Rotating electric machine for a motor vehicle drive system

Abstract

Disclosed is an electric machine (10) comprising a casing (12) and a rotating assembly (14) mounted so as to be able to move about an axis of rotation (X) inside the casing (12), the rotating assembly (14) comprising a rotor shaft (20) which has splines (22) on an external surface, the machine comprising a reduction gear (16) provided with a pinion (18) cooperating with the splines (22), the machine also comprising a sensor (24) configured to measure at least one kinematic quantity of the rotating assembly (14), the electric machine (10) being characterized in that it comprises an electrically conductive element (50) configured to electrically connect the rotating assembly (14) to ground, and characterized in that it further comprises an annular support (30) comprising a plurality of channels (32) configured to guide a lubricant towards the inside of the rotor shaft (20) in order to supply the splines (22).

Description

Description Title of the invention: Rotating electric machine for a motor vehicle engine.

[0001] The invention relates to a rotating electrical machine, and in particular a rotating electrical machine for a motor vehicle. This electrical machine is in particular an electric traction or propulsion motor intended to drive the drive wheels of a vehicle. Although such a rotating electrical machine is intended for a motor vehicle, the invention may however be applied in other fields.

[0002] Generally speaking, an electrical machine consists of a stator, attached to a casing, and a rotor, attached to a shaft designed to rotate around an axis of rotation. To ensure the machine operates properly, lubrication of its parts is essential. The lubricant used is generally oil.

[0003] Various solutions have already been developed for the lubrication of machine components. One of them provides a rotating electrical machine comprising a casing, a rotating assembly mounted to rotate inside the casing about an axis of rotation and a reducer provided with at least one pinion, the rotating assembly being connected to the reducer via the pinion. The rotating assembly also comprises a rotor shaft which has grooves on its external surface, the pinion cooperating with said grooves. The rotor shaft is partially hollow and it has at least one channel which connects its hollow part to its external surface, this channel makes it possible to supply the grooves present on the external surface of the rotor shaft with the oil present inside the rotor shaft in order to ensure the lubrication of the rotating electrical machine.

[0004] The purpose of the invention is to provide a machine with improved lubrication. In the embodiment of the machine described below, the lubrication is improved in the sense that the channeling of the oil within the machine is more efficient, in particular for the passage of the oil inside the rotating shaft. Furthermore, the embodiment described makes it possible to reduce friction within the mechanism while having better electrical conductivity. This embodiment is removable and allows easy access to the various parts in the event of repair and / or replacement of said parts.

[0005] To this end, the invention relates to an electric machine, in particular for a motor vehicle engine, said machine comprising a casing and a rotating assembly mounted to rotate about an axis of rotation inside the casing, the rotating assembly comprising a rotor shaft which has grooves on a external surface of the rotor shaft, said machine also comprising a reducer provided with at least one pinion arranged inside the casing and cooperating with said splines, said machine also comprising a sensor configured to measure at least one kinematic quantity of said rotating assembly, said electrical machine being characterized in that it comprises an electrically conductive element configured to electrically connect said rotating assembly to ground, and characterized in that it further comprises an annular support comprising a plurality of channels configured to guide a lubricant such as oil towards the inside of the rotor shaft so as to supply the splines present on the external surface of the rotor shaft.

[0006] According to one embodiment, the electrical machine comprises a target fixed on the annular support and said annular support is fixed on the rotor shaft by means of an indexing system which is configured to angularly index said target relative to the sensor in order to ensure a reading of the angular position of the rotating assembly.

[0007] According to one embodiment, the rotor shaft comprises a shoulder having a groove configured to accommodate the indexing system of the annular support.

[0008] According to one embodiment, the electrically conductive element comprises a ring with conductive eyelashes, the conductive eyelashes being in contact with a second ring comprising an electrical grounding track.

[0009] According to one embodiment, said second ring has a conical external surface with which the conductive eyelashes of the electrically conductive element are in contact.

[0010] According to one embodiment, the electrically conductive element and the annular support together delimit a housing intended to accommodate at least one conductive elastic element configured to allow circulation of an electric current between the rotor shaft and the electrically conductive element.

[0011] According to one embodiment, at least a portion of the channels of the annular support have a portion helix shape.

[0012] According to one embodiment, the housing includes a rib configured to scrape oil.

