Hydroelastic bearing with axial damping

Abstract

An axially damped hydroelastic bearing is proposed, a central longitudinal axis (A) protruding through it, comprising a core (4) extending along the central longitudinal axis (A) and provided with a continuous through-hole (28) for accommodating a fastening, an outer tube (6) arranged on a circumferential side of the core (4), an elastomer (8) arranged between the core (4) and the outer tube (6), a first membrane (10) separating a first fluid chamber (14) from an axially spaced second fluid chamber (16), a damping channel (18) fluidically connecting the fluid chambers (14, 16) in fluid communication, wherein a second membrane (12) is provided, the second membrane at least locally at least delimiting the first fluid chamber (14) in axial direction, wherein each of the two membranes (10, 12) comprises a thicker cross-sectional portion and a thinner cross-sectional portion compared thereto.

Description

Technical Field

[0001] This invention relates to a hydraulically elastic support with axial damping. Background Technology

[0002] Hydraulic damping elastic supports, also known as hydraulic supports, are used in motor vehicles as chassis supports, such as subframe supports, to dampen and / or reduce vibrations. Axially damped hydraulic supports comprise axially spaced fluid chambers, separated from each other by diaphragms and / or elastomers and connected by a damping channel. During axial relative movement of the core to the outer tube or the outer tube to the core, one of the two fluid chambers is at least locally compressed or the other fluid chamber is at least locally enlarged. Consequently, fluid displaced within these chambers flows from one fluid chamber to the other via the damping channel. This achieves a damping effect and / or vibration reduction, particularly relevant to large-amplitude, low-frequency vibrations. Summary of the Invention

[0003] This invention relates to an axially damped hydroelastic support member that can be used in the chassis area, particularly for supporting a rear subframe, which corresponds to the rear axle and can be designed to accommodate at least one electric motor or other powertrain, such as a rear axle transmission. Such a support member can also be referred to as a subframe support member and is used to support and dampen forces and vibrations acting on the subframe. For this purpose, the support member can be inserted into receiving holes formed in the subframe or bolted to a flange. Thus, the radial structural space of the axially damped support member is defined by the diameter of the receiving hole or flange. A large portion of the support member can be mounted within the radially defined structural space by its fluid cavity. Alternatively, such a support member can also be used to support other vehicle structures requiring axial damping, such as supporting the vehicle body on a ladder frame, supporting an internal combustion engine on a connecting structure, or supporting a battery for a floating suspension.

[0004] In electric vehicles, a large mass, in the form of an electric motor and / or transmission, is typically mounted in a subframe on the rear axle. Here, vibrations in the Z-direction (vehicle vertical) are extremely advantageous when damped by a hydraulic support, as this support is generally designed as a cylinder with its longitudinal axis extending along the Z-direction in the mounted state. A particular challenge in axially damped hydraulic subframe supports is the high preload along the Z-direction, which may be caused by a large load and / or battery and / or transmission. This preload can then cause a large offset along the Z-direction due to low stiffness requirements within a large linear range. It is necessary for the support to also be able to traverse the relevant displacement along the Z-direction under high load conditions in order to displace sufficient fluid volume and thus potentially induce pumping action and associated damping. This can be considered if the Z-displacement is defined by a suitable end stop, as damping is almost imperceptible after the Z-stop is installed. The difficulty in achieving operating frequency coordination is also related to the fundamental stiffness of the support. For the sake of a relatively constant operating frequency, a curve for Z-stiffness that varies as linearly as possible within the Z-displacement range is often required. If the Z-stop is finally installed, there will be a significant increase in rigidity, and naturally, there will also be displacement of the hydraulic support components at their operating frequency.

[0005] Simultaneously, such supports should typically exhibit high compliance in the X direction (vehicle longitudinal or travel direction) to allow for comfortable rolling over obstacles, for example, when traversing ditches. Although large displacements sometimes occur simultaneously in both the X and Z directions, the two axially spaced fluid chambers within the support must be kept separate to prevent fluid from being pumped from one axial chamber to the other under additional dynamic axial excitation in all operating conditions. Therefore, axially damped hydraulic supports incorporate an elastomeric diaphragm between the two fluid chambers to ensure the required compliance.

[0006] This diaphragm must withstand large offsets or displacements in the X, Y (vehicle lateral) and / or Z directions, while simultaneously being expansionally rigid to achieve sufficient pumping action between axially positioned cavities, ultimately enduring for its lifetime the high pressure differential between fluid cavities that might occur under impact loads. This is a difficult conflict of requirements to resolve, but it can be addressed using the diaphragm geometry according to EP3589861A1 for this task. This disclosure proposes a functional division between a first elastic body (axial support) that is expansionally rigid and withstands Z-loads on one hand, and a second elastic body (radial support) on the other. The first elastic body, together with the diaphragm, generates high pressure in one fluid cavity (working cavity) or creates a high pressure differential between the axially spaced fluid cavity (balance cavity) when offset in the Z direction, while the second elastic body is primarily responsible for setting or extending the X / Y rigidity, but is not itself part of the hydraulic system. The balance cavity itself is defined in the Z direction by the expansionally rigid diaphragm and radially outward by the expansionally flexible diaphragm. Therefore, hydraulic systems with a working chamber (=high pressure) and a balance chamber (=low pressure close to ambient pressure) have emerged.

[0007] From the aforementioned prior art, the present invention aims to provide an axially damped hydraulic elastic support that is less complex, more cost-effective, and has fewer components while maintaining at least the same functional capabilities.

[0008] With regard to at least one membrane and its connection, reference is made in connection to application EP3589861A1, filed on March 12, 2018, the contents of which are hereby incorporated herein.

