Inductive position sensor with improved fluid circulation system

Abstract

The present invention relates to an inductive position sensor (1) for a rotating electrical machine comprising a printed circuit board (12) housed in at least one enclosure (10), having on its main face (120) at least one emitting element (13) for emitting an oscillating magnetic field towards a rotating target (2) to generate a modified oscillating magnetic field, and at least one receiving device (14) for detecting the modified oscillating magnetic field, the sensor comprising fluid circulation means (16, 17, 18) for allowing the circulation of a fluid into a rotor shaft (22) of the electrical machine (3), the fluid circulation means being formed by at least one double bottom (105) of the cover (11) of the sensor (1) forming a conduit (17) which allows the circulation of a lubricating fluid. Figure 1.

Description

Title of the invention: Inductive position sensor with improved fluid circulation system

[0001] The present invention relates to the field of position sensors. And more particularly to an inductive position sensor comprising a fluid circulation system.

[0002] Inductive position sensors, known as eddy current sensors, use a magnetic field to determine the angular position of the rotating target which forms a coupling element.

[0003] These position sensors are notably used in electric motors of electric or hybrid vehicles comprising a rotor rotating relative to a stator.

[0004] The angular position of the rotor is determined relative to the stator. The target is mounted at the end of a rotor shaft to modify a magnetic field transmitted by a transmitter. The target is centered with respect to a rotor axis of rotation. The target comprises several vanes that provide a repeating and periodic magnetic field pattern with respect to the rotor axis of rotation.

[0005] The position sensor is fixed relative to the stator, opposite the target and the rotor. The position sensor comprises a printed circuit board (PCB), oriented away from the target and the rotor, having at least one emitting element intended to emit an oscillating magnetic field towards the target, generating a modified oscillating magnetic field at a given frequency.

[0006] The printed circuit board includes a receiver device for detecting the modified oscillating magnetic field and transmitting it to a signal processing unit provided on the printed circuit board to deduce the angular position of the target. The sensor is enclosed by a cover located above the printed circuit board, which can be glued, soldered, screwed, or clipped to the housing of a motor.

[0007] The disadvantage of these prior art sensors stems from the fact that they are not suitable for allowing effective lubrication of the electric motor.

[0008] The present invention therefore aims to overcome one of the drawbacks of those of the prior art by proposing a position sensor comprising an improved electric motor lubrication system.

[0009] To this end, the present invention proposes an inductive position sensor for a rotating electrical machine comprising a printed circuit board, housed in at least one casing, having on its main face at least one emitting element intended to emit an oscillating magnetic field towards a rotating target to generate a modified oscillating magnetic field, and at least one receiving device intended to detect the modified oscillating magnetic field, the sensor comprising fluid circulation means to permit the circulation of a fluid into a rotor shaft of the electric machine, the fluid circulation means being formed by at least one double bottom of the sensor cover forming a conduit which permits the circulation of a lubricating fluid.

[0010] According to one embodiment of the invention, the double bottom is formed by an additional piece arranged parallel to the lid, between the lid and the printed circuit board at a distance from the lid allowing the circulation of the lubricating fluid.

[0011] According to one embodiment of the invention, the double bottom comprises a part parallel to the lid.

[0012] According to one embodiment of the invention, the double bottom is fixed to the housing by laser welding, ultrasonic welding or gluing.

[0013] According to one embodiment of the invention, a first fluid inlet conduit formed in the body of the sensor housing opens into the second fluid circulation conduit, the second circulation conduit itself opening into a third fluid circulation conduit.

[0014] According to one embodiment of the invention, the double bottom has an opening allowing communication between the second conduit and the shaft of the electric machine motor.

[0015] According to one embodiment of the invention, the double bottom is fixed to the housing by laser welding, ultrasonic welding or gluing.

[0016] The invention also relates to an electrical machine comprising a sensor according to the invention.

[0017] The invention also relates to a mobility device, for example a motor vehicle, comprising an electric machine according to the invention.

[0018] Other objects, features and advantages of the invention will be better understood and will become more apparent upon reading the description given below, with reference to the accompanying figures, given by way of example and in which:

[0019] - Fig. 1 is a representation of a longitudinal cross-sectional view of the sensor and of the drive shaft according to one embodiment of the invention,

[0020] - [Fig. 2] is a representation of a bottom view of the sensor according to a mode of realization of the invention with the target,

[0021] - [Fig. 3] is an exploded elevation view of the sensor system according to a mode of realization of the invention,

[0022] - [Fig. 4] is a top elevation view of the sensor closed according to a mode of realization of the invention.

[0023] The invention relates to an inductive position sensor 1, as illustrated in [Fig. 1] to [Fig. 4] incorporating means for circulating the lubricating fluid of an electrical machine.

[0024] The inductive position sensor 1 uses a magnetic field to determine the angular position of a visible rotating target 2 [Fig.2] which is used as a coupling element.

