BODY SOUND ACTUATOR FOR A MOTOR VEHICLE AND MOTOR VEHICLE

Description

[0001] Structure-borne sound actuator for a motor vehicle and motor vehicle. The invention relates to a structure-borne sound actuator for a motor vehicle, which comprises an electrodynamic excitation unit. The excitation unit is designed with an excitation side configured to excite a sound body. The invention also relates to a motor vehicle with a corresponding structure-borne sound actuator.

[0002] US 5 884 736 A discloses the features of the preamble of claim 1.

[0003] Structure-borne sound actuators are well-known in the art. Structure-borne sound actuators are used in the audio sector to acoustically excite surfaces using the bending wave principle. These actuators function similarly to conventional diaphragm speakers, as both are based on an electrodynamic transducer principle. The two systems differ in design in that structure-borne sound actuators do not have a diaphragm, surround, or speaker frame, making them significantly lighter and smaller than conventional diaphragm speakers. However, structure-borne sound actuators typically require a suitable excitation surface for sound radiation.

[0004] For broadband sound wave radiation, actuators must be coupled to a suitable surface or sound body. This coupling enables the vibrations generated by the actuator to be transmitted to the sound body. This creates bending vibrations across the entire excitation surface. These vibrations become audible through the airborne sound excited by the vibrating sound body.

[0005] The type of coupling between the actuator and the sound body is therefore crucial for optimal transmission and high efficiency of the vibration system. Currently common structure-borne sound actuators are often attached directly to the surface to be excited or the sound body using an adhesive or screw connection. For this purpose, a direct connection is created between the fixed part of the actuator and the surface, the dimensions of which usually correspond to the diameter of the coil carrier or magnet. This form of direct coupling primarily serves the purpose of providing a long-term stable attachment between the excitation source or the structure-borne sound actuator and the sound body itself.

[0006] It is an object of the present invention to provide a structure-borne sound actuator and a motor vehicle with which a sound body can be excited more effectively.

[0007] This object is achieved by a structure-borne sound actuator and a motor vehicle according to the independent claims.

[0008] A structure-borne sound actuator according to the invention for a motor vehicle comprises an electrodynamic excitation unit. In particular, the structure-borne sound actuator comprises a housing and a power supply interface. The excitation unit is designed with a, in particular flat, excitation side. The excitation side is configured to excite a sound body. An important concept is that an acoustically rigid intermediate element is attached to the excitation side, and the intermediate element has a coupling side facing away from the excitation side, which is configured for coupling to the sound body.

[0009] The invention is based on the discovery that a sound emitted by the sound body can be influenced by a variety of intermediate elements arranged between the excitation unit and the sound body. For example, the frequency and / or volume of the sound can be influenced. The frequency can be increased or decreased, for example. However, specific frequency bands of the sound can also be emphasized, reduced, or suppressed. The precise adaptation of the sound depends on the design of the intermediate element.

[0010] For example, the intermediate element can be shaped to enhance a central portion of the (audible) frequency band of the sound emitted by the sound body. For this purpose, the intermediate element can be designed in a variety of shapes and / or made of a variety of materials.

[0011] In particular, however, it is provided that the intermediate element is mounted between the excitation unit and the sound body in such a way that an excitation movement of the excitation unit can be transmitted to the intermediate element, and the excitation movement can be passed on from the intermediate element to the sound body. The excitation unit and the sound body are connected, in particular exclusively, via the intermediate element. Thus, there is no direct contact between the excitation unit and the sound body.

[0012] The intermediate element is acoustically rigid. This means, in particular, that essentially no audible sound, i.e. no sound between 16 Hz and 20 kHz, is emitted by the intermediate element itself. In particular, the intermediate element is designed to be so rigid that essentially no bending waves are generated in the intermediate element by the excitation unit that are radiated. This means, in particular, that when the structure-borne sound actuator is installed, at least 95%, preferably at least 98%, of the sound power of the structure-borne sound actuator is emitted by the sound body. Consequently, in particular, only a maximum of 5%, preferably a maximum of 2%, of the sound power of the structure-borne sound actuator is emitted by the intermediate element.

