EP1397938A2

EP1397938A2 - Loudspeaker

Info

Publication number: EP1397938A2
Application number: EP02737944A
Authority: EP
Inventors: Leonhard Kreitmeier; Jürgen RINGLSTETTER
Original assignee: Harman Becker Automotive Systems GmbH; Harman Becker Automotive Systems Straubing Division GmbH
Current assignee: Harman Becker Automotive Systems GmbH
Priority date: 2001-04-25
Filing date: 2002-04-11
Publication date: 2004-03-17
Also published as: WO2002089522A2; WO2002089522A3; DE10120281C1; US20040165746A1; US7292707B2

Abstract

A loudspeaker consisting of a diaphragm, an oscillation coil carrier secured to the diaphragm in a central area, an oscillation coil wound around said oscillation coil carrier, a magnet system which is inserted into the oscillation coil carrier and oscillation coil in a partial or complete manner, a basket supporting the magnet system and enclosing the diaphragm on one half side thereof, an elastic bead secured to the basket and an edge area of the diaphragm, and a centering device fixed to the basket and secured to the diaphragm in a central area, said centering device being provided with an elastic bead which is directly or indirectly secured to the basket and the diaphragm.

Description

description

speaker

The invention relates to a loudspeaker with a membrane having an edge area and a central area; a voice coil bobbin attached to the diaphragm in the central area; a voice coil wound around the voice coil bobbin; a magnet system in which the voice coil carrier and voice coil are fully or partially immersed; a basket that half-encloses the membrane and to which the magnet system is attached; an elastic bead, which is attached on the one hand to the edge area of the membrane and on the other hand to the basket; and a centering device that is attached to the central area of the membrane on the one hand and to the basket on the other.

Such a loudspeaker is known, for example, from Ivar Veit, Technical Acoustics, second edition 1978, page 91, a centering spider attached to the basket and membrane being provided as the centering device. The current in the voice coil and the magnetic field in the air gap of the magnet system interact with one another in such a way that Lorentz forces occur in the direction of the axis of symmetry. This converts the input voltage at the voice coil into a mechanical movement of the voice coil and, accordingly, the diaphragm. The suspension of the vibratory system, consisting of a bead and a centering spider, generates restoring forces and holds the voice coil, which is connected to the radiating diaphragm, in position. The damping in this oscillating overall system is now carried out electrically on the one hand by the magnet system and mechanically by the suspension consisting of a bead and centering spider.

Since the magnetic force and thus the electrical damping in the working area of the loudspeaker is not constant with standard loudspeakers, this results in a deflection-dependent total damping, which weakens towards large excursions. Constructions that avoid this are large and cannot be economically manufactured due to the large winding widths and strong magnets required.

For this reason, it is necessary to increase the mechanical damping, with the result that the variation in the total damping becomes smaller. In addition, the material and type of movement of the centering spider, in particular due to bends in the edge area and stretching in the main area, mean that it does not contribute any significant part to the overall damping.

The object of the present invention is to provide a loudspeaker in which the mechanical damping is increased.

The object is achieved by a loudspeaker according to claim 1. Refinements and developments of the inventive concept are the subject of subclaims.

The advantage of the invention is that high mechanical damping is achieved with little effort. A desired damping range can also be achieved through easy-to-implement variations in material and construction.

This is achieved in detail in the case of a loudspeaker of the type mentioned at the outset in that a further elastic bead is provided as the centering device, which is attached directly or indirectly to the basket and membrane.

At least one of the two beads is preferably made of foam or rubber. The influencing components for achieving the desired damping in the case of foam beads are in particular the type of material, the density and the thickness of the bead. For rubber surrounds, these are the type of material, the thickness and the shear hardness. The further bead is preferably attached indirectly or directly to the membrane and / or the basket by means of a bead holder. The bead holder can be provided by any structure, such as, for example, an injection molded part, a honeycomb structure, a membrane or another shaped part.

Furthermore, a support structure can be provided, which can be arranged between the membrane and a further bead and can be connected directly or indirectly to both. Filling or support structures serve to stiffen the entire membrane or partial areas of the membrane in order to suppress certain modes.

Such a support structure can, for example, also be arranged between the membrane and the bead holder and can be connected directly or indirectly to the latter.

The support structure preferably consists essentially of honeycomb material or of foamed material. In addition, the support structure can also consist of membrane material.

The invention is also used in particular in loudspeakers whose diaphragm is essentially flat, the support structure and / or the bead holder

The distance between the two beads compensates for each other in the direction of vibration of the membrane.

In particular, an inverse membrane cone is used as the support structure.

In addition, it can be provided that in addition to the one further bead, at least one second additional bead is provided, which is attached directly or indirectly to the membrane and basket. Furthermore, it can be provided that at least one further bead has a semicircular bend and a flat area, the thickness of the bead being smaller in the area of the bend than in the flat area.

