Improved inductive position sensor

Abstract

The present invention relates to an inductive position sensor (1) for a rotary electric machine, comprising a printed circuit board (10) which has two substrates (101, 102) and on which at least one transmitting antenna (11) for transmitting an oscillating magnetic field towards a coupling element (20) that is rotating in order to generate a modified magnetic field and at least one receiving antenna (12) for detecting the modified magnetic field are arranged, at least one receiving antenna (12) is arranged within at least one transmitting antenna (11), at least one signal processing unit (13) is positioned within a transmitting antenna (11) and / or a receiving antenna (12), at least one element (14) for connecting at least one transmitting antenna (11) to at least one signal processing unit (13) passes through a receiving antenna region (12) without intersecting a receiving antenna.

Description

[0001] Description

[0002] Title of the invention: Improved inductive position sensor The present invention relates to the field of position sensors, and more particularly to an inductive position sensor.

[0003] Inductive position sensors, also known as eddy current sensors, use an oscillating magnetic field to determine the angular position of a rotating target that forms a coupling element.

[0004] These position sensors are notably used in the electric motors of electric or hybrid vehicles comprising a rotor rotating relative to a stator.

[0005] The angular position of the rotor is determined relative to the stator. The target is mounted at the end of, or through, a shaft of the rotor to modify an oscillating magnetic field transmitted by a transmitter. The target is centered about an axis of rotation of the rotor. The target comprises several vanes that provide a magnetic field pattern about the axis of rotation of the rotor.

[0006] The position sensor is fixed relative to the stator, facing the target and around or facing the end of the rotor. The position sensor comprises a printed circuit board (PCB) containing at least one emitting element designed to emit an oscillating magnetic field towards the target, generating a modified oscillating magnetic field at a given frequency.

[0007] The printed circuit board includes at least one receiver device for detecting the modified oscillating magnetic field and transmitting it to a signal processing unit located on the printed circuit board to determine the angular position of the target. The printed circuit board also includes openings for connecting wires or metallic elements.

[0008] In general, the number of windings in a receiving element is proportional to the number of angular sectors in the target. At least one transmitting element defines a concentric circular area with a circular area defined by at least one receiving element, and at least one signal processing unit is located outside the circular areas. Such a sensor is bulky. To overcome space constraints, it is possible to place all or part of the signal processing unit inside the circular areas.

[0009] One disadvantage of this type of sensor is that the linking element necessarily passes above or below the receiving device, and must not be in contact with the latter, which is not possible for sensors with only two layers of substrate forming the electronic board, because these layers are already used for the receiving device.

[0010] The present invention therefore aims to overcome one of the drawbacks of those of the prior art by proposing a position sensor whose configuration is improved to limit disturbances and improve performance.

[0011] To this end, the present invention proposes an inductive position sensor for a rotating electrical machine comprising a printed circuit board, with two substrates, on which are arranged at least one transmitting antenna intended to emit an oscillating magnetic field towards a rotating coupling element to generate a modified magnetic field, and at least one receiving antenna intended to detect the modified magnetic field, at least one receiving antenna is arranged inside at least one transmitting antenna, the signal processing unit is placed inside one of the transmitting and / or receiving antennas, at least one linking element from at least one transmitting antenna to at least one signal processing unit passes through a receiving antenna area without crossing a receiving antenna.

[0012] It is therefore possible to have a sensor with two substrate layers and the signal unit inside the antennas without overlap of the linking elements with the antennas, which reduces the size of the sensor.

[0013] The expression "without crossing" here means without direct overlap of one by the other, without direct contact. In other words, the linking element is not in direct contact with a portion of the receiving antenna.

[0014] According to one embodiment of the invention, the connecting element runs along a portion of the receiving antenna.

[0015] According to one aspect of the invention, the connecting element comprises at least one portion which runs along a portion of the receiving antenna.

[0016] According to one aspect of the invention, the receiving antenna area is delimited between at least two receiving antenna portions. According to another aspect of the invention, the linking element, in particular at least a portion of the linking element, extends from a transmitting antenna to the signal processing unit within a receiving antenna area delimited by at least two receiving antenna portions. In other words, at least two receiving antenna portions are arranged on either side of the linking element, in particular at least a portion of the linking element, said linking element extending from a transmitting antenna to the signal processing unit.

[0017] According to one embodiment of the invention, at least one linking element is connected to the transmitting antenna at one end, and to the signal processing unit at another end, passing over a single substrate layer.

[0018] According to one embodiment of the invention, a first substrate layer comprises at least one portion of a transmitting antenna disposed at the periphery and a second substrate layer comprises at least another portion of a transmitting antenna disposed at the periphery.

