Hydraulically damping elastomer bearing

#The present invention relates to a hydraulically damping elastomer bearing suitable for mountings in a motor vehicle.

#German Published Patent Application No. 38 21 240 describes an elastomeric bearing, in which an elastic bearing part, for example, made of an elastic or elastomeric plastic or rubber, is arranged between a sleeve-shaped outer part and an inner part coaxial thereto. With the aid of this bearing part, an elastic connection between the outer sleeve and the inner part is made, which allows relative movements between the parts. The elastomeric bearing also has two chambers which are filled with a liquid damping medium and communicate with one another via a throttle duct. Elastomeric bearings of this type are used in order to mount a vibrating assembly on a non-vibrating holding device. The elastomeric bearings serve, in this context, for vibration insulation or vibration damping. For example, elastomeric bearings of this type are used in vehicle construction in order to mount vehicle axles, a transmission or an engine on the vehicle body. One of the parts is connected to the vibrating assembly, while the other part is coupled to the non-vibrating holding device. The vibrations of the assembly give rise to relative movements between the parts which reduce the volume of one chamber and simultaneously increase the volume of the other chamber. At the same time, the liquid damping medium is exchanged correspondingly between the chambers via the throttle duct. By virtue of the throttling action of the throttle duct, this arrangement results in a damping of the relative movements and therefore to a damping of the vibrations capable of being transmitted between the sleeves.

#Due to the selected arrangement of the chambers, conventional elastomeric bearings include a working direction which depends on the application. Thus, a reduction in volume of one chamber, with a simultaneous increase in volume of the other chamber, is possible only for those relative movements between the parts which have a direction component extending parallel to the working direction. Accordingly, a conventional elastomeric bearing can damp hydraulically only those loads or vibrations which include a direction component extending parallel to the working direction. In some applications of such elastomeric bearings, particularly in vehicle construction, however, different loads with different loading directions may occur. For example, on a vehicle, propulsive forces and braking forces, impacts and wheel-load changes in different directions may act on the respective elastomeric bearing.

#FIG. 1 is a schematic longitudinal cross-sectional view of an example embodiment of an elastomeric bearing according to the present invention.

#FIG. 2 is a schematic cross-sectional view of the elastomeric bearing illustrated in FIG. 1 taken along the line II—II.

#FIG. 3 is a schematic longitudinal cross-sectional view of another example embodiment of an elastomeric bearing according to the present invention.

#As illustrated in FIG. 1, an elastomeric bearing 1 according to the present invention includes a sleeve-shaped outer part 2 and, coaxially to the outer part 2, an inner part 3 having an axial central passage orifice 4. Arranged radially between the outer part 2 and the inner part 3 is an elastic or elastomeric bearing part 5 which connects the two parts 2 and 3 elastically to one another. For example, the bearing part 5 may be vulcanized onto one of the parts or onto both parts 2, 3. Furthermore, the elastomeric bearing 1 includes four chambers 6, 7, 8 and 9 which are filled with a liquid damping medium. In the example embodiment of the present invention illustrated, to form the chambers 6 to 9 in each axial half of the bearing part 5, corresponding recesses are cut out in an axially outer region of the bearing part 5, so that the chambers 6 to 9 are delimited radially inwardly and radially outwardly and also axially inwardly by elastic wall material of the bearing part 5.

#As illustrated in FIG. 1, the four chambers 6 to 9 are arranged in one plane, i.e., in the drawing plane or the sectional plane of FIG. 1. A system of coordinates including two axes perpendicular to one another, which are designated by X and Z, extend in this plane. The Z-axis is arranged coaxially and concentrically to the parts 2 and 3. The two axes X and Z form four quadrants Q1, Q2, Q3 and Q4 in the XZ plane. One of the chambers 6 to 9 is arranged in each of these quadrants Q1 to Q4. In the example embodiment of the present invention illustrated, the chambers 6 to 9 are arranged mirror-symmetrically both with respect to the Z-axis and with respect to the X-axis. The axes X and Z may also intersect at an angle different from 90°.

#As further illustrated in FIG. 1, a ring 10 of L-shaped cross-section is attached, e.g., vulcanized, onto each of the axial ends of the bearing part 5. Disc-shaped covers 11 are fastened to the axial ends of the inner part 3, each of these covers 11 having a central orifice 12 which is in alignment with the passage orifice 4 of the inner part 3. The covers 11 are inserted into one of the rings 10 and fastened thereto by an axially projecting collar 13 of the ring 10 being bent and positively engaged over.