EP3954133B1 - Vibration actuator for rigid structures for high-performance bass playback in automobiles - Google Patents

Description

The invention relates to an actuator for exciting at least one component of a motor vehicle with vibrations, a component arrangement with such an actuator and a motor vehicle with such a component arrangement.

Entertainment systems that allow audio playback from sources such as radio, CD or electronic recordings are standard in today's motor vehicles. For balanced audio playback in vehicles, the audio signal is usually divided into different frequency ranges and played back using elements optimized for each. To reproduce deep tones, loudspeakers that are sufficiently heavy and large as well as large volumes are required in order to produce a correspondingly powerful sound. However, there are usually only small volumes available inside the vehicle without limiting the usable space. Furthermore, the typically high weight of such loudspeakers has a negative impact on fuel consumption and thus also on pollutant emissions and range.

Loudspeakers for the reproduction of particularly low tones are often integrated into a housing in the vehicle interior. This already includes the resonance volume adapted to the loudspeaker. However, such loudspeaker-housing combinations have the disadvantages mentioned above, such as, in particular, a large volume and a high weight.

It is therefore an object of the invention to provide an alternative and/or improved option for audio playback in motor vehicles.

This is achieved according to the invention by an actuator according to claim 1. Advantageous embodiments can be found, for example, in the respective subclaims be removed. The content of the claims is made the content of the description by express reference.

The invention relates to an actuator for exciting at least one component of a motor vehicle with vibrations. The actuator has a housing which is designed to be connected to the component. The actuator has an electrical coil which is rigidly connected to the housing and is designed to generate a magnetic field when an electrical current flows through it. Furthermore, the actuator has a magnet which is arranged in the housing for limited movement. The actuator has at least one first pole plate, which is assigned to the magnet, wherein the outwardly directed surface of a first pole plate, i.e. facing away from the magnet, is concave, so that it has a greater thickness on the outer edge than in its center.

The at least one component which is excited to vibrate by the actuator is particularly preferably a structure of several components, most preferably comprising the housing.

The actuator can preferably excite such components to oscillate in a suitable manner, which in turn can emit airborne sound. The use of such actuators in motor vehicles allows a considerable saving of space and weight compared to known loudspeakers used in motor vehicles.

It is appropriate that the actuator is designed for a rigid structure as a component to be stimulated for high-performance bass reproduction in the automotive sector. The actuator does not emit sound itself, but rather stimulates structures present in the vehicle, at least one of which is a component to be excited, to vibrate. This excitation causes the structure to form vibrations and ultimately radiate sound in an advantageous manner compared to conventional subwoofers. No additional resonance volume is necessary. The installation space requirement is reduced to a minimum. The actuator is advantageously 5-10 times smaller and 2-5 times lighter than a conventional subwoofer. The performance of the bass reproduction - especially with regard to extreme power peaks and sustained maximum load - far exceeds that of conventional subwoofers.

One purpose of the actuator can be, for example, to generate vibrations or oscillations in order to achieve radiation of airborne sound or sound reproduction using suitable structure(s).

The structure expediently comprises several components, in particular components connected to one another, which are jointly or partially excited to vibrate.

The actuator is preferably designed so that it is particularly suitable for reproducing deep tones or bass reproduction, the actuator being suitable for frequencies below 100 Hz or 200 Hz, in particular below 100 Hz or 200 Hz down to at least 60 Hz, particularly preferably down to to at least 40Hz, in each case expediently with an amplitude drop of up to -6dB, in particular -3dB, is suitable or is also suitable.

The actuator is expediently designed to reproduce a maximum sound pressure level of at least 100dB.

The actuator is particularly designed so that it can continuously generate a sound pressure level of at least 80dB for at least an hour.

The housing of the actuator is preferably connected directly to the component or indirectly via at least one fastening means. The connection between the housing and the component is directly or indirectly designed to be essentially rigid and/or stiff.

The component is expediently designed as one of the following structures of a motor vehicle, floor panel, door structure panel, trunk lid, spare wheel well, roof structure, cross member, fender, side member, door support, front wall or frame part and in particular as one of the following structures floor panel, trunk lid, or front wall. This structure is particularly preferably designed as carbon and/or glass fiber reinforced plastic GRP and/or carbon fiber reinforced plastic CFK.

The preferred rigid arrangement of the electrical coil in the housing effectively prevents relative movements between the coil and the housing. This can prevent wear and tear on components that may rub against each other. This may also apply to a cable for connecting the electrical coil, which will be discussed in more detail below.

