Incremental magnetic encoder

Abstract

Incremental Magnetic Encoder The present invention relates to an incremental magnetic encoder defining an encoder axis and comprising a fixed body and a movable body; one of the bodies, referred to as the first body, comprising: - a first ring (51) extending along a first longitudinal direction and a first circumferential direction, one of said first directions corresponding to the first encoding direction, the first ring (51) defining at least two different magnetic alternations; the other body, referred to as the second body, comprising: - at least one first notching tooth (71) adapted to be positioned opposite each magnetic alternation of the first ring (51) to create notching with at least two different notching pitches depending on the position of the second body; - a first pair of magnetic detectors positioned opposite the first ring (51). Figure for the abstract: Figure 4

Description

Title of the invention: Incremental magnetic encoder FIELD OF INVENTION

[0001] The present invention relates to an incremental magnetic encoder.

[0002] More particularly, the present invention relates to an encoder capable of providing binary logic signals representing increments of the relative position of two elements of the encoder, the two elements being movable relative to each other. Advantageously, such an encoder is applicable in the aeronautical field, for example in an aircraft cockpit.

[0003] Typically, in an application for aeronautical equipment, an angular and / or linear encoder can be used to indicate to an autopilot computer an altitude or speed setpoint that the operator selects by pressing a control button on the encoder. The reliability of the encoder and the information it provides is therefore an essential element of the encoder. The typical requirement for an aeronautical encoder may include one or more of the following: compactness, the ability to perform multiple rotations and / or linear travel, incrementing and detenting capabilities, etc. In order to be certified, the aeronautical encoder must also be able to meet high DAL (Design Assurance Level) safety standards, particularly DAL A.

[0004] In particular, with regard to compactness, an encoder typically has a control button with a diameter between 10 and 100 mm and a length between 5 and 50 mm (typically 0.16 mm x 1.16 mm) and a body with a diameter between 10 and 100 mm and a length between 5 and 100 mm (typically 0.25 mm x 1.50 mm) concealed behind the mounting panel or fixed in front of it. In the latter case, the button encompasses the encoder body, which is fixed to the panel, and allows it to be placed around, or even slightly overlapping, a monitor or screen.

[0005] With regard to the incrementing capability, each notch (or step) constitutes an increment of one unit of rotation or translation. The angular or linear resolution is defined per notch (or step). The number of steps per revolution is on the order of 1 to 32 steps (typically 12 steps). The number of steps in translation is from 1 to 10 notches (typically 1 notch in each direction to obtain a "push / pull" button with a stable state between the two notches).

[0006] To detect the direction of rotational and / or translational movement, the encoder generally has at least two detectors (one for rotation and one for translation) physically offset from each other (typically by an odd number of quarter steps). These two detectors allow the rotational and / or translational movement to be encoded using two bits. Thus, the encoding produces the successive values The following values ​​are used: 00, 01, 11, 10 when the encoder rotates and / or translates in one direction, and the following successive values: 00, 10, 11, 01 when the encoder rotates and / or translates in the opposite direction. It is therefore possible to determine not only the occurrence of a rotational and / or translational increment (a change of state in one of the bits) but also the direction of rotation (by comparing a detected state with the immediately preceding state).

[0007] Regarding the detenting capacity of the encoders, the passage of the encoded detent generally results in tactile feedback that an operator must feel when maneuvering the device. The angular detenting torque can, for example, be on the order of 1 to 700 mN.m (typically 12 mN.m) and the linear detenting force on the order of 0.5 to 20 N (typically 6 N).

[0008] The most complex encoders have rotational and translational encoding and detenting. Rotational encoding and detenting must not be blocked by translational encoding and detenting. In this case, rotational and translational detection and detenting must be able to be used simultaneously without loss of performance. For example, to enter a speed, the driver must simultaneously push the encoder button and turn it to the desired value.

[0009] Finally, in certain cases, to secure the encoder and in particular to guarantee its DAL security level (for example DAL A), the detection (or encoding) functions are at least doubled. STATE OF THE ART

[0010] To meet the aforementioned needs, the encoders used in aeronautical applications are often based on opto-mechanical solutions (optical detection and mechanical detenting) or electromechanical solutions (detection by electrical contact and mechanical detenting) and sometimes magneto-mechanical solutions (magnetic detection and mechanical detenting) or opto-magnetic solutions or even purely magnetic solutions.

[0011] For example, opto-mechanical encoders are described in documents FR 2937129 and FR 2954491. According to these documents, rotational and / or translational detection (encoding) is performed by an optical encoder, while maintaining a stable position (ratcheting) is ensured mechanically by at least one ball pressurized by a spring on a ball track (or cam). Even though these recent innovations meet the needs described above and aim to simplify their implementation, these opto-mechanical and electromechanical encoders remain complex assemblies made up of numerous high-precision parts.

[0012] More generally, current mechanically driven solutions generate friction (e.g., ball against cam) and wear, which limits the lifespan of the device, particularly when plastic parts are used. In encoders In electromechanical systems, detection and detenting are sometimes linked by at least one common mechanical part that serves both as a click and as a detection mechanism via an electrical contact. This contact is often subject to wear and fretting corrosion, thus limiting the device's lifespan. Furthermore, in optomechanical and sometimes electromechanical devices, detection and detenting are decoupled, meaning they result from different solutions and / or phenomena and are physically separated. This decoupling increases the number of parts and, consequently, the risk of misalignment between detection and detenting. In the case of complex and secure encoders, the number of parts is even greater. To ensure good performance and reliability, modern complex encoders require high-precision, and therefore more expensive, components.

[0013] We also know of document FR 2370350 which describes a rotary magnetic encoder with moving magnets in which the detenting and encoding are based on the magnetic phenomenon. However, the encoder in this document is only rotary and uses moving magnets which are exposed to risks of friction and jamming.

