Elastic bearing with reduced stiffening under high-frequency loading

Abstract

Elastic bearing (1) with - a first bearing element (3), - a second bearing element (5) and - a support spring (13-16) made in one piece from elastomer material (11), - which is coupled to the first bearing element (3) and to the second bearing element (5) and extends over a spring length (20) along a spring axis (21) between the first bearing element (3) and the second bearing element (5) and - which has a local cross-sectional enlargement at distances (29, 30) from the first bearing element (3) and the second bearing element (5), characterized in that the local cross-sectional enlargement forms a resonance frame (22) closed around the spring axis (21), the frame height (28) of which along the spring axis (21) is not greater than 35% of the spring length (20), the projection (27) of which over surface areas (23, 24) of the suspension spring (13-16) adjoining it amounts to at least 80% of its frame height (28), that the resonance frame (22) can oscillate relative to the rest of the suspension spring (13-16), specifically in such a way that it reduces a dynamic stiffening of the suspension spring (13-16) under high-frequency loading in all spatial directions, wherein this reduction is based on an absorption of natural vibrations of the suspension spring (13-16) at the respective high Frequency in the respective spatial direction with the resonance frame (22) acting as a vibration absorber.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to an elastic bearing with a support spring formed integrally from an elastomer material, which extends over a spring length along a spring axis between a first bearing element and a second bearing element and which has a local cross-sectional enlargement at intervals from the first bearing element and the second bearing element. More specifically, the invention relates to an elastic bearing with the features of the preamble of independent claim 1.

[0002] The suspension spring made of elastomer material serves to decouple vibrations between the two bearing elements. The increased cross-section of the suspension spring increases the cross-section of the suspension spring in the spatial area of ​​its lowest stiffness. This increased cross-section thus increases the overall stiffness of the suspension spring, so that the suspension spring can be made of a fundamentally softer elastomer material while maintaining the same load-bearing capacity. This has a positive effect on the vibration recovery behavior of the suspension spring under high-frequency loading. In particular, dynamic stiffening of the suspension spring is reduced under such high-frequency loading. The dynamic stiffening of the suspension spring reduces the vibration decoupling intended with the elastic bearing. STATE OF THE ART

[0003] WO 2020 / 070069 A1 discloses an elastic bearing with annular elastomer springs between an inner bearing element and an outer bearing element. Annular, axially projecting tuning elements are formed on the annular spring elements. The tubular-section-shaped tuning elements, formed integrally with the annular elastomer springs, serve to reduce the dynamic stiffening of the elastomer springs.

[0004] WO 2020 / 175640 A1 discloses an elastic bearing with an annular elastomer spring extending between an inner bearing element and an outer bearing element. Annular tuning elements are arranged on both free sides of the elastomer spring. The tuning elements, formed integrally with the elastomer spring, are tubular in shape and protrude axially from the elastomer springs.

[0005] DE 10 2006 055 128 A1 discloses an elastic bearing with spring elements, each of which serves to provide support in one of two main load directions. The spring elements acting in one of the main load directions are each provided with two resonance elements that protrude transversely to the corresponding main load direction from the spring element, which has a rectangular cross-section and is formed integrally with the spring element from an elastomer material. The resonance elements reduce the stiffness of the respective spring element at higher frequencies.

[0006] DE 10 2018 221 375 A1 discloses an elastic bearing comprising an outer part, an inner part, and at least one supporting body arranged between the outer part and the inner part. The supporting body has at least one additional mass, which extends at least substantially perpendicular to the supporting body and is designed to be movable parallel to the supporting body, at least in sections, in order to execute a counter-oscillation to the supporting body. The additional mass is formed integrally with the supporting body from an elastomeric material. Several additional masses with different designs can be present. Specifically, the additional masses protrude from a side surface of the supporting body, essentially in a circumferential direction around the inner part of the elastic bearing.

[0007] DE 10 2008 019 121 A1 discloses an elastic bearing with two V-shaped elastomeric suspension springs extending from an inner bearing element to an outer bearing element. Local mass projections made of the elastomeric material protrude from the end faces of the suspension springs.