[0013] The intermediate element is preferably connected to a movable cylinder or a movable coil element of the excitation unit. Additionally or alternatively, the intermediate element can also be connected to other parts of the excitation unit or to a housing of the structure-borne sound actuator.

[0014] According to the invention, the intermediate element is designed to be flat, and the surface area of ​​the coupling side is larger than or equal to the surface area of ​​the excitation side. Due to the larger surface area of ​​the coupling side, the excitation movement can be introduced into a larger area of ​​the sound body than would be the case with a direct coupling of the excitation unit to the sound body. It is also advantageous that the excitation unit itself can still be small and space-saving, despite the larger surface area of ​​the coupling side due to the intermediate element.

[0015] Furthermore, the invention provides that the intermediate element is designed with a prestress and that the coupling side is curved in the decoupled state, in particular concavely facing away from the excitation side. Due to the prestress, a different pressure is exerted by the intermediate element on the sound body. The pressure or the force exerted by the intermediate element on the sound body varies depending on the prestress of the intermediate element. If, for example, the intermediate element is designed concavely opposite to the excitation side, a greater force is exerted on the sound body in the edge region of the intermediate element than is the case, for example, in a central region of the coupling side. This is the case, for example, if the sound body is planar or flat.If the sound body is also curved, the prestressing offers the additional advantage that the intermediate element can be applied to the curved sound body over a large area.

[0016] Furthermore, it is preferably provided that the intermediate element has a rectangular central piece in the plane of the coupling side with at least two webs that are spaced apart from one another and extend from the central piece, in particular radially. The webs are preferably uniformly designed and the central piece is preferably square. The webs extend in directions that are distributed at equal angles starting from the center of the intermediate element. Furthermore, it is preferably provided that the webs extend from the central piece at the same distance from one another. With four webs arranged on the central piece, a cross shape is produced, whereby the intermediate element is then cross-shaped. The central piece and the webs extend in particular in the same plane.The design of the intermediate element with the center piece and the webs is advantageous because the webs allow a kinetic energy coupling point to be determined in a variety of ways. For example, the webs can be attached to the center piece in such a way that they extend from the center piece at a specific angle and also have different lengths, for example. This allows the kinetic energy or vibration from the excitation unit to be introduced into the sound body via the intermediate element with particular precision and in a situation-appropriate manner.

[0017] Furthermore, it is preferably provided that the intermediate element has at least two webs directed away from the excitation side of the excitation unit and the coupling side is formed only by ends of the rods directed away from the excitation side. In this embodiment, the intermediate element is quasi three-dimensional. The intermediate element can also have a plurality of rods directed away. The rods then give the intermediate element an appearance, for example, of spider-shaped or octopus-shaped nature, so that the rods at least partially encompass a three-dimensional air space. The rods can be curved once or multiple times. However, it is also possible for the rods to be straight. Preferably, however, only the end of the respective rod directed away from the excitation side is designed as the coupling side, and thus only that end is in contact with the sound body.The vibration energy is thus introduced into the sound body only at those points where the ends of the rods are in contact with the sound body. This is advantageous because it allows sound bodies with complex shapes to be coupled to the excitation unit in a suitable and effective manner for introducing vibration energy.

[0018] Furthermore, it is preferably provided that the intermediate element is formed with at least two material layers, particularly made of different materials, that are evenly spaced from the coupling side. The different material layers can, for example, create a prestress on the intermediate element. However, the different material layers also make it possible to adjust a frequency emitted by the excitation unit and thus influence the noise emitted by the sound body. The intermediate element can also be formed from more than two material layers.