[0014] In summary, electromechanical solutions present the highest risk of fatigue, both in the detenting and encoding stages, because they generate the most friction. Furthermore, the electrical encoding is susceptible to fretting corrosion. These drawbacks reduce reliability and limit the device's lifespan.

[0015] Opto-mechanical and magneto-mechanical solutions retain the risk of fatigue at the level of the mechanical notching.

[0016] Opto-magnetic solutions use different contactless phenomena. These solutions are more cumbersome if a more complex (example: rotary encoder with "push / pull") and secure encoder is desired.

[0017] Purely magnetic solutions do not allow us to meet all of the aforementioned needs.

[0018] French patent FR 3135791 is now known, proposing a purely magnetic solution for implementing coding along one of the chosen directions, for example, the direction of translation and the direction of rotation, while ensuring detenting along the same direction. According to this patent, the coding and detenting are created by the same magnetic effect between the moving and fixed bodies. Thus, this patent resolves all the aforementioned problems. However, the solution proposed in this patent can still be improved. Summary of the invention

[0019] The present invention aims to provide an incremental encoder that meets all the aforementioned needs, while improving the solution proposed in particular by document FR 3135791.

[0020] To this end, the invention relates to an incremental magnetic encoder defining an encoder axis and comprising a fixed body and a movable body relative to the fixed body along at least a first coding direction and a second coding direction perpendicular to the first coding direction;

[0021] one of the bodies, called the first body, comprising:

[0022] - a first ring extending along a first coincident longitudinal direction with the encoder axis and a first circumferential direction perpendicular to the first longitudinal direction, one of said first directions corresponding to the first coding direction, the first ring defining at least two different magnetic alternations, each magnetic alternation extending along the first coding direction;

[0023] the other body, called the second body, comprising:

[0024] - at least one first serration tooth made of ferromagnetic material or magnetic suitable to be positioned opposite each magnetic alternation of the first ring to create, during a movement of the moving body along the first coding direction, a notching with at least two different notching pitches depending on the position of the second body relative to the first body along the second coding direction;

[0025] - a first pair of magnetic detectors arranged opposite the first ring and configured to quantify each movement of the moving body according to the first coding direction.

[0026] Equipped with these features, the encoder according to the invention makes it possible to implement coding along one of the chosen directions, while simultaneously ensuring detenting along the same direction. The coding and detenting are created by the same magnetic effect between the moving and fixed bodies. Furthermore, the encoder according to the invention makes it possible to implement different detent pitches along the first coding direction depending on the respective positions of the bodies along the second coding direction. Thus, for each respective position of the bodies along the second coding direction, it is possible to associate a function with a specific detent pitch. For example, the functions associated with the different positions of the bodies can correspond to different levels of precision in setting numerical values ​​entered via the encoder. These levels of precision can, for example, correspond to fine, medium, and coarse adjustments.Thus, using such an encoder becomes particularly convenient and intuitive.

[0027] By "magnetic alternation" is meant a succession of ferromagnetic or magnetic elements alternating their direction of magnetization according to a predetermined rule.

[0028] According to some embodiments, each magnetic alternation is defined by a constant alternation step.

[0029] Thus, it is possible to ensure a constant notching pitch according to the corresponding coding direction.

[0030] According to certain embodiments:

[0031] - the first body further comprises a second ring extending along a a second longitudinal direction coinciding with the encoder axis and a second circumferential direction perpendicular to the second longitudinal direction, one of said second directions corresponding to the second encoding direction, the second ring defining a single magnetic alternation extending along the second encoding direction;

[0032] - the second body, comprising:

[0033] + at least one second serration tooth made of ferromagnetic material or magnetic arranged opposite the second ring to create a notch with the same notch pitch during a movement of the mobile body along the second coding direction;

[0034] + a second pair of magnetic detectors arranged opposite the second ring and configured to quantify each movement of the moving body according to the second coding direction.

[0035] Thanks to these characteristics, it is possible to ensure notching according to each coding direction.

[0036] According to some embodiments, the second coding direction corresponds to a translation along the encoder axis according to a predetermined translation stroke length and the first coding direction corresponds to a rotation around the encoder axis.

[0037] Thanks to these features, it is possible to ensure different rotational detent pitches depending on the translational position of the moving body. Thus, to use the encoder, the operator can first perform a translational movement to select the desired position and then perform a rotary movement whose detent pitch depends on the selected translational position. A default rotational detent pitch can also be associated when no translational movement is performed.

[0038] According to some embodiments, the first ring comprises a plurality of elementary rings arranged coaxially next to each other according to the second coding direction, at least two elementary rings defining the two different magnetic alternations.

[0039] Thanks to these characteristics, it is possible to achieve at least two different magnetic alternations in a simple manner.

[0040] According to some embodiments, the first ring comprises at least three elementary rings arranged coaxially next to each other along the second coding direction, the elementary rings defining at least three different magnetic alternations with an increasing or decreasing alternation step along the second coding direction.

[0041] Thanks to these characteristics, it is possible to obtain at least three different notching pitches in rotation depending on the position of the moving body in translation.

[0042] According to some embodiments, the second ring comprises a plurality of elementary rings arranged coaxially next to each other to define the magnetic alternation along the second coding direction;

[0043] the width of each elementary ring of the first ring is less than or equal to the width of each pair of elementary rings of the second ring.

[0044] According to certain embodiments:

[0045] - the second ring defines at least one central notch and two peripheral notches;

[0046] - a stable translational position being defined when the second tooth of the notch is positioned opposite the central notch.

