WO2021233598A1

WO2021233598A1 - Axially damping hydraulic elastomer bearing

Info

Publication number: WO2021233598A1
Application number: PCT/EP2021/057794
Authority: WO
Inventors: Philipp Werner; Hilrich Kardoes
Original assignee: Vibracoustic Se
Priority date: 2020-05-19
Filing date: 2021-03-25
Publication date: 2021-11-25
Also published as: CN115552143A; DE102020113527A1

Abstract

The invention relates to an axially damping hydraulic elastomer bearing through which a central longitudinal axis (A) runs, comprising a core (4) which extends along the central longitudinal axis (A) and which provides a continuous through-opening (28) in order to receive a securing element; an outer tube (6) which is arranged around the circumference of the core (4); an elastomer body (8) which is arranged between the core (4) and the outer tube (6); a first membrane (10) which delimits a first fluid chamber (14) from an axially spaced second fluid chamber (16), said fluid chambers (14, 16) being filled with a fluid; and a damping channel (18) which fluidically connects the fluid chambers (14, 16) together, wherein a second membrane (12) is provided which at least partly delimits at least the first fluid chamber (14) in the axial direction, and each of the two membranes (10, 12) comprises one section with a thicker cross-section and one section with a thinner cross-section compared thereto.

Description

Axial damping, hydraulic elastomer bearing

The invention relates to an axially damping, hydraulic elastomer bearing according to the Oberbe handle of claim 1.

Hydraulically damping elastomer bearings are also referred to as hydraulic bearings and are used as chassis bearings, such as subframe bearings, in motor vehicles in order to dampen and / or eliminate vibrations that occur. Axial damping hydraulic bearings comprise axially spaced fluid chambers which are separated from one another by membranes and / or elastomer bodies and connected to one another in a fluid-conducting manner via a damping channel. During a relative movement from a core to an outer tube or vice versa in the axial direction, one of the two fluid chambers is at least partially compressed or the other is enlarged at least partially. As a result, the fluid located therein flows via the damping channel from one fluid chamber into the other fluid chamber. In this way, a damping and / or damping effect is achieved, this particularly affecting vibrations with large amplitudes and low frequencies.

The present invention is concerned with an axially damping hydraulic Elastomerla ger that can be used in the chassis area and in particular for mounting a rear subframe, the rear subframe being assigned to the rear axle and designed to accommodate at least one electric motor or other units such as a rear axle transmission can be. Such a bearing can also be used as a subframe bearing and serves to support and dampen the forces and vibrations acting on a subframe. For this purpose, the bearing can be used in a receiving eye formed in the subframe or screwed to a flange. As a result, the radial installation space of the axially damping bearing is limited by the diameter of the Aufnah meauges or the flange. A large part of the bearing with its fluid chambers can be accommodated in this radially limited installation space. Alternatively, such a bearing can also be used to mount other vehicle structures that require axial damping, for example to mount a vehicle body on a ladder frame, to mount an internal combustion engine on a connection structure or to mount a swinging battery.

In electric vehicles, large masses in the form of electric motors and / or transmissions are often built into subframes on the rear axle. The damping of vibrations in the Z direction (vertical vehicle direction) by means of hydraulic bearings is particularly advantageous here, since these bearings are generally cylindrical and their longitudinal axis runs in the Z direction in the assembled state. The particular challenge with axially damping hydraulic auxiliary frame bearings are high preloads in the Z direction, which can be caused by large loads and / or batteries and / or gearboxes. These preloads can then lead to high deflections in the Z direction in wide linear areas due to the low rigidity requirements in the Z direction. It is necessary that the bearing can still cover relevant distances in the Z-direction even in a highly loaded condition so that a sufficient liquid volume is displaced and a pumping effect and the associated damping can occur. This must be taken into account when limiting the Z-travel by means of suitable end stops, since after the Z-stops have been inserted, damping can hardly be observed. To make matters worse, the coordination of the working frequency is also dependent on the basic rigidity of the bearing. For this reason, the most linear possible profile of the Z stiffness over the Z path is often required for an operating frequency that is as constant as possible. If the Z-stops finally come into play, there is a considerable increase in rigidity and thus naturally also a shift in the working frequency of the hydraulic bearing.

At the same time, such bearings should often have great resilience in the X direction (vehicle longitudinal direction or direction of travel) in order, for example, to enable comfortable rolling over the obstacle when crossing edges. Despite this, in some cases, the large paths in the X and Z directions occur simultaneously, two axially spaced fluid chambers within the bearing must be separated from one another in such a way that, in the event of an additional dynamic axial vibration excitation in all operating states, fluid from one ner axial fluid chamber can be pumped into the other fluid chamber. Axi aldämpfende Flydrolager often have an elastomeric separating membrane between the two fluid chambers to ensure the necessary flexibility.

Such a separating membrane must on the one hand withstand the large deflections or paths in the X, Y (transverse vehicle direction), and / or Z direction, but at the same time be rigid so that a sufficient pumping effect can be achieved between the axially arranged chambers and ultimately large Differences in pressure between the fluid chambers, as they can occur with shock loads, withstand life. This represents a conflict of requirements that is difficult to solve, but which could be solved for this task with a membrane geometry according to EP 3589861 A1. This disclosure suggests a functional separation between, on the one hand, a Z-load-bearing, inflation-resistant first elastomer body (axial bearing) which, together with the membrane, generates a high pressure in one fluid chamber (working chamber) when deflected in the Z direction, or a high differential pressure to the axially spaced other Fluid chamber (compensation chamber) causes, and on the other hand a second elastomer body (radial bearing), which is largely responsible for setting or spreading the X / Y stiffness, but is not itself part of the hydraulic system. The compensation chamber itself is delimited in the Z-direction by the inflatable membrane and delimited radially outward by a flexible membrane. This creates a hydraulic system with a working chamber (= high pressures) and an equalization chamber (= low pressures close to ambient pressure).

