GB2251050A

GB2251050A - A support bearing

Info

Publication number: GB2251050A
Application number: GB9126357A
Authority: GB
Inventors: Einhard Kleinschmit; Richard Nagler; Peter Tattermusch; Ulrich Zech
Original assignee: Daimler Benz AG; Mercedes Benz AG
Current assignee: Daimler Benz AG
Priority date: 1990-12-18
Filing date: 1991-12-11
Publication date: 1992-06-24
Anticipated expiration: 2011-12-11
Also published as: DE4040426C2; DE4040426A1; GB9126357D0; FR2670549A1; GB2251050B; FR2670549B1

Abstract

A support bearing for the resilient connection of, for example, an axle carrier to a vehicle body, comprises an inner and an outer bearing part 20 and 18 respectively, connected to one another via web-like rubber bodies which are vulcanised to the two bearing parts in the region of one bearing end face on surface parts c extending obliquely relative to the bearing axis and on surface parts b adjoining these and parallel to the bearing axis. The bearing parts 20, 18 have flat faces between which the rubber bodies extend in web-like manner, leaving a number of interspaces. <IMAGE>

Description

2 -2 3 10 3,3 1 A SuDl:)ort Bearinq The invention relates to a support

bearing for the resilient connection of vehicle parts, with an outer bearing part fastenable to one vehicle part and an inner bearing part fastenable to the other vehicle part, which, starting from the same bearing end face, each have a circumferential surface part extending inwards equally obliquely and an axis-parallel circumferential surface part adjoining this, and with rubber bodies introduced between the two bearing parts and vulcanised respectively onto the two bearing parts at least in the region of the circumferential surface parts axis-parallel to one another.

Support bearings of this type are known and are designed for resilient connection of the front-axle and rear-axle carriers to the body of passenger cars of the 190E type of Mercedes-Benz AG.

In these support bearings, the web-like rubber bodies vulcanised in between the outer and inner bearing parts extend, in relation to the installation position of the support bearings, essentially over the entire length of these from the top, outside, obliquely down-wards and inwards.

For the bearing softnesses in mutually perpendicular radial directions and in the axial direction, the angle of incidence of the rubber bodies, their dimensions and the rubber quality are of principal importance.

In view of prevailing conditions of space for the installation of such support bearings, a desired ratio of these bearing softnesses relative to one another often cannot be obtained.

The reason for this is that the space receiving the rubber bodies, located between the inner and outer bearing parts, cannot be made sufficiently large on grounds of room available.

Therefore, a comprise has to be found with respect of the angle of incidence and the dimensions of the rubber bodies perpendicularly to the faces of the two bearing parts 2 to be connected to these by vulcanisation, which makes it almost impossible to coordinate the bearing softnesses with one another acceptably because the rubber volume to be accommodated between the two bearing parts is too small.

Besides the fact that the bearing softnesses, resulting from such a compromised solution, in the direction of the radial extension of the rubber bodies and in the axial direction of the support bearing are too low, disadvantages in terms of the uncoupling of structure-borne noise must also be taken into account, since the reduced rubber volume at the same time causes a corresponding decrease in the insulating effect of the rubber.

The present invention seeks to provide a support bearing the construction of which allows a desired coordination of radial and axial bearing softnesses with one another, even when conditions of space for installation make it necessary to adopt a correspondingly compact form of execution.

According to the invention there is provided a support bearing for the resilient connection of two vehicle parts, with an outer bearing part fastenable to one vehicle part and an inner bearing part fastenable to the other vehicle part, which, starting from the same bearing end face, each have a circumferential surface part extending inwards equally obliquely and an axis-parallel circumferential surface part adjoining this, and with rubber bodies introduced between the two bearing parts and vulcanised respectively onto the two bearing parts at least in the region of the circumferential surface parts axisparallel to one another, wherein the inner bearing part.is in one piece and has a rhombic cross-section, the outer bearing part has casing portions parallel to the rhombus faces of the inner bearing part, and the rubber bodies are assigned in web-like manner to the rhombus faces and are vulcanised onto these.

Preferably, the portions of the web-like rubber bodies extending parallel to the bearing axis have the 3 greater length. The rubber bodies may have a recess extending at least over a part of their axial length. Preferably, resilient stops are formed opposite one another on the inner circumference of the outer bearing part between the web-like rubber bodies.

The obliquely set rubber-body portions are provided, preferably, outside a receptacle for the outer bearing part.

According to the invention, the rubber bodies extend between the two bearing parts in parallel over a first portion and obliquely relative to the bearing axis over a further portion. This course of the rubber bodies between the inner and outer bearing parts affords possibilities of action to obtain an advantageous coordination of bearing softnesses.