[0047] Thanks to these features, it is possible to obtain a stable translational position of the moving body and at least two peripheral positions. Each peripheral position can be reached by pressing on the moving body or by pulling on it (the "PUSH / PULL" principle). Different rotational notching pitches can then be associated with each of these positions. Depending on different embodiments, the peripheral positions can be stable or unstable.

[0048] According to some embodiments, the surface of the tooth or each notching tooth has an extent less than or equal to the smallest notching pitch of the corresponding ring.

[0049] Thanks to these characteristics, the notching tooth has sufficient sensitivity to ensure any notching step.

[0050] According to some embodiments, the magnetic detectors of the first same pair of detectors are offset from each other by a fraction of the smallest notch pitch.

[0051] Thanks to these characteristics, it is possible to efficiently detect each movement of the moving body corresponding to a notching step.

[0052] According to some embodiments, in which the first body is the moving body and the second body is the fixed body.

[0053] Thanks to these features, in particular the notching teeth and magnetic sensors are arranged in the fixed body. Thus, the arrangement of these elements as well as their possible wiring can be significantly simplified.

[0054] According to certain embodiments, the encoder further comprises:

[0055] - a magnetorheological fluid in a space formed between the first body and the second body;

[0056] - a magnetic loop configured to form a magnetic field at least in a part of said space and to modify the intensity of this magnetic field according to the position of the second body relative to the first body along the second coding direction.

[0057] Thanks to these characteristics, it is possible to modify the toothing torque along the first coding direction. Indeed, each change in the intensity of the magnetic field created by the magnetic loop modifies the viscosity of the magnetorheological fluid. DESCRIPTION OF THE FIGURES

[0058] These features and advantages of the invention will become apparent from the following description, given solely by way of example and not limitation, and made with reference to the accompanying drawings, in which: - [Fig.1] [Fig.1] is a schematic perspective view of a magnetic encoder according to a first embodiment of the invention, the encoder being partially fixed behind a panel forming a dashboard; - [Fig.2] [Fig.2] is an exploded perspective view of the encoder of [Fig.1], the encoder comprising a fixed body and a moving body; - [Fig.3] [Fig.3] presents a partial view of a section along the plane longitudinal III of [Fig.l] and three other sections along the encoder axis of [Fig.l]; - [Fig.4] [Fig.4] is a perspective view of the internal elements functional of the fixed body and the mobile body of the [Fig.2]; - [Fig.5] [Fig.5] is a perspective view of the moving body of [Fig.2]; - [Fig. 6] [Fig. 6] is a cross-sectional perspective view of the inserted moving body in the fixed body of the [Fig.2]; - [Fig.7] [Fig.7] is a schematic perspective view of an encoder according to a second embodiment of the invention, the encoder being fixed on a panel forming a dashboard while remaining in front of this panel; - [Fig.8] [Fig.8] is an exploded perspective view of the encoder in [Fig.7]; and - [Fig.9] [Fig.9] is a view analogous to that of [Fig.3], the magnetic encoder being according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0059] Figure 1 illustrates an incremental magnetic encoder 10 according to a first embodiment of the invention. Preferably, the encoder 10 is mounted in a cockpit for piloting an aircraft.

[0060] The term "aircraft" means any flying machine, such as an airplane, helicopter, or drone, for example. Such an aircraft can be piloted directly from within it. In such a case, the cockpit is advantageously located inside the aircraft. According to another embodiment, such an aircraft is remotely controlled. In such a case, the cockpit is located at a distance from the aircraft and includes, for example, a ground station. In all cases, the aircraft is configured to be piloted by an operator, for example, a pilot, from the cockpit located inside the aircraft.

[0061] According to the invention, the encoder 10 allows the operator to control at least one avionics function. For example, such an encoder 10 can be used by the operator to control an avionics system and is part of a control system for such an avionics system. Alternatively, the encoder 10 is part of a control system for several avionics systems. For example, the encoder 10 according to the invention is part of a system called a "Flight Control Unit" (FCU), "Integrated Standby Instrument System" (ISIS), "Closer Control Device" (CCD), or "Keyboard Cursor Control Device" (KCCD), etc.

[0062] In the example of [Fig. 1], the encoder 10 is partially integrated into a panel 12. This panel 12 forms, for example, an instrument panel in the aircraft cockpit for one of the aforementioned control systems. In the example of [Fig. 1], the encoder 10 is arranged partially in the front portion 12A of the panel 12 and partially in the rear portion 12B of this panel 12. In particular, in the example of [Fig. 1], the front portion 12A of the panel 12 faces the operator, while the rear portion 12B of this panel faces the interior of the instrument panel. Of course, other arrangements of the encoder 10 relative to the panel 12 or to any other mounting means are also possible.

[0063] With reference to [Fig.2], the encoder 10 comprises a movable body 21, also called in the example of this figure first body, and a fixed body 22, also called in the example of this figure second body.

[0064] The movable body 21 includes a button 31 and a rotor 33.

[0065] The button 31 protrudes from the panel 12 and is arranged in the front part 12A of this panel 12. The button 31 is movable in translation along an X-axis encoder and in rotation about the X-axis encoder. More particularly, the Button 31 is movable along a first coding direction C1, which in this example corresponds to the direction of rotation around the encoder axis X, and a second coding direction C2, which in this example corresponds to the direction of translation along the encoder axis X. Advantageously, button 31 is movable in each direction along each coding direction C1, C2. In particular, in the direction of rotation, button 31 is movable in both clockwise and counterclockwise directions, and in the direction of translation, button 31 is movable towards the instrument panel and towards the operator. Advantageously, button 31 defines, in particular, a button surface 34 that is intended to be oriented towards the operator. This surface 34 therefore represents an external surface of button 31 that is visible to the operator and can be grasped by the operator.