On the basis of the aforementioned prior art, the invention is based on the object of creating an axially damping, hydraulic elastomer bearing which is less complex and less expensive while having at least the same functionality and has a smaller number of components.

The main features of the invention are set out in the characterizing part of claim 1. Designs are the subject of claims 2 to 10.

With regard to at least one membrane and its connection, reference is made in this regard to the application EP 3589861 A1 with the application date of March 12, 2018, the content of which is hereby incorporated into this application.

According to the invention, an axially damping hydraulic elastomer bearing is proposed through which a central longitudinal axis protrudes, comprising a core which extends along the central longitudinal axis and for receiving a fastening element a through Current through opening provides an outer tube, which is arranged on the circumference of the core, an elastomer body which is arranged between the core and the outer tube, a first membrane which delimits a first fluid chamber from an axially spaced second fluid chamber, the fluid chambers with a Fluid are filled, and a damping channel which connects the fluid chambers to one another in a fluid-conducting manner. A second membrane is provided which delimits at least the first fluid chamber at least in sections in the axial direction, each of the two membranes comprising a section with a thicker cross section and a section with a thinner cross section. The cross-sectionally thicker sections can be arranged facing one another.

The first membrane can be supported on the inner circumference side, that is to say radially on the inside, on the core or an inner sleeve and / or on the outer circumference, that is to say radially on the outside, on the outer tube or on an outer sleeve. The second membrane can also be supported on the inner circumference, that is to say radially on the inside, on the core or a cover or ring element and / or on the outer circumference, that is on the radial outside, on the outer tube or an outer sleeve. The two membranes include the first fluid chamber, which can be designed as a working chamber. The two membranes can be designed to achieve a requirement-specific pumping action. Each of the two membranes can comprise an expandable section and an expandable soft section, the expandable section being formed by the section with a thicker section and the expandable section being formed by the section with a thinner section. Rigid sections are used to generate a sufficient pumping effect. It is conceivable that the expansion-resistant sections are from the mutually facing sections. Conceivable design aspects can be the arrangement, the shape, the cross-sectional thickness and / or the choice of material of the membranes. In this way, too, a good pumping effect can be achieved with a simple and inexpensive design.

The section with a thinner section and the section with a thicker section lie in a cross-sectional plane in which the central longitudinal axis also lies and / or can be exposed to a fluid or can be arranged to delimit a fluid chamber.

According to a further development, it is conceivable that the elastomer body forms a main support cushion and is the only support cushion in the space between the core and the outer tube. The main support cushion is characterized by the fact that it bears the primary load and / or at least in some areas has a positive connection overlap height of the elastomer body. The connection overlap height of the elastomer body is that distance, preferably axially, in which two connection sections of the elastomer body overlap in the longitudinal direction. According to a further development, the invention can provide the functional integration of the axial bearing and the radial bearing in a single component, namely the main support cushion. Compared to previous concepts, two functions of two components so far are combined in a single component in the camp according to the invention, so that it can be manufactured more cost-effectively and more compactly. In addition, the main support cushion can be arranged between the core and the outer tube in such a way that it is able to seal off one of the hydraulic chambers axially on the outside.

In the case of the axially outside sealing of a chamber, it is conceivable, according to a further development, that the elastomer body both forms the main support cushion and also includes a membrane section. This can be designed monolithically with the elastomer body and / or as an elastomer membrane.

According to a further development, the elastomer bearing according to the invention can be designed in such a way that the elastomer body delimits at least one of the fluid chambers at least in sections in the axial direction, preferably delimits the second fluid chamber configured as a compensation chamber. The elastomer body as the main support cushion can therefore be arranged between the core and the outer tube in such a way that it forms an axial limit for this at least one fluid chamber. It can be arranged both radially on the inside on the core and on the radially outside on the outer tube.

According to a further embodiment of the elastomer bearing according to the invention, the second membrane delimits the first fluid chamber, which is designed as a working chamber. Alternatively or additionally, the first membrane, as an intermediate membrane, can separate the first fluid chamber, which is designed as a working chamber, from the second fluid chamber, which is designed as a compensation chamber. A fluid chamber can thus be delimited by two membranes and a fluid chamber by a membrane and the elastomer body. It can be structurally complex to seal the working chamber, at least in sections, with an elastomer membrane or a membrane section as a supplement to the main support cushion, since the elastomer body, which can comprise the main support cushion and the elastomer membrane or the membrane section, has to endure all of the deflections of the bearing in its entirety. As a result, the elastomeric membrane or the membrane section is to be designed to be relatively long in order to minimize the elongations that occur and to distribute them evenly. Such a long membrane, however, has too little inflation rigidity to generate a high differential pressure with respect to the equalization chamber and thus a high pumping capacity. Since such an elastomer body with a relatively long membrane and a main support cushion cannot generate sufficiently high differential pressures, a solution is proposed in which the fluid chamber, which is usually designed as a compensation chamber, becomes the pressurized working chamber and the primary pumping work takes over for the hydraulic damping. This chamber can be delimited in the axial direction by two membranes, which can be manufactured and assembled separately. Since both components can be mounted separately on the core, they can be preloaded in the assembly position in such a way that the load on the bearing in the K ₀ position counteracts this preload, the K ₀ position being understood as the construction position. Since the position of a vehicle changes continuously during operation, the K ₀ position is specified as the reference point, i.e. the position of the vehicle that it has at rest on its wheels. In this way, the first and second membrane can experience lower loads than the long membrane or membrane section adjoining the flake support body, the first and second membrane here being able to be made shorter and, above all, more rigid. The two membranes can be made of an elastomeric material or elastomeric membranes.