[0013] According to one embodiment, the housing comprises at least one passage configured to guide a lubricant such as oil to at least a portion of the channels of the annular support.

[0014] According to one embodiment, the rib extends perpendicular to the axis of rotation of the rotor shaft.

[0015] According to one embodiment, the rib is contiguous to the first pass.

[0016] The invention also relates to an electric vehicle equipped with such an electric machine.

[0017] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment made without limitation in relation to the attached figures among which:

[0018] [Fig.l] illustrates a schematic sectional view of the rotating electrical machine according to the invention.

[0019] [Fig.2] is a first perspective view of the ring support.

[0020] [Fig.3] is a second perspective view of the ring support from another viewing angle.

[0021] [Fig.4] is a detail view of the rotor shaft.

[0022] [Fig.5] is a sectional view of certain components of the rotating electrical machine according to the invention.

[0023] [Fig.6] is a detail view of the schematic sectional view of [Fig.l],

[0024] [Fig.7] is a detailed view of the casing of the rotating electrical machine according to the invention.

[0025] In [Fig.l] is illustrated a schematic sectional view of a rotating electrical machine 10 which comprises a casing 12 and a rotating assembly 14 mounted to rotate about an axis of rotation X inside the casing 12.

[0026] The rotating electrical machine 10 also comprises a reducer 16 provided with at least one pinion 18 arranged inside the casing 12. The rotating assembly 14 is connected to the reducer 16 via the pinion 18. More precisely, the rotating assembly 14 comprises a rotor shaft 20 which has splines 22 on its external surface, the drive pinion 18 arranged inside the casing 12 cooperates with said splines 22. The reducer 16 makes it possible in particular to modify the speed ratio and / or the torque between the rotor shaft 20 and the rotating assembly 14.

[0027] In this [Fig.l], the rotor shaft 20 has an axis housing merged with the axis of rotation of the rotating assembly. The rotor shaft 20 also has at least one channel 23 which extends radially and which connects said axis housing to the external surface of the rotor shaft 20. The channel 23 makes it possible to supply the splines 22 present on the external surface of the rotor shaft 20 with a lubricant such as oil present inside the axis housing of the rotor shaft 20.

[0028] The rotating electrical machine 10 further comprises an annular support 30 comprising a plurality of channels 32 configured to guide a lubricant such as oil towards the interior of the rotor shaft 20 so as to supply the splines 22 present on the external surface of the rotor shaft 20 via the at least one channel 23.

[0029] An embodiment of the annular support 30 is illustrated in particular in [Fig. 2] and in [Fig. 3]. In this embodiment, the annular support 30 is in the form of a single-piece part of generally cylindrical geometry. The support annular 30 has in particular a bore 34 and it is centered by adjustment of said bore 34 on the rotor shaft 20.

[0030] According to a particular embodiment, at least a portion of the channels 32 of the annular support 30 have a helix portion shape. In other words, at least a portion of the channels 32 of the annular support 30, or even all of the channels 32 of the annular support 30 have a curved and oblique shape, as illustrated in particular in [Fig.2] and in [Fig.3]. In this same embodiment, the channels 32 are distributed at constant angular distances, which means that the channels 32 are distributed regularly within the cylindrical body formed by the annular support 30.

[0031] The channels 32 are intended to convey a lubricant such as oil towards the inside of the rotor shaft 20 so as to supply the grooves 22 present on the external surface of the rotor shaft 20. Their portion-helical shape promotes the flow of the oil. The winding direction of the channels 32 having a portion-helical shape is consistent with the preferred direction of rotation of the electric machine 10. In the case where the electric machine 10 is an electric traction or propulsion motor intended to drive the drive wheels of a vehicle, the winding direction consistent with the preferred direction of rotation corresponds to the direction adopted for forward movement of the motor vehicle.

[0032] The rotating electrical machine 10 also comprises an inductive sensor 24 which is configured to measure at least one kinematic quantity of said rotating assembly 14, the kinematic quantity being for example the angular position and / or the rotation speed of the rotating assembly 14 of said rotating electrical machine 10.

[0033] More particularly, the electrical machine 10 comprises a target 36 configured to interact with said sensor 24 in order to ensure a reading of the angular position of the rotating assembly 14. The target 36 comprises for example blades formed by angular sectors. The number of angular sectors corresponds to a number of pairs of poles of said machine. In the example illustrated in [Fig.2], the target 36 comprises in particular four blades.

