Electrodynamic sound transducer for integration into the interior structure of a vehicle and vehicle with sound transducer

Abstract

The invention relates to an electrodynamic sound transducer comprising: - a transducer basket (4, 15, 23) with at least one air passage (14), wherein the transducer basket (4, 15, 23) is preferably formed as part of the supporting structure of the vehicle, - a flexible membrane (9), - a magnet system (1, 19) with a central and continuous opening (25); - a voice coil (2); - a central damper (17) arranged connectingly between the magnet system (4, 15, 23) and the membrane (9) and formed by an open structure; - additional damping (16) on partial surfaces of the underside of the membrane (9); - and optionally a support film (10, 18) on the upper side of the membrane (9), which is coated on each side with adhesive layers of varying thicknesses. The invention further relates to a vehicle equipped with such an electrodynamic sound transducer.

Description

[0001] The invention relates to an electrodynamic sound transducer, a transducer basket with at least one air passage, a flexible membrane which is bead-free and centered in the peripheral area, a magnet system with a pole plate for driving the membrane via a voice coil, wherein the contour of the membrane and the contour of the voice coil, viewed in the plane of greatest extent, differ in such a way that they are not linearly scalable to one another, i.e., they have different basic shapes which cannot be made congruent by simply enlarging and reducing the size, wherein a one-sided adhesive damping layer is arranged between the membrane and the transducer basket in the edge area, and wherein, viewed from the magnet system, there is a damping layer in front of the membrane, which is arranged at least in the edge area and connected to the membrane, wherein the damping layer has a centrally arranged recess,to connect the voice coil to the membrane without an intermediate damping layer.

[0002] Furthermore, the invention also relates to a vehicle, in particular a land, air or water vehicle, which is equipped with such a sound transducer.

[0003] A similar sound transducer with the aforementioned features is already known from DE 10 2022 118 813 A1. It can be integrated discreetly and space-savingly into the interior trim of a vehicle. Part of the surface of the interior trim is usually bonded to the transducer's membrane, thus becoming part of the sound-generating system. However, it has been shown that the desired sound quality could not yet be fully achieved in the design described there.

[0004] It is therefore an object of the invention to further improve the above-mentioned electrodynamic sound transducer with regard to its sound quality.

[0005] This problem is solved by the features of the independent patent claims. Advantageous developments of the invention are the subject of subordinate claims.

[0006] The inventor has recognized the following: In vehicle construction, especially in the automotive and aviation sectors, the integration of the existing sound transducers in the remaining surfaces of the panels in the doors, sides, ceilings and instrument panels is a very big problem, since these are usually relatively deep and heavy and can, above all, visually disrupt the design.

[0007] However, due to the need for acoustic signals for communication between vehicle and user, the installation of sound transducers cannot be dispensed with, but the audio quality of the sound transducers is an essential feature for assessing vehicle quality.

[0008] For example, in the automotive sector, tweeters are usually installed in the mirror triangles, A-pillars or horizontally in the corners of the instrument panels, and at the rear in the C- or D-pillars or in panel trim. The situation is more difficult with deeper and larger diameter midrange and bass speakers. Sufficient space must be provided for all speakers for the wiring, a rear cover, adapters, protective grilles and numerous amplifier channels to transmit the appropriate power. In addition, there is a growing number of electronics, batteries and safety features such as stiffeners or airbags, especially in new hybrid and electric vehicles, in the doors or instrument panels, in the rear parcel shelf or the A-, B-, C- and D-pillars or the side members. This is why reduced installation space requirements, efficiency and weight savings are playing an ever greater role.

[0009] As already described in the publication PCT / DE2021 / 000031, this type of electrodynamic sound transducer features a basket integrated into the supporting structure of a vehicle component, a membrane that uses the surface of the vehicle component to generate sound, without a surround or centering. In other words, the sound transducer merges with the respective vehicle component, for example, with the supporting structure of a panel.

[0010] Compared to the sound transducer described in DE 10 2022 118 813 A1, the inventor recognized that to achieve the goal of improved reproduction, the following elements and components should be fundamentally changed, modified, replaced, or supplemented. Individual changes and additions do not necessarily lead to success, but rather success only results from synergistic effects in the interaction of several changes. This essentially concerns the following aspects: the design of the central damper, which ensures a damping connection between the membrane and the magnet system; the damping of the membrane surface against resonances; and optionally the support foil regarding its construction and connection to the membrane and bonding of a possible lamination material.

[0011] Central damper design: It has been shown that one reason for the suboptimal audio quality of the prior-art loudspeaker was the solid central damper. Replacing this solid central damper with a damper with an open structure surprisingly led to a significantly improved acoustic result. Although the new damper had approximately the same mass as the prior-art solid damper, producing roughly the same damping properties, the open structure led to an improvement, which is suspected to be due to improved ventilation of the interior of the voice coil and the inner area of ​​the diaphragm.The closed structure of the known damper probably led to a heating of the voice coil due to a lack of air exchange and compression of the trapped air inside the voice coil. This meant that the diaphragm was prone to distortions, standing waves, resonances and ultimately to a deformation of the diaphragm due to the compression and the considerable heating of the air.

[0012] The new design of this central damper, with its most open structure possible, ensures sufficient ventilation of the inner area of ​​the voice coil and the central area of ​​the diaphragm, thus avoiding the aforementioned problems. The central bore and open, flexible webs allow air to escape, exchange air, and cool down. In addition, the damping can now be optimized by adapting the geometric structure of the damper, for example with the help of finite element calculations, so that maximum uniform damping and a somewhat larger movement and amplitude of the diaphragm are now possible in both axial directions. It has proven advantageous to manufacture the central element preferably from rubber, silicone or similarly flexible and, above all, durable materials that behave as uniformly as possible even under temperature fluctuations and other environmental influences.

