Rotating electric machine for motor vehicle propulsion.

Abstract

Rotating electric machine for motor vehicle propulsion. Electric machine (10) comprising a housing (12) and a rotating assembly (14) mounted movably about an axis of rotation (X) inside the housing (12), the rotating assembly (14) comprising a rotor shaft (20) having splines (22) on an external surface, said machine comprising a reducer (16) provided with a pinion (18) cooperating with said splines (22), said machine also comprising a sensor (24) configured to measure at least one kinematic quantity of said rotating assembly (14), said electric 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) having a plurality of channels (32) configured to guide a lubricant towards the interior of the rotor shaft (20) so as to supply the splines (22). Figure for the abbreviation: Fig. 1,

Description

Title of the invention: Rotating electric machine for motorizing an automobile.

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

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

[0003] Various solutions have already been developed for lubricating machine components. One of these provides for a rotating electrical machine comprising a housing, a rotating assembly mounted for free rotation within the housing about an axis of rotation, and a gearbox equipped with at least one pinion, the rotating assembly being connected to the gearbox via the pinion. The rotating assembly also includes a rotor shaft having splines on its external surface; the pinion engages with these splines. The rotor shaft is partially hollow and has at least one channel connecting its hollow portion to its external surface. This channel supplies the splines on the external surface of the rotor shaft with oil from inside the rotor shaft to ensure lubrication of the rotating electrical machine.

[0004] The object of the invention is to provide a machine with improved lubrication. In the machine embodiment described below, lubrication is improved in that the oil channeling within the machine is more efficient, particularly for the passage of oil inside the rotating shaft. Furthermore, the described embodiment reduces friction within the mechanism while exhibiting improved electrical conductivity. This embodiment is demountable and allows easy access to the various parts for repair and / or replacement.

[0005] To this end, the invention relates to an electric machine, in particular for motorizing a motor vehicle, said machine comprising a housing and a rotating assembly mounted to rotate about an axis of rotation inside the housing, the rotating assembly comprising a rotor shaft having splines on an external surface of the rotor shaft, said machine also comprising a reducer having at least one pinion arranged inside the housing 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 includes an electrically conductive element configured to electrically connect said rotating assembly to ground, and characterized in that it further comprises an annular support having a plurality of channels configured to guide a lubricant such as oil into the rotor shaft so as to supply the splines present on the external surface of the rotor shaft.

[0006] According to one embodiment, the electric machine includes 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 with respect 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 has 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 an external surface of conical shape with which the conducting cilia of the electrically conducting element are in contact.

[0010] According to one embodiment, the electrically conductive element and the annular support together define a housing intended to accommodate at least one conductive elastic element configured to allow the flow 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 helical portion shape.

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

[0013] According to one embodiment, the housing includes 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 perpendicularly 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, features and advantages of the present invention will be described in detail in the following description of a particular embodiment, given by way of non-limiting example, with reference to the accompanying figures, among which:

[0018] Fig. 1 illustrates a schematic cross-sectional view of the rotating electrical machine according to the invention.

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

[0020] Fig. 3 is a second perspective view of the annular support according to another angle of view.

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

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

[0023] Fig. 6 is a detail view of the schematic cross-sectional view of Fig. 1.

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

[0025] Figure 1 shows a schematic cross-sectional view of a rotating electrical machine 10 which includes a housing 12 and a rotating assembly 14 mounted movably in rotation about an axis of rotation X inside the housing 12.

[0026] The rotating electrical machine 10 also includes a reducer 16 equipped with at least one pinion 18 arranged inside the housing 12. The rotating assembly 14 is connected to the reducer 16 via the pinion 18. More specifically, the rotating assembly 14 comprises a rotor shaft 20 which has splines 22 on its external surface; the drive pinion 18 arranged inside the housing 12 cooperates with said splines 22. The reducer 16 notably allows the speed ratio and / or torque between the rotor shaft 20 and the rotating assembly 14 to be changed.

[0027] In this [Fig. 1], the rotor shaft 20 has a shaft housing that coincides with the axis of rotation of the rotating assembly. The rotor shaft 20 also has at least one channel 23 that extends radially and connects said shaft housing to the external surface of the rotor shaft 20. The channel 23 supplies the splines 22 on the external surface of the rotor shaft 20 with a lubricant such as oil present inside the shaft housing of the rotor shaft 20.

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

[0029] One embodiment of the annular support 30 is illustrated in particular in [Fig. 2] and [Fig. 3]. In this embodiment, the annular support 30 is in the form of a single piece with an overall cylindrical geometry. The support annular 30 has in particular a bore 34 and is centered by fitting said bore 34 onto the rotor shaft 20.

[0030] According to a particular embodiment, at least some of the channels 32 of the annular support 30 have a helical shape. In other words, at least some 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 [Fig. 3]. In this same embodiment, the channels 32 are distributed at constant angular distances, which means that the channels 32 are regularly distributed within the cylindrical body formed by the annular support 30.

