PRINTED CIRCUIT BOARD FOR AN INDUCTIVE SENSOR FOR MEASURING THE ANGULAR POSITION OF A ROTATING MECHANICAL PART

Abstract

One aspect of the invention relates to a printed circuit board 1 for an inductive sensor intended to measure the angular position of a rotating mechanical part, the printed circuit board 1 comprising: At least two secondary windings 3 each consisting of at least one pair of poles 4, the two secondary windings 3 forming a first circular arc 5; andA primary winding 2 comprising a first part 2a forming a second circular arc running along the periphery of the first circular arc 5; The printed circuit board 1 being remarkable in that it is C-shaped and in that the primary winding 2 has a second part 2b for electrically connecting the two ends 6a, 6b of the first part 2a of the primary winding 2. Figure to be published with the abstract: Figure 2A

Description

Title of the invention: PRINTED CIRCUIT BOARD FOR AN INDUCTIVE POSITION MEASURING SENSOR ANGULAR OF A ROTATING MECHANICAL PART TECHNICAL FIELD OF THE INVENTION

[0001] The field of the invention is that of detecting the position of a moving mechanical structure, for example a rotor of a rotating electrical machine, using a target mounted integrally with said rotor.

[0002] The invention relates more particularly to a printed circuit board for an inductive angular position sensor, configured to measure a position of a rotating mechanical part, in particular, but not exclusively, of a rotor of a rotating electrical machine. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] In a manner known per se, angular inductive sensors have a structure similar to that of linear inductive sensors: they comprise a fixed part, called a “transformer” comprising a fixed primary winding and at least two fixed secondary windings, and a mobile part constituted by a metal target which is rigidly connected to the mechanical part to be angularly controlled.

[0004] The fixed primary winding and the fixed secondary windings are usually produced on a printed circuit board, and each consists of electrically conductive tracks traced on the printed circuit board.

[0005] The operating principle of such a sensor is based on the variation in coupling between the primary winding and the secondary windings, together forming a transformer operating at high frequency. In use, currents induced in the target modify voltages induced in the secondary windings by the primary winding. In other words, the coupling between the primary and secondary windings varies depending on the position of the target. By adapting the configuration of the windings and, where appropriate, knowing the current injected into the primary winding, measuring the voltage induced in the secondary windings makes it possible to determine the position of the target.

[0006] When the inductive sensor is an angular position measuring sensor, it is known to arrange the primary and secondary windings on a disc-shaped printed circuit board. An example of such a sensor is described for example in patent application US 2014 / 0167788 AL

[0007] Figures 1A and 1B illustrate windings arranged on a printed circuit board 100 of an inductive angular position measuring sensor according to the art. previous. The windings here comprise a primary winding and two secondary windings. For ease of understanding, [Fig.lA] shows the primary winding 101 and a first secondary winding 102, and [Fig.lB] shows a second secondary winding 102.

[0008] The primary winding 101 forms a first circle, with an opening for the arrival and exit of an electric current. It can be formed of several concentric circles, superimposed on different layers and / or faces of a printed circuit board. It surrounds the secondary windings 102.

[0009] Each of the secondary windings 102 forms a circular area and has an opening for the inflow and outflow of an electric current. The secondary windings 102 are arranged concentrically with the primary winding 101.

[0010] Each of the secondary windings 102 is formed of at least one pair of poles 103, here two pairs of poles.

[0011] The two secondary windings 102 are substantially identical and differ from each other only by a rotation of an angle [3, with |3=360° / (4*N), with N equal to the number of pairs of poles, here N= 2.

[0012] It should be noted that the printed circuit board 100 has an unused central area 104.

[0013] The material used for this central zone 104 represents an unnecessary cost for the manufacturer. Summary of the invention

[0014] An objective of the invention is to propose a solution for reducing the manufacturing cost of a printed circuit board for an inductive sensor for measuring the angular position of a rotating mechanical part.