The vibrations are preferably mechanical vibrations. This can be expressed, for example, in a vibration of the actuator. Such vibrations can be transmitted to at least one component, which then also carries out corresponding vibrations. The vibrations of the actuator are preferably vibrations which, in particular after transmission to at least one component, lead to the emission of airborne sound waves or to the generation of sound waves, which then spread further through the air. In particular, the vibrations can have frequencies between 20 Hz and 20 kHz, which roughly corresponds to a typical human hearing range.

The actuator preferably has an electrical connection, for example by means of a plug or clamp connection, which can be completely or partially integrated into the housing and is electrically connected to the coil. For example, a cable can be used for this. This can form an electrical connection between the connection and the coil. Such a cable can also be used, for example, to locate the electrical connection away from the housing.

The electrical connection is advantageously rigidly connected to the housing. In this way, in particular, a relative movement between the electrical connection and the housing can be prevented, which can prevent wear.

An electrical connection between the electrical connection and the coil is preferably completely fixed to the housing. This allows a relative movement between the electrical connection, for example a cable, and the Housing can be effectively prevented. This avoids friction and fatigue of the materials and thus wear and tear.

The magnet can preferably be excitable and/or deflectable in particular by means of the magnetic field generated by the coil. This can generate vibrations.

The magnet can preferably be movable in only one spatial direction defined in the housing. A spatial direction can correspond to a combination of one direction and an exactly opposite direction. In other words, the magnet can be moved one-dimensionally along an axis defined in the housing.

The actuator preferably has a spring arrangement which is designed to bias the magnet into a rest position. From this rest position, the magnet can then be deflected in particular by means of the magnetic field generated by the coil, which has already been mentioned.

The spring arrangement can preferably be designed to prestress the magnet to the rest position along every possible direction of movement. The possible directions of movement can, for example, be those directions which are defined by the spatial direction already mentioned above.

The spring arrangement preferably has a first spring element and a second spring element, the magnet being held between the first spring element and the second spring element. The first spring element preferably biases the magnet in a first direction. The second spring element preferably biases the magnet in a second direction or orientation that is opposite to the first. This can be particularly advantageous if, as already mentioned above, the magnet can be moved in one spatial direction or only in one dimension. The magnet is then biased in both directions by the spring arrangement.

Alternatively, it is also possible to use only one spring element, which can, for example, generate a preload in one or all relevant directions.

Preferably, the spring element or the first spring element has a number of spring arms for biasing the magnet. The second spring element also preferably has a number of spring arms for prestressing the magnet. Such a design has proven to be advantageous for typical applications. The magnet can in particular be attached at a respective point at which the spring arms come together.

The spring arms of the first spring element can preferably be arranged in a star shape or spiral shape. The spring arms of the second spring element can also preferably be arranged in a star shape or spiral shape. For example, the magnet can be attached in the middle of such a star shape, with the resulting spring effect proving to be advantageous.

The arrangement of the spring arms is expediently designed symmetrically or, alternatively, preferably asymmetrically in order to prevent natural vibrations. The asymmetry is particularly preferably designed as a rotational asymmetry or as a translational asymmetry.

The material thickness or material thickness of the spring elements can preferably be constant or, in particular, of different thicknesses. It is therefore advisable to provide different thicknesses at different points of the spring elements in order to achieve special vibration properties and special restoring characteristics of the spring. For example, a spring element can be given a more pronounced progressive restoring characteristic through profiling.

At least one spring arm or the spring arms and/or at least one spring element is expediently designed to be profiled in order to further improve the rigidity and the vibration properties. The profiling is there particularly preferably carried out by at least one rib and/or at least one bead and/or at least one edge and/or at least one curvature, very particularly preferably for each spring arm and/or each spring element.

Preferably, the first spring element and the second spring element are as far apart as possible within the housing and/or arranged at opposite ends of the housing. This allows the best possible generation of the spring force to be achieved, in particular in that a position of the housing can be freely selected. The magnet is suitably biased into its rest position in any position of the housing relative to the earth's surface or to another external element and can be deflected as intended by the magnetic field without restriction. The greatest possible distance can refer in particular to the spatial direction already mentioned above, which indicates an axial movement of the magnet.

The spring elements can be made, for example, from plastics, metals or composite materials. This can influence the acoustic behavior. In particular, the damping behavior of the spring elements can be influenced by this.

