Vibration absorber with an absorber mass elongated along a main axis and ending with support and tuning pins

Abstract

Vibration damper (1) with - two holding devices (5), - a damping mass (2) extending along a main axis (11) between two cylindrical section-shaped axial end regions (12) and - two spring elements (3) made of elastomer material (4), each designed to support one of the two axial end regions (12) of the damper mass (2) on one of the two holding devices (5), - wherein the retaining devices (5) each hold a connection area (10) of one of the spring elements (3) without play in the radial and axial directions with respect to the main axis (11), - wherein the damper mass (2) has a reduced connection diameter (27) in its two axial end regions (12) compared to its maximum diameter (14) and - wherein the spring elements (3) manufactured separately from the damping mass (2) each have a receptacle (19) for force-fit reception of one of the two axial end regions (12) of the damping mass (2) and a tubular spring region (22) between the receptacle (19) and the connection region (10), characterized in that - that the two axial end regions (12) of the damper mass (2) form support and tuning pins (18), - wherein the connection diameter (27) is reduced by at least 70% compared to the maximum diameter (14), - wherein the spring elements (3) manufactured separately from the damping mass (2) are mounted on the support and tuning pins (18) of the damping mass (2) and abut against adjacent end faces (17) of the damping mass (2) and - wherein inner circumferential surfaces (21) of the spring elements (3) each pass continuously between the receptacle (19) and the adjoining tubular spring area (22).

Description

TECHNICAL AREA OF INVENTION

[0001] The invention relates to a vibration damper with two holding devices, a damper mass extending along a main axis between two cylindrical-section-shaped axial end regions, and two spring elements made of elastomeric material, each designed to support one of the two axial end regions of the damper mass against one of the two holding devices. In particular, the present invention relates to a vibration damper with the feature of the preamble of independent claim 1.

[0002] The vibration damper can be used, for example, in a motor vehicle. One specific application is the tailgate of the vehicle, to reduce disruptive vibrations. In this application, the vibration damper must require minimal installation space and be resistant to the impact loads when the tailgate is closed. STATE OF THE ART

[0003] From EP 1 303 710 B1, a vibration damper is known with a damping mass supported on a damping base by several cup-shaped spring elements. The spring elements have grooves circumferentially around their outer circumference at both axial ends, into which circumferential projections engage in receiving openings in the damping mass and the damping base. Tuning cores with a suitable hardness can be inserted into the cavities of the cup-shaped spring elements to adjust the stiffness of the coupling between the damping mass and the damping base via the spring elements. The tuning cores fill the entire cavity of the respective spring element and extend from the damping mass to the damping base.

[0004] From DE 10 2017 106 019 B4, a vibration damper is known, comprising a damping mass and two spring elements arranged at opposite ends of the damping mass for elastically coupling the damping mass to a structure. Each of the two spring elements has a tubular section made of elastomeric material extending from the damping mass to a mounting contour on its outer circumference, which is designed for attachment in a recess in a mounting base of the structure. A pin-shaped deflection limiter is arranged in each of the two tubular sections, limiting the deflection of the damping mass relative to the structure. The two tubular sections made of elastomeric material are bonded to the damping mass. The two pin-shaped deflection limiters are part of a rigid body forming the damping mass and terminate at an axial distance in front of the mounting contours.The outer circumferential surfaces of the pin-shaped deflection limiters have a free distance in all radial directions from the inner circumferential surface of the tubular sections when the damper mass is not deflected. To manufacture this known vibration damper, the entire damper mass must be placed in a mold to form the spring elements and heated therein.

[0005] A vibration damper for a motor vehicle, in particular for a tailgate of a motor vehicle, which has the features of the preamble of independent claim 1, is known from DE 10 2019 112 108 A1. A damper element is elastically coupled to a support structure via an elastomer assembly. The elastomer assembly comprises a plurality of elastomer elements. At each end section of the damper element, an associated elastomer element is arranged with a cap-like section open towards the damper element, with which the respective elastomer element overlaps the damper element. The support structure has receptacles, each associated with one of the elastomer elements. Each of the elastomer elements has a retaining section for fastening the respective elastomer element in the area of ​​the associated receptacle of the support structure by means of an associated retaining element.The respective associated retaining element is designed to overlap, at least partially, the cap-like section of the respective elastomer body in order to limit the deflection of the elastomer body from a rest position. Following the respective cap-like section open towards the damper body, the elastomer bodies have continuous, closed-edge central holes extending to their end furthest from the damper body. As a result, functional sections of the elastomer bodies, which are described as cylindrical, are actually tubular. In the use of the known vibration damper, it turns out that the support of the damper body in the cap-like sections of the elastomer bodies open towards the damper body is softer than the functional sections of the elastomer bodies, and thus the damper's natural frequency, which is supposed to be determined by the functional sections of the elastomer bodies, is significantly detuned.This makes it more difficult to adjust the damper's natural frequency to a specific frequency to be attenuated for the respective tailgate. Furthermore, relative movements occur between the end sections of the damper body and the cap-like section of the elastomer bodies, which negatively affect the service life of the known vibration damper.

