FR2931334A1 - Electrodynamic loudspeaker device for use on e.g. acoustic baffle, has movable assembly fixed to sealed chassis at level of spacer by pleated impregnated fabric positioner, and at periphery of faces of membrane by double suspension - Google Patents

Abstract

The device has a hollow membrane with distant faces (1a, 1b) joined by a concentric tubular spacer (2) traversing an annular magnetic circuit of an internal motor. The membrane is interiorly actuated by a spool (4) that evolves in a gap (8) of the circuit and carried by a tubular support (3). A movable assembly is fixed to a sealed chassis (11) at the level of the spacer by a pleated impregnated fabric positioner (9), and at periphery of the faces by a double suspension formed of reversed sealed rubber semi-rings (10a, 10b). The faces, spacer, spool and the support form the assembly.

Description

The present invention relates to an electrodynamic loudspeaker device intended for the reproduction of low frequencies in air, dusty, gaseous or liquid medium.

In principle, in the electrodynamic loudspeaker, a coil, traversed by a variable current and carrying a membrane, moves along the axis of a dipolar magnet. A tight separation is maintained between the two faces of the membrane to avoid destructive interference produced by their counter-phase radiation.

In practice, the coil is wound on an upright cylindrical support often confined to the small base of a truncated right cone whose membrane forms the edge and the magnet an annular magnetic circuit in which is practiced the concentric air gap. where the coil goes. The magnetic circuit carries an open frame, often in an inverted truncated cone (ventilated basket or salad bowl, acoustically transparent), which receives the moving equipment, possibly acts as a heat sink, and provides for fixing and waterproof baffling. , plane or closed, of the loudspeaker. The mobile equipment is completed and connected to the frame, the two faces of the membrane isolated, and the voice coil positioned and balanced in the axis of the air gap: 25 - at the periphery of the membrane: by a sealed suspension; - at the junction of the often conical membrane and the support of the voice coil: by a flexible centering device.

30 This is the paradigm. Designed in this way, often built around a cone-shaped membrane (right cone radiating from the base and actuated by the top), the electrodynamic loudspeaker traditionally suffers from the inconvenience of congestion, restriction of action, limitations use, difficulty of design 35 and asymmetry of presentation following: - deep space: chassis and magnetic circuit must accommodate the height of the moving equipment (addition of the height of the conical membrane and the support of the voice coil which is accoled) increased by the peak amplitude of its displacement at the level of the peripheral suspension, the centraliser and the heel (bottom of the gap);

concentration of the action on the membrane at a single, central point (the circumference of the small base of the truncated right cone 10 whose membrane forms the ridge);

- opening of the chassis (ventilation, acoustic transparency necessary for the free back radiation of the membrane) because of a potential vulnerability • to dust - metal particles in particular, • effective to hygrometric variations, • strong to gaseous fluids, damaging to liquids, limiting its use, as it is, only for use in a dry atmosphere;

- Achieving the chassis offering a difficult compromise between aeration (opening, acoustic transparency), rigidity and thermal conductivity, possibly at high power and high acoustic pressures, supported;

- distinct aesthetics for both sides of the speaker having a membrane side and a motor side.

Various manufacturers have equipped or equip some of their electrodynamic loudspeakers with flat membranes (made of a solid cone of polystyrene or formed of a honeycomb sandwich). This modification, made by simple substitution, justified by acoustic considerations or dictated by aesthetic imperatives, partially remedies the first disadvantage mentioned (the encumbrance in depth); it does not release the electrodynamic loudspeaker of the other restrictions of action, 2931334 - 3 - limitations of use, difficulty of conception and asymmetry of presentation noted above.

The device according to the invention makes it possible to free the electrodynamic loudspeaker from all these constraints. It comprises indeed, according to a first characterization:

- a hollow membrane and pane (H-shaped capital lying, side view) whose two remote faces are held rigidly 10 united by one or more spacers;

- one or more motors, arranged in series, in parallel or in parallel series, incorporated in the membrane (actuated from the inside); - A closed frame, necessarily closed, naturally sealed, that is to say a housing, structurally rigid and notable surface;

20 - a potentially completely symmetrical external presentation: the two faces of the speaker - those of the membrane - are indeed a priori identical;