Advantageously, at least one membrane or the intermediate membrane, at least in sections, has a very low expandability with respect to differential pressures between the adjoining fluid chambers, since a sufficient pumping effect is only achieved with a low expandability. The intermediate membrane also advantageously has a region which has a high level of flexural flexibility in the axial direction, so that it can follow large axial relative movements of its radially inner and radially outer connection structure in the axial direction without being greatly stretched. Furthermore, the membrane advantageously has an area that is primarily sheared when there is a radial relative movement from a radially inner to the radially outer connection structure, so that hardly any tensile or compressive strains occur in the membrane even with radial loads. This leads to the fact that such a membrane is exposed to extremely low expansions with a typically occurring superposition of high axial and radial paths with simultaneously high differential pressures between the chambers and thus has a long service life.

The first and second diaphragms can additionally be protected from excessively high pressures in a pressure differential direction, since they can at least indirectly be supported on their connection structure, for example on the core, on the inwardly or outwardly facing side. In the case of high pressure differences in the other direction to the pressure difference direction, on the other hand, high tensile loads can arise on the radially inner connecting section of the membranes.

It can be provided in the elastomer bearing according to the invention that at least one of the two membranes, preferably both membranes in each case, has a first leg, a second leg and a base connecting the two legs, with an average thickness of one of the legs is at least twice as thick as that of the other leg. The section with a thicker cross section can be formed by the limb that is at least twice as thick and the section with thinner section can be formed by the other limb. In the context of the invention, average thickness is understood to mean the average value of the thickness of a leg over its entire length, that is, from the base to its free end. If there is a radial relative movement between the inner and outer connection structure of the bearing, both legs are primarily subjected to thrust. Since the mean thickness of one leg is at least twice as large as the other leg, the thinner leg is more flexible than the thicker leg. Therefore, the thinner leg primarily contributes to compliance in the radial direction, while the thicker leg is relatively soft in the radial direction. This results in a functional separation between the thicker and thinner legs for the radial flexibility. In addition, an intermediate membrane is insensitive to inflation due to high differential pressures between the two fluid chambers filled with fluid. In most operating states, this leads to a high degree of Blähstei strength of the membrane, which results in a large pump volume and thus in an improved damping effect. In addition, this configuration ensures that the membrane is very stiff at differential pressures between the fluid chambers. The base is advantageously U-shaped or L-shaped in cross-section with a uniform thickness, the legs protruding from the U-shaped or L-shaped base.

According to a further development, it is conceivable that the cross-section of the limb, which is at least twice as thick on average, of at least one of the membranes, starting from the base, widens steadily or un steadily. The leg, which is at least twice as thick on average, can, for example, increase in cross section starting from the base in a funnel-shaped or exponential-shaped manner. As a result, the leg, which is at least twice as thick, is very rigid when compared to the other leg of the membrane, but at the same time it has a harmonious bending line in the case of large translational deflections, which leads to low tensile stress and thus a long service life of a first or second intermediate membrane Membrane leads. Due to the decreasing thickness of the leg towards the base of the leg and advantageously additionally supported by a bulging of the leg, the leg, which is at least twice as thick, is flexible in the axial direction. As a result, the leg, which is at least twice as thick and tapers towards the base, which preferably has a bulge, primarily contributes to the compliance in the axial direction, while the thinner leg does not have to have any noteworthy axial compliance. This achieves a functional separation between the thicker and thinner legs for the axial compliance.

In order to further optimize the formation of such a harmonious bending line, the leg, which is at least twice as thick on average, can have a cross-sectional arched course according to a further development. In this case, the limb, which is at least twice as thick on average, can also be slightly protruding in the direction in which the limb extends when a pressure is applied Fluid chamber, for example the working chamber, would bend further. This curvature has the advantage that the thick limb is not compressed or stretched during axial displacement, but rather the limb can bend. The thin leg can be largely cylindrical / tubular and have a linear cross-section, so that it can yield in the axial direction primarily only by upsetting or pulling.

In an advantageous embodiment, the elastomer bearing is designed in such a way that the leg, twice as thick on average, of a membrane, preferably the first membrane or the intermediate membrane, is at a pressure difference at which the fluid chamber formed as a working chamber has a higher pressure than that as the compensation chamber has formed fluid chamber, bends in the direction of the core, preferably the base connecting the two legs rests against an inside element. In this position, the membrane is particularly rigid, so that a high pump output and, associated with it, a high level of damping can be achieved.

Additionally or alternatively, in a further advantageous embodiment, the elastomer bearing can be designed in such a way that the leg of a membrane, on average twice as thick, is in front of the second membrane, at a pressure difference at which the fluid chamber formed as a working chamber has a higher pressure than the has fluid chamber designed as a compensation chamber, bends in the direction of the outer tube, preferably the base connecting the two legs rests against an element on the outer circumference. In this position, the membrane is particularly rigid, so that a high pump output and, associated with it, a high level of damping can be achieved.

In an advantageous embodiment of the elastomer bearing, the leg, which is twice as thick on average, has a first length and the other leg has a second length, the first length being greater than or equal to the second length. As a result, the longer leg can advantageously ensure a high degree of mobility in translational directions through a high degree of flexibility in the axial direction. At the same time, however, a greater length can lead to a low inflation rigidity and thus a low pumping capacity. This can be compensated for by a suitably greater thickness of the longer leg. In this way, a membrane geometry is realized that is characterized by a long service life, but at the same time also allows a good pumping effect in the axial direction.