[0009] Therefore, according to the present invention, an axially damped hydraulic elastic support is provided, having a central longitudinal axis protruding through it, comprising a core extending along the central longitudinal axis and having a continuous through-hole for accommodating a fixing member, an outer tube disposed on the circumferential side of the core, an elastic body disposed between the core and the outer tube, a first membrane separating a first fluid cavity from an axially spaced second fluid cavity, and a damping channel, wherein the fluid cavities are filled with fluid, and the damping channel fluidly connects these fluid cavities. A second membrane is provided, which at least partially defines the first fluid cavity in the axial direction, wherein each of the two membranes includes a thicker cross-section and a relatively thinner cross-section. The respective thicker cross-sections may be arranged opposite each other.

[0010] The first membrane can be supported on the inner circumference, i.e., radially inward, on the core or inner sleeve, and / or on the outer circumference, i.e., radially outward, on the outer tube or outer sleeve. The second membrane can also be supported on the inner circumference, i.e., radially inward, on the core, cover, or annular component, and / or on the outer circumference, i.e., radially outward, on the outer tube or outer sleeve. The two membranes enclose a first fluid cavity, which can also be designed as a working cavity. The two membranes can be designed to achieve a specific pumping action. Each of the two membranes can include an expansion-rigid section and an expansion-flexible section, wherein the expansion-rigid section can be formed by a thicker cross-section, and the expansion-flexible section can be formed by a thinner cross-section. The expansion-rigid section is used to generate sufficient pumping action. It is conceivable that the expansion-rigid sections are sections facing each other. Contemplative structural aspects here include the arrangement, shape design, cross-sectional thickness, and / or material selection of the membranes. Therefore, good pumping action can be achieved in a simple and inexpensive design.

[0011] The thinner and thicker portions of the cross-section are located in a cross-sectional plane, the central longitudinal axis is also located in the cross-sectional plane, and / or are arranged to encounter fluid or define fluid cavities.

[0012] According to the improved design, the elastomer forms the main support pad, and the only support pad is located within the gap between the core and the outer tube. This main support pad is characterized by bearing the main load and / or at least partially having a positive connection overlap height of the elastomer. The connection overlap height of the elastomer is preferably the following axial distance, with the two connecting portions of the elastomer overlapping longitudinally at this distance.

[0013] According to the improved version, the present invention can specify that the functions of axial support and radial support are integrated into a single component, namely the main support pad. Compared with the previous concept, the support component of the present invention integrates the two functions of two components to date into a single component, so that it can be manufactured in a low-cost and compact manner. In addition, the main support pad can be arranged between the core and the outer tube in such a way that it can seal one of the hydraulic chambers axially on the outside.

[0014] In cases where a cavity is sealed on the axially outer side, an improved design could be conceived where the elastomer not only forms the main support but also includes a membrane portion. It could be designed integrally with the elastomer and / or designed as an elastic membrane.

[0015] According to the improved embodiment, the elastic support according to the invention can be designed such that the elastic body at least partially defines at least one of the fluid cavities in the axial direction, preferably defining a second fluid cavity designed as a balancing cavity. The elastic body, serving as the main support, can therefore be arranged between the core and the outer tube such that it forms the axial boundary for the at least one fluid cavity. Here, it can be positioned not only radially inward on the core but also radially outward on the outer tube.

[0016] According to another design of the elastic support according to the invention, a second membrane defines a first fluid cavity designed as a working cavity. Alternatively or additionally, the first membrane can serve as an intermediate membrane separating the first fluid cavity, designed as a working cavity, from a second fluid cavity, designed as a balancing cavity. Thus, a fluid cavity can be defined by two membranes, and a fluid cavity can be defined by a single membrane and the elastomer. Structurally, the working cavity may be at least partially sealed with an elastomer membrane or a membrane portion supplemented by a main support, because the elastomer, which may include a main support and an elastomer membrane or membrane portion, must fully tolerate all offsets of the support. Therefore, the elastomer membrane or membrane portion is designed to be relatively long in order to minimize the resulting strain and distribute it evenly. However, such a long membrane has excessively low expansion stiffness to generate a high pressure differential relative to the balancing cavity and consequently high pumping power. Because such an elastomer with a relatively long membrane and main support cannot generate a sufficiently high pressure differential, a solution is proposed whereby the fluid cavity, typically designed as a balancing cavity, becomes a pressure-bearing working cavity and undertakes the main pumping work for hydraulic damping. This cavity can be defined axially by two membranes that can be manufactured and installed separately. Because the two components can be mounted individually on the core, they can be pre-tightened in their mounting position such that the load-bearing capacity of the support member up to the K0 posture resists this pre-tightening, where the K0 posture refers to the configuration posture. Since the vehicle's posture changes continuously during movement, the K0 posture, i.e., the vehicle's posture when stationary on its wheels, is designated as a reference point. Therefore, the first and second membranes can encounter smaller loads than the longer membrane or membrane portion adjacent to the main support, allowing the first and second membranes to be designed to be relatively short and, in particular, more expansion-rigid. Both membranes can be made of a more elastic material or as elastomeric membranes.

[0017] Advantageously, at least one membrane or intermediate membrane has at least partially low extensibility relative to the pressure differential between adjacent fluid cavities, thus providing sufficient pumping action only when the extensibility is low. Also advantageously, the intermediate membrane has a region with high axial flexibility, allowing it to follow large relative axial movements of its radially inward and radially outward connecting structures without significant elongation. The membrane also advantageously has a region that primarily bears shear loads during radial relative movements of the connecting structures from radially inward to radially outward, thus exhibiting almost no tensile or compressive strain within the membrane even under radial stress. This results in a long service life for such a membrane, encountering large axial and radial displacements while experiencing high pressure differentials (i.e., low strain) between cavities under typical overlapping conditions.