The support structure can also be designed as a bead holder.

Finally, the magnet system can be arranged so that it is arranged on the side of the basket facing the membrane. This results in a very compact design, in particular of a flat speaker.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the figures of the drawing, half of a rotationally symmetrical structure being shown in each case in cross section. In detail shows:

FIG. 1: a basic embodiment of a loudspeaker according to the invention,

FIG. 2: the loudspeaker according to FIG. 1 with an additional support structure,

Figure 3: an embodiment of an inventive

Loudspeaker with a flat diaphragm,

Figure 4: the embodiment of Figure 3 with additional

Support structure

Figure 5: an embodiment of an inventive

Speaker with multiple beads,

FIG. 6: an embodiment of a loudspeaker according to the invention with a shape of the bead which is optimized with regard to the attenuation curve over the membrane deflection, Figure 7: the optimized bead according to the embodiment of Figure 6 in detail and compared to a conventional bead and

Figure 8: an embodiment of a loudspeaker according to the invention with a raised magnet system.

Figure 1 shows half of the cross section of a basic embodiment of a loudspeaker according to the invention. A funnel-shaped basket 1 is provided as an essential supporting element, in which an opening is made at least in the central area and a pot-shaped magnet system 2 is fastened. At a central opening in the basket 1, a voice coil 3 is arranged, which is axially movable through the opening in the basket and dips into the magnet system 2. The voice coil 3 is wound around a voice coil support 4, which in turn is attached to a membrane 5. The membrane 5 is attached to the outer region of the basket 1 so that it can vibrate via a bead 6. In the area of the connection between the voice coil support 4 and the membrane 5, a dust protection cap 7 is provided to protect the drive system consisting of the magnet system 2 and the voice coil 3 from the ingress of dust.

According to the invention, a further bead 8 is now provided as the centering device, which is attached on the one hand to a corresponding projection of the basket 1 and on the other hand is connected to the central area of the membrane 5 with the interposition of a bead holder 9. With a corresponding design of the further beads 8, the bead holder 9 could also be dispensed with, but a bead holder is required, for example, if the two beads 6 and 8 are of identical design. Since a bead, in contrast to the usual centering membrane, is not so extensive, the bead holder 9 is also used in particular to compensate for the distance between the further bead 8 and the membrane 5. The bead holder 9 can be any molded part made of any material, provided that it meets the spatial requirements and is as light as possible. A plastic injection molded part or a further, adapted membrane is therefore preferably provided as the bead holder.

The exemplary embodiment shown in FIG. 2 emerges from the exemplary embodiment according to FIG. 1 in that a support structure 10 is additionally provided. The support structure 10 is wedge-shaped and arranged at the angle between the membrane 5 and the bead holder 9. It runs sharply towards the interface between membrane 5 and bead holder 9 and is glued to both, for example. The support structure 10 can be located, for example, in the area of the loudspeaker on which the movable parts of the centering membrane used to be. The support structure 10 is designed, for example, as a honeycomb structure or as a foamed part.

In the embodiment shown in FIG. 3, a basket 11 is provided which has an opening at a central point which is closed to the outside by a pot-shaped magnet system. Through the opening in the basket 11, a voice coil 13, which is wound on a voice coil support 14, plunges into the magnet system 12. The voice coil former 14 is connected essentially at right angles to a flat membrane 15, which in turn is firmly connected to a bead 16. The bead 16 is fastened on its edge facing away from the flat membrane 15 to the outer edge region of the basket 11.

A further bead 17 is in turn provided as the centering device, which is attached on the one hand via a bead holder 18 at the interface between the voice coil support 14 and the flat membrane 15 and on the other hand is firmly connected to the basket 11 via a spacer element 19. When used in a flat membrane speaker, the bead holder 18 is designed so that the required height distance between the two 1 φ ß ß

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be separated. The addition of a further bead in the function of the centering device increases the available mechanical damping. The mechanical damping of the entire vibration system can thus be further increased by adding additional suspension elements. The number of further beads depends in particular on the necessary size of the vibrating mass and the resulting efficiency.

The exemplary embodiment shown in FIG. 6 has been modified from the exemplary embodiment shown in FIG. 1 to the effect that a specially designed bead 25 is now used instead of the bead 8.

In Figure 7, the two beads 8 and 25 are placed opposite each other. The bead 8 used in Figure 1 has a constant thickness over the entire radial extent, i.e. a constant extent perpendicular to the radial direction. In contrast, the modified bead 25 is tapered in the area of the central bend 26 and reinforced in the transition areas 27 from the middle bend to the edge surfaces.

If the bead or the bead construction, which takes over the centering function, is geometrically specially shaped (for example, as shown), then both the damping curve and the rigidity over the membrane deflection can be modulated and optimized.