[0008] CN 1 10 978 975 A discloses an elastic bearing with four X-shaped elastomeric suspension springs arranged between an inner bearing element and an outer bearing element. Resonator bodies made of elastomeric material are formed integrally with the suspension springs on the end faces of the suspension springs.

[0009] From CN 1 13 022 284 A, an elastic bearing with four support springs arranged in an X-shape between an inner bearing element and an outer bearing element, the side surfaces of which are strongly concavely curved, is known. Different vibration isolation blocks are arranged on the support springs. One of the lower support springs does not have a vibration isolation block. The other lower support spring has a vibration isolation block on an axially aligned end face. The two upper support springs have two different vibration isolation blocks that extend from their axial end faces over their side faces. The vibration isolation blocks enclose the upper support springs in the area of ​​their smallest width between their side faces and only protrude slightly beyond the adjacent areas of the strongly concavely curved side faces.

[0010] From CN 1 12 440 712 A, an elastic bearing is known in which four suspension springs extend in an X-shape between an inner bearing element and an outer bearing element, of which the upper suspension spring and lower suspension spring, arranged on the same side of the inner bearing element, are connected at one end to a common closed arched element. The suspension springs each have extended cross-sectional enlargements over a substantial part of their length, which form U-shaped subframes around the suspension springs, ending at the arched elements. The cross-sectional enlargements are intended to reduce the stiffness of the suspension springs in the frequency range above 1,000 Hz, thus improving the vibration isolation effect of the elastic bearing under high-frequency conditions.

[0011] An elastomeric bushing bearing with switchable stiffness is known from DE 10 2009 001 757 A1. The bushing bearing consists of a cylindrical metallic inner part, a tubular outer part, and an elastomeric bearing body arranged between them, as well as a bearing sleeve accommodating the aforementioned parts. The bushing bearing further has at least two working chambers arranged offset with respect to the circumferential direction of the bearing for receiving a fluid. By means of an actuator, the radial stiffness of the bearing can be changed by blocking or releasing the inflow or outflow of damping medium into or from a working chamber. The bearing body is divided in the radial direction into two spring assemblies with an outer switch assembly by at least one insert element arranged therein parallel to the bearing axis.Specifically, the insert element is an intermediate plate that is vulcanized into the bearing body and projects parallel to the bearing axis over the adjacent bearing body.

[0012] US Pat. No. 5,899,431 discloses an elastic bearing comprising a first bearing element, a second bearing element, and a block made of elastomer material extending between the first bearing element and the second bearing element. The block is divided in this direction of extension by a lamination to increase its rigidity in this direction. The lamination projects beyond the elastomer material transversely to the extension of the block between the bearing elements.

[0013] DE 10 2005 003 945 A1 discloses a bushing bearing with circumferentially varying radial stiffness. The bushing bearing consists of an inner part and an elastomeric bearing body surrounding the inner part, designed to be received by an outer sleeve, with at least one radial web of high radial stiffness. In the area of ​​the radial web, elements made of metal or plastic are inserted into the bearing body, forming a radial layer sequence with the elastomer, and arranged on its radial outer surfaces.

[0014] DE 39 21 968 A1 discloses a soundproofing device consisting of a cover plate, an elastic layer, a mass-bearing intermediate layer, and a base plate, which, like the cover plate, is provided with a projecting threaded bolt. The approximately cylindrical intermediate layer surrounds the elastic layer at a distance. The approximately cylindrical elastic layer is surrounded by an annular extension formed integrally with the elastic layer, which is narrower than the height of the elastic layer and to which the approximately cylindrical intermediate layer adjoins. The also approximately cylindrical mass-bearing intermediate layer is non-elastic and is connected to the annular extension by vulcanization or other means. OBJECT OF THE INVENTION

[0015] The invention is based on the object of demonstrating an elastic bearing which, compared to the prior art assessed above, has a further reduced stiffening under high-frequency loading, namely under loading in all spatial directions. SOLUTION

[0016] The object of the invention is achieved according to the invention with the features of patent claim 1. Further preferred embodiments of the invention can be found in the dependent patent claims. DESCRIPTION OF THE INVENTION

[0017] In an elastic bearing according to the invention with a first bearing element, a second bearing element and a support spring formed in one piece from elastomer material, which is coupled to the first bearing element and to the second bearing element and extends over a spring length along a spring axis between the first bearing element and the second bearing element and which has a local cross-sectional enlargement at distances from the first bearing element and the second bearing element, the local cross-sectional enlargement forms a resonance frame closed around the spring axis, the frame height of which along the spring axis is not greater than 35% of the spring length and the projection of which over adjacent surface areas of the support spring is at least 80% of its frame height.