[0019] According to one embodiment of the invention, a first substrate layer comprises at least two portions of a transmitting antenna arranged at the periphery and a second substrate layer comprises at least one other portion of a transmitting antenna arranged at the periphery and the second substrate layer comprises two interlocking circular transmitting antenna portions arranged without crossing each other.

[0020] According to one embodiment of the invention, at least one linking element of at least one transmitting antenna to at least one signal processing unit comprises a portion parallel to a portion of a receiving antenna.

[0021] According to one embodiment of the invention, two connecting elements each comprise a portion parallel to a portion of receiving antennas.

[0022] According to one embodiment of the invention, the transmitting antennas are configured to bypass elements such as vias, receiving antennas, or the elements connecting the transmitting antennas to the signal processing unit.

[0023] The invention also relates to an electrical machine comprising a sensor according to the invention.

[0024] According to one embodiment of the invention, the rotating electric machine is an electric motor of an electric or hybrid vehicle comprising a rotor rotating relative to a stator. The invention also relates to the use of the sensor according to the invention to measure the angular position of a rotor relative to a stator of an electric machine.

[0025] 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, which are given by way of example and in which:

[0026] - Figure 1 is a schematic elevation representation of a sensor according to the invention without a cover,

[0027] - Figure 2 is a representation of a bottom view of the sensor according to an embodiment of the invention with the target,

[0028] - Figure 3 is a schematic elevational representation of a longitudinal section of the sensor according to an embodiment of the invention.

[0029] - Figure 4 is a schematic elevation representation of a sensor according to the invention with a cover,

[0030] - Figure 5 is a schematic elevation representation of a sensor according to the invention with a shielding element,

[0031] - [Fig. 6] is a schematic representation of a first layer a) and a second layer b) of the printed circuit board with a sensor transmitting antenna according to an embodiment of the invention,

[0032] - [Fig. 7] is a schematic representation of a first layer a) and a second layer b) of the printed circuit board with two sensor transmission antennas according to an embodiment of the invention,

[0033] - [Fig. 8] is a schematic representation of part of a layer of the sensor's printed circuit board according to an embodiment of the invention.

[0034] The invention relates to an inductive position sensor 1, as illustrated in [Fig. 1] to [Fig. 4]. The inductive position sensor 1, associated with a coupling element 20 [Fig. 2], is intended to be mounted in a rotating electrical machine 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.

[0035] The sensor includes an electronic circuit board 10 on which are arranged at least one transmitting antenna 11, at least one receiving antenna 12 and at least one signal processing unit 13. According to one embodiment of the invention, at least one receiving antenna 12 is arranged inside at least one transmitting antenna 11.

[0036] During sensor operation, at least one transmitting antenna 11 emits an oscillating magnetic field at a given frequency. A coupling element 20 is positioned to modify this magnetic field. According to one embodiment of the invention, the coupling element 20 is mounted on one end of a rotor shaft to modify the magnetic field emitted by the transmitting antenna 11. The modified magnetic field generates an electromotive force in the receiving element 12. This electromotive force is processed by the signal processing unit 13 to provide output signals for measuring the position of the coupling element 20.

[0037] According to one embodiment of the invention, the coupling element 20 is a rotating element, for example with the rotor of the electric motor.

[0038] According to one embodiment of the invention, the electronic circuit board 10 has openings 15 allowing connection to wires or metallic connecting elements. According to another embodiment of the invention, the number of windings of at least one receiving element 12 is proportional to the number of angular sectors of the casting element 20.

[0039] According to one embodiment of the invention, the electronic card 10 consists of two substrate layers 101, 102, visible [Fig. 6] and [Fig. 7],

[0040] According to one embodiment of the invention, the links between the transmitting antenna 11 and receiving antenna 12 and at least one signal processing element 13 are made with linking elements 14.

[0041] According to one embodiment of the invention, the electronic circuit board 10 is arranged in a plastic case 30.

[0042] According to one embodiment of the invention, the electronic circuit board 10 is fixed to the housing 30 by fastening elements 310.

[0043] According to one embodiment of the invention, the signal processing unit 13 is placed inside the transmitting and / or receiving antenna area.

[0044] According to one embodiment of the invention, the openings 15 are also placed inside the transmitting and receiving antenna area.

[0045] According to one embodiment of the invention, the openings 15 are intended to be connected to metallic connecting elements, for example metallic connecting grids 16 overmolded in the plastic housing 30 [Fig. 3]. The connection between the connecting grids 16 and the openings 15 is, for example, brazing, welding, or a contact solution of the pressure-fit type.

[0046] The 16 metal connection grids allow an electrical connection between the electronic circuit board 10 and at least one connector 35.