[0013] According to the invention, the central element is replaced by a central damper, which, due to its open structure in the axial direction of movement, allows for a somewhat greater, more uniform movement, but also better damping and ventilation of the diaphragm compared to a solid damper. This applies primarily to the center or inner region of the diaphragm and the area of ​​the voice coil with adapter located there. For this purpose, the central damper according to the invention is equipped with an open structure. It can be designed with small, outwardly curved webs located between the two cylindrical adhesive surfaces, via which the underside of the diaphragm is connected to the top of the magnet system in a ventilating, flexible, and damping manner.This central damper can preferably be made of rubber, silicone or similarly flexible and, above all, durable materials that behave as consistently as possible even in the face of temperature fluctuations and other environmental influences.

[0014] It should be noted that the central damper described here harmonizes and functions particularly advantageously in conjunction with the sound transducer otherwise described here, but such a damping element in the design with the open structure can also be used in conjunction with other known sound transducers and can also lead to an improvement in the sound result there.

[0015] Avoiding modes, resonances, and standing waves across the membrane surface: It has been found that in the known sound transducer, in the longitudinal area, in the freely moving surface of the membrane, there is also significant membrane and surface resonance formation, resulting in vibration modes, or modes for short. The larger the surface area, the longer the membrane, the greater the mode and resonance formation, especially in the lower frequency range. Neither the sandwich formation of multiple layers of membrane and lamination, adhesive films, damping layer, etc., nor the new central damper with an open structure could completely prevent this behavior. Only a reduction of this phenomenon could be achieved.

[0016] The problem was simply shifted to a slightly higher or lower frequency range, depending on the size of the transducer. Accordingly, the uncontrolled vibrations in the surface of the diaphragm, especially in the longitudinal direction, now had to be localized and damped depending on the shape and design of the diaphragm surface.

[0017] For this purpose, damper pads made of very soft foam, preferably adhesive on both sides, were placed between the damper layer, or directly with the underside of the membrane and the basket surface, to prevent the free surfaces of the membrane from rocking uncontrollably and resonating.

[0018] As an alternative to gluing damper pads to the membrane, the basket beneath the membrane can also be raised at the maximum amplitudes of the surface resonances that would otherwise occur, so that these parts of the basket are bonded to the underside of the damper layer. This results in a similar, or even almost identical, effect to that achieved by gluing damper pads to the same location on the membrane. However, the damping, hardness, and density of the damper layer should be adjusted to achieve maximum effect.

[0019] Another method that works for smaller resonances or higher-order frequency disturbances and their nonlinearity is the use of ground pads that are attached either to the underside of the damping layer or directly to the underside of the diaphragm. Depending on the frequency or the intensity of the disturbance, the mass and area must be adjusted; the higher the frequency of the disturbance, the smaller the area and mass of the ground pads.

[0020] Modification of the support foil: In order to protect the now more flexible, freely vibrating area of ​​the diaphragm not only against damage, denting, or impact, but also to prevent pronounced surface resonances, uncontrolled modes, reflections, and interference with the desired ring mode propagation, it has been found that it can be advantageous to coat the support foil with adhesive layers of varying thicknesses in a transducer design with a laminated layer over the diaphragm. It is also advantageous to make the adhesive layer thicker toward the top of the diaphragm than toward the laminated layer, as this creates a controlled, flexible sandwich, which, in the double-sided adhesive version, is also suitable for bonding to the laminated material. This also significantly saves assembly time, components, and costs.

[0021] Preferably, the side that is bonded to the top of the membrane and / or the basket rim is coated with a thicker adhesive. When using a backing material over the support film, the other side of the support film is preferably coated with a thinner adhesive. This, in conjunction with the membrane and the damping layer underneath, creates a better sandwich with more linear movement, which prevents further resonances and modes. However, the flexibility of the membrane with the damping layer, in conjunction with the new single-sided or double-sided adhesive support film, should be redesigned to ensure linear flexibility in both directions of movement, thus achieving an optimally distortion-free acoustic result.

[0022] The improvements of the sound transducer according to the invention essentially improve the existing problems with sound transducers of this type in the prior art with regard to heat build-up, standing and reflecting modes, surface resonances, non-linear frequency response and susceptibility to harmonic distortion of the membrane.

[0023] Based on the above, the inventor proposes an electrodynamic sound transducer for integration into a supporting structure of a vehicle, which has at least the following features: a transducer basket with at least one air passage, a flexible membrane without beads in the peripheral area, a magnet system for driving the membrane via a voice coil, wherein the magnet system is provided with a central through-opening, preferably along the axis of symmetry of the magnet system, wherein, viewed in the plane of the greatest extent of the membrane, the contour of the membrane and the contour of the voice coil differ in such a way that they are not linearly scalable to one another, wherein a one-sided adhesive damping layer is applied between the membrane and the transducer basket, at least in the edge area, which maintains the free mobility of the membrane during sound generation, wherein the damping layer has a central recess for attaching the voice coil to the membrane, wherein a damping central element is attached between the magnet system and the membrane,which consists of an open structure made of a flexible and damping material, and wherein in the area of ​​the membrane in the region of the maximum amplitude of a standing wave that develops without damping during operation, at least two additional membrane-damping elements are attached to the underside of the membrane.