In an advantageous embodiment, the first length of one leg is at least twice as large as the second length of the other leg. The upper surface and the lower surface of the membrane can each have a profile that is as uniform as possible, so that the membrane has no larger or no thickness jumps at all. The length of each Leg is determined by the distance in the Z direction between the lower reversal point of the base and the highest connection section in the X direction of the respective leg or by the distance in the Z direction between the highest reversal point of the base and the lower connection section in the X direction respective leg defined. Since the thinner leg is advantageously at most half as long as the thicker leg, it is relatively stiff and bulky. In this way, a membrane geometry is realized which has a particularly good pumping action in the axial direction.

In the case of surfaces of the at least one membrane that run as uniformly as possible, as a result of which the membrane has no larger or no thickness jumps at all, the mathematical derivation of the function describing the upper surface is equal to zero at the reversal point of the base. The same applies to the derivation of the functions describing the lower geometry of the legs, the mathematical derivation of which at its highest point either also becomes zero, alternatively ends in a stiff connection area or can have a discontinuity.

According to a further development of the elastomer bearing, in a membrane, preferably in the first membrane, the leg at least twice as thick on average forms the radially outer leg and / or in a membrane, preferably in the second membrane, the leg at least twice as thick on average the radially inner leg. This makes it possible for the connecting sections of the first and second diaphragms to come close to one another in the radial direction or even to overlap in sections. The further the connec tion sections approach or even overlap in the radial direction, the greater the volume change of the fluid chamber or working chamber enclosed by the two membranes during an axial movement of the bearing. A large change in volume is synonymous with a large effective pumping area, which results in a high pumping capacity and thus good damping properties. An increasing convergence of the connecting sections of the two membranes in the radial direction thus leads to an increasing pump output.

The thick legs of two membranes can also face each other. According to a further development, in the elastomer bearing according to the invention, the on average at least twice as thick limb of a membrane, preferably the first membrane, and the on average at least twice as thick limb of another membrane, preferably the second membrane, can face one another in the longitudinal axial direction and / or be arranged opposite one another with respect to a fluid chamber. The two legs can thus turn vorei n one another even with a correspondingly curved or angled course. ok

The functional integration of the axial and radial bearings in a single main support cushion results in the disadvantages of less creative freedom with regard to the compromise between the identifier setting and the coordination of the hydraulic damping properties. The setting of the desired stiffness requirements, however, requires a great deal of design freedom with regard to the main support cushion. In particular, low demands on the rigidity of the bearing in the X direction could be met by means of kidneys running in the X direction or longitudinal direction. However, since the main support cushion should also axially seal the hydraulic chamber facing it, the kidneys would have to be sealed with membranes in such a way that the membranes to be added only negligibly affect the X stiffness in the entire Z load range. Therefore, these tend to be long, thin, and stretch out in the Z-direction. So when the bearing is deflected in the X direction under all Z loads, you will not be squeezed between its outer and inner connection points or subjected to pressure, but will primarily experience shear loads. Such thin membranes, however, lead to the fact that they are very flexible under internal pressure and thus the overall expansion resistance of the main cushion is too low to generate a high differential pressure with respect to the equalization chamber and thus a high pumping capacity. Due to the advantageous opposite or opposite arrangement of two proposed membranes, all disadvantages can be compensated, which result from the functional integration in the main support cushion.

Since it can be structurally complex to seal a working chamber with a main support cushion according to the invention in such a way that sufficiently high differential pressures between the fluid chambers can be achieved, it can be provided that the fluid chamber, which is usually designed as a compensation chamber, becomes the pressurized working chamber and the primary pumping work takes over for the hydraulic damping. The working chamber can therefore be delimited axially by two membranes. The first and second diaphragms can be protected from excessively high pressures in a pressure differential direction in that their base is at least indirectly supported on the connection structures associated with the thin legs, for example the core and / or the first outer sleeve. Such a support also leads to an increase in the inflation rigidity, which further promotes the pumping effect. In the case of high pressure differences in the opposite direction to the pressure difference direction, high tensile loads can arise on the radially inner connecting section of the membranes. Knowing this advantageous property, the membrane can consequently be arranged in such a way that it is now protected against high pressures in the former compensation chamber, since in the embodiment proposed according to the invention this generates the higher pressures compared to the chamber delimited by the main support cushion. A second membrane can be used as the closing membrane of the working chamber, but wel che has the wide membrane base or the leg at least twice as thick on the core side and the other leg on the outer circumference side. The two membranes are thus arranged in opposite directions to one another or opposite one another.

If one compares this solution with conventional known constructions, it quickly becomes apparent that with these the load-bearing rubber spring simultaneously generates the pumping effect. The fiction proposed according to separation, however, of supporting geometry and pumping geometry opens up a significant increase in the damping properties of the bearing with a cost-effective design and a long service life. By arranging the two membranes in the opposite arrangement to one another, a working chamber is enclosed, which has a high degree of inflation rigidity, especially when the membrane described is used. This expansion stiffness increases even further when the membrane bases are placed against the connection structures associated with the thin leg, so that high damping properties can still be observed even when the bearing is subjected to high dynamic loads. Since the diaphragms described tolerate large movements in the X / Y / Z direction due to their geometry, they protect themselves from damage in the event of a high pressure difference in the critical direction. The two membranes thus have a two-stage expansion stiffness. With small deflections or amplitudes, they cause the fluid to be pumped. In the case of larger deflections or amplitudes, on the other hand, the membrane can rest against the core or the outer sleeve or the outer tube, preferably with its thick limb, and thereby become very rigid. In this state, the membrane can absorb greater hydraulic forces and therefore make a significant contribution to the load-bearing capacity.

