Hydraulically damped engine mount having improved throttle ports

#This invention relates to an engine mount having hydraulic damping.

#A hydraulically damped engine comprises a working chamber which is defined by a bearing member, a bearing spring and a bearing wall and a compensation chamber which is defined by a resilient buffer wall with a partition wall disposed between the working chamber and the compensation chamber. A throttle port connects the working chamber and the compensation chamber in fluid communication. A hydraulic fluid fills the working chamber, the compensation chamber and the throttle port. German Patent Application No. 94 58 99 generally describes an engine mount of this type. The throttle ports of the engine mount of this reference have short identical lengths and the same cross section.

#It is an object of the present invention to provide an improved hydraulically damped engine mount of the type hereinbefore described that achieves an improved damping effect and thus an improved insulation upon the simultaneous introduction of oscillations of small and large amplitude. Small amplitude oscillations are those of less than about 0.1 mm. These and other objects of the present invention will be apparent from the following description and claims in conjunction with the drawings.

#Preferred embodiments of the present invention will be described in conjunction with the figures of the drawings.

#FIG. 1 is a schematic cross-sectional view taken along the section I--I shown in FIG. 4 of one embodiment of an engine mount in accordance with the present invention.

#FIG. 2 is a physical equivalent diagram illustrating the operation of one embodiment of an engine mount in accordance with the present invention.

#The engine mount shown in FIG. 1 contains a working chamber 12 delimited by a bearing member 1, a bearing spring 2, a bearing wall 9 and a partition wall 7. The bearing spring 2, which is an elastic material such as rubber, connects the bearing member 1 to the bearing wall 9. A compensating chamber 10 is defined by the partition wall 7 and a resilient buffer wall 3. The outer portion of the partition wall 7 is rigidly connected to the bearing wall 9. The working chamber 12 and the compensating chamber 10 are connected in fluid communication by two parallel throttle ports 4,4'. The throttle ports 4,4', located in the rigidly held part of the partition wall, are separated from each other by a radially extending annular wall 29 shown in FIGS. 1, 3 and 4A, and may differ from each other in length and diameter. Like the working and the compensating chamber, the throttle ports 4,4' are filled with a fluid of low viscosity, e.g., glycol and water. When the engine mount is installed in a motor vehicle, the bearing member 1 would be connected to the engine and the bottom plate below the resilient buffer wall 3 would be connected to the structural frame of the vehicle.

#The partition wall 7 comprises in its central area a compensating part movable between the working chamber 12 and the compensating chamber 10. The compensating part is formed by two circular inertial masses 6 lying radially within each other. The inertial masses 6 are connected with each other and with the rigidly fixed part of the partition wall 7 by means of annular diaphragms 8. The annular diaphragms are suitably an elastomer material.

#The range of motion of the inertial masses 6 is limited in the axial direction by stops 5. The stops 5 form a single piece component of the rigid part of the partition wall 7. Sounds of the inertial masses making contact with the stops are avoided by annular stop buffers 27, e.g. made of rubber, which are vulcanized in one piece to the inertial masses 6 lying on the inside.