Large-diameter segmented rotary transformer

Abstract

The invention relates to a resolver mounted about an axis of rotation, the resolver consisting of a plurality of stator ring segments (22a, 22b) and a plurality of rotor ring segments (24a, 24b), the juxtaposition of these ring segments (20) forming a stator ring and a rotor ring consisting of a basic stator magnetic circuit and a basic rotor magnetic circuit, the basic stator magnetic circuit comprising an outer magnetic core (30) and a first electrical winding (32), the basic rotor magnetic circuit comprising an inner magnetic core (34) and a second electrical winding (36) to enable transmission of electrical energy by electromagnetic induction between the outer stator ring and the inner rotor ring, the inner magnetic core and the outer magnetic core being separated by an air gap present on either side of the inner magnetic core; at least the outer magnetic core has an extension at the air gap to avoid discontinuity of the magnetic lines during rotation of the movable shaft.

Description

Technical Field

[0001] The present invention relates to the field of power transmission between a fixed reference frame and a rotating reference frame for electric de-icing of propeller blades of aircraft turbine engines, and to a single-phase rotary transformer for transmitting electrical energy between a first electrical winding and a second electrical winding of the single-phase rotary transformer by electromagnetic induction. Existing technology

[0002] In electric or hybrid aircraft, as in conventional aircraft, there are numerous surfaces on the stationary and rotating parts of the turbine engines that need to be protected from ice. The protection envisaged for the rotating parts is usually solely electrothermal protection based on electric heating mats consisting of a network of electrical resistors covering the surface to be protected.

[0003] In order to ensure the transmission of electricity and therefore the transfer of electrical energy from the stationary part to the rotating part on which the electric heating pads are mounted, it is known to use devices called “slip rings”, the principle of which consists in rubbing a plurality of stationary conductive rings fixed to a circular conductive track and to the rotating part in order to establish an electrical connection between the stationary and rotating parts of the turbine engine.

[0004] Furthermore, it is well known that the integration of electrical equipment is a major challenge due to the harsh environment (thermal, electromagnetic, and vibration) present in hybrid aircraft containing many electrified engine loads, and multiple constraints must be met, including the feasibility of installation / removal and routing of power cables with large curvature radii, as well as cooling limitations.

[0005] Therefore, there is a need for a reliable, long-life solution for transmitting power from a fixed reference frame to a rotating reference frame suitable for large diameter rotating shafts while meeting the constraints of underwing line replaceable units (LRUs). Summary of the Invention

[0006] Therefore, the main purpose of the present invention is to provide a large-diameter rotary transformer, divided into four equal parts, whose maintenance is facilitated and does not interfere with other systems and modules of an aircraft turbine engine, despite being installed in a confined area, restricted and difficult to access. Another objective is to industrialize such a rotary transformer at a low cost and to limit material waste during its manufacture.

[0007] These objectives are achieved by a rotary transformer intended to be mounted around a rotating movable shaft, the rotary transformer consisting of a plurality of outer annular stator parts and a plurality of inner annular rotor parts, these outer annular stator and inner annular rotor parts being juxtaposed through 360° to form an outer stator ring and an inner rotor ring comprising a set of elementary stator magnetic circuits and elementary rotor magnetic circuits, each elementary stator magnetic circuit comprising an outer magnetic core and a first electric winding; and each elementary rotor magnetic circuit comprising an inner magnetic core and a second electric winding, allowing electrical energy to be transmitted between the outer stator ring and the inner rotor ring by electromagnetic induction, the inner magnetic core and the outer magnetic core being separated by two air gaps present on either side of the inner magnetic core, characterized in that at least the outer magnetic core has an extension at each of the two air gaps to avoid discontinuity of the magnetic field lines during rotation of the movable shaft, and the inner rotor annular segments are identical and interchangeable with each other.

[0008] Thus, through this contactless power transmission, the reliability, lifespan, and operating costs of the transformer are improved. Furthermore, better access to the transformer is achieved, facilitating its integration into aircraft turbine engine systems and modules. This rotary transformer is advantageously used for electrical de-icing of aircraft turbine engine propeller blades.

[0009] Preferably, the outer stator ring segments are identical and interchangeable with each other, and the number of elementary stator magnetic circuits and elementary rotor magnetic circuits of each ring segment differs from the number of stators and the number of rotors.

[0010] Advantageously, the outer stator annular segments are electrically interconnected to each other by interconnection members which are accessible for assembly / disassembly through circumferential access openings, and the inner rotor annular segments are electrically interconnected to each other and accessible for assembly / disassembly through circumferential access openings.