Particularly preferably, the spring elements are, in particular additionally, coated, for example with one or more plastics with relatively high damping or with relatively high-mass materials, in order to dampen and/or detune the natural vibration behavior of the spring elements.

The magnet can preferably be movable within the coil. The mobility within the coil results in a particularly good effect of the magnetic field generated by the coil.

The actuator preferably has a ring as a housing or housing part, which surrounds the coil and is made of magnetically conductive and/or heat-conducting material. By designing it from magnetically conductive material, a magnetic connection can preferably be generated on the side of the coil.

This significantly improves the effect of the magnetic field generated by the coil.

Preferably, the housing of the actuator is made of a material with a thermal conductivity of at least 25 W/(m K), in particular at least 40 W/(m K). This enables a particularly advantageous dissipation of heat generated inside the housing. This heat can arise in particular from the current flowing through the coil and possible friction effects due to the moving magnet. By being made of heat-conducting material, this heat can preferably be dissipated, for example to components connected to the housing or the component to be excited. Overheating of the actuator is thereby advantageously prevented.

The housing of the actuator preferably has a heat capacity of at least 0.08 kJ/K, in particular at least 0.1 kJ/K. Due to this particularly high specific heat capacity, high heat input resulting from temporary load peaks can be absorbed by the coil.

The fixed connection of the coil to the housing can preferably be produced by an adhesive connection made of relatively highly thermally conductive adhesive. The adhesive has a thermal conductivity of at least 0.8 W/(m K), in particular at least 1 W/(m K). The layer thickness of the adhesive is expediently a maximum of 0.3 mm, in particular less than 0.1 mm. This ensures efficient heat dissipation from the coil into the housing.

It is preferred that the coil carrier of the coil, which is firmly connected to the housing, is made of a relatively highly thermally conductive material with a thermal conductivity of at least 0.8 W/(m K), in particular at least 1 W/(m K), in order to achieve a To ensure efficient heat dissipation from the coil into the housing.

It is preferred that the inner surface of the housing, which is connected to the coil and/or the coil support by means of an adhesive connection, is structured and/or profiled. The inner surface or the surface of the interior of the housing, in particular in the area in which it is connected to the coil and/or the coil support, has, for example, rectangular profiles and/or triangular profiles and/or sinusoidal profiles and/or circular arc profiles as surface structuring, to ensure efficient heat dissipation from the coil into the housing by increasing the contact surface. Additionally or alternatively, further profiles/ribs can expediently be applied to the outside of the housing, which ensure improved heat transfer into the environment.

According to a preferred embodiment, the housing has a first cover cap at a first axial end with respect to the coil. This can in particular be made of plastic, of a non-magnetically conductive and/or of a non-heat-conducting material or of a heat-conducting material. Likewise, the housing can have a second cover cap at a second axial end with respect to the coil. This can also be made in particular from plastic, from a non-magnetically conductive and/or from a non-heat-conducting material or from a heat-conducting material.

Due to the particularly preferred design of a respective cover cap made of non-magnetically conductive material, a magnetic flux can be kept completely or partially in the housing, which, for example, prevents interference with other components. By being made of non-heat-conducting material, heat emission from the actuator to a contacting element can be prevented or reduced.

Plastics such as PA6 (polyamide 6), ABS (acrylonitrile-butadiene-styrene copolymer) or PP (polypropylene) are preferably used as non-heat-conducting, non-magnetically conductive materials.

In particular, a three-part structure of the housing, i.e. with a ring and two cover caps, can be provided.

However, a respective cover cap can also be designed to be heat-conducting, for example. In particular, it cannot be designed to be magnetically conductive at the same time. This allows heat to be transferred to another element, which prevents the actuator from overheating. For example, aluminum or magnesium can be used as a thermally conductive and non-magnetically conductive material.

The housing preferably has an externally accessible bore with an internal thread or another externally accessible fastening means. Such a fastening means can also be designed, for example, as a through hole without a thread or in another suitable manner. As a result, the housing can, for example, be additionally fastened rigidly to an element other than the already mentioned component of the motor vehicle, for example to a body or to a floor of the motor vehicle. This allows a reference to another element, in particular a more rigid element, to be established, so that the component can be excited in an advantageous manner.

The magnet preferably has a mass which is in a range between 80% of the mass of the other components of the actuator and 120% of the mass of the other components of the actuator. Such values have proven to be particularly advantageous from an acoustic point of view.