[0047] According to one embodiment of the invention, the plastic housing includes one or more fastening means 31, 32, 33 allowing the sensor to be fixed, for example by screwing, onto the interface of an electric motor.

[0048] According to one embodiment of the invention, the plastic housing 30 has one or more holes 34 allowing angular indexing of the sensor on the interface of the electric motor. According to one embodiment of the invention [Fig. 4], a cover 50 closes the opening of the sensor through which the printed circuit board 10 is inserted. This cover 50 makes the sensor 50 watertight. According to one embodiment of the invention, this cover 50 can be glued or soldered to the plastic housing 30.

[0049] According to another embodiment of the invention, the cavity in which the printed circuit board 10 is inserted is sealed by depositing resin in this cavity. The resin is deposited so as to completely enclose and cover the printed circuit board. Thus, the printed circuit board is not in contact with the external environment.

[0050] According to another embodiment of the invention, a shielding element 60 [Fig. 5] is assembled onto the plastic housing 30, on the outer part of the electric motor. The objective is to protect the sensor from external interference, but also to ensure electrical continuity between the metal housing of the electric motor and the shielding element, in order to ensure that the motor assembly acts as a Faraday cage.

[0051] In the context of the invention, the printed circuit board thus comprises 2 superimposed layers of substrates 101, 102.

[0052] According to one embodiment of the invention, a first substrate layer 101 comprises at least one portion of a transmitting antenna 111 arranged helically around its periphery [Fig. 6] a). According to one embodiment of the invention, the first substrate layer 101 comprises two interlocking circular transmitting antenna portions 111, 113 arranged helically around its periphery without crossing each other [Fig. 6] a) and [Fig. 7] a). According to one embodiment of the invention, a second substrate layer 102 comprises at least one portion of a transmitting antenna 112 arranged helically around its periphery [Fig. 6] b). According to one embodiment of the invention, the second substrate layer 102 comprises two interlocking circular transmitting antenna portions 112, 114 arranged helically around its periphery without crossing each other [Fig. 6] b) and [Fig. 7] b).

[0053] Thus the sensor has at least one transmitting antenna 11 divided into two portions 111, 112, one portion 111 being on a first substrate 101, a second portion 112 being on a second substrate 102. When the sensor has two transmitting antennas 11, each of the antennas is divided into two portions, two portions 111, 113 being on a substrate 101, two other portions 112, 114 being on a second substrate 102.

[0054] According to one embodiment of the invention, the portions of the same transmitting antenna are connected to each other by conductive vias through the printed circuit board.

[0055] According to one embodiment of the invention, a first substrate layer 101 comprises at least one part of a receiving antenna 121 disposed on a circular portion between the transmitting antenna and the signal processing unit 6 [Fig. 6] a). According to another embodiment of the invention, the first substrate layer 101 comprises two receiving antenna parts 121, 123 disposed on a circular portion between the transmitting antenna and the signal processing unit 6 [Fig. 6] a) and [Fig. 7] a).

[0056] According to one embodiment of the invention, a second substrate layer 102 comprises at least one portion of a receiving antenna 122 disposed on a circular portion between the transmitting antenna and the signal processing unit 6 [Fig. 6] b). According to one embodiment of the invention, the second substrate layer 102 comprises two receiving antenna portions 122, 124 disposed on a circular portion between the transmitting antenna and the signal processing unit 6 [Fig. 6] b) and [Fig. 7] b).

[0057] Thus the sensor comprises at least one receiving antenna 12 divided into two parts 121, 122, one part 121 being on a first substrate 101, a second part 122 being on a second substrate 102. When the sensor comprises two receiving antennas 12, each of the antennas is divided into two parts, two parts 121, 123 being on a substrate 101, two other parts 122, 124 being on a second substrate 102. Each substrate thus comprises several receiving antenna parts. According to one embodiment of the invention, the parts are formed by several portions, for example 121a, 121b, 121c arranged radially [Fig. 6] a) In the context of the invention, at least one linking element 14 from at least one transmitting antenna 11 to at least one signal processing unit 13 passes through the receiving antenna area 12.To achieve this, the linking element 14, or in particular a portion of it, runs alongside a portion of the receiving antenna 121, 122, 123, 124 without crossing that same portion of the receiving antenna. The expression "without crossing" here means without direct overlap, without direct contact. In other words, the linking element is not in direct contact with the portion of the receiving antenna.

[0058] Thus, one end of at least one linking element 14 is connected to the transmitting antenna by one end, and to the signal processing unit 13 by another end, passing over a single substrate layer between two receiving antenna portions.

[0059] The receiving antenna area is specifically delimited between at least two receiving antenna sections.