[0031] The channels 32 are designed to convey a lubricant such as oil to the interior of the rotor shaft 20 so as to supply the splines 22 present on the external surface of the rotor shaft 20. Their helical shape facilitates the flow of oil. The winding direction of the helical-shaped channels 32 is consistent with the preferred direction of rotation of the electric machine 10. In the case where the electric machine 10 is a traction or propulsion electric 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 includes an inductive sensor 24 which is configured to measure at least one kinematic quantity of said rotating assembly 14, the kinematic quantity is for example the angular position and / or the rotational speed of the rotating assembly 14 of said rotating electrical machine 10.

[0033] More specifically, the electric machine 10 includes a target 36 configured to interact with said sensor 24 in order to provide a reading of the angular position of the rotating assembly 14. The target 36 includes, for example, blades formed by angular sectors. The number of angular sectors corresponds to a number of pole pairs of said machine. In the example illustrated in [Fig. 2], the target 36 includes, 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, in the manner of a lid.

[0035] In this same specific embodiment, the annular support 30 is fixed to 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 straight, oblong rib 38. On its longitudinal sides, the rib 38 is, for example, bordered on both sides by flexible walls 39 which give the indexing system 37 a diamond shape. The flexible walls 39 are configured to deform when the indexing system 37 of the annular support 30 is inserted into a groove 40 on the rotor shaft 20 to index the annular support 30 onto the rotor shaft 20.

[0036] More particularly, the rotor shaft 20 includes, 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 include an annular groove 44 configured to accommodate a circlip configured to provide axial restraint of the annular support 30 relative to the rotor shaft 20 on which it is angularly indexed. The annular groove 44 for the circlip 46 is illustrated in particular in [Fig. 4].

[0038] To prevent the formation of electrical arcs between the rotor teeth and the ball bearings that allow the rotor shaft 20 to rotate about the axis of rotation X in the housing 12 of the electric machine 10, the latter includes an electrically conductive element 50 configured to electrically connect said rotating assembly 14 to ground. In the embodiment of the electric machine 10 illustrated in Figures 1 and 6, the electrically conductive element 50 is in the form of a ring with conductive teeth 52. Said ring is shrink-fitted onto the housing 12, which is itself connected to ground. The conductive teeth 52 of the electrically conductive element 50 are in contact with a second ring 54 which includes an electrical grounding track.

[0039] According to a particular embodiment, said second ring 54 comprises a conical external surface 56 with which the conductive hairs 52 of the electrically conductive element 50 are in contact. This is illustrated more particularly in [Fig. 5] and [Fig. 6]. The conical external surface 56 facilitates 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 improve electrical contact with the conductive hairs 52 for grounding the electrically conductive element 50. More specifically, the conical profile of the external surface 56 with which the conductive hairs 52 are in contact promotes a specific orientation of said hairs 52, which makes it possible to homogenize the direction in which the hairs 52 are bent in the assembled state of the electrical machine 10.

[0040] This second ring 54 is more specifically mounted to slide on the annular support 30. This allows for 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 include 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 allows on the one hand the target 36 to be fixed and on the other hand the second ring 54 mounted sliding on said annular support 30 to be carried.

[0042] According to a particular embodiment, the electrically conductive element 50 and the annular support 30 together define a housing 60 intended to accommodate at least one conductive elastic element 62 configured to allow the flow 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 increases the electrical conductivity and thus improves 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 stacked one on top of the other so as to be aligned with each other, parallel to the axis of rotation X. This is illustrated more particularly in [Fig. 5] and [Fig. 6]. In this embodiment, the elastic washers 64 are clamped onto 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 housing 12 includes 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 housing 12 illustrated in [Fig. 7], the housing 12 includes a first passage 73 and 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 opposed to each other.

[0045] In addition or as an alternative, the housing 12 of the electric machine 10 may include a rib 72 configured to scrape oil, so as to recover excess oil and direct it to areas where oil lubrication is required. The rib 72 extends, in particular, perpendicularly to the axis of rotation X of the rotor shaft 20. In the embodiment illustrated in [Fig. 7], the rib 72 is contiguous with the first passage 73 in order to supply it with the oil scraped by the rib 72.

[0046] When the rotating electrical machine 10 is in operation, the oil driven into rotation by the teeth of the pinion 18 is projected onto the rib 72 and flows through 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 inside of the rotor shaft 20.

Claims

Demands

1. An electric machine (10), in particular for motorizing a motor vehicle, said machine comprising a housing (12) and a rotating assembly (14) mounted to rotate about an axis of rotation (X) inside the housing (12), the rotating assembly (14) comprising a rotor shaft (20) having splines (22) on an external surface of the rotor shaft (20), said machine also comprising a reduction gear (16) having at least one pinion (18) arranged inside the housing (12) and cooperating with said splines (22), said machine also comprising a sensor (24) configured to measure at least one kinematic quantity of said rotating assembly (14), said electric 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) having a plurality of channels (32) configured to guide a lubricant such as oil into 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), and characterized in that it comprises a target (36), in that said target (36) is fixed to the annular support (30), and in that said annular support (30) is fixed to the rotor shaft (20) by means of an indexing system (37) which is configured to angularly index said target (36) with respect to the sensor (24) in order to ensure a reading of the angular position of the rotating assembly (14).

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

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

4. An electric machine (10) according to the preceding claim, characterized in that said second ring (54) has a conical external surface (56) with which the eyelashes conductors (52) of the electrically conductive element (50) are in contact.

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

6. Electric 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 helical portion shape.

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

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

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

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