Inductive position sensor with fluid circulation system

Abstract

The invention relates to an inductive position sensor (1) for a rotating electrical machine, comprising: a printed circuit board (12) on which at least one emitting element (13) is arranged, the emitting element being intended to emit an oscillating magnetic field towards a rotating target (2) in order to generate a modified oscillating magnetic field; and at least one receiving device (14) intended to detect a modified oscillating magnetic field, in which the inductive position sensor (1) is configured to allow a fluid to flow into the interior of the rotor shaft (31) of the electric machine (3).

Description

Position sensor with fluid circulation system Technical Field

[0001] This invention relates to the field of position sensors. More specifically, it includes position sensors for fluid circulation systems. Background Technology

[0002] A position sensor, also known as an eddy current sensor, uses a magnetic field to determine the angular position of a rotating target that forms a coupling element.

[0003] These position sensors are particularly useful in electric motors of electric or hybrid vehicles that include a rotor rotating relative to a stator. The angular position of the rotor relative to the stator is determined. A target is mounted at the end of the rotor shaft to modify the magnetic field emitted by the transmitter. The target is centered relative to the rotor's axis of rotation. The target includes multiple blades that provide a repeating and periodic magnetic field pattern relative to the rotor's axis of rotation.

[0004] The position sensor is fixed relative to the stator and faces the target and rotor.

[0005] The position sensor includes a printed circuit board (PCB) comprising at least one emitting element designed to emit an oscillating magnetic field toward a target, thereby generating a modified oscillating magnetic field at a given frequency. The PCB includes a receiving device for detecting the modified oscillating magnetic field and transmitting it to a signal processing unit provided on the PCB to infer the angular position of the target. The sensor is enclosed by a cover and can then be glued, soldered, or clamped to a motor housing.

[0006] The drawback of these existing sensors stems from the fact that they do not allow for motor lubrication and instead require additional external equipment. Summary of the Invention

[0007] Therefore, the present invention aims to overcome one of the shortcomings of the prior art by proposing a position sensor that includes a lubrication system for an electric motor.

[0008] To this end, the present invention proposes a sensing position sensor for a rotating electric motor, comprising a printed circuit board having at least one transmitting element arranged on the printed circuit board for transmitting an oscillating magnetic field toward a rotating target to generate a modified oscillating magnetic field, and at least one receiving device for detecting the modified oscillating magnetic field, the sensor being configured to allow fluid circulation into the interior of the motor's rotor shaft.

[0009] According to one embodiment of the present invention, the sensor includes a first channel and a second channel, the first channel being configured to communicate with a fluid container and bring fluid to the second channel, the second channel being formed in the lower part of the sensor body and configured to lead to a rotor shaft.

[0010] According to one embodiment of the invention, the first channel is formed in the sensor body or is an additional element attached to the sensor body by welding, gluing, clamping or any other holding method.

[0011] According to one embodiment of the present invention, the first channel and the second channel are arranged coaxially with the axis of the rotor and perpendicular to the printed circuit board of the sensor.

[0012] According to one embodiment of the invention, the second channel is an open channel for at least a portion of its length, taking the form of a groove in which fluid circulates.

[0013] According to one embodiment of the present invention, the second end of the first channel is open between the lower part of the sensor body and the target, allowing fluid to flow into the second channel by gravity.

[0014] According to a variant of the invention, the first channel extends into the second channel.

[0015] According to one embodiment of the present invention, an extension of the first channel is formed in the lower wall of the sensor body.

[0016] According to one embodiment of the invention, the extension of the first channel is formed by an additional conduit that allows connection between the first channel and the second channel.

[0017] According to one embodiment of the invention, the sensor includes a fluid circulation device to allow fluid to circulate through at least one channel into the interior of the motor's rotor shaft. These devices enable the fluid to be guided and directed into the channels. This prevents fluid dispersion.

[0018] According to one embodiment of the present invention, the sensing position sensor includes a first channel opening between the inner surface of the housing and the target, and a second channel formed by the inner surface of the housing.

[0019] According to one embodiment of the invention, a fluid circulation device is formed on the inner surface of the housing.