[0060] For example, the linking element, in particular at least a portion of the linking element, extends from a transmitting antenna to the signal processing unit in a receiving antenna area delimited by at least two receiving antenna portions.

[0061] In other words, at least two receiving antenna portions are arranged on either side of the linking element, in particular at least one portion of the linking element, said linking element extending from a transmitting antenna to the signal processing unit.

[0062] According to one embodiment of the invention, the sensor comprises two linking elements 14, 18 each connecting a transmitting antenna 11 to at least one signal processing unit 13 and passing through the receiving antenna area 12.

[0063] According to one embodiment of the invention, at least one linking element 14, 18 of at least one transmitting antenna to at least one signal processing unit comprises a portion 14a, 18a parallel to a portion of the receiving antenna.

[0064] According to one embodiment of the invention, two connecting elements 14, 14', 18, 18' each comprise a portion 14a, 18a parallel to a portion of the receiving antenna. In this case, the portions 14a, 18a, 14'a, 18'a of the connecting elements are arranged on either side of the portion of the receiving antenna [Fig. 6] a) and [Fig. 7] a).

[0065] According to one embodiment of the invention, a linking element 14', 18' of a first substrate 101 connects a transmitting antenna of a second substrate 102 to at least one signal processing unit 13. According to one embodiment of the invention [Fig. 8], the transmitting antennas are configured to bypass elements such as vias, receiving antennas, or the linking elements of the transmitting antennas to the signal processing unit. In this case, the circular shape of the transmitting elements is locally modified to bypass these elements [Fig. 8].

[0066] The invention also relates to an electrical machine comprising a sensor according to the invention.

[0067] According to one embodiment of the invention, the rotating electric machine is an electric motor of an electric or hybrid vehicle comprising a rotor rotating relative to a stator.

[0068] The invention also relates to the use of the sensor according to the invention to measure the angular position of a rotor relative to a stator of an electrical machine.

[0069] The invention also relates to an electric or hybrid vehicle comprising an electric machine including a sensor according to the invention.

[0070] 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 illustrative only and may be modified without departing from the scope defined by the claims.

Claims

DEMANDS 1. Inductive position sensor (1) for rotating electrical machine comprising a printed circuit board (10), with two substrates (101, 102), on which are disposed at least one transmitting antenna (11) for emitting an oscillating magnetic field towards a rotating coupling element (20) to generate a modified magnetic field, and at least one receiving antenna (12) for detecting the modified magnetic field, at least one receiving antenna (12) is disposed inside at least one transmitting antenna (11), at least one signal processing unit (13) is placed inside one of the transmitting antennas (11) and / or receiving antennas (12) characterized in that at least one linking element (14) from at least one transmitting antenna (11) to at least one signal processing unit (13) passes through a receiving antenna area (12) without crossing a receiving antenna.

2. Inductive position sensor (1) according to claim 1, in which the linking element (14) runs along a portion of the receiving antenna (12).

3. Inductive position sensor (1) according to claim 1 or 2, wherein at least one linking element (14) is connected to the transmitting antenna (11) by one end, and to at least one signal processing unit (13) by another end, passing over a single substrate layer (101).

4. Inductive position sensor (1) according to any one of claims 1 to 3, wherein a first substrate layer (101) comprises at least one portion of a transmitting antenna (111) disposed at the periphery and a second substrate layer (102) comprises at least another portion of a transmitting antenna (112) disposed at the periphery.

5. Inductive position sensor (1) according to any one of claims 1 to 4, in which a first substrate layer (101) comprises at least two portions of a transmitting antenna (111) arranged at the periphery and a second substrate layer (102) comprises at least one other portion of a transmitting antenna (112) arranged at the periphery and the second substrate layer (102) comprises two interlocking circular transmitting antenna portions (112, 114) arranged without crossing each other.

6. Inductive position sensor (1) according to any one of claims 1 to 5, wherein at least one linking element (14, 18) of at least one transmitting antenna (11) to at least one signal processing unit (13) comprises a portion (14a, 18a) parallel to a portion of the receiving antenna.

7. Inductive position sensor (1) according to any one of claims 1 to 6, in which two linking elements (14, 14', 18, 18') each comprise a portion (14a, 18a) parallel to a portion of receiving antennas.

8. Inductive position sensor (1) according to any one of claims 1 to 7, wherein the transmitting antennas (11) are configured to bypass elements such as vias, receiving antennas or elements connecting the transmitting antennas to the signal processing unit 9. Electric machine comprising a sensor (1) according to any one of claims 1 to 8.

10. Electric machine comprising a sensor (1) according to any one of claims 1 to 8, wherein the rotating electric machine is an electric or hybrid vehicle electric motor comprising a rotor rotating relative to a stator.

Images