[0018] The resonance frame therefore extends over all surfaces of the suspension spring around the spring axis. The frame height of the resonance frame is a maximum of about one-third and usually less than one-third of the spring length, and the resonance frame projects at least a similar distance, and usually at least as far, beyond the rest of the suspension spring transversely to the spring axis, as it extends along the spring axis, which is equivalent to its frame height. This arrangement and these dimensions of the resonance frame ensure that the resonance frame can oscillate relative to the suspension spring in such a way that it reduces the dynamic stiffening of the suspension spring under high-frequency loading in all spatial directions. This reduction is based on the absorption of natural vibrations of the suspension spring at the respective high frequency in the respective spatial direction with the resonance frame acting as a vibration absorber.

[0019] The feature that the projection of the resonance frame transversely to the spring axis over surface areas of the suspension spring adjacent to the resonance frame is at least similar in size to, and generally at least as large as, its frame height applies at least locally, i.e., to its local projection relative to its local frame height. This implies that the frame height along the spring axis does not have to be the same everywhere around the spring axis, and accordingly, the projection of the resonance frame over surface areas of the suspension spring adjacent to it does not have to be the same everywhere around the spring axis.

[0020] Typically, the frame height of the resonance frame along the spring axis in the elastic mount according to the invention is not less than 5% of the spring length. Preferably, the frame height is not greater than 30% of the spring length, and even more preferably, the frame height is not greater than 25% of the spring length. This makes it clear that the resonance frame, although it also locally enlarges the cross-section of the suspension spring, is primarily a part of the suspension spring that is capable of vibration compared to the rest of the suspension spring and thus a vibration damper coupled to the rest of the suspension spring.

[0021] The distances between the resonance frame and the first bearing element and the second bearing element are each at least 30% and preferably at least 50% of the frame height and / or at least 10% and preferably at least 20% of the spring length. These distances, which can also be greater, ensure that the resonance frame, except for its elastic coupling to the rest of the suspension spring, can oscillate freely relative to the rest of the suspension spring and does not strike the bearing elements.

[0022] The projection of the resonance frame over the surface areas adjacent to it can be up to approximately 400% of its frame height. Preferably, the projection of the resonance frame is in a range of 100% to 300% of its frame height. Relative to a diameter of the suspension spring that is limited by its surface areas adjacent to the resonance frame and that runs normal to these surface areas and transverse to the spring axis, which is therefore in particular a spring width or spring depth of the suspension spring, the projection of the resonance frame over the surface areas adjacent to it can be in the range of 3% to 30%. A range of 5% to 20% of the diameter of the suspension spring is preferred. An outer diameter of the resonance frame normal to the adjacent surface areas and transverse to the spring axis is then in a range of 106% to 160% or preferably from 110% to 140% of the diameter of the suspension spring.

[0023] The ratio of frame height and overhang determines a resonance frequency of the resonance frame and thus the frequency at which the resonance frame is effective by reducing the dynamic stiffening of the suspension spring.

[0024] The frame volume of a resonance frame typically ranges from 2% to 20% of the volume of the suspension spring without the resonance frame. The same applies to the frame mass.

[0025] The suspension spring is typically molten, meaning it is chemically bonded to the first bearing element and the second bearing element. This can be achieved by vulcanizing or other direct injection of the elastomer material or a preform of the elastomer material and forming a chemical bond with the bearing elements.