According to particular embodiments: the planar membrane (honeycomb sandwich structure with ceramic skin, composite or other), possibly curved but still hollow profile, may be circular, elliptical, rectangular, square , hybrid (square and circle for example) or any other desired form; the two faces of the membrane, precisely spaced apart and rigidly united by one or more spacers, may be, at their periphery, connected to the frame by a double outer suspension sealed in a half-roll of rubber or flat pleated impregnated cloth; The internal faces of the membrane are acoustically disconnected and the external faces isolated from each other by a sealed, closed, sealed frame; - Made in the form of rods, tubes, columns, pillars, bars, beams, or spacers rigidly joining the two faces of the membrane can be • internal and concentric to the (x) engine (s) if the engine used is external air gap or piercing of the core and perimeter of the rear field plate in the case of a motor with internal air gap; • external and eccentric to the motor (s) - the spacers possibly cross the sole that carries and brings the engine (s) to the chassis; in the form of tubes, hollow (possibly perforated or pierced with lumens), the spacer (s) rigidly joining the two faces of the membrane may optionally house sensors and electronic circuits, analyzers, comparators, compensators, flexible or rigid, but also desiccant;

in the form of tubes again, hollow (and sealed), the spacer (s) rigidly joining the two faces of the membrane may possibly contribute to the production of a mechanical low-pass or acoustic band-pass filter;

- An engine represents one or more magnets (rings, no-pins), contiguous faces or not, the common magnetic circuits associated with them and the coil or coils circulating in the air gap or gaps that are practiced there; designed around an annular magnet, the motor may be of internal and / or external type, the air gap - in U, seen in profile - being internal and / or external to the barium ferrite rings - FeBa - or neodymium and Boron - NdFeB - (or Yttrium Ferrite, Dysprosium and Boron - YdyFeB - in the near future) more or less commonly used; -. 5 - - in a drive configuration of internal and external type - U redoubled in capital S lying down or W seen in profile -, the double annular magnetic circuit, internal and external to the Ferrite ring, can contribute to move, exemplarily, two concentric coils or a coil and Ln sensor;

in a configuration with several motors, they can be - symmetrically - arranged • in two-engine and in series the motors are then mounted one behind the other o air-gaps back to back: the coil or coils can then be mounted on separate supports, attached to the faces of the membrane (each coil on its support actuating one side, one side or the other of the membrane); o air gaps vis-à-vis: the coaxial coil or coils are then mounted on a common support which can be rigidly united, by means of a ring, to the central spacer which connects the two faces of the membrane; o Back-to-back air-gaps (internal and external configuration in S or hippocampus), each pair of coaxial coils able to take up the previous mounting characteristics: on separate supports for a pair, on a rigidly common support united to a central spacer for the other; • in multi motors in parallel: the motors are then placed next to each other in inverted position (or not), the coils mounted on separate supports related to the 30 faces of the membrane (each coil on its support acting on one side, one side or the other of the membrane); • multi-motors in parallel series (combination of the previous ones);

35 - in the case of a two-engine configuration series (back-to-back gaps, single or double, U or W), the rear pole pieces (bottom plates and hollow central core or not) may have the following characteristics: 6 you will be common to both engines that are now only one, two (three) or four gaps - structure in capital H seen in profile; in all cases of configuration and mounting of the motors (internal and / or external air gaps, in U, in S or in W, back to back and / or vis-à-vis, in series and / or in parallel, H-structure, other, or not), the coaxial coils or coils can be mounted on a common support confused with a spacer connecting the two faces of the membrane; the bottom plates of the motors are then in place concentrically split, in the axis of the gap (at the heel), recessed, to allow passage to the spacer / support coil - spacer / longitudinal support-ment perforated in its central portion or one and / or the other of its ends depending on the configuration and mounting of the motors;

- the motor (s) - magnetic circuits and mobile coil (s) if not their (s) supports) - may be possibly removed to achieve a passive radiator (passive mechanical resonator);