[0019] Preferably, the material layers are made of different materials. These different materials can include, for example, various plastics, plastic blends, Plexiglas, aluminum, urea, carbon, wood, or fiberglass. The different materials allow the frequency of the excitation unit to be adjusted and transmitted to the sound body in a customized manner.

[0020] Furthermore, it is preferably provided that the intermediate element has a raised, in particular cylindrical, mounting area on a side opposite the coupling side, designed for attaching the intermediate element to the excitation unit. The mounting area allows the intermediate element to be attached to the excitation unit more easily and securely. For example, the intermediate element can be designed such that only the mounting area can be attached to the excitation side of the excitation unit. The design of the mounting area can also influence the adjustment of the frequency of the kinetic energy emitted by the excitation unit. In particular, the mounting area is cylindrical. The cylinder is preferably designed such that a rotation axis of the cylinder is perpendicular to the excitation side of the excitation unit.

[0021] Furthermore, it is preferably provided that the intermediate element is fastened to the excitation side of the excitation unit with a non-destructively removable connection, in particular with a screw connection. Due to the non-destructively removable connection, the intermediate element can, for example, be fastened to different excitation units. This way, the excitation unit can, for example, be replaced with a new excitation unit in the event of a malfunction. The intermediate element is then not destroyed or damaged and can continue to be used. Preferably, the intermediate element can, for example, remain coupled to the sound body while the excitation unit is replaced. In particular, it is provided that the intermediate element is fastened to the excitation unit with the screw connection, for example with one or more screws.However, the intermediate element can also be attached to the trigger unit by means of a material bond, for example, by adhesive or a hardening filler. It is also possible for the intermediate element to be attached to the trigger unit using various types of clips.

[0022] The invention also relates to a motor vehicle with a structure-borne sound actuator according to the invention.

[0023] The motor vehicle is preferably designed as a passenger car. The structure-borne sound actuator is preferably arranged in an area of ​​the motor vehicle that is not visible from the passenger compartment of the motor vehicle.

[0024] Preferably, the structure-borne sound actuator is coupled, in particular exclusively, to a sound body via a coupling side of an intermediate element, wherein the sound body is designed as an interior trim part of the motor vehicle. The interior trim part is designed, for example, as an interior door trim, cockpit trim, interior roof trim, wheel house trim, pillar trim, or seat trim. Preferably, the structure-borne sound actuator is attached to an inner side of the interior trim part and is thus not visible to an occupant of the passenger compartment of the motor vehicle. The inner side of the trim part therefore faces, in particular, the component of the motor vehicle that is thereby covered.

[0025] Preferably, the structure-borne sound actuator is a component of an audio system of the motor vehicle for vehicle occupant entertainment.

[0026] Advantageous designs of the structure-borne sound actuator are to be regarded as advantageous designs of the motor vehicle.

[0027] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0028] Embodiments of the invention are explained in more detail below with reference to schematic drawings.

[0029] They show: Fig. 1 is a schematic plan view of an embodiment of a motor vehicle according to the invention with a structure-borne sound actuator; Fig. 2 is a schematic view of an embodiment of the structure-borne sound actuator with an intermediate element; Fig. 3 is a schematic view of an embodiment of the intermediate element with a center piece, four webs, and a mounting area; Fig. 4 is a schematic view of an embodiment of the intermediate element with a prestress; and Fig. 5 is a schematic view of an embodiment of the intermediate element with two rods.

[0030] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0031] In Fig. 1 A schematic plan view of a motor vehicle 1 with a structure-borne sound actuator 2 is shown.

[0032] According to the exemplary embodiment, the structure-borne sound actuator 2 is coupled to an interior trim part 4 of the motor vehicle 1 via an intermediate element 3.

[0033] However, the structure-borne sound actuator 2 can also be coupled to any component of the motor vehicle 1. In this case, the interior trim part 4 is designed as a door interior trim.

