Electric powertrain and position sensor

Abstract

Electric powertrain and position sensor. Position sensor (20) for a rotating shaft, in particular a motor vehicle rotor shaft (11), comprising a sensor body (22), characterized in that it comprises an oil conduit (21) arranged at least partially inside the sensor body (22), extending between an oil inlet (23) adapted to receive lubricating oil, and an oil outlet (24) adapted to convey lubricating oil to an area to be lubricated. Figure for the abstract: Fig. 1

Description

Title of the invention: Electric powertrain and position sensor

[0001] The invention relates to a position sensor, and to an electric powertrain, or even to any rotating device. It also relates to a motor vehicle as such comprising such a powertrain.

[0002] A powertrain requires the optimal integration of various components to minimize its size and optimize its operation. Among these components are, for example, a position sensor, which measures the rotor's rotational speed, and a set of elements belonging to a lubrication system.

[0003] The objective of the present invention is to propose a powertrain, in particular electric, in particular synchronous, whose arrangement allows optimal operation with minimal bulk. Summary of the invention

[0004] To achieve this objective, the invention relates to a position sensor for a rotating shaft, in particular a motor vehicle rotor shaft, comprising a sensor body, characterized in that it includes an oil conduit arranged at least partially inside the sensor body, extending between an oil inlet suitable for receiving lubricating oil at the inlet, and an oil outlet suitable for transmitting lubricating oil at the outlet towards an area to be lubricated.

[0005] The oil conduit can be oriented along a main direction, and the oil inlet and oil outlet can be oriented perpendicular to said main direction and / or the oil inlet and oil outlet can be oriented in directions parallel to each other.

[0006] The invention also relates to a rotating device comprising a position sensor as described above for measuring the rotational speed of the rotating shaft, the lubrication device being able to transmit lubricating oil to an area to be lubricated around the rotating shaft, and the lubricating oil passing through the position sensor via said oil conduit.

[0007] This rotating device can be an electric vehicle powertrain automobile.

[0008] The invention also relates to an electric powertrain for a motor vehicle, comprising a rotor shaft, the second end of which comprises a pinion, characterized in that it comprises a lubrication device, including a reservoir, a pump for drawing oil from the reservoir and conveying it to an area at lubricate, and in that it includes a position sensor as described above, so that the oil passes through the position sensor via its oil conduit before reaching the area to be lubricated.

[0009] The powertrain may include a central opening arranged in the rotor shaft at its second end, and may include an axial tube extending within said central opening, coaxially with the rotor shaft, from the oil outlet of the position sensor to one end within the central opening, so as to allow the oil supply to the central opening, and the peripheral wall of the central opening may include distribution holes so as to conduct the oil by gravity and / or centrifugation through the distribution holes to an area to be lubricated around the rotor shaft.

[0010] The oil channel of the position sensor may extend in a main radial direction and / or the oil inlet and / or the oil outlet may be arranged close to a position sensor fixing screw to promote sealing.

[0011] The powertrain may include a chamber arranged between two oil conduits respectively located within a first mechanism casing and a second machine casing, so as to receive oil in the event of oil overpressure.

[0012] The powertrain can be a synchronous electric powertrain, comprising a first end comprising an electrical excitation device capable of acting on a wound rotor, arranged at the first end of the rotor shaft.

[0013] The invention also relates to a vehicle, in particular a motor vehicle, characterized in that it includes a position sensor as described above or in that it includes a powertrain as described above. Presentation of the figures

[0014] These objects, features and advantages of the present invention will be described in detail in the following description of an embodiment given by way of non-limiting reference in relation to the accompanying figures, among which:

[0015] Fig. 1 is a schematic cross-sectional view of an electric powertrain for a motor vehicle according to an embodiment of the invention.

[0016] Fig. 2 is a schematic view of the end of the electric powertrain for a motor vehicle according to the embodiment of the invention.

[0017] Fig. 3 is a partial schematic cross-sectional view of the electric powertrain for a motor vehicle according to the embodiment of the invention.

[0018] Fig. 4 is a partial schematic cross-sectional view of the electric powertrain for a motor vehicle according to a variant of the embodiment of the invention. Detailed description

[0019] Figure 1 shows a schematic cross-sectional view of an electric powertrain according to an embodiment of the invention. More particularly, the powertrain is equipped with a synchronous electric motor, in particular a wound synchronous motor.

[0020] On a first end of the electric motor, the stator 1 of the motor is equipped with an electrical excitation device 2, configured to act on a first end 12 of a rotor shaft 11 of a rotor, via a winding associated with the rotor shaft 11, so as to drive this rotor shaft 11 into rotation.

[0021] On a second end of the electric motor, opposite the first end, the rotor shaft 11 is equipped with a device for transmitting its rotational motion. For this purpose, the rotor shaft 11 includes on its second end a pinion 13 associated with a bearing housing, having flanks comprising splines, so as to transmit the transmission motion as efficiently as possible.