[0020] According to one embodiment of the invention, the fluid circulation device is formed by at least one region with a reduced thickness relative to the remaining surface of the housing. This region allows fluid to be guided and directed into channels. This prevents fluid dispersion.

[0021] According to one embodiment of the present invention, the thickness reduction region is arranged at the entrance of the first channel and the entrance of the second channel.

[0022] According to one embodiment of the present invention, the dimensions of the thickness reduction region are calculated to optimize the fluid channel.

[0023] According to one embodiment of the present invention, the thickness reduction region forms a hollow portion with a depth between 0.1 mm and 3 mm.

[0024] According to one embodiment of the invention, the fluid circulation device further includes at least one groove formed on the inner surface of the housing and leading to the thickness reduction region. The presence of at least one groove allows fluid to be guided and directed via the groove to the thickness reduction region and thus to the channel.

[0025] According to one embodiment of the invention, the fluid circulation device further includes an edge disposed at the edge of the region, the edge being opposite to the edge of at least one groove opening. Therefore, fluid arriving at the thickness reduction region via the groove and the first channel is contained within the region due to the edge or lower wall and discharged toward the second channel.

[0026] The present invention also relates to a motor including a sensor according to the present invention. Attached Figure Description

[0027] Other objects, features, and advantages of the invention will be better understood and will become more apparent from the following description with reference to the accompanying drawings, which are given by way of example, wherein:

[0028] [Figure 1] is an illustration of a sensor according to the invention, fixed to the first side of a motor.

[0029] [Figure 2] is an illustration of the sensor according to the invention based on the second side.

[0030] [Figure 3] is an illustration of a sensor with a target according to the present invention.

[0031] [Figure 4] is a schematic longitudinal cross-sectional view of a motor having a sensor according to one embodiment a) and another embodiment b) of the present invention.

[0032] [Figure 5] is an illustration of a sensor with a plug according to the present invention.

[0033] [Figure 6] is a longitudinal cross-sectional view of the sensor according to the first variant of the present invention.

[0034] [Figure 7] is a top view of the sensor according to the first variant of the present invention.

[0035] [Figure 8] is a longitudinal cross-sectional view of the sensor according to a second variant of the present invention.

[0036] [Figure 9] is a detailed illustration of a sensor according to a second variation of the present invention.

[0037] [Figure 10] is a detailed illustration of a sensor according to a second variant of the present invention.

[0038] [Figure 11] is a longitudinal cross-sectional view of a sensor according to a second embodiment of a second variant of the present invention.

[0039] [Figure 12] is a detailed illustration of a sensor according to an embodiment of the present invention.

[0040] [Figure 13] is a schematic diagram of a sensor with different thickness reduction regions according to an embodiment of the present invention. Detailed Implementation

[0041] The present invention relates to a position sensor 1, as shown in [Figure 1] to [Figure 3], which integrates a motor lubrication system.

[0042] The sensing position sensor 1 uses a magnetic field to determine the angular position of the rotating target 2, which is used as a coupling element and is visible in [Figure 2].

[0043] The sensing position sensor 1 and the target are intended to be installed in a rotating motor 3 shown in [Figures 4]a and b, such as the motor of an electric or hybrid vehicle, which includes a rotor 32 that rotates relative to a stator 33. The angular position of the rotor 32 is determined relative to the stator 33.

[0044] According to one embodiment of the invention, the sensor is fixed to the cover of the motor by a screw-type fixing system 19.

[0045] As shown in [Figure 4]a and b, target 2 is mounted on one end of shaft 31 of rotor 32 to modify the magnetic field emitted by the transmitter.

[0046] According to one embodiment of the invention, target 2 includes a rotation axis X aligned with the rotation axis of rotor 32. Target 2 includes a plurality of blades 21 that provide a repeating and periodic magnetic field pattern relative to the rotation axis of the rotor.

[0047] According to one embodiment of the invention, sensor 1 is arranged to face target 2 at the end of rotor shaft 31. More specifically, position sensor 1 is fixedly mounted relative to stator 33, facing target 2 at the end of rotor shaft 31.