[0018] The first and second membranes are also protected from excessive pressure in the direction of the pressure difference because they can be at least indirectly supported inward or outward by their connecting structures, such as the core. However, under high pressure differentials in a direction other than the direction of the pressure difference, tensile loads may occur at the radially inward connecting portions of the membranes.

[0019] According to the improved embodiment, in the elastic support member according to the invention, at least one of the two membranes, preferably both membranes, has a first arm, a second arm, and a bottom connecting the two arms, wherein the average thickness of one arm is at least twice the thickness of the other arm. The thicker portion in cross-section may be formed by the arm at least twice as thick, and the thinner portion in cross-section may be formed by the other arm.

[0020] In the context of this invention, average thickness refers to the average thickness of the arm over its entire length, i.e., from the bottom to its free end.

[0021] If radial relative movement occurs between the inner and outer connecting structures of the support, the two arms primarily bear shear loads. Because the average thickness of one arm is at least twice that of the other, the thinner arm is more susceptible to shear deformation than the thicker arm. Therefore, the thinner arm primarily contributes to radial compliance, while the thicker arm is relatively flexible radially. This achieves power splitting for radial compliance between the thicker and thinner arms. Furthermore, the membrane positioned between them is insensitive to expansion caused by the high pressure differential between the two fluid-filled chambers. This results in high expansion stiffness of the membrane under most operating conditions, leading to a large pump volume and improved damping effect within the joint. Additionally, the design ensures that the membrane remains rigid under the pressure differential between the fluid chambers. The bottom is advantageously designed in cross-section as a U-shape or L-shape with uniform thickness, wherein the arms protrude from the U-shaped or L-shaped bottom.

[0022] According to the improved design, the cross-section of at least one arm, which is at least twice the thickness of the membrane, widens continuously or discontinuously from the bottom. The arm, at least twice the thickness, can, for example, increase in a funnel or exponential shape from the bottom in cross-section. Thus, the arm, at least twice the thickness, is extremely expansionally rigid compared to the other arm of the membrane, but simultaneously possesses a harmonious elastic curve under large translational displacements. This results in low tensile stress and consequently, a long service life for the first or second membrane designed as an intermediate membrane. With the arm thickness decreasing towards the bottom and preferably supported by a pre-bulge in the arm, the arm, at least twice the thickness, is axially flexible. Therefore, the arm, at least twice the thickness, narrowing towards the bottom and preferably pre-bulged, primarily contributes to axial compliance, while the thinner arm need not possess noteworthy axial compliance. This achieves a functional division of axial compliance between the thicker and thinner arms.

[0023] To further optimize the design of this coordinated elastic curve, the arm, which is at least twice as thick on average, can, according to the improved design, have a bulging direction in the cross-section. Here, the arm, which is at least twice as thick on average, can also be easily pre-bulged in the direction in which the arm will bend further under pressure in a fluid cavity, such as a working chamber. This bulging has the advantage that the thick arm is not compressed or elongated during axial displacement, but rather that the arm can bend. The thin arm can be designed to be essentially cylindrical / tubular with a linear curve in its cross-section, so that it can sag primarily in the axial direction only due to upsetting or tension.

[0024] In an advantageous embodiment, the elastic support is designed such that the membrane, which is twice as thick on average, preferably a first membrane or an intermediate membrane, bends toward the core under a pressure differential where the fluid cavity designed as the working chamber has a higher pressure than the fluid cavity designed as the balancing chamber. Preferably, the bottom of the two connected arms rests against the inner component. In this position, the membrane has high expansion stiffness, thus achieving high pump power and, consequently, high damping effect.

[0025] Additionally or alternatively, in another advantageous embodiment, the elastic support can be designed such that an arm of membrane, preferably twice the average thickness of a second membrane, bends toward the outer tube under a pressure differential where the fluid cavity, designed as a working chamber, has a higher pressure than the fluid cavity designed as a balancing chamber. Preferably, the bottom of the two arms, where they are joined, rests against the outer peripheral component. In this position, the membrane has high expansion stiffness, thus achieving high pumping power and, consequently, high damping effect.

[0026] In an advantageous design of the elastic support, one arm has a first length that is twice the average thickness, and the other arm has a second length, wherein the first length is greater than or equal to the second length. Thus, the longer arm can advantageously guarantee high mobility in the translational direction due to its high axial flexibility. However, the larger length may lead to low expansion stiffness and consequently low pumping power. This can be compensated for by an appropriately larger thickness of the longer arm. Therefore, a membrane geometry is achieved that features a long service life while simultaneously allowing for good pumping action along the axial direction.

[0027] In an advantageous design, the first length of one arm is at least twice the second length of the other arm. The upper and lower surfaces of the membrane can each have as similar an orientation as possible, so that the membrane does not have large or even no abrupt changes in thickness. The length of each arm is defined by the Z-direction distance between the lower turning point at the bottom of the respective arm in the X-direction and the highest connecting portion, or by the Z-direction distance between the highest turning point at the bottom of the respective arm in the X-direction and the lower connecting portion. Because the length of the thinner arm is advantageously at most half that of the thicker arm, it has higher expansion stiffness. This achieves a membrane geometry that provides excellent axial pumping performance.

[0028] If the surface of at least one membrane varies as uniformly as possible, and the membrane does not have large or even no abrupt changes in thickness, the mathematical derivative of the function describing the upper part of the membrane is zero at the turning point at the bottom. The same applies to the derivative of the function describing the lower geometry of the arm, whose mathematical derivative may also become zero at its highest point, or may have a large bend into the rigid connection region, or may be discontinuous.