[0066] The rotor 33 extends along the encoder axis X so as to form a fixed connection with the button 31 at one of its ends. Thus, like the button 31, the rotor 33 is movable along the first encoding direction C1 and along the second encoding direction C2 in each of the aforementioned directions of movement. The rotor 33 receives internal functional elements from the movable body 21, which will be explained in more detail later.

[0067] The fixed body 22 includes a support 41, a cover 42 and a flange 43.

[0068] The flange 43 is, for example, disposed in a hole 35 through the panel 12 and allows the button 31 and the rotor 33 to be supported. In the example of [Fig.2], the flange 43 is fixed to the panel 12 while remaining in the rear part 12B of it, using for example screws accessible from the front part 12B of the panel 12.

[0069] The support 41 receives internal functional elements from the fixed body 22 which are intended to cooperate with the internal functional elements of the moving body 21, as will be explained in more detail later. In particular, and as will become apparent later, the internal functional elements of the fixed body 22 are held at a distance from those of the moving body 21 by the support 41. To achieve this, the support 41 is configured to receive at least partially the rotor 33, with the internal functional elements of the moving body 21 carried by this rotor 33.

[0070] The support 41 is, for example, connected to the moving body 21 via a movable link in each coding direction. This link can, for example, be formed at each end of the rotor 33 and have plain bearings, for example polymer bearings or sintered bronze bearings. These bearings preferably have a flange to serve as a mechanical stop. According to another example, these bearings are rolling element bearings such as ball bushings. Figure 3 shows, in particular, the bearings 37 connecting the rotor 33 to the second body 22. In the example in this figure, the bearings 37 connect one end of the rotor 33 directly to the support 41 and the other end of the rotor 33 to support 41 via flange 43. In this example, flange 43 is configured to cooperate with support 41 in order to fix it to panel 12

[0071] The cover 42 is intended to protect all the components of the encoder 10 which are arranged in the rear part 12B of the panel 12.

[0072] In the example of figures 4 and 5 illustrating in more detail the functional internal elements of the fixed body 22 and the moving body 21, the rotor 33 has for example a cylindrical shaft 45 extending along the encoder axis X.

[0073] With reference to Figures 4 and 5, the internal functional elements of the moving body 21 comprise a first ring 51, called the rotation ring, and a second ring 52, called the translation ring. Each of these rings 51, 52 is fixed to the shaft 45 along the encoder axis X and remains spaced apart from the other ring 51, 52. In some embodiments, the rings 51, 52 are connected to each other by a magnetic or ferromagnetic component 53, which improves the efficiency of the encoder (greater torque and detent force without increasing the size of the fixed magnets) and prevents field leakage and external interference. This component 53, for example, has a sleeve or tube inserted onto the shaft 45, with the two rings 51, 52 fixed to this sleeve.

[0074] In addition, each of these rings 51, 52 has one or more axial magnetic alternations in the case of the translation ring 52 and circumferential in the case of the rotation ring 51.

[0075] In the example shown in Figures 4 and 5, the translation ring 52 exhibits a single axial magnetic alternation. In particular, this translation ring 52 extends along the encoder axis X and comprises a plurality of elementary rings 52-1, ..., 52-N2 arranged side by side, for example, by gluing. Each elementary ring 52-1, ..., 52-N2 is, for example, made from a single block or from several parallelepiped magnets or arc-shaped magnets. Such an elementary ring can also be made from a "polymagnet" or a "programmable magnet" called Polymagnets®.

[0076] In order to achieve axial magnetic alternation, in the example of [Fig. 5], these elementary rings 52-1, ..., 52-N2 have radial magnetization and are arranged side by side so that adjacent rings are magnetized in opposite directions along the radial axis. According to another possible arrangement, axial magnetic alternation is achieved using a Halbach-type arrangement. In particular, according to such an arrangement, the elementary rings are magnetized alternately along the radial and circumferential axes. Furthermore, the direction of magnetization of each elementary ring is chosen so as to concentrate the magnetic field on the surface of the translation ring 52 opposite the functional internal elements of the fixed body 22. In the example of the arrangement relative to the moving body 21 and the fixed body 22 of [Fig.2], such a magnetic field is concentrated on the outer surface of the translation ring 52.

[0077] The translation ring 52 has a width L2 corresponding to its extent along the encoder axis X. This width L2 is formed by the sum of the widths of the elementary rings 52-1, ..., 52-N2 that make up this translation ring 52. The width of each elementary ring or each pair of elementary rings forms a translational notch pitch. In one embodiment, the elementary rings have the same width. In such a case, the translation ring 52 has a uniform translational notch pitch.

[0078] In the example of Figures 4 and 5, the number N2 of elementary rings 52-1, ..., 52-N2 is equal to 6. In other words, these elementary rings form 3 pairs of rings, each pair being composed of adjacent rings having different magnetizations. Among these pairs of elementary rings, one pair of elementary rings is arranged between the other two pairs and is then called the central pair. The other two pairs are called the peripheral pairs. The central pair thus has a central notch and the peripheral pairs have peripheral notches.

[0079] The rotation ring 51 also extends along the encoder axis X and has a width L1 corresponding to its longitudinal extent. Advantageously, the width L1 is substantially the same as the width L2 of the translation ring 52. In some other examples, the width L1 is, for instance, substantially less than the width L2. The rotation ring 51, for instance, has the same diameter as the translation ring 52.

[0080] According to the invention, the rotating ring 51 has a plurality of circumferential magnetic alternations having different alternation pitches. To this end, the rotating ring 51 has a plurality of elementary rings 51-1, ..., 51-N1 arranged side by side along the encoder axis X. At least two elementary rings 51-1, ..., 51-N1 have different circumferential magnetic alternations and therefore different alternation pitches. Advantageously, all elementary rings 51-1, ..., 51-N1 have different circumferential magnetic alternations and therefore different alternation pitches.