The housing can preferably be designed to be completely or essentially radially symmetrical. This has proven to be an easy design to manufacture and use. However, other designs, for example a square, square, rectangular or a design with a different number of corners, are also possible.

The housing can, for example, be closed, open or partially open. A closed design can in particular ensure that a certain level of protection against the ingress of dust, liquids or other contaminants is achieved.

The magnet preferably has a magnetic middle part, a first pole plate and a second pole plate. The middle part is preferably surrounded by the first pole plate and the second pole plate. The magnetic middle part can in particular be arranged along a single possible direction of movement of the magnet or the spatial direction between the first pole plate and the second pole plate. Such designs have proven to be advantageous.

The first and/or second pole plates are preferably assigned to the magnet, in particular on two opposite sides, the magnet between the pole plates, particularly preferably in the middle, in the undeflected state of the actuator. The outward-facing surface of an expedient first pole plate, i.e. facing away from the magnet, the pole plate being assigned to the magnet, is concave, in particular with regard to its cross section, so that it has a greater thickness on the outer edge than in its center. The transition between the thicker, outer edge and the thinner middle part is designed, in particular, to slope linearly or to slope in a circular arc or to slope parabolically. Furthermore, the pole plate particularly preferably has a collar along its outer edge, in particular the outer edge of the outwardly directed surface, in particular of essentially constant thickness, which can have up to 20% of the total extent of the pole plate. The surface of the first pole plate that is aligned towards the magnet is expediently designed to be essentially flat.

Likewise, a second pole plate is preferably formed on its outward-facing side like the first pole plate on its outward-facing surface. In particular, in the case of the second pole plate, the side or surface facing the magnet is essentially flat. Through such a thing Execution can be achieved on the one hand that the magnetic flux density in the outer region of the pole plates becomes higher and on the other hand a respective adjacent spring element can be arranged closer to the pole plate. This means that overall installation space can be saved.

The first and/or second pole plates are expediently designed with regard to their outward-facing surface in such a way that they have a substantially flat partial surface or a plateau in the middle.

It is expedient for the first and/or the second pole plate to be essentially flat on the side facing the magnet and for the outer side facing away from the magnet to be concave in terms of its cross section and thus for the entire cross section of the pole plate to be concave . The outer side of the first and/or the second pole plate has a collar, in particular on the peripheral edge, on which the pole plate has a greater thickness or material thickness than in the middle, with the pole plate/s in the area of the middle of the outer side. in particular each has/have a substantially flat plateau. The transition between collar and plateau is particularly preferably designed as a linear transition or a circular arc-shaped or a parabolic transition or a combination of two or three of these transition shapes.

The magnet or the magnetic middle part can consist, for example, of a neodymium alloy or a ferrite alloy.

In general, an actuator or vibration exciter can be described that does not emit sound itself, but rather stimulates existing structures in the vehicle. This excitation causes the structure to vibrate, whereupon it itself emits sound. The actuator is typically about a factor of 5 to 10 smaller and a factor of 2 to 5 lighter compared to an equivalent subwoofer.