[0024] The following should be noted regarding the definition: A component with an "open structure" is one that uses a small amount of material relative to its total volume and contains cavities. An "open structure" therefore describes a construction method that makes the component lighter and more airy, thus making it a non-solid component. This design does not refer to microstructures such as open-cell or closed-cell foam, but rather to structures of the same size as the component itself. For example, the open structure of the component can also be formed from an open-cell or closed-cell foam, in which the material itself has microstructures, or from a flexible but solid mass.The term "contours that are not isotropically scalable to one another" describes contours that have different basic shapes, i.e., shapes that cannot be made to coincide by direction-independent linear enlargement and reduction with an identical factor. Examples include a circle and a rectangle, a circle and an ellipse, a triangle and a square, etc. The underside of the membrane is defined as the side facing the magnetic system.

[0025] This overall design of a sound transducer results in a drastic improvement in its sound quality, as previously described in detail.

[0026] With regard to the design of the damping central element to improve its damping properties, it is particularly proposed that this electrodynamic sound transducer can be designed such that the damping central element has a cylindrical section on the magnet system side and / or on the membrane side, via which the central element is connected to the magnet system or the membrane.

[0027] The cylindrical section of the damping central element can be designed as a hollow cylinder, at least on the side of the magnet system.

[0028] In the electrodynamic sound transducer, the open-designed damping central element can also have a plurality of webs whose longitudinal direction runs from the magnet system to the membrane.

[0029] In this case, at least two webs of the damper can also have at least one connection between them that is not part of the end connection of the webs. In addition to the end cylindrical sections, additional connections can be created between the webs, allowing the damping characteristics to be adjusted.

[0030] In an advantageous further development of the sound transducer, the open structure of the damping central element can also be constructed in a grid-like manner.

[0031] Alternatively or additionally, the damping central element can also have centrally running cross connections, which can also influence the damping characteristics in the desired manner.

[0032] It is advantageous if the open structure of the damping central element comprises at least one hollow body.

[0033] In a particularly advantageous design for the damping central element, it is proposed that its outer contour be barrel-shaped. This allows for a larger free stroke to be achieved in a simple manner.

[0034] In order to achieve better damping of the membrane surface against the occurrence of resonances, standing waves and modes on the surface of the membrane, the following design variants of the electrodynamic sound transducer are proposed.

[0035] According to a special design, the at least two additional elements damping the membrane can be arranged symmetrically to the central axis.

[0036] Furthermore, at least some of the additional elements damping the membrane can be designed as mass elements which are indirectly connected to the membrane via the foam layer and which, due to their own mass, damp the undesired natural vibrations of the membrane.

[0037] It may also be advantageous if at least some of the additional elements damping the membrane are designed as mass elements which are directly connected to the membrane through a recess in the damper layer.

[0038] Furthermore, at least some of the additional elements damping the membrane can consist of vibration-damping foam, which on the one hand are connected indirectly via the damper layer or directly through a recess in the foam layer or damper layer to the membrane and on the other hand to the transducer basket.

[0039] It can also be particularly advantageous if at least some of the additional elements damping the membrane consist in the transducer basket having an elevation at the position to be damped such that the elevation rests against the damper layer; if necessary, the basket can also be glued to these elevations with the damper layer located on the underside of the membrane.

[0040] It is also advantageous if the damper layer is thickened in the area of ​​at least one elevation of the converter basket.

[0041] To protect the freely vibrating area of ​​the diaphragm, which is now more flexible than in the prior art due to the more delicate design of the central damper, from damage, dents, or impacts, and also to prevent pronounced surface resonances, uncontrolled modes, reflections, and interference with the desired ring mode propagation, it is advantageous to place a support film in front of the diaphragm, possibly with adhesive layers of varying thicknesses. It seems advantageous to make the adhesive layer thicker toward the top of the diaphragm, as this creates a more controlled, flexible sandwich, which, in the double-sided adhesive version, is also suitable for bonding to the lamination material. This also significantly saves assembly time, parts, and costs.

[0042] Accordingly, the inventor also proposes below to equip the electrodynamic sound transducer above the membrane with a support film with a membrane-side first adhesive layer for connecting the membrane to the support film.

[0043] Furthermore, in a special embodiment, it is proposed that the support film is additionally provided on the upper side with a second adhesive layer for connecting the support film to a lamination layer, wherein the lamination layer can optionally be part of an interior lining of a vehicle.

[0044] It can be particularly advantageous if the first adhesive layer and the second adhesive layer have different thicknesses, preferably if the adhesive layer facing the membrane side is thicker than the one on the other side of the support film.

[0045] In the following, particularly advantageous additional features are described, some of which are known from the prior art, but which combine particularly well with the previously described sound transducer and lead to improved sound results.

[0046] Accordingly, the electrodynamic sound transducer can comprise a transducer cage formed as part of the supporting structure of the interior of a vehicle, preferably a land vehicle, aircraft, or watercraft, with the diaphragm provided with a lamination layer. In particular, the lamination layer can be part of the interior paneling of a vehicle.

[0047] A particularly advantageous design of the magnet system installed in the electrodynamic sound transducer is that it has a magnet, a magnetic return, a pole plate and an air gap between the pole plate and the magnet for the voice coil, whereby the damping central element is attached to the magnet system side on the magnet itself and is immersed in an opening of the pole plate or alternatively is attached directly to the pole plate.

[0048] Furthermore, the electrodynamic sound transducer can be designed such that the voice coil is arranged on a substantially cylindrical coil carrier and is connected to the diaphragm via a mounting adapter, and the mounting adapter is designed on the voice coil side to be complementary in shape to the coil carrier of the voice coil and on the diaphragm side to be complementary in shape to the free-form surface of the diaphragm, wherein the mounting adapter is preferably designed to be stepless between the coil carrier of the voice coil and the diaphragm.