[0081] The circumferential magnetic alternation of each elementary ring 51-1, ..., 51-NI forming the rotation ring 51 is achieved by a particular arrangement of a plurality of elementary parts forming this elementary ring 51-1, ..., 51-NI, each elementary part having, for example, a permanent magnet. Each elementary part may, for example, have a substantially parallelepiped shape that is elongated along the encoder axis X. This shape may, for example, be slightly curved to form an arc of a circle around the encoder axis X. The elementary parts are arranged next to each other, for example, by gluing along the Circumferential direction. The circumferential extent of each elementary part forms an alternating pitch that also forms a rotational toothing pitch. This is a homogeneous alternating pitch when all the elementary parts have the same circumferential extent. As in the case of the elementary rings 52-1, ..., 52-N2 of the translation ring 52, each elementary part is, for example, made from a single block or from several parallelepiped magnets or arc magnets. Such an elementary part can also be made from a "polymagnet" or a "programmable magnet" called Polymagnets®.

[0082] The elementary parts of the same elementary ring 51-1, ..., 51-N 1 of the rotation ring 51 have radial magnetization and are arranged side by side so that adjacent elementary parts are magnetized in opposite directions along the radial direction. According to another example of a possible arrangement, a circumferential magnetic alternation is achieved using a Halbach-type arrangement. In particular, according to such a type of arrangement, the elementary parts are magnetized alternately along the radial and circumferential directions. Moreover, as in the previous case, the direction of magnetization of each elementary part is chosen so as to concentrate the magnetic field on the surface of the rotation ring 51 opposite the functional internal elements of the fixed body 22. In the example of the respective arrangement of the moving body 21 and the fixed body 22 of [Fig.2], such a magnetic field is concentrated on the outer surface of the rotation ring 51.

[0083] To ensure different alternating pitches between the various elementary rings 51-1, ..., 51-NI of the rotation ring 51, the elementary parts of these different elementary rings 51-1, ..., 51-NI have different circumferential extents. Between the different elementary rings 51-1, ..., 51-NI, these circumferential extents can progressively decrease or increase along the encoder axis X. Thus, the alternating pitches and consequently the notching pitches of the elementary rings 51-1, ..., 51-NI of the rotation ring 51 gradually decrease or increase along the encoder axis X. Thus, in the example of Figures 4 and 5, the number NI of elementary rings 51-1, ..., 51-NI is equal to 3 and three notching pitches are defined, namely fine, medium, and coarse. In other words, in this example, the notch pitch gradually decreases along the X encoder axis.

[0084] Advantageously, the elementary rings 51-1, ..., 51-N1 of the rotation ring 51 all have the same width. Thus, the width of each elementary ring 51-1, ..., 51-N1 of the rotation ring 51 is, for example, equal to the width of each pair of elementary rings 52-1, ..., 52-N2 of the translation ring 52. In other words, the width of each elementary ring 51-1, ..., 51-N1 of the rotation ring 51 is twice the width of each elementary ring 52-1, ..., 52- N2 of the translation ring 52. According to another embodiment, the width of each elementary ring 51-1, ...,51-NI of the rotation ring 51 is less than the width of each pair of elementary rings 52-1, ..., 52-N2 of the translation ring 52.

[0085] With reference to Figures 4 and 6, the internal functional elements of the fixed body 22 comprise at least one pair of translational magnetic detectors 62, also called second magnetic detectors, at least one pair of rotational magnetic detectors 61, also called first magnetic detectors, a plurality of translational serration teeth 72, also called second serration teeth, and a plurality of rotational serration teeth 71, also called first serration teeth. These elements 61, 62, 71, 72 are fixed to an inner surface of the support 41 (not shown in [Fig. 4]) of the fixed body 22. Furthermore, as mentioned previously, these elements 61, 62, 71, 72 are kept at a distance from the corresponding rings 51 and 52.

[0086] The magnetic translation detectors 62 are arranged opposite the translation ring 52 and allow the displacement of this ring 52 along the encoder axis X to be quantified. In other words, these detectors 62 allow each displacement of the translation ring 52 along the encoder axis X to be encoded by detecting changes in the magnetic flux through the axial magnetic alternation of the elementary rings constituting this translation ring 52. For example, the translation detectors 62 are offset from each other by a fraction of the translational notch pitch defined by this translation ring 52. Advantageously, the number of translation detectors 62 is equal to 3. These translation detectors 62 are, for example, spaced evenly along the circumferential direction.

[0087] The magnetic rotation detectors 61 are arranged opposite the rotation ring 51. The rotation detectors 61 make it possible to quantify each rotational movement of the rotation ring 51 around the encoder axis X by detecting changes in the magnetic flux through the circumferential magnetic alternation implemented by the elementary parts of each elementary ring 51-1, ..., 51-N1 constituting the rotation ring 51. For example, the magnetic detectors 61 are offset by a fraction of the smallest rotational notch pitch defined by the rotation ring 51. Advantageously, the number of rotation detectors 61 is equal to 3. These rotation detectors 61 are, for example, spaced evenly along the circumferential direction.

[0088] Each magnetic detector 61, 62 has, for example, a Hall effect sensor or a magnetoresistive sensor or a solenoid. In addition, each magnetic detector 61, 62 is connected to an external controller of the encoder 10 by cables 74 visible in [Fig. 3].

