Coupling element for an improved position sensor

Abstract

The invention relates to a coupling element (20) for an inductive position sensor for an electrical machine, consisting of a stamped metal part having openings (25). The invention also relates to an electrical machine comprising such a coupling element.

Description

[0001] Description

[0002] Title of the invention: Coupling element for improved position sensor The present invention relates to a coupling element for a position sensor. This sensor is intended to measure the position of a rotating element, for example a shaft, and more precisely a rotor relative to a stator of an electrical machine used in a mobility device of the electric vehicle or electrically assisted bicycle type.

[0003] The sensor accurately measures the angular position of the shaft to optimize the operation of the machine. For this purpose, the sensor accurately detects the position of the coupling element arranged on the shaft.

[0004] Eddy current position sensors are traditionally composed of an electronic board on which are arranged at least one transmitting antenna, at least one receiving element and at least one signal processing unit. The transmitting antenna emits a magnetic field oscillating at a certain frequency. A coupling element is positioned so as to modify this magnetic field. The modified magnetic field generates an electromotive force in the receiving element. This electromotive force is processed by the signal processing unit so as to provide output signals allowing the measurement of the position of the coupling element.

[0005] Usually the coupling element is a rotating element, for example with the rotor of the electric motor, made of sintered metal and / or machined at the end of the shaft.

[0006] This type of coupling element is heavy and the installation process on the shaft is expensive. The present invention therefore aims to overcome one or more of the disadvantages of the assemblies of the prior art by proposing an improved coupling element for a position sensor.

[0007] For this purpose, the present invention proposes a coupling element, for a position sensor using inductive technology for an electrical machine, composed of a stamped metal part comprising openings.

[0008] The apertures allow for optimization of eddy currents and allow for improved sensor performance.

[0009] According to one embodiment of the invention, the openings are formed by cutting the metal part. According to one embodiment of the invention, the coupling element comprises a closed tubular zone from which at least two branches extend, meeting at the center of the area of ​​the zone.

[0010] The openings allow for optimization of eddy currents in each branch of the coupling element when the inductive technology position sensor is in operation. This operating mode allows for improved sensor performance.

[0011] According to one embodiment of the invention, the junction of the branches forms a solid circle. According to one embodiment of the invention, the branches are formed from the closed tubular area, extend in the plane of the area, then are curved and join. According to one embodiment of the invention, the openings are formed by the non-contiguous branches.

[0012] According to one embodiment of the invention, the coupling element comprises four branches, forming four openings.

[0013] According to one embodiment of the invention, the junction of the branches forms a first plane PI, the base of the openings forms a second plane P2 parallel to the first plane PI, the two planes PI and P2 being separated by a distance d of at least 1 min.

[0014] The invention also relates to an electrical machine comprising a coupling element according to the invention.

[0015] The invention also relates to the use of the coupling element according to the invention in a gearbox.

[0016] Other aims, characteristics and advantages of the invention will be better understood and will appear more clearly on reading the description given below, with reference to the appended figures, given by way of example and in which:

[0017] - [Fig. 1] is a schematic illustration of the sensor with the coupling element according to the invention,

[0018] - [Fig. 2] is an elevation view of the coupling element according to a variant of the invention,

[0019] - [Fig. 3] is an elevational view of the coupling element according to another variant of the invention. The invention relates to a coupling element 20 for a position sensor 10 intended to be used with an electric machine or an element of the transmission of a mobility device.

[0020] More specifically, the position sensor 10 is an inductive technology sensor, for measuring the position of a rotating element, for example a shaft of an electrical machine, and more specifically a rotor mounted on a shaft relative to a stator. As illustrated [Fig. 1], the sensor 10 is formed by at least one sensitive element formed by at least one printed circuit board 101 (PCB for Print Circuit Board according to English terminology).

[0021] According to one embodiment of the invention, the sensor 10 is formed by a housing 100 in which is arranged a sensitive element formed by at least one printed circuit board 101 (PCB for Print Circuit Board according to English terminology).

[0022] The card 101 comprises at least one transmitting antenna 111 and at least one receiving element 121, of the receiving antenna type.

[0023] When in use, the card 101 comprising the antennas 111, 121 is thus placed opposite a mobile coupling element 20 arranged on a rotating element 30 so as to be able to determine the position of the rotating element 30.

[0024] According to one embodiment of the invention, the rotating element is the shaft 30 of the electric machine.