• Die Spule des Aktuators ist direkt mit dem äußeren Gehäuse verbunden, beispielsweise geklebt oder auf andere Weise verbunden, wobei der Magnet typischerweise innenliegend ist, beispielsweise im Inneren des Spulendurchmessers, und typischerweise beweglich gelagert ist.
• Ein äußerer Ring als Gehäuse oder Gehäuseteil, an dem die Spule beispielsweise befestigt sein kann, kann aus einem wärmeleitenden Metall oder Material bestehen, wobei der Ring beispielsweise einen magnetischen Flusskreis schließen kann und darüber hinaus die entstehende Wärme der Spule nach außen ableiten kann und an der äußeren Seite an die Umgebung abgeben kann.
• Der Aktuator kann an unterschiedlichsten Positionen im und außerhalb des Fahrzeugs verbaut werden. Vorzugsweise kann er an Blechstrukturen wie beispielsweise einem Bodenblech, an einem Türstrukturblech, an einem Kofferraumdeckel, einer Reserveradmulde, einer Dachstruktur, einem Querträger, einem Kotflügel, einem Längsträger, einer Stirnwand oder an anderen Bauteilen eines Kraftfahrzeugs angebracht werden.
• Der Aktuator kann in allen Raumrichtungen positionierbar sein mit gleicher Eignung. Dies kann insbesondere ermöglicht werden durch eine Zentrierung des Magnetsystems bzw. des Magneten an möglichst weit voneinander entfernt liegenden Ebenen.
• Die Zentrierung und die Federung des Magnetsystems können in einem Bauteil ausgeführt sein, das aus verschiedenen Materialien bestehen kann wie beispielsweise Kunststoffen, Metallen oder Kompositmaterialien, wodurch das akustische Verhalten beeinflusst oder optimiert werden kann.
• Der Aktuator kann ein von oben nach unten durchgängiges Mittelloch aufweisen, um den Aktuator an einem Bolzen mittig befestigen zu können.
• Die Masse des beweglichen Magnetsystems bzw. Kerns kann beispielsweise etwa ±20% der Masse des äußeren Kerns bzw. der sonstigen Komponenten des Aktuators betragen. Dadurch kann der Aktuator sowohl oberhalb als auch unterhalb seiner eigenen Resonanzfrequenz betrieben werden.
• Das Aktuatorgehäuse kann grundsätzlich in verschiedenen Formen ausgeführt werden, jedoch kann eine symmetrische Ausführung vorteilhaft für die Montage und auch die Herstellung sein.
• Materialien können beispielsweise verschieden ausgeführt sein. Der Magnet kann beispielsweise aus einer Neodymlegierung oder auch aus einer Ferritlegierung bestehen. Weiterhin kann das Gehäuse offen oder teiloffen ausgeführt sein. Eine Anbindung des Aktuators kann abgesehen von dem bereits erwähnten Mittelloch auch über eine außenliegende Befestigung oder eine Klebe- oder Schweißverbindung erfolgen. Ebenfalls ist ein Aufbau denkbar, bei dem das Magnetsystem nicht vollständig innerhalb des Spulendurchmessers liegt, wobei die Spule auch teilweise vom Magneten umschlossen werden kann.

Actuators, depth actuators or vibration exciters, as described herein, can preferably have the following features, for example, which can be used individually or in combination:

• The coil of the actuator is connected directly to the outer housing, for example glued or otherwise connected, with the magnet is typically internal, for example inside the coil diameter, and is typically movably mounted.
• An outer ring as a housing or housing part, to which the coil can be attached, for example, can consist of a heat-conducting metal or material, whereby the ring can, for example, close a magnetic flux circuit and can also dissipate the heat generated by the coil to the outside and on the external side can release into the environment.
• The actuator can be installed in a variety of positions inside and outside the vehicle. Preferably, it can be attached to sheet metal structures such as a floor panel, a door structure panel, a trunk lid, a spare wheel well, a roof structure, a cross member, a fender, a side member, a front wall or other components of a motor vehicle.
• The actuator can be positioned in all spatial directions with the same suitability. This can be made possible in particular by centering the magnet system or the magnet on planes that are as far apart as possible.
• The centering and suspension of the magnet system can be implemented in a component that can consist of different materials such as plastics, metals or composite materials, whereby the acoustic behavior can be influenced or optimized.
• The actuator can have a center hole that runs from top to bottom in order to be able to attach the actuator to a bolt in the middle.
• The mass of the movable magnet system or core can be, for example, approximately ±20% of the mass of the outer core or the other components of the actuator. This allows the actuator to be operated both above and below its own resonance frequency.
• The actuator housing can basically be designed in different shapes, but a symmetrical design can be advantageous for assembly and manufacturing.
• Materials can, for example, be designed differently. The magnet can, for example, consist of a neodymium alloy or a ferrite alloy. Furthermore, the housing can be designed to be open or partially open. Aside from the center hole already mentioned, the actuator can also be connected via an external fastening or an adhesive or welded connection. A structure is also conceivable in which the magnet system is not completely within the coil diameter, and the coil can also be partially enclosed by the magnet.

Fig. 1:

einen Aktuator in einer seitlichen Explosionsansicht,

Fig. 2:

den Aktuator in einer perspektivischen Explosionsansicht,

Fig. 3:

den Aktuator in einem zusammengebauten Zustand,

Fig. 4:

eine alternative Ausführung eines Federelements,

Fig. 5:

einen Querschnitt einer Polplatte.

A person skilled in the art will find further features and advantages in the exemplary embodiments described below with reference to the accompanying drawing. Show:

Fig. 1:

an actuator in a side exploded view,

Fig. 2:

the actuator in a perspective exploded view,

Fig. 3:

the actuator in an assembled state,

Fig. 4:

an alternative version of a spring element,

Fig. 5:

a cross section of a pole plate.