[0089] Each translational serration tooth 72 is arranged opposite the translational ring 52. In particular, each translational serration tooth 72 has a surface oriented towards the translational ring 52 and has a dimension less than or equal to the translational serration pitch. Such a surface has, for example, a longitudinal extent less than or equal to the serration pitch of this ring 52. Furthermore, each translational serration tooth 72 is made of a ferromagnetic or magnetic material such as 400 series stainless steel. Each translational serration tooth 72 is preferably a magnet or a plurality of magnets arranged side by side. Each magnet is, for example, a parallelepiped magnet or a circular arc magnet. Such a magnet is, for example, derived from a "polymagnet" or a "programmable magnet" called Polymagnets®.

[0090] In the example of [Fig. 4], when the translation ring 52 consists of a central pair of elementary rings and two peripheral pairs, each translational tooth 72 defines a stable position in which it is arranged opposite the central pair. To ensure such a stable position, each translational tooth 72 comprises, for example, a pair of magnets arranged side by side along the encoder axis X and having magnetizations in opposite directions to those of the outer surface of the central pair of elementary rings.

[0091] In certain embodiments, a stable position of each translational tooth 72 is also formed when this translational tooth 72 is positioned opposite one of the peripheral pairs of elementary rings, advantageously opposite each peripheral pair of elementary rings. In such a case, each movement of the moving body 21 along the encoder axis X between the different stable positions can then be performed manually by the operator. Furthermore, preferably, the width of each elementary ring 51-1, ..., 51-NI of the rotation ring 51 is substantially equal to the width of each pair of elementary rings 52-1, ..., 52-N2 of the translational ring 52.

[0092] In certain other embodiments, an unstable position of each translational tooth 72 is formed when this translational tooth 72 is positioned opposite one of the peripheral pairs of elementary rings, advantageously opposite each peripheral pair of elementary rings. In such a case, a mechanical stop can be provided along each direction of movement of the moving body 21 about the encoder axis X. This mechanical stop prevents each translational tooth 72 from aligning with the corresponding peripheral pair of elementary rings and thus reaching a stable magnetic position. In such a case, the return of the moving body 21 about the encoder axis X from an unstable position to the stable position is achieved magnetically. Furthermore, preferably, the width of each elementary ring 51-1, ..., 51-11 the peripheral width of the rotation ring 51 is substantially less than the width of the corresponding peripheral pair of elementary rings 52-1, 52-N2 of the ring translation 52.

[0093] Each rotating serration tooth 71 is positioned opposite the rotating ring 51. As in the previous case, each rotating serration tooth 71 has a surface oriented towards the rotating ring 51 with a circumferential dimension less than or equal to that of the smallest rotating serration pitch and an axial dimension less than or equal to the width of each elementary ring 51-1, ..., 51-NI constituting the rotating ring 51. Furthermore, each rotating serration tooth 71 is made of a ferromagnetic or magnetic material such as 400 series stainless steel. Each rotating serration tooth 71 is preferably a magnet. Each magnet is, for example, a parallelepiped magnet or a circular arc magnet. Such a magnet is, for example, derived from a "polymagnet" or a "programmable magnet" called Polymagnets®.

[0094] As illustrated in [Fig.6], the serration teeth associated with the different rings 51, 52 are advantageously connected to each other by a connecting piece 77. This connecting piece 77 is for example a magnetic or ferromagnetic piece, and advantageously extends along the encoder axis X.

[0095] Advantageously, when the translating serration teeth 72 are aligned with the central pair of elementary rings of the translating ring 52, the rotating serration teeth 71 are aligned with the central elementary ring of the rotating ring 51. Thus, in this position, a medium rotational serration pitch is applied during a rotary motion. When the translating serration teeth 72 are aligned with one of the peripheral pairs of elementary rings of the translating ring 52 following a translational movement of the moving body (PUSH or PULL), a fine or coarse rotational serration pitch is applied during a subsequent rotary motion.

[0096] Furthermore, in the example in [Fig. 4], a plurality of serration teeth 71, 72 are associated with each of the rings 51, 52. In particular, in the example in this figure, three serration teeth are associated with each of the rings. Generally, to improve the balance of the encoder and avoid parasitic torque or force, it is preferable to have at least two serration teeth associated with each of the rings and distributed equidistantly along the circumferential direction.

[0097] Advantageously, according to the invention, when such a plurality of serration teeth is associated with a ring, the serration teeth are arranged equidistantly along the circumferential direction of the corresponding ring 51, 52. It should also be understood that a single serration tooth for each ring would be sufficient to provide a serrationing function along the corresponding direction.

[0098] The encoder 110 according to a second embodiment will henceforth be explained with reference to figures 7 and 8. The application of this encoder 110 is for example identical to that of the encoder 10 explained previously.

[0099] The main difference of the encoder 110 according to the second embodiment lies in the manner of its arrangement in relation to the panel 12. Indeed, as illustrated in [Fig.7], the encoder 110 according to the second embodiment is arranged entirely in the front part 12A of the panel 12.

[0100] As illustrated in [Fig.8], just like the encoder 10 according to the first embodiment, the encoder 110 according to the second embodiment comprises a movable body 121, also called the first body, and a fixed body 122, also called the second body.

[0101] The fixed body 122 is fixed, for example, directly onto the front part 12A of the panel 12. As in the previous case, the fixed body 122 includes a support 141 receiving the internal functional elements of this fixed body 122, as will be explained in more detail later. The support 141 may further include a mechanical stop 143 integrated into one of its ends.

