Hydraulic mount with spring-loaded decoupler for tuned rate dip

Abstract

A hydraulic mount assembly includes a pair of mounting members connected together to form a hollow elastomeric body closed by a resilient diaphragm so as to form a cavity for a damping liquid. A partition divides the cavity into a primary chamber formed between the partition and the hollow body and a secondary chamber formed between the partition and the diaphragm. The partition also includes a primary orifice track, a secondary orifice track and a decoupler passage providing fluid communication between the chambers. A first decoupler is mounted for limited reciprocating movement in the decoupler passage. A spring biases the first decoupler to a seated position sealing the passage. A second decoupler is mounted for limited reciprocating movement in the secondary orifice track. The primary orifice track establishes a first resonance frequency for the damping liquid. Similarly, the secondary orifice track establishes second, higher resonance frequency. Further, the force provided by the coil spring against the first decoupler is overcome by fluid pressure at a third resonance frequency higher than that of the second resonance frequency. Together these structures function to provide a rate dip and improved relatively high frequency tuning in a fully passive mount assembly.