Engine mount

Abstract

An improved and tight package vibration isolator assembly increases the strength of the mount structure without compromising the efficiency of the damping features. An exo-skeleton bracket design provides a rigid structural strength able to withstand extreme loads. The bracket also allows forces to bypass the fluid components of the damping assembly that are otherwise subject to potential passage of forces therethrough. The exo-skeleton bracket provides a stiff structure that substantially surrounds the damping assembly. Tuning of the assembly is also simplified through use of a travel limiter assembly, the cross-section of which may change in shape, or characteristics of a surrounding resilient sleeve selectively altered, to tune the damping characteristics of the damping assembly.

Having thus described the invention, it is now claimed:  
     
         1 . A vibration isolator assembly interposed between associated first and second surfaces of a vehicle, the assembly comprising: 
 a structural exo-skeleton bracket dimensioned to extend between the associated first and second surfaces for transferring forces therethrough, the bracket including means for securing the bracket to one of the associated first and second surfaces; and    a damping assembly received in the exo-skeleton that is protected from the transferred forces by the exo-skeleton bracket, the damping assembly including means for securing the damping assembly to the other of the associated first and second surfaces.    
     
     
         2 . The vibration isolator assembly of  claim 1  wherein the damping assembly includes an elastic wall portion and a shell forming a housing, the elastic wall portion having a major portion of its periphery received in the exo-skeleton.  
     
     
         3 . The vibration isolator assembly of  claim 2  wherein the bracket includes first and second bracket portions each including travel limiter support portions that receive a travel limiter therein that limits travel of the elastic wall portion of the fluid mount.  
     
     
         4 . The vibration isolator assembly of  claim 3  wherein the travel limiter support portions provide a double thickness wall at an attachment region with the travel limiter.  
     
     
         5 . The vibration isolator assembly of  claim 2  wherein the bracket includes first and second bracket portions, the first bracket portion having a continuous surface extending between the travel limiter support portion and the first securing means.  
     
     
         6 . The vibration isolator assembly of  claim 5  wherein the first and second bracket portions are joined along a seam offset from the continuous surface.  
     
     
         7 . The vibration isolator assembly of  claim 5  wherein the first securing means includes spaced attachment points.  
     
     
         8 . The vibration isolator assembly of  claim 1  further comprising a travel limiter assembly that limits movement of the damping assembly, the travel limiter assembly including a resilient portion that tunes the force versus displacement ratio of the vibration isolator assembly.  
     
     
         9 . The vibration isolator assembly of  claim 8  wherein the resilient portion is a rubber sleeve received over the travel limiter assembly.  
     
     
         10 . The vibration isolator assembly of  claim 1  wherein the damping assembly includes an elastic wall portion and a shell forming a housing, the housing including first and second chambers divided by an elongated channel that permits selective communication between the first and second chambers.  
     
     
         11 . The vibration isolator assembly, of  claim 1  wherein the damping assembly further comprises a subassembly received in the chamber and separating first and second chamber portions, the subassembly including 
 an inertia track assembly including a housing having an elongated channel with first and second ends in fluid communication between first and second, opposed surfaces thereof, respectively, and at least one opening that is also in fluid communication between the first and second surfaces thereof,  
 a diaphragm received adjacent the at least one opening of the inertia track assembly, and  
 an elastomeric member overlying the inertia track assembly.  
 
     
     
         12 . The vibration isolator assembly of  claim 11  wherein the subassembly further comprises a cover plate received over the inertia track assembly having an opening extending therethrough in fluid communication with the first end of the inertia track channel, and dividing the subassembly into first and second subchambers.  
     
     
         13 . The vibration isolator assembly of  claim 12  wherein the cover plate further comprises at least one further opening that extends therethrough.  
     
     
         14 . The vibration isolator assembly of  claim 13  wherein the diaphragm is interposed between the at least one opening in the inertia track assembly and the cover plate.  
     
     
         15 . The vibration isolator assembly of  claim 12  wherein the first subchamber is located between the elastomeric member and the cover plate.  
     
     
         16 . The vibration isolator assembly of  claim 15  wherein the second subchamber is located between the cover plate and the inertia track.  
     
     
         17 . The vibration isolator assembly of  claim 11  wherein the first chamber portion is enclosed by a first elastomeric wall member and the subassembly.  
     
     
         18 . The vibration isolator assembly of  claim 11  wherein the channel has a circuitous path that includes first and second  180 ° portions that interconnect inner and outer orbits of the channel.  
     
     
         19 . The vibration isolator assembly of  claim 11  wherein the subassembly is selectively removable from the damping assembly without compromising assembly integrity of the damping assembly.  
     
     
         20 . The vibration isolator assembly of  claim 1  wherein the damping assembly includes a fluid mount having an elastic wall portion and a shell forming a housing, the shell having a local contact that abuttingly engages one of the associated first and second surfaces to limit vibration therebetween.