[0049] It is also advantageous if, in the case of the sound transducer, the voice coil is arranged on a substantially cylindrical coil carrier and is connected to the diaphragm via a mounting adapter, and the mounting adapter is designed on the voice coil side to be complementary in shape to the coil carrier of the voice coil and on the diaphragm side to be complementary in shape to the free-form surface of the diaphragm, wherein the mounting adapter is preferably designed to be step-free between the coil carrier of the voice coil and the diaphragm.

[0050] In particular, the membrane can be designed as a three-dimensional free-form surface with the exception of conical shapes.

[0051] The membrane can also have different thicknesses across its surface, whereby the membrane can preferably be made thicker in areas of connection to force-transmitting components than in free areas without force transmission.

[0052] Furthermore, the transducer basket can have a circumferential shoulder to which the membrane is connected to the transducer basket via the damper layer, so that the membrane can move freely during sound generation.

[0053] The membrane can also have at least one convex and at least one concave area, with these areas merging seamlessly into one another.

[0054] In addition to the sound generator described above, a vehicle, in particular a land, air, or water vehicle, is also described, which has an interior and a supporting structure forming the interior, and an interior lining, which also has a lining layer, wherein the interior is equipped with at least one loudspeaker. The at least one loudspeaker is designed as an electrodynamic sound transducer having the following features: a converter basket with at least one air passage, wherein the converter basket is preferably formed as part of the supporting structure of the vehicle, a flexible membrane, a magnet system with a centrally located opening passing through the magnet system; a voice coil; a central damper, which is arranged connectingly between the magnet system and the membrane and which is formed by an open structure in order to ensure ventilation in the area surrounded by the voice coil and which

[0055] Voice coil to ensure the greatest possible free stroke while at the same time damping; Additional damping on parts of the underside of the membrane to suppress standing waves on the membrane surface; and a support film on the top side of the membrane, which is coated on each side with adhesive layers of varying thicknesses to bond it to the lamination layer of an interior trim during installation in a vehicle.

[0056] Furthermore, a vehicle, in particular a land, air or water vehicle, is also proposed, which is equipped with at least one electrodynamic sound transducer according to the invention.

[0057] The invention is described in more detail below using preferred embodiments with the aid of the figures, in which essentially only the features necessary for understanding the invention are shown. They show in detail: FIG 1: electrodynamic sound transducer in a 3D exploded view of a simple version according to the document DE 10 2022 118 813 A1 with protective film and laminating material; FIG 2: detailed longitudinal section of the sound transducer from FIG 1; FIG 3: electrodynamic sound transducer in the 3D exploded view with a membrane with double-sided adhesive protective film, the laminating material, with double-sided adhesive damper pads and the central damper; FIG 4: sectional view of the central damper from FIG 3 ; FIG 5:Detail longitudinal section of the transducer from FIG 3 ; FIG 6: electrodynamic sound transducer in the 3D exploded view with a membrane with double-sided adhesive protective film, the laminating material, with single-sided adhesive ground pads and the central damper; FIG 7: detailed longitudinal section of the sound transducer from FIG 6; FIG 8: electrodynamic sound transducer in the 3D exploded view with a membrane with double-sided adhesive protective film, the laminating material, with partial elevation for damping and the central damper; FIG 9: detailed view of the support film with two different adhesive layers; FIG 10: longitudinal section of the electrodynamic sound transducer in a detailed and sectional view with a membrane with one-sided adhesive support film, with partial elevation for damping and the central damper made of FIG 8 ; FIG 11: Longitudinal section of the transducer from Fig. 5 ; FIG 12: Longitudinal section of the transducer from Fig. 8 ; FIG 13: Comparison of the frequency responses measured in the near field of the electrodynamic sound transducers according to Figure 1 (~dotted line) and the inventive version from FIG 3 , 6 or 8(~dashed line); FIG 14: Comparison of the THD distortion curves measured in the near field over the frequency response of the electrodynamic transducer according to Figure 1 (~dotted line) and the inventive version from FIG 3 , 6 or 8 (~dashed line); FIG 15: Comparison of the K3 distortion curves measured in the near field over the frequency response of the electrodynamic transducer according to Figure 1 (~dotted line) and the inventive version from FIG 3 , 6 or 8 (~dashed line).

[0058] The Figure 1 shows the known basis of the electrodynamic sound transducer according to the document DE 10 2022 118 813 A1 as a flat supporting structure with a transducer basket 4, with a circumferential web with a groove 5. Mounted in this transducer basket 5 is the magnet system 1, consisting of at least one magnetic return path, a magnet, a pole plate and a pole core.

[0059] The diaphragm 9 with the transducer cage is mounted on the shoulder 5 via a transfer adhesive ring 6 and the single-sided adhesive damping layer 8. The lamination material is applied to the surface of the diaphragm 9 using a spray adhesive via a support film 10.

[0060] The Figure 2 shows the state of the art in longitudinal section in a design of the electrodynamic sound transducer according to the document DE 10 2022 118 813 A1 with the transducer basket 4 with circumferential web with groove 5, the air outlets 14, the central damper 7 and the electrical contacts 12 and 13.

[0061] The sectional view is limited to the magnet system with only one upper side of the converter basket, since the other lower side of the converter basket is designed symmetrically to the upper side. The same applies to the Figures 5 , 7 and 10 .

[0062] As already mentioned at the beginning, this transducer according to the state of the art from DE 10 2022 118 813 A1 still generates disturbing resonances, antiphase oscillations, standing and reflecting modes and the associated measurable and audible distortions that should be avoided or at least dampened for improved audio quality. Figure 3 The converter according to the invention with the measures mentioned above and details of the improvements with the converter cage 15, the additional partially positioned double-sided adhesive damper pads 16, the newly designed central damper 17, and the new support film 18 with two different adhesive layers, which in turn is provided with the lamination layer. The individual measures are presented in detail in the following figures and their descriptions.