[0022] In addition, the powertrain includes a lubrication device, specifically designed to lubricate an area located at the level of this pinion 13. Indeed, the area at the second end of the rotor shaft requires lubrication by engine oil, which forms a thin film between the mechanical parts, thus limiting friction between them and reducing wear. The oil also protects the parts from oxidation and corrosion.

[0023] Furthermore, the powertrain is equipped with a position sensor 20, which notably allows the angular velocity of the motor to be measured. For this purpose, the position sensor 20 is, for example, equipped with a transmitter that sends a signal to the rotor shaft 11 and receives in return a signal modified by a target comprising apertures corresponding to the number of poles and angularly indexed with respect to one of them. The characteristics of this target depend on the rotational speed, according to a well-known radar principle, thus allowing the rotational speed and the angular position to be deduced very precisely with respect to the poles. The accuracy of the angular position of a pole makes it possible to precisely control the rotating magnetic field induced by the stator. Advantageously, this position sensor 20 is arranged at the second end of the rotor shaft 11.This positioning allows it to avoid electromagnetic interference generated by the electrical excitation device 2, located at the first end of the rotor shaft. It also optimizes the overall size of the sensor.

[0024] The invention is based first on a particular position sensor 20, in that it participates in the lubrication function of the area to be lubricated at the second end of the rotor shaft 11. Indeed, as is particularly apparent from the In Figures 2 to 4, the position sensor 20 is arranged at the end of the rotor shaft, at its second end, and incorporates, at least partially, an oil conduit 21 arranged directly inside a sensor body 22. This conduit receives oil from an external reservoir at its inlet 23, and then carries the oil through the conduit 21 to an oil outlet 24 located near a central portion of the rotor shaft 11 of the powertrain. This approach allows for a compact design, as it does not require an increase in volume to integrate an oil conduit into the powertrain housing up to the pinion.Passing through the position sensor, which remains ideally placed to fulfill its primary function of measuring speed, thus makes it possible to combine an ideal speed measurement with appropriate lubrication of the powertrain, without significant bulk.

[0025] According to the invention, the powertrain is further equipped with a lubrication device, which includes a reservoir 31 and a volumetric pump 32 designed to draw oil from the reservoir 31 and convey it to the area to be lubricated, at the second end of the rotor shaft 11, as detailed above. Upon exiting the reservoir, the oil flows through initial channels 33 formed in the machine housing 3 of the powertrain, for example, in the form of a series of bores. It continues its movement within the mechanism housing 4 through intermediate channels 34 until it reaches the oil inlet 23 of the oil line 21 of the position sensor 20.Advantageously, this oil inlet 23 of the position sensor oil line is positioned near a screw 5 securing the position sensor 20, to facilitate the sealing of a gasket arranged at the interface between the oil inlet 23 of the oil line 21 and the mechanism housing 4, thus optimizing the seal. According to an advantageous and optional embodiment, a chamber 6 or cavity is arranged at the interface between the two aforementioned housings 3 and 4. This chamber acts as a relief valve in case of oil overpressure in the lubrication system, while ensuring sufficient flow to the position sensor 20.

[0026] The oil is then guided through the oil conduit 21 of the position sensor 20, in a substantially radial direction, until it reaches the oil outlet 24 of the oil conduit 21. The oil conduit therefore extends in a main direction, which is radial in this embodiment, i.e. perpendicular to the axis of the rotor shaft 11. The oil inlet 23 and the oil outlet 24 are oriented in directions that are substantially parallel to each other, and parallel to the axis of the rotor shaft 11, and substantially perpendicular to said main direction of the oil conduit 21.

[0027] The lubrication device further includes an axial tube which allows the oil to be conducted inside a central opening 15 of the rotor shaft, which is cylindrical in shape, arranged at the second end of the rotor shaft 11, the oil is thus released at the outlet of this axial tube. This end 26 forms an opening for the oil, which is then able to spread throughout the entire volume of the central opening 15 inside the rotor shaft. The oil then spreads by gravity and / or centrifugal force over the peripheral wall 16 of this central opening 15, where it reaches distribution holes 17 arranged radially in this peripheral wall 16. It can thus pass through the peripheral wall 16 of the pinion and reach the area to be lubricated, at the mounting splines. Note that the oil outlet 24 of the oil conduit 21 of the position sensor 20 and the axial tube 25 are therefore arranged coaxially around the axis of the rotor shaft.

[0028] The length of the axial tube 25 is designed to release oil into the central opening 15 of the rotor shaft 11, ensuring a sufficient quantity of oil is supplied. Similarly, the number of distribution holes 17 and the diameter of the distribution holes 17 arranged in the peripheral wall 16 of the central opening 15 of the rotor shaft 11 are designed to conduct the optimal quantity of oil into the lubrication zone.