[0029] According to an improved embodiment of the elastic support, in one membrane, preferably a first membrane, an arm with an average thickness of at least twice that of the membrane forms a radially outward arm, and / or in one membrane, preferably a second membrane, an arm with an average thickness of at least twice that of the membrane forms a radially inward arm. This allows the connection between the first and second membranes to be significantly close in the radial direction, or even partially overlap. The greater the radial proximity or overlap of the connection, the greater the volume change of the fluid cavity or working cavity enclosed by the two membranes during axial movement of the support. A large volume change has the same implications as a large pumping surface area, resulting in high pumping power and consequently good damping performance. Therefore, the gradual radial proximity of the connection between the two membranes leads to enhanced pumping power.

[0030] The thicker arms of the second membrane can also be aligned with each other. According to an improved embodiment, in the elastic support of the present invention, one membrane, preferably an arm at least twice the average thickness of the first membrane, and another membrane, preferably an arm at least twice the average thickness of the second membrane, extend successively along the longitudinal axis, facing each other and / or opposing each other with respect to the fluid cavity. The two arms can therefore also bend back and forth in the direction of a corresponding bend or fold.

[0031] Integrating the functions of axial and radial support into a single main support pad results in a relatively low degree of artistic freedom related to the trade-offs in characteristic setting and hydraulic damping performance. However, setting the desired stiffness requirements requires a high degree of design freedom associated with the main support pad. The very low stiffness requirement for the support in the X direction can be addressed by using waists extending in the X direction or longitudinally. However, since the main support pad should also be axially sealed towards its hydraulic chamber, the waists must be sealed with membranes such that the membranes to be added have only a negligible impact on X stiffness throughout the Z-load region. Therefore, they are potentially long and thin and extend in the Z direction. Consequently, they are not squeezed or pressure-bearing between their outer and inner connection points under all Z-complements when the support is offset in the X direction, but instead mainly experience shear loads. However, this membrane results in it being very compliant under internal pressure, and therefore the expansion stiffness of the main pad is generally too low for generating a high pressure differential relative to the balancing chamber and thus high pumping power. All the disadvantages arising from integrating the functions into the main support pad can be compensated by preferably arranging two proposed membranes in opposite or opposing positions.

[0032] Because sealing the working chamber with the main support pad of the present invention in a manner that achieves a sufficiently high pressure differential between the fluid chambers can be structurally complex, the fluid chamber, which is typically designed as a balancing chamber, can be transformed into a pressure-bearing working chamber, undertaking the primary pumping work for hydraulic damping. The working chamber can therefore be defined axially by two membranes. The first and second membranes can be protected from excessive pressure in the pressure differential direction by having their bottoms at least indirectly supported on connecting structures such as the core and / or the first outer sleeve associated with the thin arm. Furthermore, this support also results in increased expansion stiffness, which further benefits the pumping action. Under high pressure differentials in a direction other than the pressure differential direction, high tensile loads may occur at the radially integrated connections of the membranes. Knowing this advantageous performance, these membranes can therefore be arranged such that they are now protected from the high pressures previously found in the compensation chamber, which, in the proposed embodiment of the invention, results in higher pressures compared to the chamber defined by the main support pad.

[0033] A second membrane can be used as the closing membrane for the working chamber, but it has a wide membrane root or an arm at least twice as thick on the core side and another arm on the outer periphery side. Thus, the two membranes are arranged opposite to each other or opposite each other.

[0034] When compared with commonly known structures, this solution quickly demonstrates the simultaneous pumping action within the load-bearing rubber spring. However, the present invention, by separating the load-bearing and pumping geometries, achieves a significant improvement in support damping performance while maintaining a low-cost design and long service life. By arranging two membranes in an opposite configuration to each other, enclosing the working chamber, it exhibits high expansion stiffness, particularly when using the membranes. This expansion stiffness is further enhanced when the membrane bottoms abut against the connecting structure of the thin arm, resulting in high damping performance even under high dynamic loads on the support. Because the membranes, by their geometry, tolerate large movements in the X / Y / Z directions, they are themselves protected against damage under high pressure differentials along dangerous directions. Therefore, the two membranes possess two levels of expansion stiffness. At small offsets or amplitudes, they cause fluid pumping. At relatively large offsets or amplitudes, the membranes preferably abut against the core, outer sleeve, or outer tube with their thicker arms, thus exhibiting high expansion stiffness. In this state, the membrane can withstand higher hydraulic pressures and therefore significantly contributes to load bearing.

[0035] An improved embodiment of the elastic support of the present invention specifies that the respective connection widths of the arms of two membranes, each at least twice the thickness of the membrane, at least partially overlap radially. The overlap preferably exists in the Z-direction or longitudinal direction, for which the connection widths at least partially overlap radially. The connection width is the maximum thickness of the thick arm in its connection region, wherein the connection width can be measured in the X-direction or Y-direction. The overlapping portion of the two connection widths thus has an overlap width. The greater the overlap width, the greater the pumping effect. This is therefore advantageous because the thick connection region, or the arm at least twice the thickness of the membrane, greatly contributes to the axial support of the thick arm, and the pumping area is significantly increased. This design results in optimal pumping effect and a large pumping area.

[0036] The tangent of the central facet in at least one arm of at least twice the thickness of the membrane can at least partially enclose the central longitudinal axis at an angle ranging from 0° to 90°, preferably from 10° to 50°. The tangent of the central facet of the first membrane or intermediate membrane can primarily enclose an angle ranging from 10° to 30°. The tangent of the central facet of the second membrane or closed membrane can primarily enclose an angle ranging from 25° to 35°. The central facet can have a curved or straight orientation, or a predominantly straight or predominantly curved orientation, or a combination thereof. The smaller the enclosing angle, the greater the axial support. A larger angle is specified to provide high flexibility relative to axial offset of the support. The central facet is equidistant from both surfaces of the arm.