[0034] In this same embodiment illustrated in [Fig.2], the target 36 is fixed on the annular support 30. More precisely, the target 36 covers one end of the annular support 30, like a cover.

[0035] In this same specific embodiment, the annular support 30 is fixed on the rotor shaft 20 by means of an indexing system 37. The indexing system 37, configured to angularly index the target 36 relative to the sensor 24 in order to read the angular position of the rotating assembly 14, is for example located inside the bore 34 of the annular support 30, as illustrated in [Fig. 2]. In the embodiment illustrated in [Fig. 2], the indexing system 37 is presented in particular in the form of a rectilinear rib 38 of oblong shape. On its longitudinal sides, the rib 38 is for example bordered on either side by flexible walls 39 which give the indexing system 37 a diamond shape. The flexible walls 39 are configured to be deformed during insertion of the indexing system 37 of the annular support 30 inside a groove 40 present on the rotor shaft 20 to index the annular support 30 on the rotor shaft 20.

[0036] More particularly, the rotor shaft 20 comprises for example a shoulder 42 having the groove 40 configured to accommodate the indexing system 37 of the annular support 30, this is more particularly illustrated in [Fig.4],

[0037] Furthermore, the rotor shaft 20 may comprise an annular groove 44 configured to accommodate a snap ring configured to ensure axial stopping of the annular support 30 relative to the rotor shaft 20 on which it is angularly indexed. The annular groove 44 for the snap ring 46 is notably illustrated in [Fig.4],

[0038] In order to avoid the occurrence of electric arcs between the teeth of the rotor and the ball bearing balls which allow the rotation of the rotor shaft 20 around the axis of rotation X in the casing 12 of the electrical machine 10, the latter comprises an electrically conductive element 50 configured to electrically connect said rotating assembly 14 to ground. In the embodiment of the electrical machine 10 illustrated in FIGS. 1 and 6, the electrically conductive element 50 is in the form of a ring with conductive eyelashes 52. Said ring is shrunk onto the casing 12, which is itself connected to ground. The conductive eyelashes 52 of the electrically conductive element 50 are in contact with a second ring 54 which comprises an electrical grounding track.

[0039] According to a particular embodiment, said second ring 54 comprises an external surface 56 of conical shape with which the conductive eyelashes 52 of the electrically conductive element 50 are in contact. This is more particularly illustrated in [Fig.5] and in [Fig.6]. The external surface 56 of conical shape makes it possible to promote the flow of a lubricant such as oil towards the channels 32 of the annular support 30. Furthermore, the conical profile of the external surface 56 of this second ring 54 can make it possible to improve the electrical contact with the conductive eyelashes 52 for grounding the electrically conductive element 50. More particularly, the conical profile of the external surface 56 with which the conductive eyelashes 52 are in contact promotes a specific orientation of said eyelashes 52, which makes it possible to homogenize the direction in which the eyelashes 52 are curved in the mounted state of the electrical machine 10.

[0040] This second ring 54 is more particularly mounted sliding on the annular support 30. This allows easy disassembly of the assembly in the case of a cleaning or maintenance operation for example. According to a particular embodiment illustrated in [Fig.6], the annular support 30 may comprise a relief 31 deformable intended to fit into a groove 58 of the second ring 54 in order to hold said second ring 54 in place relative to the annular support 30.

[0041] Thus, in addition to ensuring efficient channeling of the oil within the electrical machine, the annular support 30 makes it possible on the one hand to fix the target 36 and on the other hand to carry the second ring 54 mounted slidingly on said annular support 30.

[0042] According to a particular embodiment, the electrically conductive element 50 and the annular support 30 together delimit a housing 60 intended to accommodate at least one conductive elastic element 62 configured to allow circulation of an electric current between the rotor shaft 20 and the electrically conductive element 50. The at least one conductive elastic element 62 makes it possible to exert a pressure force, which makes it possible to increase the electrical conductivity and therefore to improve the passage of the electric current for grounding.

[0043] According to a particular embodiment, the at least one conductive elastic element 62 is for example in the form of a plurality of elastic washers 64 superimposed on one another so as to be aligned with each other, parallel to the axis of rotation X. This is more particularly illustrated in [Fig. 5] and in [Fig. 6]. In this embodiment, the elastic washers 64 are tightened on the rotor shaft 20 and allow electrical contact with the second ring 54.

