alternative embodiments, the inner and outer circlips 70a, 70b may be located on the closed side 60b of the bearing 60, or the inner and outer circlips 70a, 70b may be located on opposing sides of the bearing 60. Furthermore, more than one inner and / or outer circlip 70a, 70b may be provided located on one or both the open and closed sides 60a, 60b of the bearing 60. The outer circlip 70b is located radially outward of the inner circlip 70a so as to define an annular opening therebetween. The annular opening is located on the open side 60a of the bearing 60 in the embodiment of the Figures. The annular opening is configured to permit the supply of lubricant from the transmission cavity side 54a to the plurality of rotating elements 68. The inner and outer circlips 70a, 70b are located at the same position with respect to a longitudinal axis a-a of the shaft 62. It shall be appreciated that in embodiments where the inner and outer circlips 70a, 70b are located on the closed side 60b, the opening configured to permit the supply of lubricant to the plurality of rotating elements 68 may be defined anywhere between the housing 50 and the shaft 62. It shall be appreciated that in alternative embodiments, any suitable arrangement may be used to mount the bearing 60 to the housing 50 and the shaft 62. For example, the bearing 60 may be mounted to the housing 50 and / or shaft 62 via any arrangement of fasteners, snap rings, keyways, locknuts, press fit etc. The closed side 60b of the bearing 60 is defined by a bearing shield 74 extending between the outer race 64 and the inner race 66. The bearing shield 74 is substantially annular. The bearing shield 74 is configured to inhibit passage of lubricant and / or debris from the open side 60a to the closed side 60b of the bearing 60. As such, in the embodiment illustrated in Figure 3, the bearing shield 74 helps to inhibit the passage of lubricant and debris from the transmission cavity side 54a to the electric machine cavity side 56a, thereby reducing the likelihood of damage to the electric machine 22. As the bearing shield 74 defines the closed side 60b of the bearing 60, contaminated lubricant may be supplied to the rotating elements 68, however the bearing shield 74 helps to inhibit contaminated lubricant from reaching the electric machine cavity side 56a. In embodiments where the closed side 60b (i.e. the bearing shield) is located on the transmission cavity side 54a, the bearing shield 74 prevents the ingress of contaminated lubricant into the bearing 60 (and to the rotating elements 68). This is turn inhibits contaminated lubricant from reaching the electric machine cavity side 56a. The bearing shield 74 is at least partially formed from a metal alloy, for example a steel alloy, optionally a low carbon steel alloy. The bearing shield 74 may be formed from stamped sheet metal. Bearing shields 74 formed from metal alloys have increased temperature resistance and are compatible with a range of different lubricants. Additionally, metal bearing shields 74 are impact resistant, thereby reducing damage to the bearing 60 and level of maintenance. In some embodiments, the bearing shield 74 may be formed from a polymer, or include polymer components. The bearing shield 74 is fixedly mounted to the outer race 64 and is located between the outer race 64 and the inner race 66 with respect to the radial direction. As such, the bearing shield 74 is fixedly mounted to the outer race 64 (i.e. the bearing shield 74 does not rotate with the inner race 66). The outer race 64 includes a recess, groove or channel 76, and the bearing shield 74 is received within the recess, groove or channel 76. The recess, groove or channel 76 extends circumferentially around the outer race 64. As illustrated in Figure 4, a clearance c is defined between the bearing shield 74 and the inner race 66. As such, the clearance c is an annular clearance c. The clearance c helps to inhibit the passage of debris across the bearing 60 because particle sizes bigger than the size of the clearance c cannot pass therethough. Additionally, the clearance c helps to reduce rotational losses between the fixed bearing shield 74 and the rotating inner race 66 because the bearing shield 74 does not contact the inner race 66. This helps to increase the efficiency of the bearing 60. The clearance c may be less than 400pm, for example less than 200pm. Clearances within these ranges have been found to inhibit the passage of debris across the bearing 60, particularly metallic particles which can cause harm to the electric machine 22. In an alternative embodiment, the bearing shield 74 may be a seal 74. The seal 74 may be at least partially formed from a polymer material. For example, the seal 74 may include a metallic body, for example formed from stamped sheet metal, with a polymer coating for sealingly engaging the inner race 66. The polymer coating may be a moulded elastomer material, for example rubber, or a thermoplastic material, for example polytetrafluoroethylene. The seal 74 is configured to sealingly engage the inner race 66. In particular, the seal 74 may include a lip configured to engage the inner race 66 and the lip may be formed from the polymer material. As such, in embodiments where the bearing shield 74 is a seal, the clearance may not be defined between the inner race 66 and the seal 74. It shall be appreciated that although the bearing 60 has been described as being located between the transmission cavity 54 and the electric machine cavity 56, in alternative embodiment the bearing 60 may be located at any suitable located where inhibiting passage of lubricant and / or debris across the bearing 60 is advantageous. For example, the bearing 60 may be located between any two cavities with different lubrication and / or cleanliness requirements. In an alternative embodiment, the bearing 60 may be located between the transmission cavity 54 and a wet clutch (not shown) of the EDU assembly 20 so as to inhibit passage of lubricant and / or debris therebetween. The bearing 60 may be orientated such that the open side 60a is located on the transmission cavity side 54a or the wet clutch side. The bearing 60 is advantageous in such embodiments because wet clutches typically have specific lubrication requirements. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application. It should also be noted that whilst the appended claims set out particular combinations of features described above, the scope of the present disclosure is not limited to the particular combinations hereafter claimed, but instead extends to encompass any combination of features herein disclosed.