[0006] From DE 10 2016 115 782 A1, a vibration damper for damping vibrations of a motor vehicle component is known. The vibration damper comprises a holding device, a damping mass that is capable of oscillation relative to the holding device, and a spring device that couples the damping mass to the holding device in a oscillating manner. The damping mass has at least one loss-prevention and / or displacement-limiting device that interacts with the holding device to limit the deflection of the damping mass relative to the holding device. The spring device comprises a first elastomeric spring that couples a first end face of the damping mass to a first receiving eye in a first leg of the holding device, and a second elastomeric spring that couples a second end face of the damping mass to a second receiving eye in a second leg of the holding device.The elastomer springs are vulcanized to the end faces, legs, and inner surfaces of the receiving eyes. The elastomer springs are designed as hollow cylinders into which pin elements of the loss and / or travel limitation device extend from the end faces of the damping material. The pin elements are positively, frictionally, and / or materially bonded to the damping material. Alternatively, instead of vulcanizing the elastomer springs to the end faces of the damping material, the elastomer springs can have ring-shaped structures by means of which they are fixed to the holding device and / or the damping material. In this case, a collar of the pin element can abut against one of the ring-shaped structures to fix the respective elastomer spring to the damping material. TASK OF INVENTION

[0007] The invention is based on the objective of designing a vibration damper that is easy to manufacture, whose damping natural frequency is easy to adjust and yet has a long service life. SOLUTION

[0008] The object of the invention is achieved by a vibration damper having the features of independent claim 1. Preferred embodiments of the vibration damper according to the invention are defined in the dependent claims. DESCRIPTION OF THE INVENTION

[0009] A vibration damper according to the invention comprises two holding devices, a damper mass extending along a main axis between two cylindrical-section-shaped axial end regions, and two spring elements made of elastomeric material, each designed to support one of the two axial end regions of the damper mass against one of the two holding devices. The holding devices each secure a connection region of one of the spring elements without play in the radial and axial directions with respect to the main axis. The damper mass forms support and tuning pins in its two cylindrical-section-shaped axial end regions, with a connection diameter reduced by at least 70% compared to its maximum diameter. Each spring element has a receptacle for the force-fit reception of one of the two support and tuning pins and a tubular spring section between the receptacle and the connection region.The inner circumferential surfaces of the spring elements extend continuously between the receptacle and the adjoining tubular spring section. The receptacles of the spring elements are therefore not separated from the interior of the tubular spring sections. In this way, the effective spring stiffness of the spring sections, and thus the natural frequency of the vibration damper according to the invention, can be easily influenced by varying the length of the support and tuning pins of the damper mass. The spring elements are manufactured separately from the damper mass and are mounted on the support and tuning pins of the damper mass, bearing against adjacent end faces of the damper mass. The damper mass is typically supported in the radial direction with respect to the main axis exclusively via the support and tuning pins on the spring elements.In addition, a certain degree of frictional connection can occur between the spring elements and the end faces of the damper mass adjacent to the support and tuning pins. In contrast, the damper mass is supported in the axial direction with respect to the main axis essentially via its end faces adjacent to the support and tuning pins on the spring elements, with the frictional connection between the support and tuning pins and the spring elements also present. While bonding or other material bonding between the spring elements and the support and tuning pins as well as the adjacent end faces is not excluded in the vibration damper according to the invention, it is generally unnecessary and therefore a manufacturing step that incurs unnecessary additional costs.

[0010] In the vibration damper according to the invention, the spring elements can each have a closed-edge hole extending axially from the receptacle through the tubular spring section and through the connection section, thus being tubular in shape overall. The inner circumferential surface of each spring element can extend continuously along the entire length of the closed-edge hole. Specifically, the circular inner diameters of the inner circumferential surfaces of the spring elements can decrease continuously from the damper mass. This allows them to be formed using a simple, easily demoldable, slightly conical mandrel of a mold for manufacturing the spring elements. The cone opening angle of this mandrel, and thus of the inner circumferential surfaces of the spring elements, can be in the range of 1 to 10°.

