RESONANZABSORBER

Description

[0001] The present invention relates to a resonance absorber according to the preamble of patent claim 1 and to an oscillatory device having at least one such resonance absorber according to patent claim 15.

[0002] In a wide variety of technical fields, the occurrence of vibrations, especially resonance vibrations, is undesirable, since such vibrations can lead to additional stress on the mechanical elements, to the generation of airborne sound in the form of noise, and the like.

[0003] To reduce the transmission of high-frequency structure-borne noise, insulation using elastic, low-damping structures such as rubber, i.e. vulcanized rubber, is generally used.

[0004] The disadvantage here is that vibration isolation using rubber is limited by the dynamic hardening of rubber, which increases with increasing frequency. Furthermore, natural vibrations can occur in the rubber at higher frequencies, which can significantly impair the transmission behavior in certain frequency ranges. Disturbing structure-borne noise, for example from electric motors, cannot be isolated across its entire spectrum and can lead to disruptive vibration phenomena, which can manifest themselves acoustically as airborne noise, such as a whistling sound in the passenger compartment of electric vehicles (EVs).

[0005] Passive dampers are also commonly used to reduce vibrations caused by disturbing resonance phenomena in individual frequency ranges; these dampers are specifically designed to suit the frequency range to be damped.

[0006] The disadvantage of passive dampers is that they can only suppress the additional amplification of individual vibration phenomena caused, for example, by structural resonances. However, depending on the structure, this requires a large number of passive dampers, each of which can only be effective in specific frequency ranges. Furthermore, the behavior of the passive dampers can change due to aging and / or temperature fluctuations, for example, which can lead to a reduction in the effectiveness of the passive dampers.

[0007] DE 21 63 798 A1 describes a resonance absorber for damping periodic and / or aperiodic mechanical vibrations using mechanical vibrating elements. By appropriately designing the vibrating elements, the distances between their natural frequencies are reduced, so that as many natural frequencies as possible fall within the frequency range to be damped.

[0008] Furthermore, vibrations can generally be reduced or compensated across a broad range using an active damper by accelerating an inertial mass. The damping effect of the inertial mass can be controlled by adjusting the acceleration frequency to match the frequency to be damped.

[0009] By using an active damper, structure-borne sound transmission can, in principle, be suppressed across a broad range and permanently. However, this requires actuators with relatively large forces and travel distances to generate the required acceleration of the inertial mass across the entire frequency range, which can result in expensive and large actuators.

[0010] Furthermore, combining an active damper with a resonance amplifier as a passive damper, possibly with multiple resonance amplifiers, can achieve a significantly increased damping effect at the respective resonance frequency. However, compensation in the transition regions between the individual resonances is difficult or even impossible. Such combined systems are therefore only suitable for vibration problems with discrete frequency ranges that require damping.

[0011] DE 103 21 436 A1 describes a device with a piezoelectric transducer mounted on a stationary vertical support element. Two oscillating masses are diametrically opposed and radially connected to each other via the piezoelectric transducer. Furthermore, the two oscillating masses are each connected obliquely radially to the same support element by means of two spring-elastic elements. Controlling the piezoelectric transducer causes a radial deflection of the piezoelectric transducer. Due to the spring-elastic elements, the masses oscillate predominantly up and down perpendicular to the piezoelectric transducer. The masses therefore have a vibration component in the longitudinal direction of the piezoelectric transducer as well as a pronounced vibration component perpendicular to it.

[0012] An object of the present invention is to provide a resonance absorber of the type described above that can have a damping effect not only at discrete frequencies or frequency ranges. In other words, a resonance absorber of the type described above that can have a damping effect over a comparatively wide frequency range is to be created. This should be achieved, in particular, with a comparatively low requirement for force and / or travel. This should, in particular, be implemented in a comparatively simple, compact, lightweight, cost-effective, and / or durable manner. At the very least, an alternative to known resonance absorbers is to be created.

[0013] The object is achieved according to the invention by a resonance absorber having the features according to claim 1 and by an oscillatory device having the features according to claim 15. Advantageous further developments are described in the subclaims.