[0034] The structure-borne sound actuator 2 is therefore only connected to the interior trim part 4, which is designed as a sound body, via the intermediate element 3. Kinetic energy emitted by the structure-borne sound actuator 2 is then coupled into the interior trim part 4 via the intermediate element 3. The interior trim part 4 then preferably excites the air in the interior of the motor vehicle 1 and generates sound or a noise in the audible range.

[0035] The structure-borne sound actuator 2 can be arranged in a variety of ways in the motor vehicle 1. Multiple structure-borne sound actuators 2 can also be arranged in the motor vehicle 1. For example, they can be arranged behind trim parts of the interior or on a glass surface, a body part, such as a splash guard that separates an engine compartment of the motor vehicle 1 from a passenger compartment of the motor vehicle 1, or on a longitudinal member or a cross member of a body of the motor vehicle.

[0036] Fig. 2 shows an embodiment of the structure-borne sound actuator 2. The structure-borne sound actuator 2 has a housing 5, a power supply interface 6, and an electrodynamic excitation unit 7. The housing 5 at least partially surrounds the excitation unit 7 and protects it, for example, from the ingress of dirt and other contaminants. The power supply interface 6 is configured to be connected to a power supply source of the motor vehicle 1. The required energy for the excitation unit 7 is provided via the power supply interface 6.

[0037] According to the exemplary embodiment, the excitation unit 7 comprises a magnetic element 8 and a coil element 9. The magnetic element 8 is designed to be movable relative to the coil element 9. By applying electrical energy to the energy supply interface 6, the magnetic element 8 is moved relative to the coil element 9.

[0038] According to the exemplary embodiment, the excitation unit 7 has an excitation side 10. The excitation side 10 is designed to excite the interior trim part 4. Furthermore, the excitation side 10 is provided by the magnetic element 8 and / or the coil element 9.

[0039] The intermediate element 3 is attached to the excitation side 10. The intermediate element 3 is attached to the magnet element 8 and / or the coil element 9. Additionally or alternatively, the intermediate element 3 can also be attached to the housing 5.

[0040] The excitation side 10 is designed, in particular, as a surface to transfer kinetic energy to the intermediate element 3 or to excite it. For excitation, the coil element 9 moves relative to the magnetic element 8 toward or away from the intermediate element 3. The movement of the coil element 9 occurs, in particular, in the range from 16 Hz to 20 kHz.

[0041] The intermediate element 3 is fastened to the excitation unit 10 with a non-destructively removable connection 11. The non-destructively removable connection 11 is preferably designed as a screw connection. Thus, the intermediate element 3 can be fastened to the excitation unit 7 with one or more screws. In further exemplary embodiments not shown, the intermediate element 3 can, for example, also be glued to the excitation unit 7 or fastened to the excitation unit 7 using various types of clips or clamps. The intermediate element can also be fastened to the excitation unit 7 with a hardening filler. The removable connection is present between the intermediate element 3 and the magnetic element 8 and / or the intermediate element 3 and the coil element 9.

[0042] The intermediate element 3 has a coupling side 12 facing away from the excitation side 10. The coupling side 12 is designed for coupling with the interior trim part 4. According to the embodiment of Fig. 2 the interior trim part 4 is coupled to the intermediate element 3 on the coupling side 12. The interior trim part 4 is therefore not directly contacted by the excitation unit 7. The kinetic energy is transferred from the excitation unit 7 to the interior trim part 4 exclusively via the intermediate element 3. The intermediate element 3 adjusts the force introduction into the interior trim part 4. For example, the intermediate element 3 can suppress or increase a frequency in certain ranges of the frequency spectrum emitted by the excitation unit 7. The intermediate element 3 therefore influences the radiation to the interior trim part 4 with regard to an energy-specific efficiency and / or a bandwidth of the emitted frequency, particularly due to its material properties and / or its geometry.