[0011] In principle, the support and tuning pins can also be slightly conical with a correspondingly small cone opening angle. However, they can also be cylindrical if the spring elements have a slightly decreasing inner diameter, provided that their leading edges are chamfered or rounded to prevent damage to the spring elements when they are mounted onto the support and tuning pins. Compared to the maximum diameter of the damper mass, the connection diameter of the support and tuning pins is preferably reduced by at least 75%, i.e., to one-quarter, more preferably by at least 80%, i.e., to one-fifth, or even by at least 83%, i.e., to one-sixth. In absolute terms, the connection diameter of the support and tuning pins can be in the range of 3 mm to 20 mm, or more precisely, from 5 mm to 10 mm.

[0012] The support and tuning pins typically project from the adjacent end face of the main body of the damper mass by at least 75%, preferably at least 100%, and at most 200%, or preferably 150%, of their connection diameter. The projection can be greater than these upper limits if high stiffness of the spring sections is required. In absolute terms, the support and tuning pins typically project by a distance between 4 mm and 30 mm, or more precisely, between 8 mm and 20 mm.

[0013] The support and tuning pins can be formed integrally with the damping mass. Specifically, they can be "turned" onto the damping mass during the machining of its surfaces. Alternatively, the support and tuning pins can be pressed or screwed axially into a main body of the damping mass. In this way, the natural frequency of the vibration damper according to the invention can be varied by pressing or screwing them in further or to a lesser extent until a desired natural frequency is reached. The projection of the support and tuning pins relative to the end faces of the main body of the damping mass can then be fixed, for example, by bonding the support and tuning pins to the main body.However, such adjustability of the natural frequency of the vibration damper according to the invention is not something that is generally required for mass production of the vibration damper according to the invention. More important in this context is that different natural frequencies can be achieved for different applications of the vibration damper according to the invention using the same spring elements and also with damper masses that are identical except for the projections of the support and tuning pins.

[0014] The spring elements of the vibration damper according to the invention can each form an outer ring in the axial region of their mounting, which projects radially outwards relative to the axially adjoining tubular spring section. This reinforces and stiffens the spring elements in the radial direction in the region of their mountings. In this way, a rigid coupling of the damper mass to the spring elements is achieved, so that the relevant stiffness of the coupling of the damper mass to the mounting devices results from the tubular spring sections of the spring elements.

[0015] The outer ring can be designed as a stop for the radial impact of the respective spring element against a tubular counter-stop formed on the respective mounting device. If this counter-stop extends beyond the axially adjacent areas of the damper mass, the outer ring must also project radially outwards beyond these adjacent areas of the damper mass. By impacting the spring elements at their mounting points against the counter-stops of the mounting device, the maximum radial deflection of the damper mass relative to the mounting devices is limited, with progressively increasing stiffness of the spring elements.

[0016] The mounting devices of the vibration damper according to the invention can each comprise two mounting elements joined radially around the connection area of ​​the spring element and then preferably interlocked. These mounting elements can then each be attached directly to the respective tailgate or other structure whose vibrations are to be reduced. Mounting via a common support for the mounting elements is also possible. Preferably, however, one mounting element of each mounting device is formed from a single-piece base element, onto which the other mounting elements of each mounting device are then snapped after the spring elements with the damping material have been inserted.

[0017] The holding devices are manufactured particularly cost-effectively from injection-molded plastic parts. Depending on the stresses involved, the plastic used can also be reinforced, for example, with fibers.

[0018] Advantageous further developments of the invention result from the patent claims, the description and the drawings.

[0019] The advantages of features and combinations of features mentioned in the description are merely exemplary and can have an effect alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0020] Regarding the disclosure content—not the scope of protection—of the original application documents and the patent, the following applies: Further features can be derived from the drawings—in particular, the geometries depicted and the relative dimensions of several components to one another, as well as their relative arrangement and functional connection. The combination of features from different embodiments of the invention or from features of different claims is also possible, deviating from the chosen cross-references of the claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features from different claims.Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

[0021] The features mentioned in the claims and the description are to be understood, with regard to their number, as meaning that exactly that number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least". Thus, for example, if an element is mentioned, this is to be understood as meaning that exactly one element, two elements, or more elements are present. The features listed in the claims may be supplemented by further features or may be the only features that the subject matter of the respective claim possesses.