[0014] Thus, the present invention relates to a resonance absorber with at least one resonance structure as a passive damper with a plurality of oscillating elements that extend radially around a common longitudinal axis, at least in sections, preferably substantially, particularly preferably completely, wherein the oscillating elements are spaced apart from one another at least in sections in the circumferential direction of the longitudinal axis. The oscillating elements can also be referred to as webs. The resonance absorber represents a resonance-enhanced active damper, since it can enhance the damping through its own resonances.

[0015] The resonance absorber according to the invention is characterized by at least one excitation element as an active damper, which is designed to excite the oscillating elements of the resonance structure to vibrate together along the longitudinal axis. At least several oscillating elements immediately adjacent in the circumferential direction, preferably all oscillating elements, are elastically coupled to one another across the respective distance in a vibration-transmitting manner. Any suitable type of drive can be used as the excitation element. In particular, electrodynamic or electromagnetic actuators can be used.

[0016] In other words, a passive resonance absorber, such as that known from DE 21 63 798 A1, is further developed around an excitation element as an active damper. Furthermore, its immediately adjacent oscillating elements in the circumferential direction are connected to one another in such a way that the oscillation of one oscillating element is transmitted by the coupling to at least one immediately adjacent oscillating element, so that this element is also excited to oscillate. This can be done for only some of the oscillating elements and preferably for all oscillating elements.

[0017] The present invention is based on the finding that, in known resonance absorbers, only discrete frequencies or narrow-band frequency ranges can be damped by the vibrations of a single vibrating element at resonance. This creates gaps in the frequency range that cannot be damped by any of the vibrating elements. This applies to passive dampers as well as active dampers.

[0018] According to the invention, immediately adjacent vibrating elements are elastically connected to one another and thus coupled to transmit vibrations, thus achieving a coupling of the eigenmodes of the interconnected vibrating elements. This also allows for an increase in excitation in the frequency range between the resonant frequencies of the two interconnected vibrating elements. Damping can be achieved with a correspondingly broad and seamless range using the excitation element.

[0019] According to one aspect of the invention, the respective gap between the oscillating elements is at least partially, preferably completely, filled with an elastic material that couples the immediately adjacent oscillating elements to one another in a vibration-transmitting manner. This can represent a simple but effective way of achieving the previously described coupling between immediately adjacent oscillating elements.

[0020] For this purpose, only the gaps between the vibrating elements can be partially or completely filled with elastic material. The partial filling of the gaps between the vibrating elements with elastic material can extend along the longitudinal axis and / or radially.

[0021] Furthermore, the vibrating elements can also be partially or completely covered by the elastic material so that, in addition to the vibration-transmitting coupling, a coating of the vibrating elements can be achieved in order to protect them against external influences such as moisture.

[0022] According to a further aspect of the invention, the elastic material preferably comprises an elastomeric material, preferably rubber, or a thermoplastic material. This allows the corresponding material properties to be utilized to implement the present invention.

[0023] According to a further aspect of the invention, the respective distance between the oscillating elements is filled in sections with a thinner material thickness of the material of the oscillating elements as a material weakening, which couples the immediately adjacent oscillating elements to one another in a vibration-transmitting manner. Alternatively or in addition to the previously described vibration-transmitting coupling by means of an elastic material, the immediately adjacent oscillating elements can thus also be formed in one piece, i.e. integrally, wherein the actual oscillating elements are connected to one another in a vibration-transmitting manner by thinner material regions, which can be referred to as material weakening. The material weakening is designed with such thin walls that elastic vibration transmission can take place as described above. This can also implement a vibration-transmitting coupling as described above.

[0024] According to a further aspect of the invention, the immediately adjacent oscillating elements are coupled to one another in a vibration-transmitting manner by means of at least one connecting element. Alternatively or in addition to the previously described possibilities for vibration-transmitting coupling, additional elastic elements can thus also be used to realize a vibration-transmitting coupling. Such connecting elements can be arranged, in particular, above and / or below the oscillating elements, which can minimize the design effort required for implementation.

[0025] According to a further aspect of the invention, the oscillating elements, preferably including the material weakening, comprise a metallic material or a thermosetting material. This allows the corresponding material properties to be utilized to implement the present invention.

[0026] According to a further aspect of the invention, the oscillating elements are configured to extend radially at different distances from the longitudinal axis, preferably in a helical shape. In this way, the oscillating elements can essentially be constructed identically in terms of their contour or shape. However, their radial extension can be used to tune them to different resonant frequencies.