[0048] Therefore, for positioning on the shaft, there is a rotor 32 / stator 33, then a target 2, and then a position sensor 1. These components are arranged coaxially with the axis X of the rotor shaft.

[0049] According to one embodiment of the invention, the sensor 1 is through, that is, the rotor shaft 31 passes through the center of the sensor [Fig. 4a].

[0050] According to one embodiment of the invention, sensor 1 is non-through, that is, it is arranged at the end of the rotor shaft 31 [Fig. 4b].

[0051] The sensing position sensor 1 includes at least one printed circuit board 12 (referred to as PCB) which includes at least one emitting element 13 designed to emit an oscillating magnetic field toward a target 2, which returns the modified oscillating magnetic field at a given frequency.

[0052] The printed circuit board 12 includes a receiving device 14 for detecting a 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 of a given frequency in the receiving device 14. This electromotive force is processed by the signal processing unit 6 to provide an output signal that allows the position of the target 2 to be measured. A position sensor 1 is fixedly mounted relative to the stator 33. The transmitting element 13 and the receiving device 14 of the position sensor 1 are positioned facing the target 2.

[0053] According to one embodiment of the invention, the receiving device 14 includes a plurality of windings and has a circular cross-section, more precisely, an annular shape.

[0054] According to one embodiment of the invention, the number of windings in the receiving device 14 is proportional to the number of blades 21 (or corner sectors) in the target 2. According to one embodiment of the invention, the target 2 includes at least two corner sectors 21, such as 3, 4, 5, or 6 corner sectors.

[0055] The printed circuit board 12, the transmitting element 13, and the receiving device 14 are housed in at least one housing 10 and supported by the base of the housing 10. The housing forms the body 10 of the sensor 1.

[0056] According to one embodiment of the present invention, the signal processing unit 6 is positioned on the same substrate as the transmitting and receiving elements or on another substrate and is housed in a housing.

[0057] According to one embodiment of the invention, the housing 10 is closed by a cover 11. In the context of the invention, the sensor 1 is configured to allow fluid circulation into the interior of the shaft 31 of the rotor 32.

[0058] For this purpose, sensor 1 includes a first fluid inlet channel 16. The channel 16 is configured to communicate with fluid container 4.

[0059] According to one embodiment of the invention, the first channel 16 is formed in the body 10 of the sensor 1. In this case, the sensor 1 includes a plug 15 to seal the opening formed in the body of the sensor 1 during the creation of the first channel [FIG. 5].

[0060] According to one embodiment of the invention, the first channel 16 is an additional element that is connected to the sensor body by welding, gluing, clamping or any other holding method.

[0061] According to one embodiment of the present invention, the first channel 16 is arranged coaxially with the axis X of the rotor and perpendicular to the printed circuit board 12 of the sensor 1.

[0062] According to one embodiment of the present invention [FIG. 6], the first channel 16 opens from the body of the sensor 1 through an opening at its first end 165, which is configured to be positioned at the fluid container 4 to receive fluid from the container by gravity.

[0063] According to one embodiment of the invention, sensor 1 includes a second channel 17 formed by the lower portion of the body of sensor 1. The lower portion is the portion on which a printed circuit board rests, opposite to the upper portion, which is open and has a cover positioned thereon. More specifically, the second channel is formed by the inner surface 101 of housing 10 facing machine 3.

[0064] According to one embodiment of the present invention, the second channel 17 is molded or coated with the housing 10.

[0065] According to one embodiment of the invention, the second channel 17 is arranged parallel to the rotor axis X, and therefore parallel to the first channel 16.

[0066] According to a second variation of the invention, the first channel 16 extends into the second channel 17.

[0067] According to one embodiment of the invention, the second channel 17 is an open channel in the form of a groove for at least a portion of its length. That is, it forms a U-shape or any other equivalent shape in which fluid circulates [Fig. 9].

[0068] According to one embodiment of the present invention, the longitudinal opening of the channel is oriented toward the first channel.