A further development of the elastomer bearing according to the invention provides that the respective connection widths of the legs of the two diaphragms, which are at least twice as thick, overlap at least in sections in the radial direction. The overlap is preferably in the Z direction or in the longitudinal direction, so that the connection widths overlap at least in sections in the radial direction. A connection width is the maximum thickness of the thick leg that it has in its connection area, this connection width being dimensioned in the X or Y direction. The overlapping sections of both connection widths therefore have an overlap width. The greater this coverage width, the greater the pumping effect. This is advantageous because the thick connection area or the leg of the membrane that is at least twice as thick makes a major contribution to the axial support effect of the thick leg and significantly increases the pumping area. This configuration leads to the best possible pumping action and a large pumping area. A tangent of a central area in the at least twice as thick leg of at least one membrane can, at least in sections, enclose an angle with the central longitudinal axis in the range from 0 ° to 90 °, preferably in the range from 10 ° to 50 °. The tangents of the central central surface of the first membrane or intermediate membrane can predominantly enclose angles in the range from 10 ° to 30 °. The tangents of the central central surface of the second membrane or closing membrane can predominantly include angles in the range from 25 ° to 35 °. The central central surfaces can have a curved or straight course or a predominantly curved or predominantly straight course or a combination thereof. The smaller the included angle, the greater the axial support effect.

On the other hand, large angles are to be preferred in order to have a high level of flexibility in relation to axial deflections of the bearing. The central middle surface is at the same distance from both surfaces of the leg.

According to a further embodiment of the elastomer bearing according to the invention, the two connection structures on which the two membranes are arranged can overlap at least in sections in the radial direction. The connection structures can each have a flange section which runs in the space between the core and the outer sleeve or outer tube and / or protrudes into this. The connection structures can be, for example, a second outer sleeve for the first membrane and a ring element for the second membrane. The connection structures can be rigid structures and thus enable a change in volume of the chambers. The greater the radial overlap of these connection structures, the greater the pumping effect. However, it is also conceivable that the connection structures do not overlap, but rather protrude without overlap into the gap between the core and the outer sleeve or outer tube, for example by up to 25% of the gap width, preferably by up to 50% of the gap width, with also different Lich wide extensions into the space are conceivable. For example, one connection structure can have an extension of 24% and the other connection structure an extension of 76%.

It is advantageous to jointly design the at least partial overlap of the at least twice as thick legs of the two membranes in the radial direction and the overlap to at least partial overlap or the gap between the two connection structures of the membrane. These elements are thereby brought into axial alignment, which leads to a good pumping effect and makes large axial loads bearable.

According to a further development, the elastomer body and the first membrane or the elastomer body, the first membrane and the second membrane can be separate elements in the elastomer bearing. Thus, the elastomer bearing can only have two or three elastomer parts in total or in the space between the core and the outer tube, which, compared to bearings with more than three separately manufactured elastomer elements, leads to a considerable reduction in complexity and costs due to reduced manufacturing and assembly costs. The separate elements can be arranged at least partially one above the other and spaced apart in the longitudinal direction of the elastomer bearing. This results in two axially spaced apart fluid chambers.

According to a further development, at least one membrane in the elastomer bearing can be designed to be largely rotationally symmetrical. It is also conceivable that at least one of the legs is designed to be largely rotationally symmetrical, preferably the base and the legs protruding therefrom are designed to be largely rotationally symmetrical. The center of the rotational symmetry can form the central longitudinal axis. Even if there may be slight asymmetries, for example due to X-stops or filling holes, it is still advantageous to make the geometry of the membrane itself as uniform as possible in the circumferential direction in order to avoid unfavorable stress distributions under load. Additionally or alternatively, the elastomer body can be designed to be rotationally symmetrical. Additionally or alternatively, the elastomer bearing can be designed to be rotationally symmetrical.

According to a further development, the outer tube of the elastomer bearing can either be part of an assembly comprising the elastomer body. This is shown in the figures. Alternatively, the outer tube can be installed as a separate component. A multi-part design of the outer tube is then advantageous, for example a two-part structure - a metal sleeve could be used, for example, into which 3 internal assemblies (first membrane, second membrane, elastomer body) are mounted, which results in advantageous press-out forces over the service life and no relaxation occurs. Alternatively, the outer tube can be part of a first outer sleeve or a second outer sleeve.

According to a development of the elastomer bearing, the first membrane and the second membrane are arranged overlapping at least in sections in the longitudinal direction. This leads to a compact design.

According to a further development, a connection overlap height of the elastomer body in the longitudinal direction of the elastomer bearing can correspond at least in sections to between 0.2 and 0.6 times, preferably between 0.3 and 0.5 times the height of the elastomer bearing. The connection sections can be formed from opposite sides with respect to the elastomer body. According to a further development, in the case of the elastomer bearing, the elastomer body can be designed at least in sections as a wedge bearing in the longitudinal direction. The connection sections are at least partially, preferably completely, tilted with respect to the central longitudinal axis. The tilt can vary along the circumferential direction. Preferably, angles lying diametrically with respect to the central longitudinal axis are identical. The two connection sections can be tilted at the same angle, but also at different angles. Alternatively, the elastomer body can have at least one connection section in the longitudinal direction that is not tilted with respect to the central longitudinal axis.

According to a further development, in the elastomer bearing, a connection overlap height of the elastomer body in the longitudinal direction can be at most zero, at least in sections. The binding overlap height of the elastomer body is understood as the distance in which two connection sections of the elastomer body overlap in the longitudinal direction. The lower the overlap of the connection overlap height of the elastomer body in the second direction, the lower the radial rigidity in this direction and the greater the spread of the identifier. This means that the longitudinal behavior of the elastomer bearing is flexible and comfortable and the transverse behavior of the elastomer bearing is stiff for agile driving behavior.