[0027] According to a further aspect of the invention, the oscillating elements are designed to be at least substantially, preferably exactly, diametrically opposite one another in pairs and to extend at least substantially, preferably exactly, the same distance from the longitudinal axis, and the pairs of oscillating elements are designed to extend radially different distances from the longitudinal axis. This aspect of the present invention is based on the finding that if only one oscillating element or the oscillating elements immediately adjacent to one another can be excited to oscillate, a tilting moment can be generated at this point, which can cause corresponding loads relative to the longitudinal axis. If the resonance structure is therefore designed symmetrically to the longitudinal axis, two oscillating elements that are at least substantially or even exactly diametrically opposite one another to the longitudinal axis are simultaneously excited to resonant oscillation.Since this occurs with the same amplitude, the tilting moments essentially or even completely cancel each other out, and corresponding loads relative to the longitudinal axis can be avoided. This can be achieved for at least one pair of such oscillating elements, as well as for multiple pairs of such oscillating elements.

[0028] According to a further aspect of the invention, at least some, preferably all, of the oscillating elements are designed to be inclined relative to the longitudinal axis. This allows a vibration component to be generated that may be unequal to the longitudinal axis.

[0029] According to a further aspect of the invention, the resonance absorber comprises a plurality of resonance structures as passive dampers, which are arranged offset from one another along the longitudinal axis. The excitation element is designed as an active damper to excite the oscillating elements of all resonance structures to oscillate together along the longitudinal axis. This allows the previously described effects of the resonance structures to complement and reinforce each other. Alternatively, the same effect can be achieved by combining several smaller resonance structures.

[0030] According to a further aspect of the invention, the resonance structures are designed to function similarly, preferably identically. This can simplify implementation by eliminating the need to design and construct different resonance structures, especially of different types.

[0031] According to a further aspect of the invention, the resonance structures are designed to act at least substantially, preferably exactly, diametrically opposite to the longitudinal axis, preferably identically. This can, for example, help prevent tilting moments as described above.

[0032] According to a further aspect of the invention, the excitation element is a piezoelectric element, preferably a piezoelectric ring or a piezoelectric rod, which is designed to act at least substantially, preferably exactly, perpendicular to the orientation of the oscillating elements. This allows the properties of piezoelectrically acting drive elements or excitation elements to be utilized to implement the invention.

[0033] The present invention also relates to a vibration-capable device, preferably a motor vehicle, particularly preferably an electric motor vehicle, comprising at least one resonance absorber as described above. In this way, the properties and advantages of a resonance absorber according to the invention can be utilized in a vibration-capable device to dampen vibrations therein. This can be used particularly in motor vehicles, and especially in electric motor vehicles, to prevent noise in the passenger compartment.

[0034] According to one aspect of the invention, the excitation element, preferably a piezoelectric element, is arranged in a prestressed manner between the resonant structure and a structural component of the shrinkable device. In other words, a prestress is applied to the excitation element directly via the resonant structure. This can, particularly when using a piezoelectric element as the excitation element, promote the effect of the excitation element along the longitudinal axis in both directions.

[0035] For this purpose, a preload or connecting element such as a screw or rivet can preferably be passed through a central opening within the resonance absorber. This preload or connecting element can generate a preload force on the resonance absorber, which can then deform elastically and transfer the preload to the piezo element. After a certain deflection and thus at a defined preload force, the resonance absorber can bear directly or indirectly against the structural component, so that a connecting force of the resonance absorber that exceeds the required preload force of the piezo element is applied to the structural component to be calmed and not to the piezo element. This prevents damage to the piezo element, ensures a defined preload force, and minimizes the number of components of the resonance absorber.

[0036] Several embodiments and further advantages of the invention are explained below in conjunction with the following figures. Figure 1 shows a perspective schematic sectional view of a resonance absorber according to the invention according to a first embodiment; Figure 2 shows a simulation diagram of the frequency of the oscillations over the mode number (left) and two top views of the resonance absorber of the Figure 1 with two different vibration forms (top right, bottom right) of the measurement diagram; Figure 3 a perspective schematic sectional view of a resonance absorber according to the invention according to a second embodiment; Figure 4 a schematic side view of the Figure 3 ; and Figures 5-8 various detailed views of the resonance structure of the resonance absorber in cross section.