[0011] Preferably, the inner magnetic core and the outer magnetic core are formed of a stack of laminations, a wound lamination or a magnetic powder block.

[0012] Advantageously, the laminations are in the form of packets of laminations of magnetic material such as FeSi, FeNi or FeCo, the rolls are in the form of amorphous or nanocrystalline magnetic material, and the magnetic compacts are in the form of amorphous powders.

[0013] Preferably, the outer core has a C or U shape terminating in an extension at the level of the air gap, and the inner core has an H shape defining an extension at the level of the air gap.

[0014] Advantageously, the extension is formed by a rod having a notch, such that the branches of the C or U are inserted into the notch, thereby providing a larger contact surface between the branches and the rod.

[0015] According to an exemplary embodiment, the U-shaped outer core is obtained by cutting a magnetic torus formed by rolling a sheet into two parts, and the extension portion is obtained by cutting a cylindrical magnetic torus formed by rolling a sheet into four quarter arcs.

[0016] According to another exemplary embodiment, the outer magnetic core is formed by an interlocking of three sets of U-shaped sheet packs.

[0017] According to another exemplary embodiment, the outer core is formed by a C-shaped part, the parts on either side of the central portion of which are machined to obtain extensions at the level of the air gap.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other characteristics and advantages of the invention will emerge more clearly from the description given below, with reference to the accompanying drawings, which show exemplary embodiments without any limiting character, and in which:

[0020] Figure 1 shows a portion of an aircraft turbine engine in which a rotary transformer according to the invention is integrated;

[0021] Figure 2 Shows Figure 1 One quarter of the resolver;

[0022] Figure 3 Shows the composition Figure 2 A first example of a resolver quarter stator and rotor magnetic circuit;

[0023] Figure 4 Shows the composition Figure 2 A second example of a resolver quarter stator and rotor core;

[0024] Figure 5 Shows the composition Figure 2 A third example of a resolver quarter stator and rotor core;

[0025] Figure 6 Shows the composition Figure 2 A variant of the stator of the third example of a rotary transformer quarter stator and rotor core;

[0026] Figure 7 Shows the composition Figure 2 A fourth example of a resolver quarter stator and rotor core, and;

[0027] Figure 8 Shows the composition Figure 2 Fifth example of a resolver quarter stator and rotor cores. DETAILED DESCRIPTION

[0028] The principle of implementation of the invention is based on the division of the rotary transformer into several annular segments or quarters, each of which has a quality and a replacement time adapted to ground maintenance operations, which limits the downtime of the aircraft and makes the replacement intervention (assembly / disassembly) very convenient, and can be carried out using conventional tools through dedicated access ports, without having to disassemble or interfere with other parts of the aircraft turbine engine.

[0029] like Figure 1 , which is part of an aircraft turbine engine, a rotary transformer 10 according to the invention is mounted between a rotatably movable transmission shaft 12 forming the rotating part of the turbine engine and a casing 14 forming the stationary part of the turbine engine, the casing 14 being provided with a circumferential access opening 14 a through which each quarter portion or annular sector of the rotary transformer can be accessed for installation or easily removed for repair or maintenance and then reinstalled once these replacement interventions have been carried out.

[0030] Figure 2 More specifically, an annular segment or quarter 20 of the rotary transformer 10 is shown. In the example shown, the rotary transformer 10 includes two axially offset redundant channels (labeled with reference numerals a and b). Each channel includes a stationary stator quarter 22a, 22b fixed to the housing and a rotating rotor quarter 24a, 24b fixed to the drive shaft. The rotor and stator quarter of each channel are mounted concentrically and separated by an air gap (visible in the lower figure). The rotary transformer, formed by the quarters 20 arranged 360°, has a large diameter on the order of one meter or more, which allows the rotor to accommodate a drive shaft of similarly large diameter, such as a propeller shaft.

[0031] According to the present invention, these different annular segments of the stator and rotor are juxtaposed 360° to form an outer stator ring comprising a plurality of single-phase basic stator magnetic circuits and an inner rotor ring comprising a plurality of single-phase basic rotor magnetic circuits. The outer stator ring comprises a stator core 30 and a first (primary 32) electrical winding, and the inner rotor ring comprises a rotor core 34 and a second (secondary 36) electrical winding. The stator core and the rotor core are separated by the same air gap present on both sides of the rotor core, and these segments can be electrically interconnected in series or in parallel for transmitting electrical energy through electromagnetic induction between the first and second electrical windings of these basic stator magnetic circuits and basic rotor magnetic circuits. The respective annular segments on the stator and rotor are identical and interchangeable with each other. On the other hand, the number of these basic magnetic circuits per annular segment is not necessarily the same as that of the stator and rotor. The selection of the number of magnetic circuits of the stator and rotor is guided by design and performance optimization considerations.