Claims

1. A bearing for rotatably supporting a shaft of an electric drive unit assembly, wherein the bearing is located, in use, between a transmission cavity side of the EDU assembly and an electric machine cavity side of the EDU assembly, the bearing comprising:a fixed outer race;a rotary inner race located radially inward of the outer race and configured to rotate relative to the outer race, in use;a plurality of rotating elements located between the inner race and the outer race;the bearing having an open side configured to permit a supply of lubricant from the transmission cavity side or the electric machine cavity side to lubricate the plurality of rotating elements, and a closed side opposing the open side;the closed side being defined by a bearing shield extending between the outer race and the inner race, wherein the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the open side to the closed side.

2. The bearing according to claim 1, wherein the bearing shield is substantially annular.

3. The bearing according to claim 1 or claim 2, wherein a clearance is defined between the bearing shield and the inner race.

4. The bearing according to claim 3, wherein the clearance is less than 400 microns, optionally wherein the clearance is less than 200 microns.

5. The bearing according to any preceding claim, wherein the bearing shield is at least partially formed from a metal alloy, optionally wherein the bearing shield is formed from a steel alloy.

6. The bearing according to any one of claim 1 to claim 4, wherein the bearing shield is a seal, optionally wherein the seal is at least partially formed from a polymer material.

7. The bearing according to claim 6, wherein the seal is configured to sealingly engage the inner race.

8. The bearing according to any preceding claim, wherein the bearing shield is fixedly mounted to the outer race and is located between the outer race and the inner race with respect to a radial direction.

9. The bearing according to claim 8, wherein the outer race comprises a recess, groove or channel, and wherein the bearing shield is received within the recess, groove or channel, in use, optionally wherein the recess, groove or channel extends circumferentially around the outer race.

10. The bearing according to any preceding claim, wherein the bearing comprises an inner circlip configured to engage with the shaft, and an outer circlip configured to engage with a housing of the EDU assembly, optionally wherein the inner and outer circlips are located on the open side.

11. The bearing according to claim 10, wherein the outer circlip is located radially outward of the inner circlip to define an annular opening therebetween, and wherein the annular opening is configured to permit the supply of lubricant from the transmission cavity side or the electric machine cavity side to lubricate the plurality of rotating elements.

12. The bearing according to any preceding claim, wherein the bearing is a dry bearing that is lubricant free upon installation.

13. An electric drive unit assembly for a vehicle, the EDU assembly comprising:an EDU housing comprising a transmission cavity and an electric machine cavity and defining a transmission cavity side and an electric machine cavity side;a rotatable shaft extending at least partially through the transmission cavity and the electric machine cavity;a bearing according to any preceding claim located within the EDU housing and disposed on the shaft for rotationally supporting the shaft;wherein the open side of the bearing is located on one of the transmission cavity side and the electric machine cavity side, and the closed side of the bearing is located on the other of the transmission cavity side and the electric machine cavity side, and wherein the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the open side to the closed side.

14. The EDU assembly according to claim 13, wherein the open side of the bearing is located on the transmission cavity side and the closed side of the bearing is located on the electric cavity side such that the bearing shield is configured to inhibit passage of lubricant and / or debris across the bearing from the transmission cavity side to the electric machine cavity side.

15. A vehicle comprising an EDU assembly according to claim 13 or claim 14.Application No: GB2404963.7Examiner: Ian ChoiClaims searched: 1-15Date of search: 12 September 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-10, 12-14 GB 2290837 A (MASSEY FERGUSON SA) See especially figures 1-3, 6-8, 2:33-3:3, 3:29-33, and 4:30-35. X 1-10, 12- 14 US 2733081 A (SAYWELL) See especially figures, 1:65-2:9, 2:39-58, and 3:25-53. X 1-10, 12- 14 US 2600433 A (SAYWELL) See especially figures, 1:57-2:33, 3:3-5, and 3:46-60. X 1-10, 12-14 JP 2007177858 A (NTN TOYO BEARING CO LTD) See especially figures 1 and 3 and paragraph 18. X 1-10, 12- 14 JP 2009275759 A (NSK LTD) See especially figures 1, 3 and 4 and paragraphs 10, 14 and 16. v A 1-10, 12-14 JP 2009162262 A (NSK LTD) See especially figures 1,4-9 and 16 and paragraphs 26-28, 32 and 54. X 1-10, 12- 14 CN 203548587 U (WUXI HUAYANG ROLLING BEARING CO LTD) See especially figure and paragraphs 11-13.Categories:v Ak Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if p Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB, EP, WO &US patent documents classified in the following areas of the UKCX :Worldwide search of patent documents classified in the following areas of the IPC_____________F16C_______________________________________________________The following online and other databases have been used in the preparation of this search reportSEARCH-PATENTInternational Classification:Subclass Subgroup Valid From F16C 0033 / 78 01 / 01 / 2006 F16C 0033 / 66 01 / 01 / 2006

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