According to a further embodiment of the elastomer bearing according to the invention, a binding overlap height of the elastomer body varies in the longitudinal direction along the circumferential direction around the central longitudinal axis, preferably those diametrically opposite the central longitudinal axis are identical. The connection overlap height of the elastomer body is the distance in which two connection sections of the elastomer body overlap in the longitudinal direction. As a result, the elastomer body can form the main support cushion in sections and the membrane section in sections.

According to a further development, the elastomer body of the elastomer bearing can be designed in such a way that in an assembled state it has at least twice as high static rigidity in the unloaded state in the vehicle transverse direction as in the vehicle longitudinal direction.

It is also conceivable to use a hydraulically damping elastomer bearing according to this disclosure as an axially damping bearing in a vehicle, preferably an electric vehicle, preferably as a bearing operatively connected to a rear subframe for receiving at least one electric motor.

Further features, details and advantages of the invention emerge from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. Show it: 1 shows a plan view of an elastomer bearing according to the invention and FIG. 2 shows a sectional view along the line II-II according to FIG. 1.

In the figures, elements that are the same or that correspond to one another are each denoted by the same reference symbols and will therefore not be described again unless expedient. Features already described are not described again to avoid repetition and can be applied to all elements with the same or corresponding reference characters, unless explicitly excluded. The disclosures contained throughout the description can be applied mutatis mutandis to the same parts with the same reference numerals or the same component names. The position details chosen in the description, such as above, below, to the side, etc., refer to the figure immediately described and shown and must be transferred to the new position in the event of a change in position. Furthermore, individual features or combinations of features from the various exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

Although the reference document uses different reference symbols, elements with the same name, unless technically excluded, are to be considered to be identical or have the same effect as the elements of this application. To facilitate understanding of the description and the figures, a three-dimensional, right-angled, Cartesian coordinate system should be used for orientation. With regard to the elastomer bearing, this means that the X-axis and the Y-axis each define a transverse axis and the Z-axis corresponds to the longitudinal axis of the bearing. With regard to a conceivable assembly state in a vehicle, the X direction is understood to mean the direction in which a motor vehicle moves along the X axis (longitudinal direction of the vehicle). The Y direction is understood to mean a direction transverse to the direction of travel (transverse direction of the vehicle) and the Z direction is the direction in the fleas of the motor vehicle, i.e. the direction opposite to the weight force (vertical direction of the vehicle), which represents the axial direction of the bearing in the assembled state. In FIG. 2, the Z-direction arrow runs downwards, since the elastomer bearing is shown upside down with regard to its assembly position. FIG. 2 shows the elastomer bearing with a section arranged at 90 ° along the line II-II.

In Figures 1 and 2, a hydraulically damping elastomer bearing 2, in particular a hydraulic damping subframe bearing, is shown, which is used to support a subframe, not shown, of a motor vehicle. Flierzu the camp 2 is used in a not shown on receiving eye of the frame. A central longitudinal axis A extends through the elastomer bearing 2 along the longitudinal direction L of the elastomer bearing 2. With respect to the central longitudinal axis A, a radial direction R and a circumferential direction U are plotted. The bearing 2 has a core 4 and an outer tube 6 surrounding the core 4 with the formation of a distance. The core 4 is formed in one piece and is cylindrical and has a through opening 28 through which a fastening element for fastening the bearing 2 to the vehicle body can be passed. The through opening 28 enables a structure arranged on one axial side of the bearing to be screwed to a structure arranged on the other side, passing through the bearing. About the outer tube 6, the bearing 2 is inserted into a receiving eye of a subframe, in particular pressed. The core 4 and the outer tube 6 can be made of metal or plastic.

An elastomer body 8, a first membrane 10 and a second membrane 12 are arranged between the core 4 and the outer tube 6, so that only three elastomer elements are provided in the space. The elastomer body 8 partially forms a main support pad 78 and serves both as an axial bearing 30 and as a radial bearing 32. In the circumferential direction U, the main support pad 78 alternates at a 90 ° angle with a membrane section 76, which is shown in the right half of FIG you can see. The elastomer body 8 encloses with the first membrane 10, which here serves as an intermediate membrane, a second fluid chamber 16 which functions as a compensation chamber. The first membrane 10, with the second membrane 12, encloses a first fluid chamber 14 which functions as a working chamber. Both fluid chambers 14, 16 are filled with a fluid and connected to one another in a liquid-conducting manner via a damping channel 18. The elastomer body 8, the first membrane 10 and the second membrane 12 overlap at least in sections in the longitudinal direction L.

The elastomer body 8 is approximately hollow cone-shaped at least in sections and integrally connected to the core 4 and the outer tube 6 via inner and outer connection sections 52, 54, preferably vulcanized. The core 4 runs conically in the area of the connection section 52 in the left half of FIG. 2 and has a radial extension 74 in the area of the connection section 52 in the right half of FIG. 2, with the aid of which the pumping surface of the second fluid chamber 16 can be adjusted . The first membrane 10 is connected on the inside to an inner sleeve 42 and on the outside to a second outer sleeve 46, preferably vulcanized on. The second membrane 12 is connected on the inside to a ring element 40 and on the outside to a first outer sleeve 44, preferably anvulka nized. The inner sleeve 42 is pushed onto the core 4, in particular pressed on. The Au ßenhülsen 44, 46 are pushed into the outer tube 6, in particular pressed. The ring element 40 can serve as a stop plate and is supported axially on the core 4 and can be pressed with this. These connections can be press fits. A filling device 56 for filling the fluid chambers 14, 16 is formed in the ring element 40. The second outer sleeve 46 forms the damping channel 48 with a ring element 58. Also are formed on the second outer sleeve 46 two radial stops 37, which limit the relative movement of the core 4 to the outer tube 6 in the vehicle longitudinal direction X. The radial stops are opposite one another with respect to the central longitudinal axis A and are arranged in the X-plane. The radial stops 37 thus have a radial effective direction and can each be arranged on an axially extending section of the second outer sleeve 46. The radial stops 37 can each be configured monolithically with the first membrane 10 and / or arranged in a fluid chamber 14, 16. The radial stops 37 can be arranged in the elastomer bearing 2 in such a way that they are arranged in an axial central area between the two axially outer elastomer elements. In the embodiment shown, the Ra dial stops 37 are arranged centrally between the one end axially outer second membrane 12 and the other end axially outer elastomer body 8.