[0037] According to another design of the elastic support of the invention, the two connecting structures housing the two membranes can at least partially overlap radially. Each connecting structure can have a flange extending and / or protruding into the gap between the core and the outer sleeve or tube. The connecting structure can, for example, be a second outer sleeve for the first membrane and an annular member for the second membrane. The connecting structure can be a rigid structure and thus allows for volume variations in the cavity. The greater the radial overlap of the connecting structures, the greater the pumping effect. However, it is also conceivable that these connecting structures do not overlap, but rather protrude non-overlappingly into the gap between the core and the outer sleeve or tube, such that they occupy, for example, 25% of the gap width respectively, preferably 50% of the gap width respectively, and it is also conceivable that they extend into the gap at different distances. Thus, for example, one connecting structure can have an extension of 24%, and the other connecting structure can have an extension of 76%.

[0038] It is advantageous for the two membranes to have at least twice the thickness of their arms to overlap at least partially in the radial direction, and for the two connecting structures of the membranes to overlap at least partially or for a void to protrude together. These components are thus positioned in axial alignment, which results in good pumping performance and the ability to withstand large axial loads.

[0039] According to the improved design, in this elastic support, the elastomer and the first membrane, or the elastomer, the first membrane, and the second membrane, are separate components. Therefore, the elastic support can include only two or three elastomer components in total, or within the gap between the core and the outer tube. This results in a significant reduction in complexity and cost compared to supports with more than three separately manufactured elastomer components, due to reduced manufacturing and installation costs. These separate components can at least partially overlap and be spaced apart in the longitudinal direction of the elastic support. This results in two axially spaced fluid cavities.

[0040] According to the improved design, at least one membrane in the elastic support can be designed to be substantially rotationally symmetrical. It is also conceivable that at least one of the arms is designed to be substantially rotationally symmetrical, preferably the bottom and the two protruding arms therefrom. The center of rotational symmetry can form the central longitudinal axis. Even when slight asymmetry may exist, for example due to X-stops or filling holes, it is advantageous that the geometry of the membrane itself is arranged as uniformly as possible in the circumferential direction to avoid unfavorable stress distribution under load. Additionally or alternatively, the elastomer can be designed to be rotationally symmetrical. Additionally or alternatively, the elastic support can be designed to be shape-symmetrical.

[0041] According to the improved design, in this elastic support, the outer tube may be a component of an assembly including an elastomer. It is not shown in these figures. Alternatively, the outer tube may be installed as a separate component. Therefore, it is advantageous to design the outer tube as a multi-piece, such as a two-piece structure, where, for example, a metal sleeve may be used, in which three internal components (a first membrane, a second membrane, and an elastomer) are installed, thereby obtaining advantageous compressive force during operation without relaxation. Alternatively, the outer tube may be a component of either a first outer sleeve or a second outer sleeve.

[0042] According to an improved embodiment of the elastic support, the first and second membranes are arranged to at least partially overlap longitudinally. This results in a compact structure.

[0043] According to the improved design, in the elastic support, the longitudinal overlap height of the elastic body can at least partially correspond to 0.2 to 0.6 times, preferably 0.3 to 0.5 times, the height of the elastic support. The connection portion can be formed from opposite sides of the elastic body.

[0044] According to the improved design, the elastic body in the elastic support can be at least partially designed as a wedge-shaped support in the longitudinal direction. Here, these connections are at least partially, preferably completely, inclined about the central longitudinal axis. The inclination can vary circumferentially. The angles that are completely opposed radially about the central longitudinal axis are preferably the same. The inclinations of the two connections can be at the same angle, but they can also be at different angles. Alternatively, the elastic body can have at least one connection in the longitudinal direction that is not inclined relative to the central longitudinal axis.

[0045] According to the improved design, in this elastic support, the longitudinal overlap height of the elastomers is at least partially equal to zero. The elastomer overlap height refers to the distance by which the two connecting portions of the elastomers overlap longitudinally. The smaller the overlap height in the second direction, the lower the radial stiffness and the greater the characteristic span in that direction. This results in a smooth and comfortable longitudinal characteristic for agile driving, while the lateral characteristic of the elastic support is stiff.

[0046] According to another design of the elastic support member of the present invention, the longitudinal overlap height of the elastic body varies circumferentially about the central longitudinal axis, and the radially opposite overlap heights about the central longitudinal axis are preferably the same. The overlap height of the elastic body is such that the two connecting portions of the elastic body overlap longitudinally at this distance. Thus, the elastic body can partially form the main support pad and partially form the membrane portion.

[0047] According to the improved design, the elastic body in the elastic support can be designed such that its static stiffness in the unloaded state in the lateral direction of the vehicle during installation is at least twice that in the longitudinal direction of the vehicle.

[0048] It is also conceivable to use the hydraulically damped elastic support according to this article as an axial damping support in vehicles, preferably electric vehicles, preferably as a support that cooperates with a rear subframe for accommodating at least one electric motor. Attached Figure Description

[0049] Other features, details, and advantages of the invention will become apparent from the following description of embodiments taken in conjunction with the figures, wherein:

[0050] Figure 1 A top view of the elastic support member of the present invention is shown, and

[0051] Figure 2 Show along according to Figure 1 The cross-sectional view of line II-II. Detailed Implementation

[0052] In the figures, identical or corresponding components are represented by the same reference numerals, and therefore are not redescribed unless inappropriate. Features already described are not redescribed to avoid duplication and can be used for all components with the same or corresponding reference numerals, unless explicitly excluded. The disclosure contained throughout the specification is applicable, by its meaning, to the same parts having the same reference numerals or the same component names. Locational descriptions selected in the specification, such as upper, lower, lateral, etc., may also relate to the immediately preceding description and the figures shown, and are applied, by their meaning, to new locations as the location changes. Furthermore, individual features or combinations of features from the different embodiments shown and described may be independently inventive or solutions according to the invention.