[0032] The annular segments of the stator or rotor are designed as LRUs (Line Replaceable Units) which can be removed and replaced under the wing through a circumferential access hatch 14a. They are electrically interconnected by interconnecting components (not shown) which can also be accessed through the circumferential access hatch 14a for assembly / disassembly.

[0033] Note that in the shown case where the power transmission solution is redundant, the annular segment in the stator or rotor is composed of all elements of two identical channels arranged side by side in the axial plane.

[0034] Depending on the envisaged frequency of use, the type of material used for the magnetic core may be different. Thus, for low-frequency use, it is conceivable that the stator and rotor are in the form of stacked sheets of magnetic material (for example FeSi, FeNi or FeCo). For medium-frequency or high-frequency use, it is conceivable that the stator and rotor are in the form of cores in the form of amorphous or nanocrystalline rolled sheets or powder blocks of any other suitable magnetic material (for example formed from amorphous powder). However, a mixture of materials is possible and it is conceivable that the stator is made of medium-frequency or high-frequency material and the rotor is made of low-frequency material, or vice versa.

[0035] Figures 3 to 8 Different possible topologies of each basic magnetic circuit of the stator and rotor are shown, allowing the production of a rotary transformer according to the invention. Note that such a magnetic circuit can be mounted horizontally (axial air gap as shown) or vertically (radial air gap). These topologies all have in common the fact that the stator core (or outer stator core 30) has an extension 30a, 30b at each of the two air gaps 38a, 38b, which corresponds to the stator and improves the power transmission efficiency by avoiding discontinuities in the magnetic lines of force during the rotation of the movable shaft. The rotor core (or inner rotor core 34) can also be provided with or without extensions 34a, 34b (see for example Figure 5 and Figure 6 ). It should be noted that for reasons of simplicity only the stator and rotor cores are shown. Figures 4 to 8 The electrical windings 32, 36 not shown in the figure can be wired or tape wound according to different constraints of integration and performance to be met, and the three-wire series appearing on the core often show the arrangement of the sheets that make them up.

[0036] exist Figure 3 In the embodiment of the present invention, corresponding to low-frequency use, the outer core or stator core 30 has a U-shape terminating in extensions 30a, 30b at the level of two axial air gaps 38a, 38b. The inner core or rotor core 34 has an H-shape defining extensions 34a, 34b at the level of the two axial air gaps present on either side of the inner core 34.

[0037] Figure 4An economical embodiment for medium or high frequency applications without wasting material is shown, wherein the inner core 40 has an H-shape obtained by stacking sheets in a vertical plane, and the outer core 42 is composed of a three-part assembly: a U-shaped part 44, formed by cutting a magnetic torus formed from rolled sheet into two parts, and two extensions 46, 48, formed by cutting a cylindrical magnetic torus formed from rolled sheet into four quartered arcs. The shape of the extension can, of course, be adjusted for weight reduction by modifying the width of the joint surface between the extension and the U-shaped part 44.

[0038] exist Figure 5 In FIG, a C-shaped outer core 50 is cut at the air gap to make room for adding rods 52, 54 on each side of the cut to form extensions, between which an I-shaped inner core 56 is arranged so that the inner core has no extensions. Figure 6 As shown, these rods 52 , 54 may advantageously each have a notch 58 allowing the branches 50 a , 50 b of the C-shaped part to be inserted therein and thus providing a larger contact surface between the two parts (C / rods).

[0039] exist Figure 7 In an exemplary embodiment, more particularly adapted for low-frequency use and without wasting material when cutting, the inner core 60 also has an H shape, formed by stacking sheets in a vertical plane, and the outer core 62 is composed of three U-shaped sheet packages 64, 66, 68 interlocked.