[0025] In the context of the invention, the coupling element 20, illustrated [Fig. 2] and [Fig. 3], is arranged at one end 31 of the rotating shaft 30 of the electrical machine.

[0026] The coupling element 20 is composed of a metal part stamped so as to have a shape allowing it to be arranged at the end 31 of the shaft 30.

[0027] Using a stamping process to obtain the coupling element allows a financial gain in the manufacturing process compared to the sintering or machining process of the prior art.

[0028] According to one embodiment of the invention, the coupling element 20 has the shape of a cap comprising openings 25. The openings 25 are formed by cutting out the piece of metal. More precisely, the coupling element comprises a closed tubular zone 21, for example a closed ring 21, from which at least two branches 23 extend, joining at the center of the area of ​​the ring. The junction of the branches forms a solid zone 24. The branches 23 are formed from the tubular zone 21, extend in the plane of the tubular zone or ring 21, then are curved and join together. The branches 23 are not contiguous, they are separated by a space 25 thus making it possible to form the openings 25.

[0029] More precisely, the junction of the branches forms a first plane PI, the base of the openings forms a second plane P2 parallel to the first plane PI, the two planes PI and P2 are arranged one above the other and are separated by a distance d of at least 1 mm. According to one embodiment of the invention, the two planes are separated by at least 2 mm. According to one embodiment of the invention, the two planes are separated by 2 mm. This allows a better distribution of the eddy currents and improves the performance of the sensor.

[0030] According to one embodiment of the invention, the coupling element 20 comprises four branches 23. These four branches 23 thus form four openings 25.

[0031] The openings 25 make it possible to optimize the eddy currents in each branch 23 of the coupling element 20 when the inductive technology position sensor 10 is in operation. This mode of operation allows an improvement in the performance of the sensor.

[0032] According to one embodiment of the invention, the coupling element 20 comprises as many branches 23 as the electric motor has pairs of poles.

[0033] According to one embodiment of the invention, the surface formed by each branch 23 is identical to the empty surface formed by the openings 25.

[0034] According to one embodiment of the invention, the coupling element 20 is pressed onto the end of the shaft 30 to be held in place. The diameter of the coupling element 20 is thus adapted to allow the positioning of the coupling element 20 on the shaft 30. More precisely, the diameter of the coupling element 20 is greater than that of the shaft to allow the insertion of the end of the coupling element onto the shaft 30.

[0035] According to one embodiment of the invention, the diameter of the coupling element 20 is less than the diameter of the shaft 30. The coupling element is thus pressed onto the end of the shaft, by its internal diameter.

[0036] The invention also relates to the use of the coupling element 20 for a position sensor 10 in an electrical machine used in a mobility device of the electric vehicle, hybrid vehicle or electrically assisted bicycle type. During use, the transmitting antenna emits a magnetic field oscillating at a certain frequency. The coupling element is positioned so as to modify this magnetic field. The modified magnetic field generates an electromotive force in the receiving element. This electromotive force is processed by a signal processing unit so as to provide output signals allowing the measurement of the position of the coupling element. The scope of the present invention is not limited to the details given above and allows embodiments in many other specific forms without departing from the scope of the invention.Therefore, the present embodiments should be considered illustrative, and may be modified without departing from the scope defined by the claims.

Claims

CLAIMS 1. Coupling element (20), for inductive technology position sensor (10) for electric machine, composed of a stamped metal part comprising openings (25).

2. Coupling element (20) according to claim 1, in which the openings (25) are formed by cutting the piece of metal.

3. Coupling element (20) according to one of claims 1 or 2, comprising a closed tubular zone (21) from which at least two branches (23) extend, joining in the center of the area of ​​the zone.

4. Coupling element (20) according to one of claims 1 to 3, in which the junction of the branches forms a solid circle (24).

5. Coupling element (20) according to one of claims 2 to 4, in which the branches (23) are formed from the closed tubular zone (21), extend in the plane of the zone (21), then are curved and join together.

6. Coupling element (20) according to one of claims 2 to 5, in which the openings (25) are formed by the non-contiguous branches (23).

7. Coupling element (20) according to one of claims 2 to 6, comprising four branches (23), forming four openings (25).

8. Coupling element (20) according to one of claims 2 to 7, in which the junction of the branches forms a first plane PI, the base of the openings forms a second plane P2 parallel to the first plane PI, the two planes PI and P2 being separated by a distance d of at least 1 min.

9. Electrical machine comprising a coupling element according to one of claims 1 to 8.

10. Use of the coupling element according to one of claims 1 to 9 in a gearbox.

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