- The centering of the one or more moving coils can be reinforced and / or offset on the spacers rigidly joining the two fa-ces of the membrane; in the case of a passive radiator or a twin-engine configuration with a central spacer or spacer merged with the voice coil support, the centralizer, internal to the motors (as in their absence), can be unique, geometrically centered, and the mobile equipment suspended diabolo; - The centering of the mobile coil or coils can be optionally removed, its role then being devolved to the double external suspension of the membrane - flat suspension pleated impregnated fabric construction and lateral stiffness characteristics similar to those of a centraliser; - closed by acoustic necessity, the chassis became a case in principle married as close to the organs of the speaker as -. 7 - clutch - respecting shape and profile of the membrane, engine dimensions, centering convenience and elongation provisions; seen in profile, the casing forms an H, and its construction is similar to that of a rim whose hub would be a single-engine or twin-engine; this frame / electrodynamic rim may be provided with clamping jaws with an electronic tire (amplification circuit, feedback circuit, correction and filtering, otherwise power) with an elaborate connectivity; waterproof by nature and necessity (IEC protection rating: IP 66), the housing can be filled with different gases (argon, helium); a pressure regulator (tire or buoy) can encircle the device for underwater use (IEC protection rating: IP 68); structurally rigid, the housing can be made in a wide variety of materials: metal, plastic, MDF (Medium Density Fiberboard), High Performance Concrete, composite, in a reduced thickness, and by a wide range of manufacturing processes: 3D printing ( rapid prototyping), sheet metal, molding, forming; of notable surface (theoretically doubling that of the membrane) the housing, made of non-magnetic metal, may possibly-ment-office, entirely of heat sink (or even, otherwise realized, thermo acoustic generator).

The accompanying drawings illustrate the invention:

Figure 1 shows in section a single engine device of the invention.

Figure 2 shows in section a two-engine device of the invention. Figure 3 shows in section a parallel multi-engine device of the invention. FIG. 4 shows in section a parallel multi-engine device of the invention. Figure 5 shows in section a single-engine device with peripheral centering of the invention. FIG. 6 is a sectional view of a passive radiator device of the invention. Figure 7 shows in section a series twin engine with vent (acoustic filter) of the invention.

Figure 8 shows in section a single-engine device with spacer / coil support, of the invention.

With reference to these drawings, the device comprises a planar hollow membrane (1) whose two remote faces (1a and 1b) are kept precisely separated and rigidly united by a concentrigse tubular spacer (2) which internally passes through the annular magnetic circuit - plate of fields (5), annular magnet (6) and bottom plate (7) of the motor (4, 5, 6, 7, 8) inserted into the closed frame (11) and internal to the membrane (1).

The membrane (1) is internally actuated, on one of its faces (la), by the tubular support (3) of the cylindrical moving coil (4), evolving in the external gap (8) of the magnetic circuit (5, 6). and 7), which is rigidly attached to it. The moving element (1a and 1b, 2, 3, 4) is completed and attached to the closed frame (11), at the level of the tubular spacer (2), by a pleated impregnated fabric flat centering device (9), and at the periphery of the two faces of the membrane, by a double semi-roll suspension of inverted rubber tight (10a and 10b).

In the embodiment according to FIG. 2, the tubular spacer (2) which keeps the two faces (1a and 1b) of the membrane (1) precisely separated and rigidly united passes internally through the double magnetic circuit (5, 6, 7). a and b) two identical motors (4, 5, 6, 7, 8 a and b) coaxially mounted in series, opposite and spaced in the same closed frame (11). The membrane (1) is internally and symmetrically actuated on each of its faces (1a and 1b) by the tubular supports (3a and 3b) of the cylindrical coils (4a and 4b), evolving in the outer air gaps (8a and 8b) of the circuits coaxial magnetic resins (5, 6, 7 a and b), which are rigidly contiguous to them. The movable element (la and lb, 2, 3a and 3b, 4a and 4b) is completed and attached to the closed frame (11), at the tubular spacer (2) and its geometric center, by a single pleated impregnated fabric flat centering device (9) and, at the periphery of the two faces of the membrane (1a and 1b), by a double semi-roll suspension of sealed inverted rubber (10a and 10b).

In the embodiment shown in FIG. 3, the device comprises a planar hollow membrane (1) with the faces (1a and 1b) hand-held precisely spaced and securely joined by a double tubular spacer (2a and 2b) which internally traverse the double magnetic circuit (5, 6, 7 a and b) of two identical motors (4, 5, 6, 7, 8 a and b) mounted parallel, contiguous and op-posed in the same closed frame (11). The membrane (1) is internally and symmetrically actuated on each of its faces (1a and 1b) by the tubular supports (3a and 3b) of the cylindrical coils (4a and 4b), evolving in the outer air gaps (8a and 8b) of the circuits contiguous magnetic systems (5, 6, 7, a and b), which are rigidly contiguous to them. The movable element (1, 2, 3, 4 a and b) is completed and attached to the closed frame (11), at the level of the tubular spacers (2a and 2b), by a double flat centering device made of pleated impregnated fabric (9a and 9b) and, at the periphery of the two faces of the membrane (1a and 1b), by a double half-roll suspension of in-sealed rubber (10a and 10b).

