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 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 a rotor shaft (22) of the electrical machine (3), the fluid circulation means being formed by at least one double bottom (105) of the housing (10) 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 allow 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 housing forming a conduit which allows the circulation of a lubricating fluid.

[0010] The double bottom thus allows for better lubrication of the electrical machine components.

[0011] According to one embodiment of the invention, the double bottom is formed by an additional piece arranged parallel to the bottom of the housing at a distance from the bottom allowing the circulation of the lubricating fluid.

[0012] According to one embodiment of the invention, the additional part comprises a portion parallel to the bottom of the housing.

[0013] According to one embodiment of the invention, the additional part is circular in shape.

[0014] According to one embodiment of the invention, the additional part is fixed by laser welding, ultrasonic welding, force insertion or gluing to the housing.

[0015] According to one embodiment of the invention, the additional part includes a first fluid inlet conduit disposed on the periphery of the first additional part coaxially to the X axis of the shaft and perpendicular to the printed circuit board of the sensor.

[0016] According to one embodiment of the invention, the first conduit extends to a second conduit formed by the double bottom configured to open into the interior of a shaft of the electric machine motor through a third conduit.

[0017] According to one embodiment of the invention, the first and third conduits are molded, overmolded or fixed by laser welding, ultrasonic welding or bonding.

[0018] The invention also relates to an electrical machine comprising a sensor according to the invention.

[0019] The invention also relates to a mobility device, for example a motor vehicle, comprising an electric machine according to the invention.

[0020] 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:

[0021] - 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,

[0022] - [Fig. 2] is a representation of a bottom view of the sensor according to a mode of realization of the invention with the target,

[0023] - [Fig. 3] is a cross-sectional view of the circulation system fluid and sensor housing according to one embodiment of the invention,

[0024] - [Fig. 4] is an elevational view of the sensor's fluid circulation system according to an embodiment of the invention a) with the conduits, b) without the conduits,

[0025] - [Fig. 5] is an elevational view of the fluid circulation system and the housing of the sensor seen from below according to an embodiment of the invention.

[0026] The invention relates to an inductive position sensor 1, as illustrated in [Fig. 1] to [Fig. 5] incorporating means for circulating the lubricating fluid of an electrical machine.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] The target 2 is mounted on one end of a shaft 22 of the rotor to modify a magnetic field emitted by a transmitter.

[0031] 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.

[0032] 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, then the position sensor 1. These elements are arranged coaxially with the X-axis of the rotor shaft.

[0033] 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

[0034] 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.

[0035] The inductive position sensor 1 comprises 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 target 2, which returns a modified oscillating magnetic field at a given frequency.

[0036] 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 the target 2. The modified oscillating magnetic field generates an electromotive force at a given frequency in the receiver 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 the target 2.

[0037] The inductive position sensor 1 is fixed relative to the stator. The printed circuit board is positioned opposite the target 2.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] According to one embodiment of the invention, the housing 10 is closed by a cover or hood 11. The sensor thus comprises, in order, a cover 11, an electronic circuit board 12 and the bottom of the housing 101.

[0042] According to one embodiment of the invention, the cover 11 is fixed by laser welding.

[0043] 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.

[0044] For this purpose the sensor 1 includes means 105 for circulating a fluid.

[0045] Within the framework of the invention, the means of circulation of a 105 are formed by at less a double bottom 105 of the housing 10 of the sensor 1. This double bottom 105 forms 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.

[0046] According to one embodiment of the invention [Fig. 1], the double bottom 105 is formed by an additional part 105 arranged parallel to the bottom 101 of the housing 10 at a distance DI from the bottom 101 allowing the circulation of the lubricating fluid. distance D1 is determined in such a way as to optimize fluid circulation, and allow for optimized lubrication.

[0047] According to one embodiment of the invention [Fig.3] and [Fig.4], the additional part 105 comprises a flat part 151 parallel to the bottom of the housing 101.

[0048] According to one embodiment of the invention, the additional part 105 is of identical shape to the bottom 101 of the housing 10, and for example circular.

[0049] According to one embodiment of the invention, this additional part 105 is fixed by laser welding, ultrasonic welding, press insertion or gluing.

[0050] According to one embodiment of the invention, the additional part 105 includes a first fluid inlet conduit 16 disposed on the periphery of the first additional part 105. The first conduit 16 is thus disposed coaxially with the X axis of the shaft 22 and perpendicular to the card 12 of the printed circuit of the sensor 1. According to one embodiment of the invention, this conduit 16 is configured to be in communication with a fluid reservoir of the machine.

[0051] According to one embodiment of the invention [Fig.1], 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 first conduit 16 is molded, overmolded or fixed by laser welding, ultrasonic welding or bonding.

[0053] According to one embodiment of the invention, the first conduit 16 extends to a second conduit 17 formed by the double bottom 105. The second end 166 of the first conduit 16 opens into the second conduit 17 for the circulation of the fluid.

[0054] According to one embodiment of the invention, the second conduit 17 is configured to open into the inside of the shaft 22 of the motor by a third conduit 18.

[0055] According to one embodiment of the invention, the third conduit 18 is arranged in the center of the double bottom to coincide with the shaft 22 of the motor.

[0056] According to one embodiment of the invention, the third conduit 18 is molded, overmolded or fixed by laser welding, ultrasonic welding, press fitting or bonding.

[0057] According to one embodiment of the invention, at least one seal is disposed at the inlet and / or outlet of the lubricating fluid, for example at the intersection of the conduits 16, 18 and the double bottom 105.

[0058] According to one embodiment of the invention, the interior of the shaft 22 allows the fluid to be distributed in 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 walls of the shaft. Thus, this configuration prevents the fluid from dispersing directly at the outlet of the reservoir. With such a configuration, the fluid is brought to the center of the rotor shaft and then dispersed through the inside of the rotor, which allows for better lubrication.

[0059] 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.

[0060] Thus such a sensor according to the invention allows optimized lubrication of the elements of the electrical machine.

[0061] 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.

[0062] 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.

[0063] 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 the casing (10) 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 bottom (101) of the housing (10) at a distance (Dl) from the bottom (101) allowing the circulation of the lubricating fluid.

3. Inductive position sensor (1) according to claim 2, wherein the additional part (105) has a portion (151) parallel to the bottom of the housing (101).

4. Inductive position sensor (1) according to claim 2 or 3, wherein the additional part (105) is circular in shape.

5. Inductive position sensor (1) according to any one of claims 2 to 4, wherein the additional part (105) is fixed by laser welding, ultrasonic welding, press fitting or bonding to the housing (10).

6. Inductive position sensor (1) according to any one of claims 2 to 5, wherein the additional part (105) has a first fluid inlet conduit (16) disposed on the periphery of the first additional part (105) coaxially to the X axis of the shaft (22) and perpendicular to the card (12) of the printed circuit of the sensor (1).

7. An inductive position sensor (1) according to claim 6, wherein the first conduit (16) extends to a second conduit (17) formed by the double bottom (105) configured to open into from a shaft (22) of the electric machine motor by a third conduit (18).

8. Inductive position sensor (1) according to claim 7, wherein the first (16) and the third conduit (18) are molded, overmolded or fixed by laser welding, ultrasonic welding or bonding.

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

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

Images