[0044] Furthermore, and according to a particular embodiment of the electrical machine 10, the casing 12 comprises at least one passage 73, 74 configured to guide a lubricant such as oil towards at least a portion of the channels 32 of the annular support 30. In the embodiment of the casing 12 illustrated in [Fig. 7], the casing 12 comprises a first passage 73 as well as a second passage 74. The first passage 73 and the second passage 74 are located on either side of the annular support 30: the first passage 73 and the second passage 74 are diametrically opposite each other.

[0045] Additionally or alternatively, the casing 12 of the electrical machine 10 may include a rib 72 configured to scrape oil, so as to recover excess oil to guide it to areas where oil lubrication is necessary. The rib 72 extends in particular perpendicular to the axis of rotation X of the rotor shaft 20. In the embodiment illustrated in [Fig. 7], the rib 72 is contiguous to the first passage 73 in order to supply the latter with the oil scraped using the rib 72.

[0046] When the rotating electrical machine 10 is in operation, the oil driven in rotation by the teeth of the pinion 18 is projected onto the rib 72 and flows via the passage 73 towards the electrically conductive element 50. This oil then flows through the channels 32 of the annular support 30 which directs the oil towards the interior of the rotor shaft 20.

Claims

Claims

1. Electrical machine (10), in particular for a motor vehicle engine, said machine comprising a casing (12) and a rotating assembly (14) mounted to rotate about an axis of rotation (X) inside the casing (12), the rotating assembly (14) comprising a rotor shaft (20) which has grooves (22) on an external surface of the rotor shaft (20), said machine also comprising a reducer (16) provided with at least one pinion (18) arranged inside the casing (12) and cooperating with said grooves (22), said machine also comprising a sensor (24) configured to measure at least one kinematic quantity of said rotating assembly (14), said electrical machine (10) being characterized in that it comprises an electrically conductive element (50) configured to electrically connect said rotating assembly (14) to ground,and characterized in that it further comprises an annular support (30) comprising a plurality of channels (32) configured to guide a lubricant such as oil towards the interior of the rotor shaft (20) so as to supply the splines (22) present on the external surface (56) of the rotor shaft (20).,

2. Electrical machine (10) according to the preceding claim, characterized in that it comprises a target (36), in that said target (36) is fixed on the annular support (30) and in that said annular support (30) is fixed on the rotor shaft (20) by means of an indexing system (37) which is configured to angularly index said target (36) relative to the sensor (24) in order to ensure a reading of the angular position of the rotating assembly (14).

3. Electrical machine (10) according to the preceding claim, characterized in that the rotor shaft (20) comprises a shoulder (42) having a groove configured to accommodate the indexing system (37) of the annular support (30).

4. Electrical machine (10) according to any one of the preceding claims, characterized in that the electrically conductive element (50) comprises a ring with conductive eyelashes (52), the conductive eyelashes (52) being in contact with a second ring (54) comprising an electrical grounding track.

5. Electrical machine (10) according to the preceding claim, characterized in that said second ring (54) has an external surface (56) of conical shape with which the conductive eyelashes (52) of the element electrical conductor (50) are in contact.

6. Electrical machine (10) according to any one of the preceding claims, characterized in that the electrically conductive element (50) and the annular support (30) together delimit a housing (60) intended to accommodate therein at least one conductive elastic element (62) configured to allow circulation of an electric current between the rotor shaft (20) and the electrically conductive element (50).

7. Electrical machine (10) according to any one of the preceding claims, characterized in that at least a portion of the channels (32) of the annular support (30) have a portion-helix shape.

8. Electrical machine (10) according to one of the preceding claims, characterized in that the casing (12) comprises a rib (72) configured to scrape oil and / or in that the casing comprises at least one passage (73, 74) configured to guide a lubricant such as oil towards at least a portion of the channels (32) of the annular support (30).

9. Electrical machine (10) according to the preceding claim, characterized in that the rib (72) extends in particular perpendicular to the axis of rotation (X) of the rotor shaft (20) and / or in that the rib (72) is contiguous to the first passage (73).

10. Motor vehicle (20), characterized in that it is equipped with an electric machine (10) according to one of the preceding claims.

Images