[0069] According to one embodiment of the invention, the second channel 17 is configured to lead into the shaft 31 of the rotor 32. The shaft 31 of the rotor 32 includes an opening 34, which allows fluid circulating in the second channel 17 to be distributed in the motor 3 through the center of the axis X of the rotor shaft due to centrifugal force pushing the fluid against the shaft wall.

[0070] Therefore, this configuration prevents the fluid from dispersing directly at the container outlet. With the configuration of this invention, the fluid is brought to the center of the rotor shaft and then dispersed through the interior of the rotor, allowing for better lubrication.

[0071] According to a first variant of the invention, the second end 166 of the first channel 16 opens between the lower part of the sensor body 10 and the target 2. Therefore, fluid can flow from the first channel 16 to the second channel 17 by gravity, circulating between the lower part of the sensor body and the target.

[0072] According to one embodiment of the invention, the second end 166 of the first channel 16 is close enough to the lower wall of the sensor body 1 so that fluid flows along the wall without being discharged into the entire compartment by the rotating target 2.

[0073] According to one embodiment of the present invention, fluid bypasses the target through a channel, such that the fluid flow in the first channel is not disturbed by the rotational speed of the target.

[0074] The advantage of this variant stems from the reduced distance between the target and the printed circuit board, and the fact that it is completely circular. This allows for a fully cylindrical antenna, which maintains good signal accuracy even in the event of target jitter.

[0075] According to a second variation of the invention, the first channel extends into the second channel.

[0076] According to the first embodiment of this second variation [Fig. 8], the extension 162 of the first channel is formed in the lower wall of the sensor body. More precisely, the extension 162 of the first channel is formed in the thickness of the lower wall of the sensor body.

[0077] The advantage of this variant in this embodiment stems from the reduced distance between the target and the printed circuit board. This is one of the important standards for signal accuracy.

[0078] According to one embodiment of the invention, the extension 162 of the first channel 16 forms a protrusion 161 at the opposite surface of the visible printed circuit board [FIG. 7], and the interior 164 of the extension 162 of the first channel 16 is visible [FIG. 10].

[0079] According to one embodiment of the invention, the connection between the first channel 16 and the extension 162 of the first channel is formed by a visible additional portion 168 [FIG. 9], which allows fluid 163 to enter the extension.

[0080] According to one embodiment of this second variation, the extension 162 of the first channel is formed by an additional conduit arranged in the thickness of the body 10 of the sensor 1.

[0081] According to one embodiment of the present invention, the extension 162 of the first channel 16 leads to the second channel 17.

[0082] According to a second embodiment of this second variation, the extension 162 of the first channel is formed by an additional conduit 18 [FIG. 11]. This additional conduit 18 allows connection between the first channel 16 and the second channel 17. According to one embodiment of the invention, the additional conduit 18 is arranged between the body 10 of the sensor 1 and the target 2.

[0083] This allows for fully cylindrical antennas 13 and 14, which ensures good signal accuracy even in the event of target jitter.

[0084] In the context of this invention, the inner surface 101 of the housing 10 includes a visible fluid circulation device 180 [FIG. 12].

[0085] According to one embodiment of the invention, the fluid circulation device 180 is formed at least by a thickness-reduced region 181 compared to the rest of the housing surface. This thickness-reduced region 181 is arranged at the arrival point of the first channel 16 and the inlet of the second channel 17 of the fluid circulation device 180. More specifically, the inner surface 101 of the housing 10 includes the region 181, which forms a hollow portion between the arrival point of the first channel 16 and the inlet of the second channel 17.

[0086] According to one embodiment of the present invention, the dimensions of the thickness reduction region 181 are calculated to optimize the fluid channel.

[0087] [Figure 13] a), b) and c) show the different dimensions of the thickness reduction region 181.

[0088] According to one embodiment of the invention, the thickness reduction region 181 forms a hollow portion, the depth of which is between 0.1 mm and 3 mm, for example 0.5 mm.

[0089] This area allows fluid to be guided and directed from the first channel 16 to the second channel 17. This prevents fluid dispersion, as shown in [Figure 13].

[0090] In the context of this invention, the fluid circulation device 180 further includes at least one groove 182 formed on the inner surface 101 of the housing. The groove has an incompletely circular shape and leads to the thickness reduction region 181.