[0043] Due to the adapted force introduction via the connecting element 3 and a resulting higher efficiency and / or a wider or narrower spectral bandwidth, the structure-borne sound actuator 2, which is also referred to as a surface radiator, can be used more efficiently in terms of its size and energy balance than is the case with a structure-borne sound actuator 2 without the intermediate element 3, which is therefore directly connected to the interior trim part 4.

[0044] Furthermore, this can also save weight and / or installation space, for example. For example, fewer and / or smaller structure-borne sound actuators 2 can be used than would be necessary to generate the same amount of sound or the same acoustic performance compared to a coupling with the interior trim part 4 without any intermediate elements.

[0045] According to the invention, it is provided that a surface 13 of the coupling side 12 is larger than a surface 14 of the excitation side 10. The surface 14 of the excitation side 10 can result, for example, from the coil element 9 and / or the magnetic element 8. The coupling between the intermediate element 3 and the interior trim part 4 is also achieved, for example, via a reversible connection or via a material connection.

[0046] The intermediate element 3 is preferably formed separately from the interior trim part 4. Thus, the intermediate element 3 is not a component or layer of the interior trim part 4.

[0047] Fig. 3 shows an embodiment of the intermediate element 3 coupled to the interior trim part 4. According to this embodiment, the intermediate element 3 has a rectangular center piece 15. In the present case, the center piece 15 is even square. Four webs 16 extend from the center piece 15 in the same plane as the center piece 15. The number of webs 16 can vary, but preferably at least two webs 16 are provided. According to the embodiment, the webs 16 are as wide as the center piece 15. The respective width of the webs 16 with respect to the center piece 15 can also vary, however. For example, the web 16 can be wider or narrower than the center piece 15. In the present case, the webs 16 form a cross with the center piece 15. According to the embodiment, it is further provided that an outer contour of the intermediate element 3 has curves at the ends of the webs 16 directed away from the center piece 15.In a further embodiment not shown, however, the center piece 15 can also have corners instead of curves.

[0048] According to the embodiment, the intermediate element 3 also has a mounting area 17. The mounting area 17 is according to the embodiment of Fig. 3 arranged on the center piece 15. The mounting area 17 is particularly cylindrical and is designed for attaching the intermediate element 3 to the excitation unit 7. The design of the intermediate element with the center piece 15 and the webs 16 allows the spectral bandwidth of the energy emitted by the excitation unit 7 to be adjusted with a particularly fine degree.

[0049] Fig. 4 shows a further embodiment of the intermediate element 3. The intermediate element 3 has a prestress 18. Due to the prestress 18, the intermediate element 3 is concavely curved towards the interior trim part 4 if it is in the uncoupled state or in the unassembled state. In the coupled or assembled state, the intermediate element 3 preferably lies completely against the interior trim part 4 with the surface 13 of the coupling side 12. Preferably, the intermediate element 3 is therefore pressed or pressed against the interior trim part 4 in the coupled state. Due to the prestress 18, the frequency range of the energy emitted by the excitation unit 7 can in turn be adapted in many different ways. For example, individual frequency ranges can be lowered or increased. However, the entire frequency spectrum can also be expanded, for example, using the intermediate element 3.Furthermore, the prestress 18 can, for example, influence the interior trim part 4. For example, the prestress can be used in the outer region of the intermediate element 3, where the force resulting from the prestress on the interior trim part 4 is greater, to couple different frequencies into the interior trim part 4 than in the central region of the intermediate element 3.

[0050] Furthermore, the intermediate element according to the embodiment of Fig. 4 with a first material layer 19, a second material layer 20, and a third material layer 21. According to the exemplary embodiment, the material layers 19, 20, 21 are of uniform thickness and extend uniformly to the coupling side 12. The material layers 19, 20, 21 can, for example, be made of the same material or of different materials. For example, the material layers can be made of solid material, rigid foam, glass, Plexiglas, aluminum, Ureol, carbon, wood, or fiberglass. According to the exemplary embodiment, only the third material layer 21 contacts the interior trim part 4. The prestress 18, for example, can be generated by the material layers 19, 20, 21.