[0025] The inductive position sensor 1 and the target 2 are intended to be mounted in a rotating electrical machine, not shown, such as an electric motor of an electric or hybrid vehicle comprising a rotor rotating relative to a stator. The angular position of the rotor is determined relative to the stator.

[0026] According to one embodiment of the invention, the sensor 1 is fixed for example to the hood or the motor housing or any compatible motor interface of the electric machine by a screw-type fixing system 19.

[0027] The target 2 is mounted on one end of a shaft 22 of the rotor to modify a magnetic field emitted by a transmitter.

[0028] According to one embodiment of the invention, the target 2 comprises a rotation axis X which is aligned with a rotation axis of the rotor. According to one embodiment of the invention, the target 2 comprises at least two angular sectors 21, and for example 3, 4, 5 or 6 which provide a repeating and periodic magnetic field pattern with respect to the rotation axis of the rotor.

[0029] According to one embodiment of the invention, the sensor 1 is positioned opposite the target 2 at the end of the rotor shaft 22. More specifically, the position sensor 1 is fixed relative to the stator, opposite the target 2 at the end of the rotor shaft 22. Therefore, in order of positioning on the shaft, there is the rotor / stator, then the target 2, and then the position sensor 1. These elements are arranged coaxially with the X-axis of the rotor shaft.

[0030] According to one embodiment of the invention, the sensor 1 is through-hole, i.e. the rotor shaft 22 passes through the center of the sensor, not illustrated

[0031] According to one embodiment of the invention, the sensor 1 is non-through, that is to say, it is disposed at the end of the shaft 22 of the rotor.

[0032] The inductive position sensor 1 [Fig.1] and [Fig.3] includes at least one printed circuit board 12, referred to as a PCB (Printed Circuit Board), having on its main face 120 at least one emission element 13 intended to emit an oscillating magnetic field towards the target 2, which returns a modified oscillating magnetic field at a given frequency.

[0033] This printed circuit board 12 includes on its main face 120 a receiver device 14 for detecting the modified oscillating magnetic field and transmitting it to a signal processing unit 6 to measure the angular position of target 2. The modified oscillating magnetic field generates an electromotive force at a given frequency in the receiving device 14. This electromotive force is processed by the signal processing unit 6 so as to provide output signals enabling the measurement of the position of target 2.

[0034] The inductive position sensor 1 is fixed relative to the stator. The printed circuit board is positioned opposite the target 2.

[0035] According to one embodiment of the invention, the printed circuit board 12 is housed in at least one housing 10 and supported by the bottom 101 of the housing 10. This housing forms the body 10 of the sensor 1. The printed circuit board 12 is arranged in a housing 100 of the housing so that its main face 120 is oriented towards the outside of the sensor 1, that is to say in a direction opposite to that in which the target 2 is located.

[0036] According to one embodiment of the invention, the housing has an opening 102, the bottom 101 is the face opposite this opening 102. The opening 102 is oriented towards the outside of the sensor, that is to say oriented in a direction opposite to that in which the target 2 is located.

[0037] According to one embodiment of the invention, the bottom 101 of the housing 10 is arranged in a plane P perpendicular to the axis X of the shaft 22 opposite the target 2.

[0038] According to one embodiment of the invention, the housing 10 is closed by a cover or hood 11 [Fig.4].

[0039] According to one embodiment of the invention, the cover 11 is fixed by laser welding.

[0040] The sensor 1 according to the invention is configured to allow the circulation of a fluid up to the inside of the shaft 22 of the rotor.

[0041] For this purpose the sensor 1 includes means 105 for circulating a fluid.

[0042] In the context of the invention, the means for circulating a fluid are formed by at least one double bottom 105 of the cover 11 of the sensor 1. This double bottom 105 forms, with the cover 11, a conduit 17 which allows the circulation of a lubricating fluid under pressure or under the effect of gravity flow, and allows better lubrication of the elements of the electrical machine.

[0043] According to one embodiment of the invention, the double bottom 105 is formed by an additional part 105 disposed between the cover 11 and the printed circuit board 12, at a distance DI from the cover 11 allowing the circulation of the lubricating fluid. The distance DI is determined so as to optimize the circulation of the fluid and allow for optimized lubrication.

[0044] According to one embodiment of the invention, the additional part 105 comprises a portion, for example flat, 151 parallel to the cover 11.

[0045] According to one embodiment of the invention, the additional part 105 is of the same shape as the cover, and for example rectangular or circular.

[0046] According to one embodiment of the invention, this additional part 105 is fixed by laser welding, ultrasonic welding or gluing to the housing 10.

[0047] The space between the cover and the additional part thus forms a second fluid circulation conduit 17 into which a first fluid inlet conduit 16 opens, the second circulation conduit 17 itself opening into a third fluid circulation conduit 18. For this purpose, the additional part has an opening 24 allowing communication between the second conduit 17 and the third conduit 18.