[0091] According to one embodiment of the present invention, the sensor includes at least two recesses 182, for example, three recesses 182.

[0092] According to one embodiment of the invention, the grooves are spaced apart from each other.

[0093] According to one embodiment of the invention, the grooves are arranged in a spiral shape.

[0094] As target 2 rotates, the direction of rotation C is indicated by the arrow in [Figure 13], and at least a portion of the fluid arriving from conduit 16 is dispersed in the region between the inner surface of the target and the housing. The presence of at least one groove allows the fluid (arrow F) to be guided and directed via the groove to the region of reduced thickness and thus to the second channel 17.

[0095] In the context of this invention, according to one embodiment of the invention, the fluid circulation device 180 further includes an edge 183 disposed at the edge of the region, opposite to the edge of at least one recess 182 opening.

[0096] According to one embodiment of the invention, the edge forms a lower wall with a height between 0.1 and 3 mm, for example 0.5 mm.

[0097] Therefore, the fluid that reaches the thickness reduction region 181 via the groove and the first channel 16 is contained in the region 181 due to the edge or lower wall, and is discharged toward the second channel 17.

[0098] The advantage of these fluid circulation devices 180 is that they can reduce the distance between the target and the printed circuit board, which is one of the important standards for signal accuracy.

[0099] These devices also allow for fully cylindrical antennas 13 and 14, which enables good signal accuracy even in the event of target hopping.

[0100] According to one embodiment of the invention, the fluid is oil, more specifically lubricating oil. The circulation of the oil via the shaft allows for the lubrication of the motor 3, and more specifically, the pinion 5 of the motor 3. Therefore, this sensor according to the invention allows for the lubrication of motor components without the need for an additional system.

[0101] According to two variations, the present invention also relates to a motor 3, which includes the sensor 1 as described above.

[0102] The scope of this invention is not limited to the details given above, and many other specific embodiments are permitted without departing from the scope of application of this invention. Therefore, this embodiment should be considered illustrative and modifications can be made without departing from the scope defined by the claims.

Claims

1. A position sensor (1) for a rotating electric motor, comprising a printed circuit board (12) on which at least one transmitting element (13) and at least one receiving device (14) are arranged, the at least one transmitting element (13) being intended to emit an oscillating magnetic field toward a rotating target (2) to generate a modified oscillating magnetic field, the at least one receiving device (14) being intended to detect the modified oscillating magnetic field, characterized in that, The sensing position sensor (1) is configured to allow fluid to circulate into the interior of the rotor shaft (31) of the motor (3).

2. The position sensor (1) according to claim 1, comprising a first channel (16) and a second channel (17), the first channel (16) being configured to communicate with a fluid container (4) and to bring fluid to the second channel (17), the second channel (17) being formed from the lower part of the sensor body and configured to lead to the rotor shaft (31).

3. The position sensor (1) according to claim 1 or 2, wherein, The first channel (16) is formed in the sensor body or is an additional element attached to the sensor body by welding, gluing, clamping or any other holding method.

4. The position sensor (1) according to any one of claims 1 to 3, wherein, The first channel (16) and the second channel (17) are arranged parallel to the rotor axis (X) and perpendicular to the printed circuit board (12) of the sensor.

5. The position sensor (1) according to any one of claims 1 to 4, wherein, The second channel (17) is an open channel for at least a portion of its length, in the form of a groove in which the fluid circulates.

6. The position sensor (1) according to any one of claims 1 to 5, wherein, The second end (165) of the first channel is open between the lower part of the sensor body and the target (2), allowing the fluid to flow into the second channel (17) by gravity.

7. The position sensor (1) according to any one of claims 1 to 5, wherein, The first channel (16) extends into the second channel (17).

8. The position sensor (1) according to claim 7, wherein, An extension (162) of the first channel (16) is formed in the lower wall of the sensor body.

9. The position sensor (1) according to claim 7, wherein, An extension (162) of the first channel is formed by an additional conduit (18) that allows connection between the first channel and the second channel.

10. An electric motor comprising a sensor according to any one of claims 1 to 9.

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