[0037] The description of the above figures is given in cylindrical coordinates with a longitudinal axis X, a radial direction R perpendicular to the longitudinal axis X and a circumferential direction U circulating around the longitudinal axis X. The longitudinal axis X, the radial direction R and the circumferential direction U can also be referred to together as spatial directions X, R, U or as cylindrical spatial directions X, R, U.

[0038] Figure 1 shows a perspective schematic sectional view of a resonance absorber 1 according to the invention according to a first embodiment.

[0039] The resonance absorber 1 has a resonance structure 10 as a passive damper 10. The resonance structure 10 has a plurality of oscillating elements 11, which extend radially at different distances from the longitudinal axis X and are spaced from one another in the circumferential direction U by distances 12. The oscillating elements 11 each have a rectangular cross-section, which has the smaller extension along the longitudinal axis X. The oscillating elements 11 as a whole form a helical structure in the circumferential direction U around the longitudinal axis X.

[0040] The oscillating elements 11 are formed in one piece or integrally with a central fastening element 14, which extends in a ring around the longitudinal axis X and has a central fastening bore 14a as a through-opening along the longitudinal axis X. A screw 3, see Figures 3 and 4 , in order to fix the resonance structure 10 on a structural component 2 of an oscillatory device (not further shown).

[0041] According to the first embodiment of the Figure 1an excitation element 15 as an active damper 15 in the form of a piezo element 15, designed as a piezo ring 15, is arranged along the longitudinal direction X between the radially outer edge of the central fastening element 14 and the upper structural part 2. The piezo ring 15 is fastened, for example, in a materially bonded manner, for example by gluing, to the central fastening element 14 and thus belongs to the resonance absorber 1. Alternatively, the piezo ring 15 can also be arranged loosely on the central fastening element 14 and held by the assembly of the resonance absorber 1 on the structural component 2. In any case, by tightening the screw 3, a piezo ring 15 projecting downwards along the longitudinal axis X beyond the central fastening element 14 can be preloaded during assembly on the structural component 2.This results in an elastic deformation of the fastening element 14 until the fastening element 14 comes into contact, directly or indirectly, with the same surface of the structural component 2 that also forms the contact surface of the piezo ring 15. This rigid structural component 2 can represent the structural component 2 to be stabilized or can be connected to it, preferably rigidly.

[0042] The distances 12 between the immediately adjacent oscillating elements 11 can each be filled with an elastic material 13 in the form of rubber 13 as elastomeric material 13, see Figure 5 Alternatively, the rubber 13 can also enclose the vibration elements 11 and thereby protect them from external influences, see Figure 6 Alternatively, the oscillating elements 11 can be formed in one piece or integrally and in the area of ​​the distances 12 each have a material weakening 11a along the longitudinal axis X, see Figure 7Alternatively, the oscillating elements 11 can also be connected by means of a connecting element 11b which is continuous in the circumferential direction U, see Figure 8 .

[0043] In any case, a vibration-transmitting coupling can be created between the vibrating elements 11, so that the resonance vibrations of a pivoting element 11 can be transmitted to the immediately adjacent vibrating elements 11. This allows a broader-band generation of resonance vibrations than in known resonance absorbers 1 to be achieved, as can be seen by way of example in the views of Figure 2 shown.

[0044] Figure 3 shows a perspective schematic sectional view of a resonance absorber 1 according to the invention according to a second embodiment. Figure 4 shows a schematic side view of the Figure 3 .

[0045] In this case, the resonance structure 10 is designed point-symmetrically to the longitudinal axis X, resulting in two semicircular, helical arrangements of the oscillating elements 11. In this way, tilting moments relative to the longitudinal axis X can be avoided.