In the embodiment according to FIG. 4, the double tubular spacer (2a and 2b) which keeps the two faces (1a and 1b) of the diaphragm (1) precisely separated and rigidly united passes internally through the quadruple magnetic circuit (5, 6). , 7a, b, c, d) of four identical motors (4, 5, 6, 7, 8a, b, c, d) connected in series parallel, coaxially opposed and spaced apart in a same closed frame (11 ). The membrane (1) is internally and symmetrically actuated on each of its faces (la and lb) by the tubular supports (3 a, b, c and d) of the cylindrical coils (4 a, b, c and d), evolving in the external air gaps (8 a, b, c and d) of the coaxially connected magnetic circuits (5, 6, 7 a, b, c and d) which are rigidly contiguous thereto. The movable element (1 and 2 a and b, 3 and 4 a, b, c and d) is completed and attached to the closed frame (11), at the level of the tubular connecting struts (2a and 2b), by a flat dual pleated impregnated fabric centering device (9a and 9b) and, at the periphery of the two faces of the membrane (1a and 1b), by a double suspension in inverted waterproof rubber roll (10a and 10b) .

In the embodiment according to FIG. 5, the device comprises a planar hollow membrane (1) whose two remote faces (1a and 1b) are kept precisely separated and rigidly joined by a tubular spacer (2) which internally passes through the annular magnetic circuit (5, 6 and 7) of the motor (4, 5, 6, 7, 8) inserted into the closed frame (11) and internal to the membrane (1). The membrane (1) is internally actuated, on one of its faces (la), by the tubular support (3) of the cylindrical moving coil (4), evolving in the external gap (8) of the magnetic circuit (5, 6). 7), which is rigidly attached to it. The moving element (1a and 1b, 2, 3, 4) is centered, completed and attached to the closed frame (11), at the periphery of the two faces of the membrane, by a double folded impregnated fabric suspension (12a and 12b).

In the embodiment according to FIG. 6, the device comprises a planar hollow membrane (1) whose two remote faces (1a and 1b) are kept precisely separated and rigidly joined by a tubular spacer (2). The moving element (1, 2) is completed and attached to the closed frame (11), at the tubular spacer (2), by a pleated impregnated fabric bowl centralizer (9) and at the periphery 30 of the two sides of the membrane (la and b), by a double suspension in half-roll of rubber inverted sealed (10a and 10b).

In the embodiment according to FIG. 7, the tubular spacer (2) holds the two faces (1a and 1b) of the diaphragm (1) precisely and rigidly together and internally passes through the double magnetic circuit (5, 6). , 7 a and b) of two identical motors (4, 5, 6, 7, 8 a and b) coaxially mounted, in series, opposite and spaced apart in the same closed frame (11) is of sealed and open wall at its ends. The membrane (1), internally and symmetrically actuated on each of its faces (la and lb) by the tubular supports (3a and 3b) of the cylindrical coils (4a and 4b), evolving in the outer air gaps (8a and 8b) of the circuits magnetic coaxial (5, 6, 7 a and b), which are rigidly contiguous thereto, is pierced on each of its faces with a central opening of diameter equal to that of the spacer which joins them.

The moving element (la and lb, 2, 3a and 3b, 4a and 4b) is completed and attached to the closed frame (11), at the tubular spacer (2) and its geometric center, by a single centralizer pleated impregnated fabric plate (9) and, at the periphery of the two faces of the membrane (1a and 1b), by a double semi-roll suspension of inverted waterproof rubber (10a and 10b).

In the embodiment according to FIG. 8, the device comprises a planar, hollow membrane (1) whose two different faces (1a and 1b) are separated, united and actuated by a supporting tubular spacer (13). the cylindrical coil (4). The cylindrical coil (4) moves in the internal gap (8) of the annular magnetic circuit (5, 6, a and b, 7) of the motor (4, 5, 6a and b, 7, 8) inserted in the frame closed (11) and internal to the membrane (1).

The tubular spacer (13), which supports the cylindrical coil (4), is pierced by openings (14) and passes through the slots (15) formed therein by means of the bottom plate (7) of the motor (4, 5, 6a and b, 7, 8). The moving element (1, 13, 4) is completed, centered and attached to the closed frame (11), at the periphery of the two faces of the membrane (1 a and b), by a double suspension made of pleated impregnated fabric (12a and 12b).