[0063] The central damper 17, which has been redesigned compared to the state of the art, is used in the Figure 4described in more detail. As already explained at the beginning, the newly designed central damper allows for a somewhat larger, more even movement in the axial directions of movement – ​​represented by the double arrow line – but also better damping and ventilation of the diaphragm.

[0064] This particularly concerns the center, i.e. the inner area of ​​the membrane and the area surrounded by the voice coil 2 with its mounting adapter 3, as can be seen from the Figure 3 can be seen. As the Figure 4The central damper 17 according to the invention is designed with a central bore and small outwardly curved webs 21, which are located between the two cylindrical adhesive surfaces 20 and 22. The webs 21 are connected via the membrane underside 9 to the upper side with the central bore 25 of the magnet system 19 in a ventilating, flexible, and damping manner. This central damper 17 is preferably made of rubber, silicone, or a similarly flexible and, above all, durable material, which should always behave consistently even under temperature fluctuations and other environmental influences.

[0065] In the Figure 5 , which shows a detailed longitudinal section of the upper part of the transducer and the Figure 11 , which shows the longitudinal section of the complete transducer from the Figure 3shows, a further new element can be seen which provides additional damping of the surface and which is intended to dampen or prevent possible surface resonances and modes in the longitudinal extent of the membrane 9. For this purpose, highly damping double-sided adhesive damper pads 16 are preferably glued either between the freely vibrating surface of the damper layer 8, or directly to the underside of the membrane 9 and the surface of the basket 15. The flexibility, Shore hardness, design of the size and shape as well as the positioning of the double-sided adhesive damper pads 16 depend on the size and shape of the membrane surface, its surface resonance, and the position of the reflecting and interfering modes within the membrane surface that are to be damped.

[0066] To save costs, as in the Figures 8, 10 and 12As shown, it may also be advantageous, instead of the double-sided adhesive foam pads 16, to partially adapt the upper side of the basket 23 by means of elevations so that this can be fixed directly to the damper layer 8, which is connected to the underside 9 of the membrane. In this case, however, a higher damping and / or softer material is preferably used for the damper layer 8. The size and shape of the partial elevation 23 as well as the positioning itself depend on the size and shape of the membrane surface, its surface resonance, and the position of the reflecting and interfering modes within the membrane surface that are to be damped.

[0067] Alternatively, as stated in the Figures 6 and 7 shown, instead of the foam pads 16 or the solution used in the Figures 8 and 10As described, flat ground pads 28 can also be used, which are mounted only on the underside of the damper layer 8 or directly on the underside of the diaphragm 9 and allow free movement between the damper layer 8 or the diaphragm 9 and the transducer cage 15. However, this type of damping only works for smaller resonances and higher-order frequency disturbances. Depending on the frequency and / or intensity of the disturbance, the mass and area of ​​the ground pads must be adjusted; the higher the frequency of the disturbance, the smaller the area and lower the mass of the ground pads 28.

[0068] In order to achieve a largely controlled and linear behavior of the entire surface of the membrane 9, it may be advantageous to apply the support foil 18 according to the Figure 9 ,without further lamination with an adhesive layer 26. If a lamination layer is used over the support film 18, this can be equipped with two adhesive layers 26 and 24 of different thicknesses. The resulting sandwich can be balanced with the flexibility of the membrane 9 in such a way that a more linear force introduction into the surface of the membrane 9 results, especially in the transition from the inner to the outer area of ​​the voice coil 2 with mounting adapter 3 located there. Experience has shown that this results in significantly less interference and distortion-free music reproduction.

[0069] The result of the sum of the individual measures is shown by the comparative near-field measurements in the Figures 13, 14 and 15. The behavior of the sound transducer from the document DE 10 2022 118 813 A1 is plotted there with the dotted line compared to the behavior of the electrodynamic sound transducer according to the invention of this application according to the Figures 3 , 6 or 8 , each represented by a solid line. Figure 13 the frequency response in which Figure 14 the distortion factor (=THD = Total Harmonic Distortion) over the frequency and in the Figure 15 the third harmonic distortion (= parameter K3) is compared over the frequency.

[0070] In the audio field, the term frequency response describes the ability of an audio device, as the sound transducer, to reproduce or transmit all frequencies in the audible range, usually between about 20 Hz and 20 kHz, to the same extent. A frequency response diagram as in the Figure 13It shows the relative levels of different frequencies and allows you to see whether the transducer is amplifying, attenuating, or distorting certain frequencies. A linear frequency response that treats all frequencies equally is considered ideal, although slight variations are acceptable in practice. A good frequency response is important for the reproduction of music and speech with high sound quality.

[0071] You can see in the Figure 13The dotted line shows the massive drop in the previously known sound transducer compared to the only slight drop in the solid line of the inventive sound transducer at approximately 600 Hz. This frequency is the center frequency of the disturbance and indicates the frequency of the maximum effect of the unwanted resonances, standing waves, modes, etc. These, however, have an effect down to 250 Hz and upwards to over 2000 Hz. In this range, without the inventive correction, the membrane oscillates uncontrollably, primarily out of phase or opposite to the wanted signal and the desired movement of the membrane. This is why there is both an increase in the lower frequency range and a reduction of up to 6 dB in the higher frequency range.