[0046] Furthermore, the piezo element 15 is designed as a piezo rod 15 and is arranged along the longitudinal direction X between a rod-shaped structural component 2 and the resonance structure 10 as described above. The piezo rod 15 can be electrically supplied and operated via a terminal 15a. List of reference symbols (part of the description)

[0047] Rradial direction Ucircumferential direction XLongitudinal axis 1Resonance absorber 10Resonance structure; passive damper 11Vibrating elements or strings of the resonance structure 10 11aMaterial weakenings of the vibrating elements 11 11bConnecting elements of the vibrating elements 11 12Distances between immediately adjacent vibrating elements 11 13Elastic or elastomeric or thermoplastic material or rubber at intervals 12 14Central fastening element 14aCentral fastening hole of the central fastening element 14 15Excitation element; active damper; piezo element; piezo ring; piezo rod 15aConnection of the excitation element 15 2Structural component 3Screw

Claims

1. Resonance absorber (1) having at least one resonance structure (10) as a passive absorber (10) having a plurality of vibrating elements (11) which are designed to radially extend, at least in sections, preferably substantially, particularly preferably completely, around a common longitudinal axis (X), wherein the vibrating elements (11) are spaced apart from one another in the circumferential direction (U) of the longitudinal axis (X), at least in sections, by spacings (12), characterized by at least one excitation element (15) as an active absorber (15) which is designed to excite the vibrating elements (11) of the resonance structure (10) to vibrate together along the longitudinal axis (X), wherein at least a plurality of vibrating elements (11), preferably all of the vibrating elements (11), immediately adjacent in the circumferential direction (U) are elastically coupled to one another in a vibration-transmitting manner over the respective spacing (12).

2. Resonance absorber (1) according to Claim 1, characterized in that the respective spacing (12) between the vibrating elements (11) is filled, at least in sections, preferably completely, with an elastic material (13) which couples the immediately adjacent vibrating elements (11) to one another in a vibration-transmitting manner.

3. Resonance absorber (1) according to Claim 2, characterized in that the elastic material (13) comprises, preferably is, an elastomeric material (13), preferably rubber (13), or a thermoplastic material (13).

4. Resonance absorber (1) according to one of the preceding claims, characterized in that the respective spacing (12) between the vibrating elements (11) is filled, in sections, with a thinner material thickness of the material of the vibrating elements (11) as a material weakening (11a) which couples the immediately adjacent vibrating elements (11) to one another in a vibration-transmitting manner.

5. Resonance absorber (1) according to one of the preceding claims, characterized in that the immediately adjacent vibrating elements (11) are coupled to one another in a vibration-transmitting manner by means of at least one connecting element (11b).

6. Resonance absorber (1) according to one of the preceding claims, characterized in that the vibrating elements (11), preferably including the material weakening (11a), comprise, preferably are, a metal material or a thermoset material.

7. Resonance absorber (1) according to one of the preceding claims, characterized in that the vibrating elements (11) are designed to extend radially away from the longitudinal axis (X) to varying extents, preferably helically.

8. Resonance absorber (1) according to one of Claims 1 to 6, characterized in that the vibrating elements (11) are designed to extend, at least in pairs, at least substantially, preferably precisely, diametrically opposite and at least substantially, preferably precisely, equally far away from the longitudinal axis (X) and the pairs of vibrating elements (11) are designed to extend radially away from the longitudinal axis (X) to varying extents.

9. Resonance absorber (1) according to one of the preceding claims, characterized in that at least some, preferably all, of the vibrating elements (11) are designed at an angle to the longitudinal axis (X).

10. Resonance absorber (1) according to one of the preceding claims, characterized by a plurality of resonance structures (10) as passive absorbers (10) which are arranged along the longitudinal axis (X) offset with respect to one another, wherein the excitation element (15) as an active absorber (15) is designed to excite the vibrating elements (11) of all the resonance structures (10) to vibrate together along the longitudinal axis (X).

11. Resonance absorber (1) according to Claim 10, characterized in that the resonance structures (10) are designed to act in a similar manner, preferably identically.

12. Resonance absorber (1) according to Claim 10, characterized in that the resonance structures (10) are designed to act in a similar manner, preferably identically, at least substantially, preferably precisely, diametrically to the longitudinal axis (X).

13. Resonance absorber (1) according to one of the preceding claims, characterized in that the excitation element (15) is a piezoelement (15), preferably a piezoring (15) or a piezorod (15), which is designed to act at least substantially, preferably precisely, perpendicular to the orientation of the vibrating elements (11).

14. Vibration-capable device, preferably motor vehicle, particularly preferably electric motor vehicle, having at least one resonance absorber (1) according to one of the preceding claims.

15. Vibration-capable device according to Claim 14, characterized in that the excitation element (15), preferably as a piezoelement (15), is arranged prestressed between the resonance structure (10) and a structural component (2) of the vibration-capable device.