In the exemplary embodiment of a loudspeaker according to the invention shown in FIG. 3, the arrangement shown in FIG. 3 is again assumed. However, the arrangement was changed in such a way that a magnet system 28 is now used instead of the magnet system 12 that, seen from the flat membrane 15, is not behind the basket 11 as shown in FIG. 3, but in front of the basket 11, that is to say to the flat membrane 15 is arranged out. Accordingly, will be in place of the voice coil bobbin 14 uses a shortened voice coil bobbin 29.

Furthermore, a support structure 30 is provided, which is wedge-shaped and is introduced into the angle formed by flat membrane 15 and bead holder 18 such that it is connected to the flat membrane 15 over its entire area, for example by gluing, and on the other hand to it that section of the further bead 17 which is also fastened to the bead holder 18 is also connected, for example by adhesive bonding, on the opposite side thereof. Depending on the application, the bead holder 18 can also be dispensed with and the support structure 30 can be used as the bead holder.

In particular by using an NdFe pot magnet system or a corresponding magnet system with small dimensions, increasing the height of this magnet system can reduce the overall depth of the loudspeaker without influencing its deflectability.

LIST OF REFERENCE NUMBERS

1 basket

2 magnet system 3 voice coil

4 voice coil carriers

5 membrane

6 beads

7 dust protection cap 8 additional beads

9 bead holder

10 support structure

11 basket

12 magnet system 13 voice coil

14 voice coil carriers

15 flat membrane

16 beads

17 additional beads 18 bead holders

19 spacer

20 support structure

21 more beads

22 further beads 23 bead holder

24 bead holder

25 surround

26 middle bend

27 transition 28 magnet system;

29 voice coil bobbins

30 support structure

Claims

claims

1 . Loudspeaker with a membrane (5, 15) which has an edge area and a central area, a voice coil support (4, 14, 29) which is fastened to the membrane (5, 15) in the central area, a voice coil (3, 13), which is wound around the voice coil support (4, 14, 29), a magnet system (2, 12, 28) into which the voice coil support (4, 14, 29) and voice coil (3, 13) are completely or partially immersed, a basket ( 1, 11), which surrounds the membrane (5, 15) on one side and to which the magnet system (2, 12, 28) is fastened, an elastic bead (6, 16), which on the one hand on the edge area of the membrane (5, 15 ) and on the other hand is attached to the basket (1, 11), and a centering device which is attached on the one hand to the central region of the membrane (5, 15) and on the other hand to the basket (1, 11), characterized in that the centering device has a further elastic Has beads (8, 17, 21, 22, 25) that directly or indirectly attach to the basket (1,11) and membrane (5, 15) is.

2. Loudspeaker according to claim 1, characterized in that the further bead (8, 17, 21, 22, 25) by means of a bead holder (9, 18, 23, 24) on the membrane (5, 15) and / or the basket (1, 11) is attached directly or indirectly.

3. Loudspeaker according to claim 1 or 2, characterized in that a support structure (10, 20, 30) is provided, arranged between the diaphragm (5, 15) and further bead (8, 17) and directly or indirectly with these connected is.

4. Loudspeaker according to claim 1 or 2, characterized in that a support structure (10, 20, 30) is provided, which is arranged between the membrane (5, 15) and bead holder (8, 9, 17, 18, 23, 24) is directly or indirectly connected to them

5. Loudspeaker according to claim 3 or 4, characterized in that the support structure (10, 20, 30) consists essentially of honeycomb material.

6. Loudspeaker according to claim 3 or 4, characterized in that the support structure (10, 20, 30) consists essentially of foamed material.

7. Loudspeaker according to claim 3 or 4, characterized in that the support structure (10, 20, 30) consists essentially of membrane material.

8. Loudspeaker according to one of claims 2 to 7, characterized in that the membrane (15) is substantially flat and the support structure (20, 30) and / or the bead holder (9, 18, 23, 24) the distance of the Corrugations (6, 16, 8, 17, 21, 22, 25) compensate for each other in the direction of vibration of the membrane.

9. Loudspeaker according to claim 7 or 8, characterized in that an inverse membrane cone is provided as the bead holder (9, 18, 23, 24).

10. Loudspeaker according to one of claims 2 to 7, characterized in that at least one second further bead (22) is provided, which is attached directly or indirectly to the membrane (5, 15) and the basket (1, 11).

11. Loudspeaker according to one of claims 1 to 10, characterized in that at least one further bead (25) has a semicircular bend and a flat area, the thickness of the bead in the area of the bend being less than in the flat area.

12. Loudspeaker according to one of claims 1 to 11, characterized in that the support structure (20, 30) also serves as a bead holder.

13. Loudspeaker according to one of claims 1 to 11, characterized in that the magnet system (28) is arranged on the side of the basket (11) facing the membrane (15).