[0015] To this end, the invention thus relates, in its broadest acceptance, to a printed circuit board for an inductive sensor intended to measure the angular position of a rotating mechanical part, the printed circuit board comprising: • At least two secondary windings each consisting of at least one pair of poles, the two secondary windings forming a first arc of a circle; and • A primary winding comprising a first part forming a second arc of a circle running along the periphery of the first arc of a circle.

[0016] The printed circuit board is remarkable in that it is C-shaped and in that the primary winding has a second part for electrically connecting the two ends of the first part of the primary winding.

[0017] Since the printed circuit board has a C shape, the space in the center of the C is hollowed out and does not contain any material. The unused area that the printed circuit boards according to the state of the art have is thus non-existent in the invention. A This results in a significant material saving. This material saving considerably reduces the manufacturing cost of such a printed circuit board for an inductive sensor.

[0018] In addition, space saving is also achieved. A vehicle element, for example made of plastic, can actually be positioned in the center of the C without influencing the operation of the inductive sensor.

[0019] In addition to the characteristics which have just been mentioned in the preceding paragraph, the printed circuit board according to this implementation may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations.

[0020] According to a non-limiting implementation of the invention, the second connection part is formed by a flexible electrical conductor.

[0021] According to a non-limiting implementation of the invention, the flexible electrical conductor is formed by an electrical wire or a flexible printed circuit.

[0022] According to a non-limiting implementation of the invention, the second connection part is formed by a rigid electrical conductor.

[0023] According to a non-limiting implementation of the invention, the printed circuit board further comprises: • A first via connecting one of the ends of the first part of the primary winding with one of the ends of the second part of the primary winding; • A second via connecting the other end of the first part of the primary winding with the other end of the second part of the primary winding.

[0024] According to a non-limiting implementation of the invention, • Each pair of poles of one of the secondary windings extends along an angular part of the first arc of a circle whose angle a' is equal to 360° / Ntot, with Ntot an integer greater than or equal to 2; and • Each secondary winding has a number N0 of pairs of poles, with l <N0<(Ntot-l).

[0025] According to a non-limiting implementation of the invention, each of the first circular arc and second circular arc has an angle α of between 200° and 340°.

[0026] According to a non-limiting implementation of the invention, the printed circuit board further comprises electronics, or an electronic device having a function of supplying electricity to the primary winding and / or a function of measuring voltage values ​​at the terminals of the secondary windings.

[0027] The invention also relates to a motor vehicle comprising a rotating electrical machine comprising a target secured to a rotor of the electrical machine. rotating, the vehicle being remarkable in that it further comprises a printed circuit board according to any one of the aforementioned implementations.

[0028] According to a non-limiting implementation of the invention, the rotating electrical machine comprises a number of pairs of poles greater than the number of pairs of poles of one of the secondary windings of the printed circuit board.

[0029] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0030] The figures are presented for information purposes only and in no way limit the invention.

[0031] [Fig.lA] and [Fig.lB] illustrate the windings of an inductive angular position measuring sensor, according to the prior art;

[0032] [Fig.2A] and [Fig.2B] illustrate an example of embodiment of the windings of a printed circuit board according to the invention.

[0033] [Fig.3] shows the C-shape taken by the printed circuit board according to the invention.

[0034] [Fig.4] illustrates, schematically, and in a perspective view, the windings of a printed circuit board according to the invention, in use with a metal target.

[0035] [Fig.5] illustrates a portion of a substrate plate in which two printed circuit boards according to the invention. DETAILED DESCRIPTION

[0036] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0037] Figures 2A and 2B illustrate an example of embodiment of the windings of a printed circuit board 1 according to the invention. [Fig.2A] illustrates the primary winding 2 and a first secondary winding 3. [Fig.2B] illustrates, for its part, a second secondary winding 3.

[0038] The printed circuit board 1 delimits a C-shaped surface (see [Fig.3], hatched area).