[0053] Although the reference documents use different reference numerals, components with the same name should be considered identical or functionally identical to those in this application unless technically excluded. For ease of understanding of the specification and figures, a three-dimensional orthogonal Cartesian coordinate system should be used. For the elastic support, this means that the X and Y axes each define a transverse axis, and the Z axis corresponds to the longitudinal axis of the support. Regarding the conceivable installation state within a vehicle, the X direction refers to the direction in which the vehicle moves along the X-axis (vehicle longitudinal direction). The Y direction refers to the direction transverse to the direction of travel (vehicle transverse direction), and the Z direction refers to the vehicle height direction, i.e., the direction opposite to gravity (vehicle vertical direction), which is the axial direction of the support in the installed state. Figure 2 In the middle, the Z-direction is oriented downstream because the elastic support is shown suspended with respect to its mounting position. Figure 2 The elastic support is shown in a 90° section along line II-II.

[0054] exist Figure 1 and Figure 2 The diagram shows a hydraulically damped resilient support 2, and more particularly a hydraulically damped subframe support, for supporting a motor vehicle subframe (not shown). For this purpose, the support 2 is fitted into a receiving hole (not shown) in the subframe. A central longitudinal axis A extends through the resilient support 2 along its longitudinal direction L. With respect to the central longitudinal axis A, radial and circumferential directions R and U are provided.

[0055] The support member 2 has a core 4 and an outer tube 6 that surrounds the core 4 in a gap. The core 4 is designed as a single piece and cylindrical in shape and has a through hole 28 through which a fastener for securing the support member 2 to the vehicle body passes. The through hole 28 allows a structure arranged on one axial side of the support member to be screwed through the support member to a structure located on the other side. The support member 2 is inserted, and in particular pressed, into a receiving hole in the subframe via the outer tube 6. The core 4 and the outer tube 6 can be made of metal or plastic.

[0056] An elastomer 8, a first membrane 10, and a second membrane 12 are disposed between the core 4 and the outer tube 6, so that only three elastomer components are disposed within this gap. The elastomer 8 partially forms a main support pad 78, and serves not only as an axial support 30 but also as a radial support 32. In the circumferential direction U, the main support pad 78 is at a 90° angle to the outer tube 6. Figure 2 The right half of the diagram shows alternating membrane sections 76. An elastomer 8 and a first membrane 10, designed as an intermediate membrane, enclose a second fluid cavity 16, which acts as a balancing cavity. The first membrane 10 and the second membrane 12 enclose a first fluid cavity 14, which acts as a working cavity. The two fluid cavities 14 and 16 are filled with fluid and are fluidly connected through a damping channel 18. The elastomer 8, the first membrane 10, and the second membrane 12 at least partially overlap in the longitudinal direction L.

[0057] The elastomer 8 is approximately designed as a hollow cone shape in at least some sections and is joined by material bonding via inner and outer connecting parts 52, 54, preferably vulcanized to the core 4 and the outer tube 6. The core 4 is... Figure 2 In the left half of the diagram, it extends in a tapered shape in the connecting part 52 region and... Figure 2 In the right half of the diagram, the region of the connection 52 has a radial widening 74, thereby adjusting the pumping area of ​​the second fluid cavity 16. The first membrane 10 is joined on the inner side, preferably vulcanized to the inner sleeve 42, and joined on the outer side, preferably vulcanized to the second outer sleeve 46. The second membrane 12 is joined on the inner side, preferably vulcanized to the annular member 40, and joined on the outer side, preferably vulcanized to the first outer sleeve 44. The inner sleeve 42 is fitted, especially pressed, onto the core 4. The outer sleeves 44, 46 are inserted, especially pressed, into the outer tube 6. The annular member 40 can serve as a stop and is axially supported on and pressed against the core 4. The connection can be a press fit. A filling device 56 for filling the fluid cavities 14, 16 is formed within the annular member 40. The second outer sleeve 46 and the annular member 58 form a damping channel 18. In addition, two radial stops 37 are formed on the second outer sleeve 46, which restrict the relative movement of the core 4 with respect to the outer tube 6 in the vehicle longitudinal direction X. The radial stops are opposite each other about the central longitudinal axis A and arranged in the X-plane. The radial stops 37 thus have a radial direction of action and can be respectively mounted on the axial extensions of the second outer sleeve 46. The radial stops 37 can be designed to be integral with the first membrane 10 and / or mounted within the fluid cavities 14, 16. The radial stops 37 can be mounted within the elastic support 2 such that they are positioned in the axially central region between the two axially outward elastic body members. Therefore, in the illustrated embodiment, the radial stops 37 are centrally arranged between the second membrane 12, which is axially outward at one end, and the elastic body 8, which is axially outward at the other end.

[0058] It can be seen that the annular member 40 at least partially protrudes into the gap between the core 4 and the outer tube 6, with its flange extending there. The flange extending from the core 4 towards the outer tube 6 carries the second membrane 12. The annular member 40 extends radially R for half the distance of the outer tube 6. Furthermore, the second outer sleeve 46 has a flange carrying the first membrane 10. The flange extends from the outer tube 6 towards the core 4 and extends radially R for half the distance of the core 4. Therefore, the flanges of the annular member 40 and the second outer sleeve 46 at least partially overlap radially R.

