Hydraulic Engine Mount Resonance Tuning for Acoustic Decoupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing axially damping hydraulic bearings face challenges in maintaining effective acoustic decoupling and reducing dynamic spring rate increases due to partial resonances, which are difficult to identify and mitigate without compromising other essential properties like damping and spring rate ratios.
Innovation Solution
The proposed solution involves a truncated cone-shaped elastomeric suspension spring with a working chamber and compensation chamber separated by a coupling membrane, where the channel part is made rigid but with low elastic resilience, allowing natural resonances to occur within the audible range, and is detuned by adding a mass element to shift resonances outside this range without affecting other bearing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional mass elements are added to detune resonances, then acoustic decoupling is improved by shifting resonances outside audible range, but the weight of the bearing increases
Solution Approach 1:
The patent modifies the mass parameter of the channel part by adding discrete mass elements. This changes the natural frequency of the channel, detuning it from the audible range and improving acoustic decoupling while minimizing weight increase through targeted mass addition.
Solution Approach 2:
The patent converts the harmful effect of resonances within the audible range into a benefit by strategically adding mass elements that shift the resonance frequency outside the audible range. The additional weight, which could be considered harmful, is converted into a beneficial tuning mechanism for noise control.
2Reliability
If the separating element channel is made flexible, then damping properties are maintained, but partial resonances increase causing dynamic spring rate increase
Solution Approach 1:
The patent changes the elastic resilience parameter of the channel part to low values, creating a rigid structure. This parameter change maintains sufficient damping properties while suppressing partial resonances that would otherwise cause dynamic spring rate increase.
Solution Approach 2:
The patent applies different local qualities to different parts of the separating element. The channel part is made rigid with low elastic resilience to suppress resonances, while other parts of the separating element maintain flexibility to preserve damping properties. This local differentiation resolves the contradiction between damping and resonance control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces the dynamic spring rate increase while maintaining damping and no-load decoupling, achieving improved acoustic decoupling by detuning natural resonances with minimal weight addition and allowing for individual tuning of resonance behavior.
Implementation Method 1
a fluid damping medium, which can escape from the working chamber into the compensation chamber during compression of axial vibrations acting on the bearing, and to move back from the compensation chamber into the working chamber during rebound. This back-and-forth oscillation of the fluid damping fluid provides additional damping for axially acting vibrations.
Implementation Method 2
a frustoconical elastomeric support spring arranged between a bearing core and an upper part of an outer shell... an elastomeric bellows, which is surrounded for mechanical protection by a lower part of the outer shell
Implementation Method 3
The two chambers are arranged one above the other in the axial direction of the bearing and are separated from each other by a separating element extending transversely to the bearing axis with a coupling membrane
Data Source
Figure 1
AI summary
The invention relates to an axially damping hydraulic mount. The invention relates to elastomer mounts such as are used for example in automotive engineering as engine mounts for damping the vibrations transmitted from the internal combustion engine to the body and for acoustic decoupling. The hydraulic mount is composed of a frustoconical elastomer support spring (2) arranged between a mount core (1) and an upper part (3) of an outer jacket (3, 3'), and has a working chamber (4) and a compensating chamber (5) for a fluid damping medium. The chambers (4, 5) are separated from one another by means of a separating element (7, 8, 8') which extends transversely with respect to the mount axis (11) and which has a coupling diaphragm (7), wherein the working chamber (4) is enclosed by the support spring (2) and the separating element (7, 8, 8'), and the compensating chamber (5) is enclosed by the separating element (7, 8, 8') and an elastomer bellows (6). A duct (9) is formed on the separating element (7, 8, 8'), which duct (9) is enclosed by at least one duct part (8, 8'). To counteract an excessive increase in the dynamic spring rate in the event of the occurrence of corresponding frequencies of axially acting vibrations, the at least one duct part (8, 8') is occupied, according to the invention, by an additional mass. For this purpose, the duct part (8, 8') is rigidly connected to at least one mass element (10, 10').