[0102] As in the previous case, the moving body 121 also includes a button 131 and a rotor 133, which is, for example, fixed to the button 131 located at its end. The same end of the rotor 133 is, for example, closed by a cover 134 having a surface oriented towards the operator. The cover 134 is connected to the rotor 133. A washer 135 is fixed to the fixed body 122 at its end. This washer 135 may provide a mechanical stop during the rotation or translation of the moving body 121. This mechanical stop may be damped by means of a return spring or an elastomer component (example material: EPDM). Alternatively, this stop may also be magnetic. In this case, this stop may be achieved by placing a magnet fixed to the fixed body in repulsion and facing a magnet fixed to the moving body. This magnetic stop is inherently damped.This magnetic stop can be independent or part of one of the rings (in order to optimize the number of parts). For example, in the case of a ring of the moving body using a Halbach-type arrangement, a magnet of the fixed body can be placed in repulsion and opposite the end of this ring, having locally axial or circumferential magnetization. In addition, at each of its ends, the rotor 133 can have bearings 136 intended to cooperate with the fixed body 122 in order to ensure the movement of the moving body 121 along each of the encoding directions, namely a first encoding direction C1 corresponding to the direction of rotation around this encoder axis X and a second encoding direction C2 corresponding to the direction of translation along the encoder axis X, in the example shown in the figures.

[0103] Unlike the previous case, the rotor 133 is intended to at least partially encompass the fixed body 122. In other words, the rotor 133 is intended to be arranged around the support 141 as can be seen in [Fig.8].

[0104] Furthermore, just as in the previous case, the moving body 121 comprises a rotation ring, also called the first ring, and a translation ring, also called the second ring. These rings are similar to the rings 51 and 52 described previously. In particular, the translation ring may exhibit a single magnetic alternation and the rotation ring may exhibit several magnetic alternations.

[0105] Unlike the previous case, the rotation and translation rings according to the second embodiment are arranged on an internal surface of the rotor 133, which then has a hollow rotating shaft as illustrated in this figure. Each of these rotation and translation rings is fixed to a shaft along the X-axis of the encoder and remains spaced apart from the other ring.

[0106] Also in a manner analogous to the previous case, the fixed body 122 comprises a plurality of pairs of magnetic detectors and a plurality of serration teeth, arranged opposite the corresponding rotation and translation rings.

[0107] Unlike the previous embodiment, the functional internal elements (i.e., the magnetic sensors and the notching teeth) of the fixed body 122 of the encoder 110, according to the second embodiment, are arranged on an external surface of the support 141 or at least in closed windows on this surface. Thus, according to this embodiment, these elements are arranged opposite the inner surfaces of the corresponding rings. In other words, according to this embodiment, the functional internal elements of the fixed body 122 are received inside the rings while remaining at a distance from them. The operation and respective arrangement of these internal elements are analogous to those described previously in relation to the first embodiment.

[0108] The encoder 210 according to a third embodiment will henceforth be explained with reference to [Fig. 9]. The application and structure of this encoder 210 are substantially analogous to those of the encoder 10 according to the first embodiment. In particular, this encoder 210 includes all the elements of the encoder 10 according to the first embodiment. These common elements will be denoted by the same numerals as those according to the first embodiment and will not be described in detail in relation to that embodiment. It should be understood, however, that at least some of these elements can be adapted to cooperate with the elements specific to that embodiment, which will be explained below.

[0109] With reference to [Fig.9], the encoder 210 according to the third embodiment defines a space 213 between the moving body 21 and the fixed body 22. This space 213 is configured to be filled with a magnetorheological fluid.

[0110] In particular, this space 213 is, for example, delimited by a portion of an external surface of the rotor 33 and a surface of a cavity in the fixed body 22 receiving the rotor 33. This space 213 extends circumferentially around the rotor 33 and axially along the encoder axis X substantially between the bearings 37 arranged on a distal end of the rotor 33 and the second ring 52. This distal end is opposite to that receiving the button 31. The space 213 can be axially delimited by a pair of seals 217.

[0111] In a manner known per se, the magnetorheological fluid has suspensions of particles of a few micrometers, or even a few nanometers, which make it possible to modify the apparent viscosity of the fluid according to the intensity of a magnetic field passing through it.

[0112] According to this embodiment, the apparent viscosity of the magnetorheological fluid is modified to modify the notching torque along the first coding direction Cl, i.e. along the direction of rotation of the rotor 33. For example, according to different embodiments, the change in the apparent viscosity of the magnetorheological fluid allows, for example, to go from a potentiometric state (almost no notch torque) to an incremental state (notch torque with variable pitch or variable torque).

[0113] To modify the magnetic field passing through the magnetorheological fluid and thus to modify its apparent viscosity, the encoder 210 includes a magnetic loop 223 allowing to create a magnetic field with a variable intensity in space 213.

[0114] Furthermore, the magnetic loop 223 is configured to modify the intensity of the magnetic field in the space 213 as a function of the position of the rotor 33 along the encoder axis X. In other words, this magnetic loop 223 makes it possible to modify the intensity of the magnetic field in the space 213 as a function of the translational displacement of the moving body 21.

[0115] According to the example in [Fig.9], the magnetic loop 223 comprises a magnetic or ferromagnetic element 265 extending at least partially around the space 213, a magnetic ring 266 disposed on the rotor 33 and a looping tooth 267 capable of closing the magnetic loop 223 when this tooth 267 is disposed opposite the magnetic ring 266.

[0116] The magnetic ring 266, for example, has an outer surface with the same magnetic polarization. This ring 266 is, for example, fixedly arranged on the rotor 33 between the first ring 51 and the second ring 52.

[0117] The loop tooth 267 is, for example, arranged on the connecting piece 77 between the corresponding serration teeth 71, 72. The loop tooth 267 is made, for example, of a magnetic or ferromagnetic material. It is, for example, in permanent contact with the magnetic or ferromagnetic element 265. In some examples, a loop tooth 267 may be arranged on each connecting piece 77.

[0118] The magnetic ring 266 is movable in translation with the rotor 33 relative to the loop tooth 267. Thus, each movement along the X encoder axis of the rotor 33 modifies the alignment of the loop tooth 267 relative to the magnetic ring 266 and therefore the intensity of the magnetic field formed by the magnetic loop 223.