[0059] The outer tube 6 has a flange 34, on which a first stop 36 is supported at one end. At the opposite end of the support member 2, the first outer sleeve 44 supports a second stop 38 at one end. Stops 36 and 38 can restrict the relative axial movement of the core 4 with respect to the outer tube 6. The first stop 36 can be designed to be integral with the elastomer 8. The second stop 38 can be designed to be integral with the second membrane 12.

[0060] The elastomer 8 is at least partially designed as a wedge-shaped support along the longitudinal direction L, with its radially inward connecting portion 52 and radially outward connecting portion 54 at least partially inclined relative to the central longitudinal axis A. The inclination is... Figure 2 The left and right halves of the diagram extend in the direction of the central vertical axis A.

[0061] The elastic support 2 has a height HL in its longitudinal direction L. The elastic body 8 has a connection overlap height HA in its longitudinal direction L. Clearly, the connection overlap height HA of the elastic body 8 in the longitudinal direction L corresponds at least partially to between 0.2 and 0.6 times the height HL of the support 2. The connection overlap height HA of the elastic body 8 varies circumferentially along a circumferential direction U centered on the central longitudinal axis A, offset by 90°, thus the connection overlap heights HA that are radially completely opposite about the central longitudinal axis A are the same. Figure 2 In the left half of the diagram, the overlap height HA has a first value because there is an overlap of the two connecting parts 52 and 54 of the elastic body 8 along the longitudinal direction L. However, Figure 2 In the right half of the diagram, the two connecting parts 52 and 54 are spaced apart along the longitudinal L axis. Therefore, the overlap height HA of this connection is theoretically negative and there is no overlap, because the overlap height HA of the connection on the right side is at most zero locally.

[0062] The two membranes 10 and 12 each have a first arm 20, a second arm 22, and a bottom 24 connecting the two arms 20 and 22. The second arm 22 is designed as a column or tube in a short section and has a connecting portion 48 in the form of a thickened portion 50 at each end. In the case of the first membrane 10, the thickened portion 50 is joined by a material bonding method, particularly vulcanized to the outer surface of the inner sleeve 42. In the case of the second membrane 12, the thickened portion 50 is joined by a material bonding method, particularly vulcanized to the inner surface of the outer sleeve 44.

[0063] The average thickness of the first arm 20 is at least twice the average thickness of the other arm 22 in the tubular segment. The cross-section of the arm 20, which is at least twice as thick on average, widens continuously from the bottom 24, corresponding to the direction or curve of an exponential function. In the first membrane 10, the arm 20, which is at least twice as thick on average, forms a radially outward arm, and in the second membrane 12, the arm 20, which is at least twice as thick on average, forms a radially inward arm. From their respective L-shaped connecting portions 68 or connecting portions, the arms 20 of the first membrane 10 and the arms 20 of the second membrane 12, which are at least twice as thick on average, extend sequentially to each other along the longitudinal axis. They are opposite each other with respect to the fluid cavity 14. However, when the first membrane 10 is radially inward in its cross-section, the second membrane 12 is radially outward in its cross-section. Therefore, they are not only opposite each other in the longitudinal direction L, but also radially opposite to each other. Each membrane 10, 12 has a central mid-surface 70. In an arm 20 that is at least twice as thick, the tangent of the central mid-surface 70 may at least partially enclose the central longitudinal axis A at an angle ranging from 0° to 90°.

[0064] Each thick arm 20 has a radially oriented connection width 26 at its connection portion 68, where it connects to the connecting structure (annular member 40, second outer sleeve 46). The connection width 26 is a length that the arm 20 has throughout its entire extension in the radial direction R. It also includes regions of the membranes 10, 12 where, if the thickness or extension dimension of the respective membrane 10, 12 has sufficient stability to withstand axial forces, it is not held back by the connecting structure in the longitudinal direction L. For example, the portion of the membrane 10 that is not supported in the longitudinal direction L ( Figure 2 The right half of the diagram extends so far in the longitudinal direction L that this portion will not avoid and therefore bear the axial force under large axial forces. Therefore, each of the two thick arms 20 has a connection width 26. Figure 2 The right half of the diagram also shows that the two connecting widths 26 of the two arms 20 of the two membranes 10, 12, which are at least twice as thick, at least partially overlap in the radial direction R, thus forming an overlap width 72. The two thick arms 20 of the two membranes 10, 12 and the two connecting structures are now at least substantially aligned axially.

[0065] The following should be referred to Figure 2The function of the elastic support 2 is illustrated in two halves of the diagram. The cut-off portion in the Y direction is shown in the left half. For high Y-stiffness, the elastic body 8 oriented in the Y direction extends over a large Z distance, or it has a large HA value. When offset in the Y direction, compressive and tensile stresses mainly occur within the main support pad 78, but compressive stress is induced within the main support pad 78 due to preloading and its wedge-shaped design. This compressive stress sometimes counteracts the tensile stress caused by the Y-movement of the support member, thus extending the service life of the main support pad. Simultaneously, this preloading causes the outer tube 6 to move downwards relative to the core 4 within the drawing. The cut-off portion in the X direction is depicted in the right half. For low X-stiffness, the connecting portions 52 and 54 of the elastic body 8 do not extend. This results in the elastic body 8 oriented in the X direction primarily bearing shear loads when offset in the X direction. The main support pad 78 is therefore more flexible in the X direction compared to its Y-stiffness. To withstand large forces in the X direction, an additional radial stop 37 is provided in the X direction. Therefore, in the installed state, the static stiffness of the elastomer 8 in the non-load-bearing state along the vehicle transverse Y is at least twice that along the vehicle longitudinal X.

[0066] This invention is not limited to one of the embodiments described above, but can be modified in various ways. All features and advantages derived from the specification and figures, including structural details, spatial arrangements, and method steps, may be important to this invention not only individually but also in various combinations.