It can be seen that the ring element 40 protrudes at least in sections into an interspace between the core 4 and the outer tube 6, a flange section of the ring element 40 running there. This flange section, which extends from the core 4 in the direction of the outer tube 6, carries the second membrane 12. The ring element 40 extends in the radial direction R over half the distance from the outer tube 6. In addition, the second outer sleeve 46 has a flange section which carries the first membrane 10. Starting from the outer tube 6, this flange section extends in the direction of the core 4 and in the radial direction R over half the distance from the core 4. The flange sections of the ring element 40 and the second outer sleeve 46 thus overlap at least in sections in the radial direction R.

The outer tube 6 has a collar section 34 which carries a first stop 36 on the end face. At the opposite end of the bearing 2, the first outer sleeve 44 carries a second stop 38 on the end face. The stops 36, 38 can restrict a relative movement from the core 4 to the outer tube 6 in the axial direction. The first stop 36 can be designed monolithically with the elastomer body 8. The second stop 38 can be formed monolithically with the second membrane 12.

The elastomer body 8 is in the longitudinal direction L at least partially leads out as a wedge bearing - both its radially inner connection sections 52 and its radially outer connection sections 54 are at least partially relative to the central longitudinal axis A tilts ver. These tilts run in the left and right halves of FIG. 2 in the direction of the central longitudinal axis A.

The elastomer bearing 2 has a flea HL in its longitudinal direction L. The elastomer body 8 has a connection overlap height FIA in the longitudinal direction L. It can be seen that the Connection overlap height HA of the elastomer body 8 in the longitudinal direction L corresponds at least in sections to between 0.2 times and 0.6 times the height HL of the bearing 2. The connection overlap height HA of the elastomer body 8 varies along the circumferential direction U around the central longitudinal axis A, here offset by 90 °, so that the connection overlap height HA lying diametrically with respect to the central longitudinal axis A are identical. In the left half of Fig. 2, the connection overlap height HA has a first value, since here an overlap of the two connection sections 52, 54 of the elastomer body 8 in the longitudinal direction L is given. In the right half of Fig. 2, however, the two connection sections 52, 54 are axially spaced from one another in the longitudinal direction L, so that the connection overlap height HA theoretically assumes a negative value here - there is no overlap, since the connection overlap height HA on the right-hand side is at most zero in sections amounts to.

Both membranes 10, 12 each have a first leg 20, a second leg 22 and a base 24 connecting the two legs 20, 22 to one another. The second leg 22 is cylindrical or tubular in a short segment and has a connecting portion 48 in the form of a thickening 50 at each end. In the case of the first membrane 10, the thickening 50 is integrally bonded to an outside of the inner sleeve 42, in particular by vulcanization. In the case of the second membrane 12, the thickening 50 is connected to an inner side of the outer sleeve 44 with a material fit, in particular vulcanized on.

An average thickness of the first leg 20 is at least twice as thick as the average thickness of the other leg 22 in the tubular segment. The cross section of the leg 20, which is at least twice as thick on average, expands steadily according to the shape or the course of an exponential function starting from the base 50. In the first membrane 10, the leg 20 which is at least twice as thick on average forms the radially outer leg and in the second membrane 12 the leg 20 which is at least twice as thick on average forms the radially inner leg. Starting from a respective L-shaped connec tion section 68 or connection section, the on average at least twice as thick leg 20 of the first membrane 10 and the on average at least twice as thick leg 20 of the second membrane 12 extend towards each other in the longitudinal axial direction. They are arranged opposite each other with respect to the fluid chamber 14. However, while the first membrane 10 curves radially inward in cross-section, the second membrane 12 curves in cross-section radially outward. So you are not only arranged opposite in the longitudinal direction L, but also in opposite directions in the radial direction. Each membrane 10, 12 has a central surface 70. In the leg 20, which is at least twice as thick, a tangent of the central area 70 can, at least in sections, enclose an angle in the range from 0 ° to 90 ° with the central longitudinal axis A. Each thick leg 20 has a radially aligned connection width 26 at its connection section 68, via which it is connected to a connection structure (ring element 40, second outer sleeve 46). The connection width 26 is that length which the leg 20 has in the radial direction R over its entire extent. This also includes the area of the membrane 10, 12 which is not engaged from behind by a connection structure in the longitudinal direction L, in the event that the thickness or extent of the corresponding membrane 10, 12 in this area has sufficient stability to absorb axial forces. For example, the section of the membrane 10 not supported in the longitudinal direction L (FIG. 2, right half of the figure) extends so far in the longitudinal direction L that this section cannot evade even with high axial forces and therefore absorbs them. Thus, each of the two thick legs 20 each has a connection width 26. The right half of FIG. 2 also shows that the two connection widths 26 of the two at least twice as thick legs 20 of the two membranes 10, 12 overlap at least in sections in the radial direction R and thus form an overlap width 72. The two thick legs 20 of the two membranes 10, 12 and the two connection structures are now at least largely brought into axial alignment.