[0026] In an elastic bearing according to the invention with an outer sleeve as the first bearing element, an inner sleeve arranged within the outer sleeve as the second bearing element, and four support springs in an X-configuration between the outer sleeve and the inner sleeve, at least two of the four support springs have resonance frames as defined here. In principle, the two resonance frames of the at least two of the four support springs with resonance frames can be arranged and / or designed differently. Preferably, however, the resonance frames are of identical design and are parts of identically designed support springs. In particular, the at least two of the four support springs with resonance frames can be arranged and designed axially symmetrically to a main direction of action of the elastic bearing. The other two of the four support springs can also have resonance frames and can in turn be arranged and designed axially symmetrically to a main action of the elastic bearing.The two pairs of suspension springs with resonance frames can be designed differently or also symmetrically to each other.

[0027] In the elastic bearing according to the invention with the four suspension springs in an X-configuration, the spring depths of the four suspension springs measured along a sleeve axis can be in the range of 50% to 200% greater than the spring widths of the four suspension springs running transversely to the respective spring depth and spring length. The cross-sections of the four suspension springs are then slightly or even more pronouncedly stretched in the direction of the sleeve axis in order to achieve an axial stiffness in the direction of the sleeve axis that is of a size that matches the radial stiffness transverse to the sleeve axis.

[0028] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0029] The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be effective alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0030] With regard to the disclosure content – ​​not the scope of protection – of the original application documents and the patent, the following applies: Further features can be found in the drawings – in particular the illustrated geometries and the relative dimensions of several components to one another, as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or features of different patent claims is also possible, deviating from the chosen references of the patent 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 of different patent 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.

[0031] The number of features mentioned in the patent claims and the description is to be understood as meaning that exactly this 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 reference is made to a suspension spring, this is to be understood as meaning that exactly one suspension spring, two suspension springs, or more suspension springs are present. The features mentioned in the patent claims may be supplemented by further features or may be the only features present in the subject matter of the respective patent claim.

[0032] The reference signs contained in the patent claims do not represent a limitation of the scope of the subject-matter protected by the patent claims. They serve solely to make the patent claims easier to understand. BRIEF DESCRIPTION OF THE CHARACTERS

[0033] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. 1 is a perspective view of an elastic bearing according to the invention. Fig. 2 is an axial plan view of the elastic bearing according to Fig. 1. Fig. 3 is a longitudinal section through the elastic bearing through two of its suspension springs according to the Fig. 1 and Fig. 2. Fig. 4 is another axial plan view of the elastic bearing according to the Fig. 1 to 3 with compared to Fig. 2 opposite viewing direction. Fig. 5 is a side view of a support spring of the elastic bearing according to the Fig. 1 to 4. Fig. 6 is a plot of the dynamic stiffness of the elastic bearing according to the Fig. 1 to 5 in axial direction. Fig. 7 is a plot of the dynamic stiffness of the elastic support according to the Fig. 1 to 5 in horizontal direction and Fig. Figure 8 is a plot of the dynamic stiffness of the elastic bearing according to the Fig. 1 to 5 in vertical direction. FIGURE DESCRIPTION

[0034] The Fig. The elastic bearing 1 shown in Figures 1 to 3 has an outer sleeve 2 as the first bearing element 3 and an inner sleeve 4 as the second bearing element 5. The inner sleeve 4 is arranged within the outer sleeve 2 and aligned coaxially therewith. The inner sleeve 4, which here is designed as a light metal extruded profile section 6, but can also be designed as a light metal die-cast body or in some other way, has a central through-opening 7 for a fastening bolt (not shown). The outer sleeve 2 is designed as a shaped body 8 made of dimensionally stable plastic and is intended to be pressed into a cylindrical bearing seat with its outer circumference 9. In order to conform to an inner circumference of the bearing seat, the shaped body 8 is provided with a structure on its outer circumference 9. The shaped body 8 is pressed in until a collar 10 projecting radially beyond its outer circumference 9 abuts an edge of the bearing seat.On one end face of the outer sleeve 2, an axial stop buffer 12 made of elastomer material 11 is formed for a component attached to the inner sleeve 4 and elastically supported by the elastic bearing 1. The inner sleeve 4 is supported on the outer sleeve 2 by four support springs 13 to 16 made of the elastomer material 11. Furthermore, radial stop buffers 17 made of the elastomer material 11 are formed on an inner circumference 18 of the outer sleeve 2. The support springs 13 to 16 are each connected to the inner circumference 18 of the outer sleeve 2 and to an outer circumference 19 of the inner sleeve 4. Each of the suspension springs 13 to 16 extends over a spring length 20 along a spring axis 21 and has a resonance frame 22 which runs around the respective spring axis 21 and projects transversely to the spring axis 21 over adjacent surface areas 23 and 24 of the respective suspension spring 13 to 16.The four suspension springs 13 to 16 including their resonance frames 22 are all of the same design and arranged symmetrically to a sleeve axis 25 running through the passage opening 7.