[0022] The reference numerals contained in the patent claims do not constitute a limitation of the scope of the subject matter protected by the patent claims. They merely serve the purpose of making the patent claims easier to understand. BRIEF DESCRIPTION OF THE FIGURES

[0023] The invention will now be further explained and described with reference to preferred embodiments shown in the figures. Fig. Figure 1 is a perspective view of a vibration damper according to the invention. Fig. 2 is a top view of the vibration damper according to Fig. 1. Fig. Figure 3 is a longitudinal section through the vibration damper according to Fig. 1 and Fig. 2 along the in Fig. 2. Section line AA is shown. Fig. 4 is a cross-section through the vibration damper according to the Fig. 1 to 3 along the in Fig. 3. Section line BB is shown. Fig. 5 is a side view of the vibration damper according to the invention. Fig. 1 to 4. Fig. 6 is a cross-section through the vibration damper according to the invention. Fig. 1 to 5 along the in Fig. 5. Section line CC is shown. Fig. Figure 7 is a section through a detail of the vibration damper according to the invention. Fig. 1 to 6 along a Fig. 6 drawn section line DD and Fig. Figure 8 shows three different components that the vibration damper contains according to the Fig. 1 to 7 next to its retarder mass. FIGURE DESCRIPTION

[0024] The vibration damper 1 shown in the figures comprises a damping mass 2, spring elements 3 made of elastomer material 4, and retaining devices 5. Each retaining device 5 has two retaining elements 6 and 7, the retaining elements 7 being parts of a one-piece base element 8. The base element 8 is provided with fastening devices 9 in the form of alignment bolts, internal threads, holes for fastening screws, or the like, to rigidly couple the base element to a structure whose vibrations are to be dampened by the vibration damper 1. The base element 8 with the retaining elements 7 and the retaining elements 6 are injection-molded plastic parts. In the assembled vibration damper 1, the retaining elements 6 and 7 are joined and interlocked around connection areas 10 of the spring elements 3.The assembled holding devices 5 accommodate the connection areas 10 of the spring elements without play in the radial and axial directions with respect to a principal axis 11 of the vibration damper 1 and the damper mass 2. The damper mass 2 is elongated in the direction of the principal axis 11 between two cylindrical end sections 12 and has a cylindrical central section 13 with a maximum diameter 14, which transitions via intermediate sections 15 with a slightly reduced diameter 16 to the end sections 12. The intermediate sections 15 have end faces 17 from which the end sections 12, designed as support and tuning pins 18, project and engage in receptacles 19 of the spring elements 3. The support and tuning pins 18 have a connection diameter 27 that is also significantly reduced compared to the diameter 16 of the intermediate sections 15.

[0025] Compared to the maximum diameter 14 of the damper mass 2, the connection diameter 27 of the support and tuning sections is reduced here to less than a quarter, i.e., about one-fifth, and thus by about 80%. The intermediate sections with a diameter 16, which is already somewhat reduced compared to the maximum diameter 14, are generally optional. The end faces 17, from which the support and tuning pins 18 project, can be formed directly on the central section. However, the gradation of the diameters 14, 16 of the damper mass 2 via the intermediate sections 15 allows for a greater variation of the damper mass 2 to larger physical masses, while maintaining the same design of the retaining elements 6, 7. The spring elements 3 are placed onto the support and tuning pins 18 until they abut the end faces 17.The receptacles 19 of the spring elements 3 are the areas facing the damper mass 2 of circular, slightly tapered, closed-edged holes 20 through the spring elements 3. The inner circumferential surfaces 21 of the spring elements 3 thus extend continuously along their entire axial length. Tubular spring sections 22 are formed between the receptacles 19 and the connection areas 10 of the spring elements 3, through which the damper mass 2 is elastically supported on the retaining devices 5. The effective stiffness of these tubular spring sections 22 depends on the extent to which the support and tuning pins 18 project into the holes 20. The tubular spring sections 22 are radially open. In the area of ​​the receptacles 19, the spring elements 3 are provided with outer rings 23.The outer rings 23 stiffen the mounts 19 in the radial direction to the main axis 11; and via the outer rings 23, which project radially outwards over both the tubular spring sections 22 of the spring elements 3 and the intermediate sections 15 of the damper mass 2, the spring elements, in the event of strong deflection of the damper mass 2 relative to the base element 8, abut tubular counter-stops 24 formed on the retaining devices 5. The counter-stops 24 are interrupted circumferentially about the main axis 11, with projections 25 of the spring elements engaging in the interruptions 26, thereby ensuring protection against relative rotation of these parts about the main axis 11. REFERENCE MARK LIST 1 vibration damper 2. Tuning mass 3 Spring element 4 Elastomer material 5 Holding device 6 retaining element 7 Holding element 8 Basic element 9 Fastening devices 10 Connection area 11 Main axis 12 End range 13 Middle range 14 maximum diameter 15 Intermediate range 16 diameter 17 Front surface 18 support and tuning pins 19th entry 20 holes 21 Interior surface 22 Spring area 23 Outer ring 24 Counterattack 25 lead 26 Interruption 27 Connection diameter