At the same time, the rubber-body portions extending parallel to the bearing axis can be given a radial dimension which is substantially greater than that of rubber bodies extending purely obliquely between the two bearing parts, since the region between the two bearing parts which, in the known bearing construction, is limited by the upper outer edge and lower inner edge of the obliquely extending rubber bodies can now be filled completely with rubber in an axisparallel orientation, and a substantially greater volume of rubber is thereby provided.

This large rubber volume makes it possible to give the support bearing a greater bearing softness in this radial plane and thus to achieve a correspondingly improved noise uncoupling. Furthermore, in comparison with the known bearing construction with rubber bodies fitted in obliquely, under axial bearing loads the axis-parallel rubber-body portions make it possible, for the same shearing stress, to obtain greater relative movements of the two bearing parts in relation to one another and consequently also an increase in the axial bearing softness.

The rubber-body portions set obliquely relative to the bearing axis are subjected to mutually superposed shearing and conpressive stresses, and by an appropriate 4 choice of the angle of incidence their compressivestress fraction and therefore the axial bearing softness can be determined.

The bearing construction according to the invention thus makes it possible so to vary or distribute compressivestress and shearing-stress fractions of the rubber bodies in their portions that, even with a compact bearing execution, bearing softnesses which are in the desired ratio to one another can be obtained.

An exemplary embodiment of the invention is illustrated in the drawing. In this, Figure 1 shows a longitudinal section through a support bearing, as seen along the line I-I of Figure 2, Figure 2 shows a cross-section of the support bearing, as seen along the line II-II of Figure 1, Figure 3 shows a longitudinal section through the support bearing along the line III-III of Figure 2 and Figure 4 shows a diagrammatic representation to explain the advantages to be afforded by the embodiment of the invention.

The underbody of a passenger car is designated by 10 and an axle carrier connected resiliently to this is designated by 12. The connection is made by means of support bearings 14 which are each pressed in a known way into a receiving lug 16 of the axle carrier 12.

The support bearings 14 have an outer bearing part 18 in the form of--- a sheet-metal casing closed on the circumference and an inner bearing part 20 or bearing core. Between the two bearing parts 18 and 20 is vulcanised in an resilient insert 22 made of rubber. This forms two mutually opposed web-like rubber bodies 24 and 26. In order to achieve a desired bearing softness in the radial plane a-a in which these lie, they can each have a recess 28 which, as shown in Figure 1, extends partially into the respective rubber bodies 24 and 26 in the axial direction of the support bearing 14; but they can just as well divide the rubber bodies 24 and 26 over their entire axial extent.

These recesses 28 are, for example, limited laterally by plane mutually parallel faces 30 and 32 of the rubber-body segments 34, 36 and 38, 40 formed thereby. As indicated by dot-and-dash lines, they could also be arranged at an acute angle opening radially outwards, depending on what bearing softness and what characteristic curve in the radial plane a-a are required.

The rubber-body segments 34, 36; 38, 40 have a preferably rectangular cross-section and are vulcanised onto mutually opposite plane circumferential surface portions 40, 42; 44, 46 or 48, 50; 52, 54 of the outer and inner bearing parts 18 and 20.

As is evident from Figure 1, the rubber-body segments 34 to 40 extend parallel to the bearing axis 56 over a portion b of their length which preferably corresponds approximately to the axial dimension of the receiving lug 16. Their remaining portion c extends, in the region of one bearing end face, between preferably obliquely outward-set surface parts, designated by 58, 60 and 62, 64, of the outer bearing part 18 and bearing core 20, the obliquely set portions c of the rubber-body segments 34 to 40 being provided on the bearing end face confronting the underbody 10.

References 66 and 68 denote approximately kidneyshaped clearances which are assigned to circumferential parts of the bearing core 20 opposite one another in a radial plane d-d perpendicular to the radial plane a-a and pass through the support bearing 14 in the axial direction and of which the limiting wall located opposite the bearing core 20 forms a radial stop 70 for the latter.

The sheet-netal casing forming the outer bearing part 18 is equipped on the outside with a rubber layer 72 which, according to Figure 1, forms on the lower bearing end face a supporting bead 74 engaging over the receiving lug 16 vertically at the edge for support purposes. In the opposite axial direction, the obliquely outward-set wall parts 58, 62 of the sheet-metal casing 18 form, according to Figure 3, 6 position-securing stops.

The bearing core 20 can be screwed by means of a fastening screw 76, for example, to a plate-shaped connection element 78 of the underbody 10, for which purpose this has a downwardly projecting cylindrical centring extension 80 which has an internal thread and which engages positively into an end depression 82 of the bearing core 20. In the screwed state, the bearing core 20 is supported with one of its end faces on the connection element 78.