By way of non-limiting example, the device will have dimen-35 sions of the order of 155 to 280 mm side or diameter and 40 to 70 mm thick. The device according to the invention is particularly intended for the reproduction of low frequencies by loudspeakers of small size in depth or in the form of a flat panel.

Claims (9)

CLAIMS1) Electrodynamic loudspeaker device for the reproduction of low frequencies characterized in that it comprises a hollow membrane (1), the two faces spaced apart (1 a and b) apart and united by a spacer (2) passing through the magnetic circuit (5, 6, 7) of the internal motor (4, 5, 6, 7, 8), actuated from the inside by a coil (4), evolving in the gap (8) carried by the support (3) attached to the face (1a), and attached to the level of the connecting strut (2), by a flexible centering device (9), and at its periphery, via a double suspension (10 a and b), to an enclosed frame forming a sealed housing (11). 2) Device according to claim 1 characterized in that the internal motorization of the hollow membrane (1) is provided by two identical motors (4, 5, 6, 7, 8 a and b) mounted coaxially, in series, spaced apart , in mirror, the hollow membrane (1) being actuated from the inside by the coils (4 a and b), evolving in the opposite air gaps (8 a and b), borne by the supports (3 a and b) contiguous respectively at each of its two faces (1 a and b). 3) Device according to claims 1 and 2 characterized in that the flexible centering device (9) of the moving element (1 a and b, 2, 3 a and b, 4 a and b, 9, 10 a and b), positioned between the serial, coaxial, spaced, mirrored motors (4, 5, 6, 7, 8 a and b) and relating to the closed frame (11) the spacer (2) which, passing through the magnetic circuits (5, 6 , 7 a and b), connects the two faces (1 a and b) of the hollow membrane (1), is unique and centered. 4) Device according to claim 1 characterized in that the internal motorization of the hollow membrane (1) is provided by two identical motors (4, 5, 6, 7, 8 a and b) mounted parallel-ment, contiguous and mirror , the hollow membrane (1) being action-born from the inside by the coils (4 a and b) evolving in the opposite air gaps (8 a and b) carried by the supports (3 a and b) contiguous respectively to each of its two faces (1 a and b) re-united by as many spacers (2 a and b) reported to as many flexible centerers (9 a and b) as engines. 5) Device according to claims 1, 2 and 4 characterized in that the internal motorization of the hollow membrane (1) is provided by two identical pairs, contiguous, of identical motors, coaxial, series, spaced apart, in a mirror (4, 5 , 6, 7, 8 a and b, c and d) mounted in parallel, the hollow membrane (1) being actuated from the inside by the pairs this coils (4 a and b, c and d) evolving in the pairs opposing air gaps (8 a and b, c and d) carried by the pairs of supports (3 a and b, c and d) respectively contiguous to each of its two: = aces (1 a and b) joined by as many spacers (2a and b) referred to as many flexible centering devices (9a and b) as pairs of series motors. 6) Device according to claims 1, 2, 4 and 5 characterized in that the centering of the moving assembly is provided by a double pleated suspension (12 a and b) connecting the periphery of each of the faces (1 a and b) from the hollow membrane (1) to the closed frame forming a sealed casing (11). 7) Loudspeaker device according to claim 1, converted by the absence of motor mechano-acoustic resonator or passive radiator for correcting the reproduction of severe frequencies, characterized in that it comprises a hollow membrane (1 ) to the two remote faces (1 a and b) separated and united by a spacer (2) attached to the spacer (2), by a flexible bowl center (9), and at its periphery, via a double suspension (10 a and b) to a closed frame forming a watertight housing (11). 8) Device according to any preceding claim characterized in that the spacer (2) which connects the remote faces (1 a and b) of the hollow membrane (1) is open at both ends and sealed wall, having shape and vent function or acoustic resonator. 9) Device according to claims 1, 2, 3, 4, 5 and 6 characterized in that it comprises a hollow membrane (1) actuated from the inside by a coil (4), moving in the gap (8) of the internal motor (4, 5, 6a and b, 7, 8) carried by the longitudinally perforated spacer (13) which passes through the split heel (bottom of the air gap) (15) of the rear fields (7) and unites its two faces (1 a and b).