[0039] The secondary windings 3 are constituted by metal tracks formed on the printed circuit board 1. The metal tracks may extend along the two opposite faces of the printed circuit board 1, with vias locally passing through the printed circuit board 1 in the thickness direction. Alternatively, the metal tracks may further extend in intermediate layers of a multi-layer printed circuit board.

[0040] In Figures 2A and 2B, the pairs of poles 4 of the secondary windings 3 are shown schematically and each comprise a loop oriented in a first direction, symbolized by the sign “+”, and a loop oriented in the opposite direction, symbolized by the sign “-”. For reasons of readability of the figures, the detail of the turns forming each of the loops has not been shown, said turns being able to be distributed over one or more layers, this aspect being an element known from the prior art and not constituting the heart of the invention.

[0041] Each secondary winding 3 has a number No of pairs of poles 4, with l <N0<(Ntot-l).

[0042] Here, we have No=3 and Ntot = 4.

[0043] Ntot is equal to the number of pairs of poles that the rotating electrical machine comprising the metal target configured to interact with the printed circuit board 1 according to the invention comprises.

[0044] In the example illustrated, the two secondary windings together form a first arc of a circle 5 whose angle a is approximately 270°.

[0045] Each of the pairs of poles 4 extends along an angular part of the first arc of a circle 5 whose angle a' is approximately equal to 360° / Ntot, with Ntot an integer greater than or equal to 2, here 4.

[0046] It should be noted that the primary winding 2 comprises a first part 2a forming a second arc of a circle running along the periphery of the first arc of a circle 5. Formulated differently, the first part 2a of the primary winding 2, namely the second arc of a circle, follows the outer contour of the secondary windings 3 and extends along the angle a of 270°.

[0047] The first part 2a of the primary winding 2 may consist of several concentric turns distributed over one or more layers. Here again, for reasons of readability, each of these turns has not been shown separately.

[0048] The primary winding 2 also comprises a second part 2b for electrically connecting the two ends 6a, 6b of the first part 2a of the primary winding 2. It should be noted that this second part 2b is not constituted by the substrate of the printed circuit board. This second part 2b is an added part. This feature makes it possible to obtain the C shape.

[0049] Here, the second electrical connection part 2b is formed by a flexible electrical conductor, such as an electrical wire or a flexible printed circuit.

[0050] In this exemplary embodiment, the printed circuit board 1 comprises: • A first connection via 7a of one of the ends 6a of the first part 2a of the primary winding 2 with one of the ends 8a of the second part 2b of the primary winding 2; and • A second connection via 7b of the other end 6b of the first part 2a of the primary winding 2 with the other end 8b of the second part 2b of the primary winding 2.

[0051] In this embodiment, the printed circuit board 1 further comprises a electronic, or electronic device 9 having a function of supplying electricity to the primary winding 2 and a function of measuring voltage values ​​at the terminals of the secondary windings 3.

[0052] The electronics, or electronic device 9 comprises for example at least one microcontroller.

[0053] [Fig. 4] illustrates schematically, and in a perspective view, the windings of a printed circuit board according to the invention, in use with a corresponding metal target 10 secured to a rotating mechanical part, for example a rotor of a rotating electrical machine included in a motor vehicle.

[0054] The target 10 comprises a plurality of blades 11 arranged in a generally circular shape. In particular, the number of blades 11 is equal to Ntot. Here, twelve blades 11. Each blade 11 extends over an angular sector of the same extent, and the angular distribution of the blades 11 is regular.

[0055] The target 10 is arranged concentrically with the printed circuit board 1 as defined above.

[0056] In the embodiment of [Fig.4], the windings of the printed circuit board 1 comprise a primary winding 2a, 2b concentric with several secondary windings 3.

[0057] [Fig.5] finally illustrates a part of a substrate plate 12 in which two printed circuit boards 1 according to the invention are arranged.