[0067] All combinations consisting of at least two features disclosed in the specification and / or figures fall within the scope of this invention.

[0068] To avoid duplication, features disclosed in relation to the apparatus should also be considered as disclosed in relation to the method and are therefore claimable. Similarly, features disclosed in relation to the method should also be considered as disclosed in relation to the apparatus and are therefore claimable.

[0069] List of reference numerals

[0070] 2. Elastic support member 50 thickened part

[0071] 4-core 52 connector

[0072] 6 outer tube 54 connection part

[0073] 8 Elastomers 56 Filling Device

[0074] 10 First membrane 58 Annular piece

[0075] 12 Second membrane at 60° angle

[0076] 14 First fluid cavity at 62 degrees

[0077] 16 Second fluid cavity at 64 degrees

[0078] 18 damping channels, 66 angles

[0079] 20 First arm 68 connecting part

[0080] 22 Second arm 70 Center mid-surface

[0081] 24 bottom 72 overlap width

[0082] 26 connection width 74 radial widening

[0083] 28 through holes, 76 membrane sections

[0084] 30 Axial Support 78 Main Support Pad

[0085] 32 Radial support A center longitudinal axis

[0086] 34 flange HL height

[0087] 36 First stop HA connection overlap height

[0088] 37 Radial stop L Longitudinal

[0089] 38 Second stop R radial

[0090] 40 circumferential ring component U

[0091] 42 Inner sleeve X vehicle longitudinal direction

[0092] 44 First outer sleeve Y vehicle lateral

[0093] 46 Second outer sleeve Z vehicle vertical

[0094] 48 Connecting parts

Claims

1. An axially damped hydraulic elastic support, wherein a central longitudinal axis (A) protrudes through the hydraulic elastic support, the hydraulic elastic support comprising a core (4) extending along the central longitudinal axis (A) and having a continuous through hole (28) for accommodating a fixing member, an outer tube (6) disposed on the circumferential side of the core (4), an elastic body (8) disposed between the core (4) and the outer tube (6), a first membrane (10) separating a first fluid cavity (14) from an axially spaced second fluid cavity (16), and a damping channel (18), wherein, These fluid cavities (14, 16) are filled with fluid, and the damping channels connect these fluid cavities (14, 16) fluidly to each other. The feature is the provision of a second membrane (12) that at least partially defines the first fluid cavity (14) in the axial direction. Each of the first membrane (10) and the second membrane (12) includes a thicker cross-section and a relatively thinner cross-section. The two membranes (10, 12) have a first arm, a second arm, and a bottom (24) connecting the first arm and the second arm to each other, wherein the average thickness of one arm is at least twice that of the other arm. Wherein, the arm of the first membrane (10) with an average thickness of at least twice that of the second membrane (12) extends successively in the longitudinal direction, or the two arms bend towards each other in the case of corresponding bends or folds. The first membrane (10) and the second membrane (12) extend successively along the longitudinal axis, with an average thickness of at least twice that of the first membrane (10) and an average thickness of at least twice that of the second membrane (12), and are opposite to each other relative to the first fluid cavity (14). The first membrane (10) is bent such that an arm of at least twice the average thickness of the first membrane (10) bends radially inward or outward from the first fluid cavity (14), and the second membrane (12) is bent such that an arm of at least twice the average thickness of the second membrane (12) bends in opposite radial directions, such that the two membranes (10, 12) extend successively in the longitudinal direction but pivot away from each other.

2. The axially damped hydraulic elastic support according to claim 1, characterized in that, The elastomer (8) at least partially defines at least one of the fluid cavities (14, 16) in the axial direction.

3. The axially damped hydraulic elastic support according to claim 1 or 2, characterized in that, The second membrane (12) defines the first fluid cavity (14) designed as a working cavity and / or the first membrane (10) as an intermediate membrane to separate the first fluid cavity (14) designed as a working cavity from the second fluid cavity (16) designed as a balancing cavity.

4. The axially damped hydraulic elastic support according to claim 1, characterized in that, The cross-section of at least one of the membranes (10, 12) having an average thickness of at least twice that of the arm is continuously or discontinuously widened from the bottom (24).

5. The axially damped hydraulic elastic support according to claim 1 or 4, characterized in that, The arm with an average thickness of at least twice that of the first membrane (10) forms a radially outward arm, and / or the arm with an average thickness of at least twice that of the second membrane (12) forms a radially inward arm.

6. The axially damped hydraulic elastic support according to claim 1, characterized in that, The respective connection widths (26) of the arms of the two membranes (10, 12) being at least twice as thick overlap radially (R).

7. The axially damped hydraulic elastic support according to claim 1, characterized in that, The connection overlap height (HA) of the elastic body (8) along the longitudinal direction (L) varies along the circumferential direction (U) centered on the central longitudinal axis (A), wherein the connection overlap height (HA) is such that the two connecting parts of the elastic body (8) overlap along the longitudinal direction (L) by such distance.

8. The axially damped hydraulic elastic support according to claim 1, characterized in that, The elastomer (8) is designed such that the static stiffness of the elastomer (8) in the vehicle transverse (Y) direction in the installed state, when not under load, is at least twice that in the vehicle longitudinal (X) direction.

9. The axially damped hydraulic elastic support according to claim 2, characterized in that, The elastomer (8) defines the second fluid cavity (16) which is designed as a balancing cavity.

10. The axially damped hydraulic elastic support according to claim 7, characterized in that, The connection overlap height (HA) of the elastomer (8) along the longitudinal direction (L) varies along the circumferential direction (U) centered on the central longitudinal axis (A), and the connection overlap height (HA) that is completely opposite in the radial direction about the central longitudinal axis (A) is the same.

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