In the following, the functionality of the elastomer bearing 2 will be discussed with reference to the two halves of the figure in FIG. In the left half of the figure, the section in the Y direction is shown. For a high Y rigidity, the elastomer body 8 oriented in the Y direction extends over a large Z distance or it has a large FIA value. With a deflection in the Y direction primarily compressive and tensile stresses arise in the flake support cushion 78, but compressive stresses are induced in the flake support cushion 78 due to the preload and the wedge-shaped design of the flake support cushion 78, some of which are induced by the Y movements of the bearing counteract the tensile stresses caused and thus increase the service life of the flake support cushion - the preload causes the outer tube 6 to move downwards in relation to the core 4 in the plane of the drawing. In the right half of the picture, the section in the X direction is shown. For a low X stiffness, the connection sections 52, 54 of the elastomer body 8 do not overlap. This leads to the fact that the elastomer body 8, which is oriented in the X direction, is primarily loaded with thrust when it is deflected in the X direction. The main support cushion 78 is therefore softer in the X direction in relation to the Y rigidity. In order to absorb high forces in the X direction, the additional Radialan strikes 37 are therefore provided in the X direction. In an assembled state in the transverse direction of the vehicle Y, the elastomer body 8 thus has at least twice as high a static rigidity in the unloaded state as in the longitudinal direction of the vehicle X. The invention is not restricted to one of the embodiments described above, but can be modified in many ways. All of the features and advantages arising from the claims, the description and the drawing, including structural details, spatial arrangements and method steps, can be essential to the invention both individually and in the most varied of combinations.

All combinations of at least two of the features disclosed in the description, the claims and / or the figures fall within the scope of the invention. In order to avoid repetitions, features disclosed in accordance with the device should also apply and be claimable as disclosed in accordance with the method. Likewise, features disclosed in accordance with the method should apply and be claimable as disclosed in accordance with the device.

Reference numbers list elastomer bearing 70 central central surface core 72 overlap width outer tube 74 radial expansion elastomer body 76 membrane section first membrane 78 flake support pad second membrane first fluid chamber A central longitudinal axis second fluid chamber HL height of damping channel HA connection overlap height of first leg L longitudinal direction of second leg R radial direction base U circumferential direction of connection width X vehicle longitudinal direction of passage Vehicle vertical direction radial bearing collar section first stop radial stop second stop ring element inner sleeve first outer sleeve second outer sleeve connection section thickening connection section connection section filling device ring element angle angle angle angle connection section

Claims

1. Axial damping, hydraulic elastomer bearing through which a central longitudinal axis (A) protrudes, comprising a core (4) which stretches along the central longitudinal axis (A) and provides a through opening (28) for receiving a fastening element, an outer tube (6), which is arranged on the circumference of the core (4), an elastomer body (8) which is arranged between the core (4) and the outer tube (6), a first membrane (10) which has a first fluid chamber ( 14) from an axially spaced second fluid chamber (16), the fluid chambers (14, 16) being filled with a fluid, a damping channel (18) which connects the fluid chambers (14, 16) to one another in a fluid-conducting manner, characterized by a second Membrane (12) which delimits at least the first fluid chamber (14) at least in sections in the axial direction, each of the two membranes (10, 12) having a thicker cross-section and a thinner cross-section Includes inner section.

2. Axial damping, hydraulic elastomer bearing according to claim 1, characterized in that the elastomer body (8) delimits at least one of the fluid chambers (14, 16) at least in sections in the axial direction, preferably delimits the second fluid chamber (16) designed as a compensation chamber.

3. Axial damping, hydraulic elastomer bearing according to claim 1 or 2, characterized in that the second membrane (12) delimits the first fluid chamber (14) designed as a working chamber and / or the first membrane (10) as an intermediate membrane defines the first fluid chamber designed as a working chamber ( 14) separates from the second fluid chamber (16) designed as a compensation chamber.

4. Axial damping, hydraulic elastomer bearing according to one of the preceding claims, characterized in that at least one of the membranes (10, 12), preferably in front of both membranes each, a first leg (20), a second leg (22) and a die has the base (24) connecting the two legs (20, 22) to one another, an average thickness of one of the legs (20, 22) being at least twice as thick as that of the other leg (20, 22).

5. Axial damping, hydraulic elastomer bearing according to claim 4, characterized in that the cross-section of the mean at least twice as thick leg (20, 22) of at least one of the membranes (10, 12) starting from the base (50) steadily or discontinuously expanded.

6. Axial damping, hydraulic elastomer bearing according to claim 4 or 5, characterized in that in the case of the first membrane (10) the limb (20, 22) which is at least twice as thick on average forms the radially outer limb and / or in the case of the second membrane (12 ) the leg (20, 22), which is at least twice as thick on average, forms the radially inner leg.

7. Axial damping, hydraulic elastomer bearing according to one of claims 4 to 6, characterized in that the on average at least twice as thick leg (20, 22) of the first membrane (10) and the on average at least twice as thick leg (20 , 22) the second membrane (10) stretch towards each other in the longitudinal axial direction.

8. Axial damping, hydraulic elastomer bearing according to one of claims 4 to 7, characterized in that the respective connection widths (26) of the at least twice as thick legs (20, 22) of the two membranes (10, 12) in the radial direction (R ) cover at least in sections.

9. Axial damping, hydraulic elastomer bearing according to one of the preceding claims, characterized in that a connection overlap height (HA) of the elastomer body (8) in the longitudinal direction (L) along the circumferential direction (U) around the central longitudinal axis (A) varies, preferably are diametrically with respect to the connection overlap heights (HA) lying in the central longitudinal axis (A) are identical, the connection overlap height (HA) being the distance at which two Anbindungsab sections of the elastomer body (8) overlap in the longitudinal direction (L).

10. Axial damping, hydraulic elastomer bearing according to one of the preceding claims, characterized in that the elastomer body (8) is designed such that in an assembled state in the vehicle transverse direction (Y) it has at least twice as high static rigidity in the unloaded state as in Longitudinal direction of the vehicle (X).