[0058] Thanks to the C shape given to each printed circuit board 1, it is possible to nest together, on the same substrate plate 12, two printed circuit boards 1 according to the invention. Thus, in comparison with the state of the art according to which the printed circuit boards are formed by a disc, on the same substrate plate 12, the number of printed circuit boards 1 manufactured is greater. This feature makes it possible to reduce the number of substrate plates to be used, the machine time and therefore the manufacturing cost of the printed circuit boards 1.

[0059] The invention is not limited to the examples and variants described above. The different examples and variants can be combined with each other. The secondary windings can be two, three, or even more in number. The secondary windings can each comprise several pairs of poles, or even a single pair of poles.

[0060] The invention applies to any rotating mechanical part for which it is desired to determine its angular position. Advantageously, the invention finds application in the field of land vehicles, in particular for vehicles of the 2-wheel, 3-wheel, 4-wheel or more type, formed, for example, by motorcycles, cars, buses, trucks or even agricultural vehicles. The invention also applies to air, sea or river vehicles. The printed circuit board according to the invention is advantageously configured to be placed at one end of a rotation shaft. In a less preferred variant, the printed circuit board according to the invention may be configured to be crossed by the rotation shaft. In any event, it differs from printed circuit boards intended to be placed on the periphery of the rotation shaft, at a distance from the axis of rotation of the shaft.

[0061] The invention makes it possible in particular to offer optimal coupling between the windings and the target, while significantly reducing the manufacturing cost.

Claims

Claims

1. Printed circuit board (1) for an inductive sensor intended to measure the angular position of a rotating mechanical part, said printed circuit board (1) comprising: - At least two secondary windings (3) each consisting of at least one pair of poles (4), said two secondary windings (3) forming a first arc of a circle (5); and - a primary winding (2) comprising a first part (2a) forming a second arc of a circle running along the periphery of said first arc of a circle (5); said printed circuit board (1) being characterized in that it is C-shaped and in that said primary winding (2) has a second part (2b) for electrically connecting the two ends (6a, 6b) of said first part (2a) of said primary winding (2).

2. Printed circuit board (1) according to the preceding claim, characterized in that the second connection part (2b) is formed by a flexible electrical conductor.

3. Printed circuit board (1) according to the preceding claim, characterized in that the flexible electrical conductor is formed by an electrical wire or a flexible printed circuit.

4. Printed circuit board (1) according to claim 1, characterized in that the second connection part (2b) is formed by a rigid electrical conductor.

5. Printed circuit board (1) according to any one of the preceding claims, characterized in that it comprises: - A first connection via (7a) of one of the ends (6a) of the first part (2a) of the primary winding (2) with one of the ends (8a) of the second part (2b) of the primary winding (2); - A second connection via (7b) of the other end (6b) of the first part (2a) of the primary winding (2) with the other end (8b) of the second part (2b) of the primary winding (2).

6. A printed circuit board (1) according to any one of claims preceding, characterized in that: - Each pair of poles (4) of one of the secondary windings extends along an angular part of the first arc of a circle (5) whose angle a' is equal to 360° / Ntot, with Ntot an integer greater than or equal to 2; and - Each secondary winding (3) comprises a number No of pairs of poles (4), with l <N0<(Ntot-l).

7. Printed circuit board (1) according to any one of the preceding claims, characterized in that each of the first circular arc (5) and second circular arc has an angle a of between 200° and 340°.

8. Printed circuit board (1) according to any one of the preceding claims, characterized in that it further comprises electronics, or electronic device (9) having a function of electrical supply to the primary winding (2) and / or a function of measuring voltage values at the terminals of the secondary windings (3).

9. Motor vehicle comprising a rotating electrical machine comprising a target (10) secured to a rotor of said rotating electrical machine, said vehicle being characterized in that it further comprises a printed circuit board (1) according to any one of the preceding claims configured to measure the angular position of said rotor.

10. Motor vehicle according to the preceding claim, characterized in that the rotating electrical machine comprises a number of pole pairs Ntot greater than the number of pole pairs (4) of one of the secondary windings (3) of the printed circuit board (1).