[0029] According to the embodiment, the central opening 15 of the rotor shaft 11 may have a diameter of approximately 12 mm. An axial tube 25 with a diameter of approximately 3 mm and a length of 40 mm can thus be used. The material thickness of the axial tube 25 can be approximately 1.5 mm. The diameter of the oil passage 21 within the position sensor can therefore be approximately 3 mm, at least at the oil outlet 24 of the oil passage.

[0030] According to the embodiment illustrated in [Fig. 3], the end of the central opening 15 of the rotor shaft is sealed around the axial tube by means of a constriction 18, which allows some play in the axial tube while ensuring a seal around its periphery. During operation, this central opening 15 is thus completely filled with oil, in a sealed manner.

[0031] Figure 4 illustrates an alternative embodiment in which a sealing strip 19 is arranged towards the end 26 of the axial tube 25. Such a sealing strip 19 prevents the central opening 15 of the rotor shaft 11 from filling completely and limits the presence of oil at the bottom of this opening, at the distribution holes 17. This sealing strip 19 can be in the form of a thin tab, for example, approximately 0.3 mm thick. It can be made of the same material as the axial tube 25, in particular as a single piece with the axial tube 25. Advantageously, it has rotational symmetry about the axial tube 25. It can have a conical shape, with a rest diameter slightly larger than that of the central opening 15 of the rotor shaft 11, so that when inserted In this central opening 15, it deforms elastically upon contact with the peripheral wall 16 of this central opening 15, while ensuring a seal at the level of this wall. The orientation of the sealing strip 19 is such that it facilitates the insertion of the axial tube 25 into the central opening 15.

[0032] The invention therefore relates to a position sensor 20 as described above, as well as to a powertrain incorporating such a position sensor. More generally, it relates to any rotating shaft device incorporating such a position sensor.

Claims

Demands

1. Position sensor (20) for a rotating shaft, in particular a rotor shaft (11) of a motor vehicle, comprising a sensor body (22), characterized in that it comprises an oil conduit (21) arranged at least partially inside the sensor body (22), extending between an oil inlet (23) adapted to receive lubricating oil at the inlet, and an oil outlet (24) adapted to transmit lubricating oil at the outlet towards an area to be lubricated.

2. Position sensor (20) for rotating shaft according to the preceding claim, characterized in that the oil conduit (21) is oriented along a principal direction, and in that the oil inlet (23) and the oil outlet (24) are oriented perpendicular to said principal direction and / or in that the oil inlet (23) and the oil outlet (24) are oriented along directions parallel to each other.

3. Rotating device comprising a rotating shaft and a lubrication device, characterized in that it comprises a position sensor (20) according to any one of the preceding claims for measuring the rotational speed of the rotating shaft, the lubrication device being capable of transmitting lubricating oil to an area to be lubricated around the rotating shaft, and in that the lubricating oil passes through the position sensor (20) via said oil conduit (21).

4. Rotating device according to the preceding claim, characterized in that it is an electric motor vehicle powertrain.

5. Electric powertrain for motor vehicle, comprising a rotor shaft (11) having a second end comprising a pinion, characterized in that it comprises a lubrication device, comprising a reservoir (31), a pump (32) for drawing oil from the reservoir (31) and conveying it to an area to be lubricated, and in that it comprises a position sensor (20) according to any one of claims 1 or 2, such that the oil passes through the position sensor (20) via its oil conduit (21) before reaching the area to be lubricated.

6. Powertrain according to the preceding claim, characterized in that it comprises a central opening (15) arranged in the rotor shaft (11) at its second end, and in which includes an axial tube (25) extending within said central opening (15), coaxially with the rotor shaft (11), from the oil outlet (24) of the position sensor (20) to an end (26) within the central opening (15), so as to permit the supply of oil to the central opening (15), and in that the peripheral wall (16) of the central opening (15) includes distribution holes (17) so as to conduct the oil by gravity and / or centrifugation through the distribution holes to an area to be lubricated around the rotor shaft (11).

7. Powertrain according to the preceding claim, characterized in that the oil conduit (21) of the position sensor extends in a main radial direction and / or in that the oil inlet (23) and / or the oil outlet (24) are arranged near a screw (5) for fixing the position sensor (20) to promote sealing.

8. Powertrain according to any one of claims 5 to 7, characterized in that it comprises a chamber (6) arranged between two oil conduits (33, 34) respectively disposed within a first mechanism casing and a second machine casing, so as to receive oil in the event of oil overpressure.

9. Powertrain according to any one of claims 5 to 8, characterized in that it is a synchronous electric powertrain, comprising a first end (12) comprising an electrical excitation device (2) capable of acting on a wound rotor, arranged at the first end of the rotor shaft (11).

10. Vehicle (1), in particular motor vehicle, characterized in that it comprises a position sensor (20) according to one of claims 1 or 2 or in that it comprises a powertrain according to one of claims 5 to 9.

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