Fig. 1 shows an actuator 5 according to an embodiment of the invention in a side exploded view.

The actuator 5 has a housing 10. The housing 10 is formed by a first cover cap 12, a second cover cap 16 and a ring 14. The two cover caps 12, 16 are arranged on the outside and consist of non-heat-conducting, non-magnetically conductive material. It should be mentioned that one or both of these two cover caps 12, 16, for example could consist of heat-conducting, non-magnetically conductive material. The ring 14 consists of heat-conducting, magnetically conductive material.

The actuator 5 has a spring arrangement 20, which is formed by a first spring element 22 and a second spring element 24. Their implementation will be discussed in more detail below.

The actuator 5 has a coil, which is formed by a coil carrier 32, a first coil section 34 and a second coil section 36. The two coil sections 34, 36 are applied to the coil carrier 32. Electrical current can flow through the coil sections 34, 36, so that a magnetic field is generated in the coil 30.

The actuator 5 has a magnet 40. This is formed by a magnetic middle part 42 and a first non-magnetic pole plate 44 and a second non-magnetic pole plate 46. The middle part 42 is accommodated between the two pole plates 44, 46.

Two sets of four screws 18, 19 are used to fasten the components mentioned. Alternatively, fastening by gluing, welding or riveting would also be possible.

Fig. 2 shows the actuator 5 in a perspective exploded view. It can be seen that the first spring element 22 has a total of four spring arms 26. Accordingly, the second spring element 24 has a total of four spring arms 28.

When assembled, the magnet 40 is designed in such a way that the two pole plates 44, 46 directly adjoin the magnetic middle part 42. The magnet 40 is then held as a whole by the two axially adjacent spring elements 22, 24. As a result, the magnet 40 is only movable in an axial direction, being biased into a central rest position by the spring elements 22, 24.

As shown, the pole plates 44, 46 are concavely curved on their outward-facing surfaces. This enables a particularly space-saving arrangement of the magnet 40 between the spring elements 22, 24 and allows a particularly high magnetic flux density in the edge region of the pole plates. When assembled, the coil 30 surrounds the magnet 40 radially. The coil 30 is firmly fixed in the housing 10. By applying an electrical voltage to the coil 30, the magnet 40 can be deflected from its rest position, causing oscillations. In particular, a voltage can be applied to which an audio signal is modulated. The magnet 40 then oscillates in accordance with this audio signal and generates corresponding oscillations. The ring 14 made of magnetically conductive material serves to provide an advantageous magnetic connection.

A first cylindrical projection 13, which extends inwards from the first cover cap 12, and a second cylindrical projection 17, which extends inwards from the second cover cap 16, serve to define the axial direction along which the magnet 40 is movable extends.

Fig. 3 shows the actuator 5 in the assembled state. It can be seen that three cylindrical contact points 7 are arranged on the outside of the first cover cap 12. With these, the actuator 5 can adjoin a component of a motor vehicle. Furthermore, a hole 8 is arranged in the middle, in which a thread is formed. This allows the actuator 5 to be attached to a component. The second cover cap 16 is also designed accordingly.

By attaching or placing the actuator 8 on a component of a motor vehicle, the vibrations already mentioned above, which the magnet 40 can generate, can be transmitted to the component. In this way, the component itself can be stimulated to vibrate, which causes it to emit sound waves. These sound waves are typically audible inside a vehicle. In this way, sound can be generated without having to provide a separate loudspeaker, which is particularly useful at low frequencies and leads to significant space and weight savings.

It should be mentioned that, for example, the bore 8 can also be used to connect the actuator 5 to a rigid component such as a body part of a vehicle and the actuator 5 on the opposite side to a component which is to be excited to vibrate. can be connected. In this way, the fixed component, such as a vehicle body, can serve as a reference relative to which the vibrations are excited.

Fig. 4 shows an alternative embodiment of a spring element, here as an example of the first spring element 22. This can be done within the framework of the with reference to Figures 1 to 3 described embodiment can be used instead of the first spring element 22 shown there and / or instead of the second spring element 24 shown there.

In contrast to the star-shaped version, which in Fig. 2 can be seen, are the spring arms 26 of the in Fig. 4 Spring element 22 shown is designed in a spiral shape. This allows a different spring characteristic to be achieved.