[0119] According to other embodiments, the magnetic loop 223 can be formed by other means. These means can be passive, i.e., operate without a specific power supply, as is the case with magnets, or active, i.e., require a power supply, as is the case, for example, with a magnetic coil.

[0120] Furthermore, in the example of [Fig.9], a toothed wheel 269 is arranged on the rotor 33 so as to be able to rotate in the space 213 in the direction of rotation Cl in any position of the rotor 33 relative to the encoder axis X. This toothed wheel 269 thus makes it possible to create or reinforce the discrete teeth during the rotation of the rotor 33 in at least one predetermined position of the rotor 33 relative to the encoder axis X.

[0121] Of course, other embodiments are also possible. For example, it should be understood that the notion of a first body with all associated elements can be applied to a fixed body, and the notion of a second body with all associated elements can be applied to a moving body. Furthermore, a plurality of magnetic alternations can be applied to the translation ring, and a single magnetic alternation can be applied to the translation ring. Finally, the principles of a magnetic loop and a magnetorheological fluid whose apparent viscosity changes according to the intensity of the magnetic field created by the loop can be applied to the encoder structure described in relation to the second embodiment.

Claims

Demands

1. An incremental magnetic encoder (10; 110; 210) defining an encoder axis (X) and comprising a fixed body and a movable body relative to the fixed body along at least a first encoding direction (C1) and a second encoding direction (C2) perpendicular to the first encoding direction (C1); one of the bodies, called the first body (21; 121), comprising: - a first ring (51) extending along a first longitudinal direction coinciding with the encoder axis (X) and a first circumferential direction perpendicular to the first longitudinal direction, one of said first directions corresponding to the first encoding direction (C1), the first ring (51) defining at least two different magnetic alternations, each magnetic alternation extending along the first encoding direction (C1); the other body, called the second body (22;122), comprising: - at least one first notching tooth (71) made of ferromagnetic or magnetic material suitable for being positioned opposite each magnetic alternation of the first ring (51) to create, during a movement of the moving body (21; 121) along the first coding direction (Cl), a notching with at least two different notching pitches depending on the position of the second body (22; 122) relative to the first body (21; 121) along the second coding direction (C2); - a first pair of magnetic detectors (61) positioned opposite the first ring (51) and configured to quantify each movement of the moving body along the first coding direction (Cl).

2. Encoder (10; 110; 210) according to claim 1, wherein each magnetic alternation is defined by a constant alternation step.

3. Encoder (10; 110; 210) according to claim 1 or 2, wherein: - the first body (21; 121) further comprises a second ring (52) extending along a second longitudinal direction coinciding with the encoder axis (X) and a second circumferential direction perpendicular to the second longitudinal direction, one of said second directions corresponding to the second encoding direction (C2), the second ring (52) defining a unique magnetic alternation extending along the second coding direction (C2); - the second body (22; 122), comprising: + at least one second notching tooth (72) of ferromagnetic or magnetic material disposed opposite the second ring (52) to create a notch with the same notching pitch during a movement of the moving body along the second coding direction (C2); + a second pair of magnetic detectors (62) disposed opposite the second ring (52) and configured to quantify each movement of the moving body along the second coding direction (C2).

4. Encoder (10; 110; 210) according to any one of the preceding claims, wherein the second encoding direction (C2) corresponds to a translation along the encoder axis (X) over a predetermined translation stroke length and the first encoding direction (Cl) corresponds to a rotation around the encoder axis (X).

5. Encoder (10; 110; 210) according to claim 4, wherein the first ring (51) comprises a plurality of elementary rings (51-1, ..., 51-NI) arranged coaxially next to each other along the second encoding direction (C2), at least two elementary rings defining the two different magnetic alternations.

6. Encoder (10; 110; 210) according to claim 5, wherein the first ring (51) comprises at least three elementary rings (51-1, ..., 51-NI) arranged coaxially next to each other along the second coding direction (C2), the elementary rings (51-1, ..., 51-NI) defining at least three different magnetic alternations with an alternation step increasing or decreasing along the second coding direction (C2).

7. Encoder (10; 110; 210) according to claim 5 or 6 taken in combination with claim 3, wherein the second ring (52) comprises a plurality of elementary rings (52-1, ..., 52-N2) arranged coaxially next to each other to define the magnetic alternation along the second encoding direction (C2); the width of each elementary ring (51-1, ..., 51-NI) of the first ring (51) is less than or equal to the width of each pair of elementary rings (52-1, 52-N2) of the second ring (52).

8. Encoder (10; 110; 210) according to any one of the preceding claims taken in combination with claim 3, wherein: - the second ring (52) defines at least one central notch and two peripheral notches; - a stable translational position being defined when the second notching tooth (72) is arranged opposite the central notch.

9. Encoder (10; 110; 210) according to any one of the preceding claims, wherein the surface of the or each notching tooth (71, 72) has an extent less than or equal to the smallest notching pitch of the corresponding ring (51, 52).

10. Encoder (10; 110; 210) according to any one of the preceding claims, wherein the magnetic detectors (61) of the first same pair of detectors are offset from each other by a fraction of the smallest notch pitch.

11. Encoder (10; 110; 210) according to any one of the preceding claims, wherein the first body (21; 121) is the moving body and the second body (22; 122) is the fixed body.

12. Encoder (210) according to any one of the preceding claims, further comprising: - a magnetorheological fluid in a space (213) formed between the first body (21) and the second body (22); - a magnetic loop (223) configured to form a magnetic field at least in a part of said space (213) and to modify the intensity of this magnetic field as a function of the position of the second body (22; 122) relative to the first body along (21; 121) the second encoding direction (C2).