The bearing construction according to the invention makes it possible to produce bearing stiffnesses in a ratio to one another which cannot be obtained with known support bearings of the relevant generic type in respect of a predetermined correspondingly confined installation space.

To explain the advantages to be afforded by this embodiment of the invention, reference may be made in this respect to Figure 4.

There, 84 denotes an outer and 86 an inner bearing part of a known support bearing of the relevant generic type. 88 denotes one of its two rubber bodies which extend at an acute angle relative to the bearing axis 90. With regard to a desired relatively high radial bearing rigidity in the X-direction, the rubber bodies 88 are subjected to mutually superposed shearing and compressive stresses, the compressive stresses greatly predominating.

The desired radial rigidity in this radial direction therefore demands a thickness e of the rubber bodies 88 which, on the one hand, cannot offer satisfactory noise uncoupling between the axle carrier and body and, on the other hand, allows a desired axial bearing softness to only a limited extent in the axial or supporting direction represented by an arrow 92.

In contrast to this, in the construction according to the preferred embodiment of the invention, the rubber bodies 24, 26, by virtue of the axis-parallel course of their portion b relative to the bearing axis 90 and the oblique course of their portion c at an angle to be fixed, 7 can acquire between the two bearing parts 84, 86 a considerably greater radial dimension than that of the known bearing construction, thus making it possible to obtain a correspondingly improved insulation against structure-borne noise.

This increased radial dimension also results, for the same shearing stress on the rubber-body portions b and c, in correspondingly greater excursions of the inner bearing part 86 and consequently greater axial bearing softness.

The fraction of compressive stress occurring under axial bearing loads takes effect solely in the obliquely set portion c of the rubber bodies 24 and 26 and is superposed on the shearing stress of the portions c.

In the radial direction d-d, the rubber-body segments 34 to 40 are subjected to shearing stress, and, as shown in Figure 2, an oblique setting of the rubber-body segments 34 to 40 makes it possible also to achieve in these a corresponding fraction of compressive stress in a circumferential direction of the bearing for a specific radial bearing flexibility.

Because the interspace 28 is shaped in the rubber bodies 24 and 26 in order to increase their free surface, the radial bearing softness in the radial plan a-a can be f inely adjusted or f ixed in such a way that the spring characteristic of the rubber bodies 24 and 26 subjected to compressive stress varies sharply progressively after a predetermined radial displacement of the bearing core 20, in that the mutually adjacent, thereby bulging side faces 30 and 32 of the rubber-body segments 34 to 40 are laid against one another.

Essentially critical factors as design parameters for coordinating the elasticities of the support bearing are:

The rubber quality, the dimension of the rubber bodies 24 and 26 in the radial direction (layer thickness), their height and width, the size of the angle of incidence for the 8 rubber-body portions c, if appropriate the arrangement of interspaces 28 and the curvature of one-piece rubber bodies 24 and 26 in the. circumferential direction of the bearing or a corresponding oblique setting of the rubber-body segments 34 to 40 at an obtuse angle to one another.

An alternative to the bearing construction explained can be to provide the rubber bodies as appropriately angled plane plates which are vulcanised in between mutually parallel plane surface parts of the two bearing parts, whilst the plane surface parts of the outer bearing part can be provided on respective legs of a U-shaped outer bearing part.

9

Claims

1. A support bearing f or the resilient connection of two vehicle parts, with an outer bearing part fastenable to one vehicle part and an inner bearing part f astenable to the other vehicle part, which, starting from the same bearing end face, each have a circumferential surface part extending inwards equally obliquely and an axis-parallel circumferential surface part adjoining this, and with rubber bodies introduced between the two bearing parts and vulcanised respectively onto the two bearing parts at least in the region of the circumferential surface parts axisparallel to one another, wherein the inner bearing part is in one piece and has a rhombic cross-section, the outer bearing part has casing portions parallel to the rhombus faces of the inner bearing part, and the rubber bodies are assigned in web-like manner to the rhombus faces and are vulcanised onto these.

2. A support bearing according to Claim 1, wherein the portions of the web-like rubber bodies extending parallel to the bearing axis have the greater length.

3. A support bearing according to Claim 1 or 2, wherein the rubber bodies have a recess extending at least over a part of their axial length.

4. A support bearing according to any one of the preceding claims, wherein resilient stops are formed opposite one another on the inner circumference of the outer bearing part between the web-like rubber bodies.

5. A support bearing according to any one of the preceding claims, wherein the obliquely set rubber-body portions are provided outside a receptacle for the outer bearing part.

6. A support bearing f or the resilient connection of two vehicle parts,