Claims

[1] Vibration damper (1) with - two holding devices (5), - a damping mass (2) extending along a main axis (11) between two cylindrical section-shaped axial end regions (12) and - two spring elements (3) made of elastomer material (4), each designed to support one of the two axial end regions (12) of the damper mass (2) on one of the two holding devices (5), - wherein the retaining devices (5) each hold a connection area (10) of one of the spring elements (3) without play in the radial and axial directions with respect to the main axis (11), - wherein the damper mass (2) has a reduced connection diameter (27) in its two axial end regions (12) compared to its maximum diameter (14) and - wherein the spring elements (3) manufactured separately from the damping mass (2) each have a receptacle (19) for force-fit reception of one of the two axial end regions (12) of the damping mass (2) and a tubular spring region (22) between the receptacle (19) and the connection region (10), characterized by , - that the two axial end regions (12) of the damper mass (2) form support and tuning pins (18), - wherein the connection diameter (27) is reduced by at least 70% compared to the maximum diameter (14), - wherein the spring elements (3) manufactured separately from the damping mass (2) are mounted on the support and tuning pins (18) of the damping mass (2) and abut against adjacent end faces (17) of the damping mass (2) and - wherein inner circumferential surfaces (21) of the spring elements (3) each pass continuously between the receptacle (19) and the adjoining tubular spring area (22). [2] Vibration damper (1) according to claim 1, characterized by , that the damper mass (2) is supported in a radial direction with respect to the main axis (11) exclusively via the support and tuning pins (18) on the spring elements (3). [3] Vibration damper (1) according to claim 1 or 2, characterized by , that the spring elements (3) each have a circumferentially closed hole (20) extending in the axial direction from the receptacle (19) through the tubular spring area (22) and through the connection area (10). [4] Vibration damper (1) according to claim 3, characterized by , that the inner circumferential surfaces (21) of the spring elements (3) each extend continuously over the entire length of the edge-closed hole (20). [5] Vibration damper (1) according to any one of the preceding claims, characterized by, that circular inner diameters of the inner circumferential surfaces (21) decrease continuously away from the damping mass (2), wherein the inner circumferential surfaces (21) optionally have conical full angles in the range of 1° to 6°. [6] Vibration damper (1) according to any one of the preceding claims, characterized by , that the connection diameter (27) of the support and tuning pins (18) - is reduced by at least 75% or 80% or 83% compared to the maximum diameter (14) and / or - lies in a range from 3 mm or 5 mm to 20 mm or 10 mm. [7] Vibration damper (1) according to any one of the preceding claims, characterized by , that the support and tuning pins (18) are each connected to an end face (17) of a main body of the damper mass (2) - by at least 75% or 100% and at most 200% or 150% of their connection diameter (27) and / or - protrude by at least 4 mm or 8 mm and at most 30 mm or 20 mm. [8] Vibration damper (1) according to any one of the preceding claims, characterized by , that the support and tuning pins (18) - are pressed or screwed axially into a main body of the damper mass (2) or - are formed in one piece with the damping mass (2). [9] Vibration damper (1) according to any one of the preceding claims, characterized by , that the spring elements (3) each form an outer ring (23) in the axial area of ​​the receptacle (19), which projects radially outwards relative to the adjoining tubular spring area (22). [10] Vibration damper (1) according to claim 9, characterized by , that the outer ring (23) is designed as a stop for a radial stop of the spring element (3) against a tubular section-shaped counter-stop (24) formed on the respective holding device (5). [11] Vibration damper (1) according to any one of the preceding claims, characterized by, that the retaining devices (5) each have two retaining elements (6, 7) joined together in a radial direction around the connection area (10) of the spring element (3) and interlocked with each other. [12] Vibration damper (1) according to claim 11, characterized by , that each holding element (7) of both holding devices (5) is formed from a one-piece base element (8). [13] Vibration damper (1) according to any one of the preceding claims, characterized by , that the holding devices (5) are made of injection-molded plastic parts.

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