Fig. 5 shows schematically a pole plate 44, 46 in cross section. The pole plate is, for example, essentially flat on the side facing the magnet (not shown) 61. The outer side or surface 62 facing away from the magnet is concave and thus the entire cross section of the pole plate is concave. The outer side has a collar 63 on the circumferential edge, on which the pole plate has a greater thickness or material thickness than in the middle. The pole plate has a substantially flat plateau 64 in the area of the middle of the outer side. The transition 65 between collar 63 and plateau 64 can be designed in various ways, for example a linear transition, a circular arc-shaped and a parabolic transition are illustrated on the left side.

Claims (14)

1. Actuator (5) for exciting at least one component of a motor vehicle with vibrations,
   wherein the actuator (5) has the following:

   - a housing (10) which is configured to be connected to the component,

   - an electrical coil (30) which is rigidly connected to the housing (10) and is configured to generate a magnetic field when an electrical current flows through it, and

   - a magnet (40) which is arranged in the housing (10) so as to be movable to a limited extent,

   - wherein the actuator has at least one first pole plate (44, 46) which is assigned to the magnet, characterized in that the outwardly directed surface (62) of the first pole plate, i.e. facing away from the magnet, is concave, and therefore said surface has a greater thickness at the outer edge than in its centre.
2. Actuator (5) according to one of the preceding claims,

   - wherein the first pole plate (44, 46) has a collar (63) along its outer edge, in particular of substantially constant thickness, which can comprise up to 20% of the total extent of the pole plate.
3. Actuator (5) according to either of the preceding claims,

   - wherein that surface of the first pole plate (61) which is oriented towards the magnet is substantially planar.
4. Actuator (5) according to one of the preceding claims,

   - wherein the first and/or a second pole plate (44, 46) are/is configured with regard to their/its outwardly directed surface (62) in such a way that they have a substantially planar partial surface and/or a plateau (64) in their/its centre.
5. Actuator (5) according to one of the preceding claims,

   - wherein the housing of the actuator (10) has a heat capacity of at least 0.08 kJ/K, in particular of at least 0.1 kJ/K.
6. Actuator (5) according to one of the preceding claims,

   - wherein the coil has a fixed connection to the housing by an adhesive connection of thermally relatively highly conductive adhesive, wherein said adhesive has a thermal conductivity of at least 0.8 W/(m K), in particular at least 1 W/(m K).
7. Actuator (5) according to Claim 6,

   - wherein the layer thickness of the adhesive here is a maximum of 0.3 mm, in particular less than 0.1 mm.
8. Actuator (5) according to one of the preceding claims,

   - wherein the inner surface of the housing, which is connected to the coil and/or to the coil carrier by means of an adhesive connection, is structured and/or profiled.
9. Actuator (5) according to one of the preceding claims,

   - which has a spring arrangement (20) which is configured to bias the magnet (40) into an inoperative position, wherein the spring arrangement (20) is configured to bias the magnet (40) in a manner returning same back to the inoperative position along every possible direction of movement.
10. Actuator (5) according to Claim 9,

    - wherein the spring arrangement (20) has a first spring element (22) and a second spring element (24),

    - wherein the magnet (40) is held between the first spring element (22) and the second spring element (24),

    - wherein the first spring element (22) biases the magnet (40) in a first direction and the second spring element (24) biases the magnet (40) in a second direction opposite to the first direction, in particular wherein the first spring element (22) has a number of spring arms (26) for biasing the magnet (40), and/or the second spring element (24) has a number of spring arms (28) for biasing the magnet (40).
11. Actuator (5) according to Claim 10,

    - wherein the spring elements (22, 24) are formed from a composite material.
12. Actuator (5) according to either of the preceding Claims 10 to 11,

    - wherein the spring elements (22, 24) are, in particular additionally, coated, for example with one or more plastics with relatively high damping or with relatively massive materials, in order to dampen and/or to detune the natural vibration behaviour of the spring elements (22, 24).
13. Actuator (5) according to one of the preceding Claims 10 to 12,

    - wherein the arrangement of the spring arms (26) is configured symmetrically or, alternatively, is preferably configured asymmetrically, in order to prevent natural vibrations.
14. Actuator (5) according to one of the preceding Claims 10 to 13,

    - wherein the spring arms (26) are profiled in order to further improve the rigidity and the vibration properties, wherein the profiling is implemented here in particular by at least one rib and/or at least one bead and/or at least one edge and/or at least one curvature.

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