[0035] Details of the design of the resonance frames 22 are now given on the basis of the Fig. 4 and Fig. 5. The rear view of the elastic bearing 1 according to Fig. 4 shows the parts of the elastic bearing 1 that are arranged within the outer circumference 9 of the outer sleeve 2. The axial viewing direction is that of those in Fig. 2 opposite. Fig. 5, on the other hand, is a side view of one of the support springs 13 to 16, viewed in the circumferential direction around the sleeve axis 25. With its main extension plane 26, the respective resonance frame 22 extends transversely to the respective spring axis 20. The respective resonance frame 22 runs as a closed frame over all adjacent surface areas 23 and 24 around the respective spring axis 20. It therefore has a projection 27 along its main extension plane 26 relative to all adjacent surface areas 23 and 24. Along the respective spring axis 21, the respective resonance frame 22 has a frame height 28 and distances 29 and 30 to the first bearing element 3 and the second bearing element 5. The projection 27, the frame height 28, and the distances 29 and 30 are not constant around the respective spring axis 21. In particular in the axial direction along the sleeve axis 25, i.e. the transverse direction of Fig. 5, the frame height 28 and the distances 29 and 30 vary to create draft angles for demolding the elastic bearing from a mold used to manufacture it. However, the frame height 28 does not locally exceed one-third of the spring length 20. Generally, it does not exceed 30% of the spring length 20; predominantly, it maintains a quarter of the spring length 20 as the upper limit. The distances 29 and 30 are everywhere more than 50% of the frame height 28. The resonance frame 22, which vibrates relative to the rest of the respective suspension springs 13 to 16, therefore does not strike the bearing elements 3 and 5. The ratio between the projection 27 and the frame height 28 is also locally at least 0.8 : 1, usually at least 1 : 1 and at most 4 : 1, usually at most 3 : 1. Further information on the dimensioning of the projection 24, the frame height 28 and the distances 29 and 30 can be found in the preceding general description of the invention.A spring depth 31 of the respective support spring 13, measured along the sleeve axis 25, is approximately 150% larger than a spring width 32 measured transversely to the spring depth 31 and spring length 20. The ratio of the spring depths 31 to the spring lengths 32 sets the ratio between axial stiffness in the direction of the sleeve axis 25 and radial stiffness in the two transverse directions 33 and 34. The transverse direction 33 can be the main working and support direction of the elastic bearing, while the elastic bearing is designed to be softer in the transverse direction 34, in which the radial stop buffers 17 are provided, for vibration decoupling.

[0036] For a concrete embodiment of the elastic bearing according to the Fig. 1 to 5 show the Fig. 6 to 8 the dynamic stiffnesses in the axial direction of the sleeve axis 25, in the horizontal transverse direction 34 and in the vertical transverse direction 33. The dynamic stiffnesses of the elastic bearing according to the Fig. Figures 1 to 5 are each represented by a dotted line, while the dynamic stiffnesses of an elastic mount with suspension springs without a resonance frame are plotted with a solid line for comparison. It is clear that the resonance frames reduce the strong peaks in dynamic stiffness in the range from approximately 650 Hz and even at higher frequencies. It is understood that the frequency at which the dynamic stiffness is reduced according to the invention depends on the specific design and dimensions of the respective elastic mount. LIST OF REFERENCE SYMBOLS 1 Elastic bearing 2 outer sleeve 3 First bearing element 4 inner sleeve 5 Second bearing element 6 Light metal extruded profile section 7 Passage opening 8 molded bodies 9 Outer circumference 10 collars 11 Elastomer material 12 Axial stop buffer 13 Suspension spring 14 Suspension spring 15 Suspension spring 16 Suspension spring 17 Radial stop buffer 18 Inner circumference of the outer sleeve 19 Outer circumference of the inner sleeve 20 spring length 21 Spring axle 22 resonance frames 23 Surface area 24 Surface area 25 sleeve axis 26 Main extension plane of the resonance frame 22 27 Overhang 28 frame height 29 Distance of the resonance frame 22 to the first bearing element 3 30 Distance of the resonance frame 22 to the second bearing element 5 31 spring depth 32 spring width 33 Transverse direction 34 Transverse direction