[0072] In the Figure 14The THD parameter is compared across the frequency between the two previously mentioned transducers. THD stands for "Total Harmonic Distortion." THD describes the amount of unwanted harmonic distortion that the transducer adds to an audio signal source. A lower THD value indicates lower distortion and thus higher sound quality. As can be seen from the Figure 14 As can be seen, the inventive sound transducer with the continuous line produces significantly less distortion in the range around 600 Hz and especially in the low frequency range than the previously known sound transducer with the dotted line.

[0073] The Figure 15The characteristic value K3 shown, the curve of which is compared with respect to the two transducer designs, describes the third harmonic distortion, i.e. the distortion that arises from the processing of an audio signal and amounts to three times the fundamental frequency. It is a measure of the quality or purity of the audio signal and is often used together with other distortion measures such as THD to evaluate the overall quality of an audio device. The lower the value for k3, the better the sound quality. As can be seen, the curve of the sound transducer according to the invention runs significantly below the dotted curve of the previously known sound transducer, thus also demonstrating the effectiveness of the improvements according to the invention.

[0074] This corresponds to the results of the three measurements of frequency response, THD, and K3. The damping measures according to the invention show a significant and broad-band reduction in interference, resonances, and the corresponding distortion.

[0075] Overall, the invention proposes a sound transducer which comprises: a transducer basket with at least one air passage, a flexible diaphragm, a magnet system with a central and continuous opening; a voice coil; a central damper which is arranged connecting the magnet system and the diaphragm and which is formed by an open structure in order to ensure better ventilation in the area surrounded by the voice coil and to guarantee the voice coil the greatest possible free stroke with the most linear damping possible; and additional damping on partial surfaces of the underside of the diaphragm in order to suppress standing waves on the diaphragm surface; optionally the use of a support film on the upper side of the diaphragm which is coated with adhesive layers of varying thicknesses on at least each side in order to bond it to the laminated surface of an interior panel when installed in a vehicle and to ensure better force introduction.

[0076] Although the embodiments have been illustrated and described in detail, the invention is not limited by these disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of protection of the invention. In particular, the invention is not limited to the specified combinations of features, but other combinations and partial combinations that are obvious to those skilled in the art can also be formed from the disclosed features. Thus, embodiments are also to be regarded as encompassed and disclosed by the invention that are not explicitly shown or explained in the figures, but which arise from and can be produced by separate combinations of features from the explained embodiments. It is also within the scope of the invention to bring about a mechanical reversal of the functions of the individual mechanical elements of the invention.