[0040] at last, Figure 8 Another particularly robust exemplary embodiment is shown, having an outer core obtained by simple machining of a C-shaped part 70, the initial width of which is equal to the width of the extension at the level of the air gap, as shown in the figure. The material corresponding to portions 72 and 74 and not in contact with portions 76 and 78 forming the extension is removed along the cutting lines indicated by dashed lines in the figure, leaving only a central portion 80. Thus, a final core is obtained whose width is less than the width of the extension at the level of the electrical winding channel. The inner core (not shown) can be H-shaped or I-shaped.

[0041] If the de-icing of aircraft turbine engine propeller blades is mentioned as an application, other possible applications, particularly in the aviation industry, can benefit from the use of resolvers. For example, we can use feedback information from torque sensors used for variable pitch aircraft blades and helicopter propeller pitch setting. For such applications, removing the traditional friction brush collector and replacing it with a resolver is advantageous because it eliminates the risk of failure due to brush wear, making the equipment more reliable.

Claims

1. A rotary transformer (10) for mounting around a rotating movable shaft (12), the rotary transformer comprising a plurality of outer stator annular segments (22a, 22b) and a plurality of inner rotor annular segments (24a, 24b); the outer stator annular segments and the inner rotor annular segments being juxtaposed 360° to form outer stator rings and inner rotor rings consisting of elementary stator magnetic circuits and elementary rotor magnetic circuits, each elementary stator magnetic circuit comprising an outer magnetic core (30, 42, 52, 62, 70) and a first electric winding (32), and each elementary rotor magnetic circuit comprising an inner magnetic core (34, 40, 56, 60, 76) and a second electric winding (36), so as to enable transmission of electrical energy by electromagnetic induction between the outer stator rings and the inner rotor rings, the inner magnetic cores and the outer magnetic cores being mounted concentrically and separated by two axial air gaps (38a, 38b) present on either side of the inner magnetic core, characterized in that At least the outer core (30) has an extension (30a, 30b) at each of the two air gaps (38a, 38b) to avoid discontinuity of magnetic field lines during rotation of the movable shaft (12), and the inner rotor annular segments are identical and interchangeable with each other.

2. The rotary transformer according to claim 1, wherein: The outer stator ring segments are identical and interchangeable with each other.

3. The rotary transformer according to claim 1, wherein: The number of elementary stator magnetic circuits and elementary rotor magnetic circuits per annular segment differs from the stator and rotor.

4. The rotary transformer according to claim 1 or 2, wherein: The outer stator ring segments are electrically interconnected by interconnecting components which are accessed for assembly / disassembly through circumferential access openings (14a).

5. The rotary transformer according to claim 4, wherein: The inner rotor annular segments are electrically interconnected and accessible for assembly / disassembly through the circumferential access opening (14a).

6. The rotary transformer according to any one of claims 1 to 5, wherein: The inner and outer magnetic cores (30, 42, 52, 62, 70; 34, 40, 56, 60, 76) are in the form of sheet stacks, rolled sheets or magnetic powder blocks.

7. The rotary transformer according to claim 6, wherein: The sheet stack is in the form of a sheet package of a magnetic material such as FeSi, FeNi or FeCo, the rolled sheet is in the form of an amorphous or nanocrystalline magnetic material, and the magnetic powder block is an amorphous powder.

8. The rotary transformer according to any one of claims 1 to 7, wherein: The outer core (30, 42, 52, 62, 70) has a C-shape or a U-shape ending in an extension (30a, 30b, 46, 48, 52, 54, 66, 68) at an air gap; the inner core (34, 40, 56, 60, 76) has an H-shape defining an extension (34a, 34b) at an air gap, or an I-shape without an extension.

9. The rotary transformer according to claim 8, wherein: The extensions (52, 54; 66, 68) are formed by a rod having a notch (58) which receives a C-shaped or U-shaped branch for insertion and thus provides a larger contact surface between the branch and the rod.

10. The rotary transformer according to claim 8, wherein: The outer magnetic core (42) is formed by cutting a magnetic torus formed by a rolled sheet (44) into two parts, and the extensions (46, 48) are formed by cutting a cylindrical magnetic torus formed by a rolled sheet (44) into four quartered arcs.

11. The rotary transformer according to claim 8, wherein: The outer magnetic core (62) is formed by interlocking three groups of U-shaped sheet packages (64, 66, 68).

12. The rotary transformer according to claim 8, wherein: The outer core is formed from a C-shaped part (70) whose portions (72, 74) on either side of a central part (80) are machined to obtain extensions (76, 78) at the air gap.

13. Use of a rotary transformer according to any one of claims 1 to 12 for the electrical de-icing of propeller blades of an aircraft turbine engine.

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