[0051] Fig. 5 shows a further embodiment of the intermediate element 3. The intermediate element 3 has two rods 22 directed away from the excitation side 10. In this embodiment, the coupling side 12 is formed exclusively by ends 23 of the rods 22 directed away from the excitation side 10.

[0052] There may also be more than the Fig. 5 The intermediate element 3 can be provided with the rods 22 shown. For example, the intermediate element 3 can be formed with a plurality of rods 22 and thereby assume a spider-like or basket-like shape.

[0053] The intermediate element 3 can, for example, also be made of metal or hybrid plastic.

[0054] For example, partial areas may be cut out of the intermediate element 3, resulting in a lattice-like or porous structure. Furthermore, it is possible, for example, for the intermediate element 3 to have a honeycomb structure, in which the honeycombs may be uniform or of different shapes and sizes.

[0055] The intermediate element 3 thus performs a frequency adjustment for frequencies emitted by the excitation unit 7. The force can be introduced into the interior trim part 4 through the intermediate element 3 in a variety of ways, depending on the geometry and material of the intermediate element 3. List of reference symbols

[0056] 1Motor vehicle 2Structure-borne sound actuator 3Intermediate element 4Interior trim part 5Housing 6Power supply interface 7Excitation unit 8Magnet element 9Coil element 10Excitation side 11Removable connection 12Coupling side 13Coupling side surface 14Excitation side surface 15Center piece 16Web 17Mounting area 18Prestress 19First material layer 20Second material layer 21Third material layer 22Rods 23Rod ends

Claims

1. Structure-borne sound actuator (2) for a motor vehicle (1), which comprises an electro-dynamic excitation unit (7), and the excitation unit (7) is formed with an excitation side (10) configured to excite an acoustic body (4), characterized in that an acoustically rigid intermediate element (3) is secured to the excitation side (10) and the intermediate element (3) has a coupling side (12), which faces away from the excitation side (10), and is configured for coupling to the acoustic body (4), the intermediate element (3) being planar in design and a surface area (13) of the coupling side (12) being greater than a surface area (14) of the excitation side (10), characterized in that the intermediate element (3) is designed with an initial tension (18) and the coupling side (12) is curved in the decoupled state.

2. Structure-borne sound actuator (2) according to Claim 1, characterized in that the intermediate element (3) has a rectangular centrepiece (15) in the plane of the coupling side (12), and at least two crosspieces (16), spaced apart from each other and extending away from the centrepiece (15).

3. Structure-borne sound actuator (2) according to either one of the preceding claims, characterized in that the intermediate element (3) has at least two bars (22) directed away from the excitation side (10) of the excitation unit (7), and the coupling side (12) is formed only by ends (23) of the bars (22) directed away from the excitation side (10).

4. Structure-borne sound actuator (2) according to any one of the preceding claims, characterized in that the intermediate element (3) is designed with at least two material layers (19, 20, 21) extending at equal distances from the coupling side (12).

5. Structure-borne sound actuator (2) according to any one of the preceding claims, characterized in that the intermediate element (3) has a raised mounting region (17), on a side opposite the coupling side (12) and configured for attaching the intermediate element (3) to the excitation unit (7).

6. Structure-borne sound actuator (2) according to any one of the preceding claims, characterized in that the intermediate element (3) is secured with a non-destructively releasable connection (11) to the excitation side (10) of the excitation unit (7).

7. Motor vehicle (1) having a structure-borne sound actuator (2) according to any one of the preceding claims.

8. Motor vehicle (1) according to Claim 7, characterized in that the structure-borne sound actuator (2) is coupled using one coupling side (12) of an intermediate element (3) to an acoustic body, the acoustic body being designed as an interior trim part (4) of the motor vehicle (1).