Claims

[1] Elastic bearing (1) with - a first bearing element (3), - a second bearing element (5) and - a support spring (13-16) made in one piece from elastomer material (11), - which is coupled to the first bearing element (3) and to the second bearing element (5) and extends over a spring length (20) along a spring axis (21) between the first bearing element (3) and the second bearing element (5) and - which has a local cross-sectional enlargement at distances (29, 30) from the first bearing element (3) and the second bearing element (5), characterized bythat the local cross-sectional enlargement forms a resonance frame (22) closed around the spring axis (21), the frame height (28) of which along the spring axis (21) is not greater than 35% of the spring length (20), the projection (27) of which over surface areas (23, 24) of the suspension spring (13-16) adjoining it amounts to at least 80% of its frame height (28), that the resonance frame (22) can oscillate relative to the rest of the suspension spring (13-16) in such a way that it reduces dynamic stiffening of the suspension spring (13-16) under high-frequency loading in all spatial directions, this reduction being based on cancellation of natural vibrations of the suspension spring (13-16) at the respective high frequency in the respective spatial direction with the resonance frame (22) acting as a vibration absorber. [2] Elastic bearing (1) according to claim 1, characterized bythat the frame height (28) along the spring axis (21) is not less than 5%, preferably not greater than 30% and even more preferably not greater than 25% of the spring length (20). [3] Elastic bearing (1) according to claim 1 or 2, characterized by that the distances of the resonance frame (22) to the first bearing element (3) and the second bearing element (5) are each at least 30% and preferably at least 50% of the frame height (28). [4] Elastic bearing (1) according to one of the preceding claims, characterized by that the distances of the resonance frame (22) to the first bearing element (3) and the second bearing element (5) are each at least 10% and preferably at least 20% of the spring length (20). [5] Elastic bearing (1) according to one of the preceding claims, characterized bythat the projection (27) of the resonance frame (22) over the surface areas (23, 24) of the suspension spring (13-16) adjacent to it is in the range of 100% to 300% of the frame height (28). [6] Elastic bearing (1) according to one of the preceding claims, characterized by that the projection (27) of the resonance frame (22) beyond the surface areas (23, 24) of the suspension spring (13-16) adjoining it is in the range from 3% to 30% and preferably in the range from 5% to 20% of a diameter of the suspension spring (13-16) which is delimited by the surface areas (23, 24) of the suspension spring (13-16) adjoining the resonance frame (22). [7] Elastic bearing (1) according to one of the preceding claims, characterized by that a frame volume of the resonance frame (22) is in the range of 2% to 20% of a volume of the suspension spring (13-16) without the resonance frame (22). [8] Elastic bearing (1) according to one of the preceding claims, characterized bythat the support spring (13-16) is integrally connected to the first bearing element (3) and the second bearing element (5). [9] Elastic bearing (1) according to one of the preceding claims with - an outer sleeve (2) as the first bearing element (3), - an inner sleeve (4) arranged within the outer sleeve (2) as a second bearing element (5) and - four suspension springs (13-16) in X-configuration between the outer sleeve (2) and the inner sleeve (4), characterized by that at least two of the four suspension springs (13-16) have resonance frames (22). [10] Elastic bearing (1) according to claim 9, characterized by that at least two of the four support springs (13-16) with resonance frames (22) are arranged and designed axially symmetrically to a main direction of action (33) of the elastic bearing (1).

Images