[0048] The third circulation conduit 18 opens into the shaft of the electric machine motor.

[0049] According to one embodiment of the invention, the first conduit 16 and the third conduit 18 are formed in the body of the housing 10 of the sensor 1.

[0050] The first conduit 16 is formed coaxially to the X axis of the shaft 22 and perpendicular to the card 12 of the printed circuit of the sensor 1 at the periphery of the additional part so that the first conduit 16 communicates with the second conduit 17.

[0051] According to one embodiment of the invention, the first conduit 16 is opened by a first end 165 which is configured to be positioned at the level of a fluid reservoir, so as to receive the fluid under pressure from the reservoir or by gravity.

[0052] According to one embodiment of the invention, the second end 166 of the first conduit 16 opens into the second conduit 17 for circulating the fluid.

[0053] According to one embodiment of the invention, the third conduit 18 is formed from the bottom 101 of the housing 11 and is arranged in the center of the housing 10 to coincide with the shaft 22 of the motor.

[0054] According to another embodiment of the invention, the third conduit 18 is fixed to the bottom 101 of the housing 11 by laser welding, ultrasonic welding or gluing, and is arranged in the center of the housing 10 to coincide with the shaft 22 of the motor.

[0055] According to one embodiment of the invention, at least one sealing gasket 23 is disposed at the point of contact between the housing 11 of the sensor 1 and the electrical machine.

[0056] According to one embodiment of the invention, the interior of the shaft 22 allows the fluid to be distributed within the electric machine through the center of the X-axis of the rotor shaft by means of the centrifugal force that propels the fluid against the shaft walls. This configuration thus prevents the fluid from being dispersed directly at the reservoir outlet. With this configuration, the fluid is brought to the center of the rotor shaft and then dispersed through the interior of the rotor, resulting in improved lubrication.

[0057] According to one embodiment of the invention, the fluid is oil, and more specifically lubricating oil. The circulation of the oil via the shaft allows the lubrication of the electrical machine, and for example of the gears of the electrical machine.

[0058] Thus such a sensor according to the invention allows optimized lubrication of the elements of the electrical machine.

[0059] According to one embodiment of the invention, the sensor comprises a connection element 20 connected to connection elements, themselves connected to the printed circuit board 12. The connection element allows a connection with another external element, for example of the vehicle, to transmit the output signal of the sensor 1.

[0060] The invention also relates to an electric machine comprising a sensor 1 as described above, as well as a mobility device comprising an electric machine equipped with a sensor according to the invention.

[0061] The scope of the present invention is not limited to the details given above and allows for embodiments in many other specific forms without departing from the field of application of the invention. Therefore, the present embodiments should be considered by way of illustration and may be modified without, however, departing from the scope defined by the claims.

Claims

Demands

1. An inductive position sensor (1) for a rotating electrical machine comprising a printed circuit board (12), housed in at least one casing (10), having on its main face (120) at least one emitting element (13) for emitting an oscillating magnetic field towards a rotating target (2) to generate a modified oscillating magnetic field, and at least one receiving device (14) for detecting the modified oscillating magnetic field, the sensor comprising fluid circulation means (16, 17, 18) for allowing the circulation of a fluid into the interior of a rotor shaft (22) of the electrical machine (3), characterized in that the fluid circulation means are formed by at least one double bottom (105) of a cover (11) of the sensor (1) forming a conduit (17) which allows the circulation of a lubricating fluid.

2. Inductive position sensor (1) according to claim 1, wherein the double bottom (105) is formed by an additional part (105) disposed parallel to the cover, between the cover (11) and the printed circuit board (12) at a distance (Dl) from the cover (11) allowing the circulation of the lubricating fluid.

3. Inductive position sensor (1) according to claim 1 or 2, wherein the double bottom (105) has a part (151) parallel to the cover (11).

4. Inductive position sensor (1) according to any one of claims 1 to 3, wherein the double bottom (105) is fixed by laser welding, ultrasonic welding or bonding to the housing (10).

5. Inductive position sensor (1) according to any one of claims 1 to 4, wherein a first fluid inlet conduit (16) formed in the body of the housing (11) of the sensor (1) opens into a second fluid circulation conduit (17), the second circulation conduit (17) itself opening into a third fluid circulation conduit (18).

6. Inductive position sensor (1) according to claim 5, wherein the double bottom (105) has an opening (24) allowing communication between the second conduit (17) and the shaft (22) of the electric machine motor.

7. 8 Inductive position sensor (1) according to any one of claims 1 to 6, wherein the double bottom (105) is fixed by laser welding, ultrasonic welding or bonding to the housing (10).

8. Electric machine (3) comprising a sensor (1) according to any one of claims 1 to 7.

9. Mobility device, for example a motor vehicle, comprising an electric machine according to claim 8.

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