[0077] Particularly advantageous variations of exemplary embodiments of the invention described above are described below: I. An electrodynamic sound transducer for integration into a supporting structure of a vehicle, comprising: I.1. a transducer basket (4, 15, 23) with at least one air passage (14), I.2. a flexible diaphragm (9) which is free of beads in the peripheral region, I.3. a magnet system (1, 19) for driving the diaphragm (9) via a voice coil (2), the magnet system (1, 19, 23) being provided with a central through-opening (25), I.4. the contour of the diaphragm (9) and the contour of the voice coil (2), viewed in the plane of the greatest extent of the diaphragm (9), differing in such a way that they cannot be scaled isotropically to one another, I.5. a one-sidedly adhesive damping layer (8) being arranged between the diaphragm (9) and the transducer basket (4, 15, 23), at least in the edge region, I.6. wherein the damper layer (8) has a central recess (8.1) for fastening the voice coil (2) to the membrane (9), I.7. wherein between the magnet system (1,19) and the diaphragm (9), a damping central element (17) is attached, which consists of an open structure made of a flexible and damping material, I.8. and wherein in the area of ​​the diaphragm (9) in the region of the maximum amplitude of a standing wave that develops without damping during operation, at least two additional elements (16) damping the diaphragm (9) are attached to the underside. II. Electrodynamic sound transducer according to the preceding embodiment I, characterized in that the damping central element (17) has a cylindrical section (20, 22) on the magnet system side and / or on the diaphragm side, via which the central element (17) is connected to the magnet system (1) or the diaphragm (9). III. Electrodynamic sound transducer according to the preceding embodiment II, characterized in that the cylindrical section (20,22) of the damping central element (17) is designed as a hollow cylinder, at least on the side of the magnet system (1, 19). IV. Electrodynamic sound transducer according to one of the preceding embodiments I to III, characterized in that the damping central element (17) has a plurality of webs (21) whose longitudinal direction runs from the magnet system (1, 19) to the diaphragm (9). V. Electrodynamic sound transducer according to the preceding embodiment IV, characterized in that on the damping central element (17), at least two webs (21) have at least one connection to one another that is not part of an end connection of the webs (21). VI. Electrodynamic sound transducer according to one of the preceding embodiments I to V, characterized inthat the open structure of at least one damping central element (17) is constructed in a lattice-like manner. VII. Electrodynamic sound transducer according to one of the preceding embodiments I to VI, characterized in that the open structure of at least one damping central element (17) has centrally extending web-like cross connections. VIII. Electrodynamic sound transducer according to one of the preceding embodiments I to VI, characterized in that the open structure of at least one damping central element (17) comprises a central hollow body. IX. Electrodynamic sound transducer according to one of the preceding embodiments I to VIII, characterized in that the damping central element (17) has a barrel-shaped outer contour. X. Electrodynamic sound transducer according to one of the preceding embodiments I to IX, characterized inthat the at least two additional elements (16) damping the membrane (9) are arranged symmetrically to the central axis of the central element (17). XI. Electrodynamic sound transducer according to one of the preceding embodiments I to X, characterized in that at least some of the additional elements (16) damping the membrane (9) are designed as mass elements that are indirectly connected to the membrane via the foam layer (8). XII. Electrodynamic sound transducer according to one of the preceding embodiments I to XI, characterized in that at least some of the additional elements (16) damping the membrane (9) are designed as mass elements that are directly connected to the membrane via a recess in the damper layer (8). XIII. Electrodynamic sound transducer according to one of the preceding embodiments I to XII, characterized inthat at least some of the additional elements (16) damping the diaphragm (9) consist of vibration-damping foam, which are connected, on the one hand, indirectly via the damper layer (8) or directly through a recess in the foam layer (8) to the diaphragm (9) and, on the other hand, to the transducer basket (4, 15, 23). XIV. Electrodynamic sound transducer according to one of the preceding embodiments I to XIII, characterized in that at least some of the additional elements (16) damping the diaphragm (9) consists in the fact that the transducer basket (4, 15, 23) has a raised portion at the position to be damped such that the raised portion rests against the damper layer (8). XV. Electrodynamic sound transducer according to the preceding embodiment XIV, characterized in that the damper layer (8) in the region of at least one raised portion of the transducer basket (4, 15,23) has a thickening. XVII. Electrodynamic sound transducer according to one of the preceding embodiments I to XV, characterized in that a support film (10, 18) with a membrane-side first adhesive layer (26) for connecting the membrane (9) to the support film (10, 18) is arranged above the membrane (9). XVII. Electrodynamic sound transducer according to the preceding embodiment XVI, characterized in that the support film (10, 18) is additionally provided on its upper side with a second adhesive layer (24) or double-sided adhesive film for connecting the support film (10, 18) to a lamination layer (11). XVIII. Electrodynamic sound transducer according to the preceding embodiment XVII, characterized in that the first adhesive layer (26) and the second adhesive layer (24) have different thicknesses. XIX. Electrodynamic sound transducer according to one of the preceding embodiments I to XVIII, characterized inthat the transducer basket (4, 15, 23) is designed as part of the supporting structure of an interior of a vehicle, preferably a land, air or water vehicle, and the membrane (9) is connected to a cladding. XX. Electrodynamic sound transducer according to one of the preceding embodiments XVII to XIX, characterized in that the cladding layer (11) is part of an interior lining of a vehicle. XXI. Electrodynamic sound transducer according to one of the preceding embodiments I to XX, characterized in that the magnet system (1, 19) has a magnet (1.2), at least one magnetic yoke (1.3), the pole plate (1.1), and an air gap between the pole plate (1,1) and the magnet (1.2) for the voice coil (2), wherein the damping central element (17) is fastened to the pole plate (1.1) on the magnet system side. XXII. Electrodynamic sound transducer according to one of the preceding embodiments I to XX,characterized in that the magnet system (1, 19) comprises a magnet (1.2), at least one magnetic return path (1.3), the pole plate (1.1), and an air gap between the pole plate (1.1) and the magnet (1.2) for the voice coil (2), wherein the damping central element (17) is attached to the magnet (1.2) on the magnet system side and extends into the pole plate (1.1). XXIII. An electrodynamic sound transducer according to one of the preceding embodiments I to XXII, characterized in that: the voice coil (2) is arranged on a substantially cylindrical coil carrier and is connected to the diaphragm (9) via a mounting adapter (3), and the mounting adapter (3) is designed to be complementary in shape to the coil carrier of the voice coil (2) on the voice coil side and complementary in shape to the free-form surface of the diaphragm (9) on the diaphragm side.wherein the mounting adapter is preferably formed steplessly between the coil carrier of the voice coil (2) and the diaphragm (9). XXIV. Electrodynamic sound transducer according to one of the preceding embodiments I to XXIII, characterized in that the diaphragm (9) is designed as a three-dimensional free-form surface with the exception of conical shapes. XXV. Electrodynamic sound transducer according to one of the preceding embodiments I to XXIV, characterized in that the diaphragm (9) has different thicknesses in its surface and is preferably thicker in areas of connection to force-transmitting components than in free areas without force transmission. XXVI. Electrodynamic sound transducer according to one of the preceding embodiments I to XXV, characterized in that the transducer basket (4, 15, 23) has a circumferential shoulder at which the diaphragm (9) is connected to the transducer basket (4, 15,23) is connected, so that free mobility is ensured during sound generation. XXVII. Electrodynamic sound transducer according to one of the preceding embodiments I to XXVI, characterized in that the membrane (9) has at least one convex and at least one concave region, and these regions merge smoothly into one another. XXVIII. Vehicle, in particular a land, air, or water vehicle, with an interior and a supporting structure forming the interior, and an interior lining which also has a lamination layer (11), wherein the interior is equipped with at least one loudspeaker, characterized in that the at least one loudspeaker is designed as an electrodynamic sound transducer having the following features: a transducer basket (4, 15, 23) with at least one air passage, wherein the transducer basket (4, 15, 23) is preferably formed as part of the supporting structure of the vehicle,a flexible diaphragm (9), a magnet system (1, 19) with a centrally located opening (25) extending through the magnet system; a voice coil (2); a central damper (17) arranged to connect the magnet system (1, 19) and the diaphragm (9) and formed by an open structure to ensure ventilation in the area surrounded by the voice coil (2) and to guarantee the voice coil (2) the greatest possible free stroke while simultaneously damping; additional damping (16) on partial surfaces of the underside of the diaphragm (9) to suppress standing waves on the diaphragm surface; and a support film (10, 18) on the upper side of the diaphragm, which is coated on each side with adhesive layers (24, 26) of varying thicknesses in order to bond it to the lamination layer of an interior lining during installation in a vehicle. XXIX. Vehicle with at least one electrodynamic sound transducer, characterized in thatthat the sound transducer is designed according to one of the embodiments I to XXVII. , List of reference symbols:

[0078] 1Magnet system 1.1Pole plate 1.2Magnet 1.3Backing plate 2Voice coil 3Mounting adapter 4Transducer basket 5Circular web with groove 6Transfer adhesive ring 7Central element 8Foam base / damper layer / foam layer 8.1Recess 9Diaphragm 10Support film 11Laminating material 12- Electrical contact 13+ Electrical contact 14Air outlet 15Transducer basket 16Damper pad 17Central damper / damping central element 18Support film with one- or two-sided adhesive layer 19Magnet system 20Lower adhesive surface / cylindrical section 21Curved webs 22Upper adhesive surface 23Transducer basket with partial adhesive surface 24Support film adhesive layer 25Central bore of magnet system 26Support film adhesive layer 27Axis of symmetry

Claims

1. An electrodynamic sound transducer for integration into a supporting structure of a vehicle, comprising: 1.1 a transducer basket (4, 15, 23) with at least one air passage (14), 1.2 a flexible membrane (9) which is free of beads in the peripheral region, 1.3 a magnet system (1, 19) for driving the membrane (9) via a voice coil (2), wherein the magnet system (1, 19) is provided with a central through-opening (25), 1.4 wherein, viewed in the plane of the greatest extent of the membrane (9), the contour of the membrane (9) and the contour of the voice coil (2) differ in such a way that they are not isotropically scalable to one another, 1.5 wherein a one-sided adhesive damping layer (8) is arranged between the membrane (9) and the transducer basket (4, 15, 23), at least in the edge region, 1.6 wherein the damping layer (8) has a central Recess (8.1) for fastening the voice coil (2) to the membrane (9), 1.7 wherein a damping central element (17) is fastened between the magnet system (1, 19) and the membrane (9), which consists of an open structure made of a flexible and damping material, 1.8 and wherein in the surface of the membrane (9) in the region of the maximum amplitude of a standing wave which forms without damping during operation, at least two additional elements (16) damping the membrane (9) are attached to the underside.

2. Electrodynamic sound transducer according to the preceding claim 1, characterized in that the damping central element (17) has a cylindrical section (20, 22) on the magnet system side and / or on the membrane side, via which the central element (17) is connected to the magnet system (19) or the membrane (9).

3. Electrodynamic sound transducer according to one of the preceding claims 1 to 2, characterized in thatthe damping central element (17) has a plurality of webs (21) whose longitudinal direction runs from the magnet system (1, 19) to the membrane (9).

4. Electrodynamic sound transducer according to one of the preceding claims 1 to 3, characterized in that the open structure of the damping central element (17) is constructed in a lattice-like manner.

5. Electrodynamic sound transducer according to one of the preceding claims 1 to 3, characterized in that the open structure of the damping central element (17) comprises a central hollow body.

6. Electrodynamic sound transducer according to one of the preceding claims 1 to 5, characterized in that at least some of the additional elements (16) damping the membrane (9) are designed as mass elements which are indirectly connected to the membrane (9) via the damper layer (8).

7. Electrodynamic sound transducer according to one of the preceding claims 1 to 6, characterized in thatat least part of the additional elements (16) damping the diaphragm (9) consists in the fact that the transducer basket (4, 15, 23) has an elevation at the position to be damped such that the elevation rests against the damper layer (8).

8. Electrodynamic sound transducer according to the preceding claim 7, characterized in that the damper layer (8) has a thickening in the region of at least one elevation of the converter basket (4, 15, 23).

9. Electrodynamic sound transducer according to one of the preceding claims 1 to 8, characterized in that a support film (10, 18) with a membrane-side first adhesive layer (26) for connecting the membrane (9) to the support film (10, 18) is arranged above the membrane (9).

10. Electrodynamic sound transducer according to one of the preceding claims 1 to 9, characterized in thatthe converter basket (4, 15, 23) is designed as part of the supporting structure of an interior of a vehicle, preferably a land, air or water vehicle, and the membrane (9) is connected to a lamination layer (11).

11. Electrodynamic sound transducer according to the preceding claim 10, characterized in that the lamination layer (11) is part of an interior paneling of a vehicle.

12. Electrodynamic sound transducer according to one of the preceding claims 1 to 11, characterized in that the magnet system (1, 19) has a magnet (1.2), at least one magnetic return path (1.3), the pole plate (1.1), and an air gap between the pole plate (1.1) and the magnet (1.2) for the voice coil (2), wherein the damping central element (17) is fastened to the pole plate (1.1) on the magnet system side.

13. Electrodynamic sound transducer according to one of the preceding claims 1 to 11, characterized in thatthe magnet system (1, 19) has a magnet (1.2), at least one magnetic return path (1.3), the pole plate (1.1), and an air gap between the pole plate (1.1) and the magnet (1.2) for the voice coil (2), wherein the damping central element (17) is fastened to the magnet (1.2) on the magnet system side and is immersed in the pole plate (1.1).

14. Electrodynamic sound transducer according to one of the preceding claims 1 to 13, characterized in that the membrane (9) has different thicknesses in its surface and is preferably thicker in areas of connection to force-transmitting components than in free areas without force transmission.

15. Electrodynamic sound transducer according to one of the preceding claims 1 to 14, characterized in thatthe transducer basket (4, 15, 23) has a circumferential shoulder to which the membrane (9) is connected to the transducer basket (4, 15, 23) via the damper layer (8), so that free mobility is provided during sound generation.

16. Electrodynamic sound transducer according to one of the preceding claims 1 to 15, characterized in that the membrane (9) has at least one convex and at least one concave region and these regions merge smoothly into one another.

17. Vehicle with at least one electrodynamic sound transducer, characterized in that the sound transducer is designed according to one of claims 1 to 16.

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